Patent Application
20190002764
The present invention is directed to sonicated and ozonized biochar compositions and methods for creating surface-oxygenated biochar materials with higher cation exchange capacity that are also free of potential toxic components for use as phosphorus solubilization reagents, filtration materials, soil amendments and carbon sequestration agents to help control climate change for energy and environmental sustainability on Earth.
Smokeless biomass pyrolysis with utilization of biochar as a soil amendment is a potentially significant approach for renewable energy production and for carbon sequestration at giga tons of carbon (GtC) scales. A central idea is that biochar, if produced cleanly and sustainably by pyrolysis of biomass wastes and used as a soil amendment, would “lock up” biomass carbon in a form that can persist in soils for hundreds to thousands of years, help to retain nutrients in soils and reduce the runoff of agricultural chemicals.
The capacity of carbon sequestration by application of biochar fertilizer in soils can be used in croplands, grasslands and a fraction of forest lands. The maximum capacity of carbon sequestration through biochar soil amendment in croplands alone is estimated to be about 428 GtC globally. This maximum capacity is estimated using the maximal amount of biochar carbon that could be cumulatively placed into soil while still beneficial to soil environment and plant growth and the arable land area suitable for biochar agricultural use.
Globally each year about 6.6 gigatons (Gt) of dry matter waste biomass (e.g., crop stovers, dead leaves, waste woods, and rice straws) are produced. Deployment of an advanced biomass pyrolysis technology can turn dry matter waste biomass into valuable biochar, bio-syngas, and biofuel products. Worldwide, this approach can produce a net reduction of greenhouse-gas emissions of about 1.8 Gt of CO2—C equivalent emissions per year, which is about 12% of the current global anthropogenic emissions. Advanced biomass pyrolysis coupled with biochar soil amendment is unique among carbon sequestration strategies in that it can simultaneously offset gigatons of CO2 emissions and build sustainability into agricultural systems. This is a unique “carbon-negative” bioenergy system approach, which on a life-cycle basis could not only reduce but also reverse human effects on climate change.
More scientific and technological development is needed before this approach can be considered for widespread commercial implementation. For example, a new generation of high-tech biochar materials with higher cation change capacity to retain soil nutrients is needed to serve as an effective soil amendment and carbon sequestration agent. Furthermore, biochar occasionally shows inhibitory effects on plant growth (Rondon et al., Biol. Fertil. Soils 43:699-708 (2007); Rillig et al., Applied Soil Ecology 45:238-242 (2010); Gundale, Thomas, DeLuca, Biol. Fertil. Soils 43:303-311(2007)).
Organic species including possible inhibitory and benign (or stimulatory) chemicals are produced as part of the biomass pyrolysis process. A number of organic compounds belonging to various chemical classes, including n-alkanoic acids, hydroxyl and acetoxy acids, benzoic acids, diols, triols, and phenols were recently identified in organic solvent extracts of biochar. Some of these biochar chemicals, including polycyclic aromatic hydrocarbons (PAHs), are potentially phytotoxic or biocidal, especially at high concentrations. More recently, using the techniques of electrospray ionization (ESI) coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) with Kendrick mass defect analysis, it was determined that the most likely biochar toxin species contain carboxyl and hydroxyl homologous series and that the phytotoxicity of biochar substances is most likely due to degraded lignin-like species rich in oxygen containing functionalities, which is also part of the PAHs type of organic molecules (Smith et al., Environ. Sci. Technol. 47:13294-13302 (2013)). In addition, certain PAHs are suspected carcinogens. If biochar were to be globally used as a soil amendment and carbon sequestration agent at GtC scales, the release of potentially toxic compounds into soil and associated hydrologic systems might have unpredictable negative consequences in the environment. Therefore, it is essential to address some of these undesirable effects in order for biochar to be used as a soil amendment and carbon sequestration agent at gigaton scales. Any new technology that could produce an advanced biochar product that has high cation exchange capacity without any undesirable side effects is highly desirable for using biochar soil carbon sequestration to control climate change towards sustainability on Earth.
Recently, phosphorus sustainability was identified as a major issue for long-term agricultural and environmental sustainability on Earth. Currently, wet and thermal routes are the main methods used to manufacture phosphate fertilizers (Silva, Kulay (2003) Int J Life Cycle Ass 8 (4):209-214). The wet route typically requires the use of strong industrial acids such as sulfuric acid, nitric acid, and/or hydrochloric acid to solubilize phosphate from phosphate rock materials (Jiang et al (1990) Fert Res 26 (1-3):11-20; Fayiga, Nwoke (2016) Environ Rev 24 (4):403-415; Khan et al (2013) J Chem Soc Pakistan 35 (1):144-146; Skut et al (2010) Przem Chem 89 (4):534-539). The thermal route is represented by thermophosphate (Fageria, Santos (2008) Commun Soil Sci Plan 39 (5-6):873-889). Both routes are quite energy intensive and are viewed as not very environmentally friendly (Rutherford et al (1994) Sci Total Environ 149 (1-2):1-38; Potiriadis et al (2011) Radiat Prot Dosim 144 (1-4):668-671; Wu et al (2016) J Clean Prod 139:1298-1307; Silva, Kulay (2005). J Clean Prod 13:1321-1325). Therefore, environmentally friendly technologies that could solubilize phosphorus from insoluble phosphate materials such as hydroxyapatite without requiring the use of strong industrial acids such as hydrochloric acid would be valuable to addressing the phosphorus sustainability issue for long-term agricultural and environmental sustainability. An environmentally friendly technology that is biochar-based and that provides other beneficial applications such as “sand soilization”, which may enable the possibility of transforming deserts to productive agricultural lands on Earth, would be highly valuable.
Recently, a method for creating carboxylated biochars was disclosed in International Patent Application No. PCT/US2014/027170 for “Carboxylated Biochar Compositions And Methods Of Making And Using The Same”. In addition, a biochar ozonization process was disclosed in International Patent Application No. PCT/US2016/045538 for “Ozonized Biochar Compositions And Methods Of Making And Using The Same”. WHAT IS THE PORPOSE OF DISCLOSING THESE? HOW IS YOUR INVENTION DIFFERENT?
The present invention discloses a systematic method for producing and utilizing a surface-oxygenated biochar composition through ozonization in combination with sonication is the method that comprises: treating a biochar source composition with sonication and an ozone-containing gas stream in a biochar sonication-ozonization treatment reactor system using a sonication-ozonization-enabled biochar-surface oxygenation operational process, wherein treating the source biochar composition comprises: a) contacting the source biochar with the ozone-containing gas stream; b) enabling biochar-surface oxygenation; c) destroying a potential biochar toxin; d) producing a surface-oxygenated biochar composition having enhanced cation exchange capacity; e) producing a special surface-oxygenated biochar composition for phosphorus solubilization from insoluble phosphate materials for producing phosphate fertilizers without using strong industrial acids; f) producing a special surface-oxygenated biochar paste composition for sands soilization; and g) producing a special surface-oxygenated biochar composition having an enhanced filtration property as exemplified in methylene blue adsorption capability for removing at least one contaminant from a medium selected from the group consisting of water and air including odor removal.
Exemplary embodiments are directed to improved methods employing the techniques of sonication and ozonization for producing surface-oxygenated biochar compositions. These sonicated and/or ozonized biochar compositions including surface-oxygenated biochar paste products are used for a number of innovative applications including: 1) as filtration materials for clean water and air including odor removal; 2) as phosphorus solubilizing reagents to mix with phosphate rock materials such as hydroxyapatite or fluorapatite to make a slow-releasing phosphate fertilizer; 3) as biochar soil additives to help solubilize phosphorus from the insoluble phosphate materials found in certain soils, reducing phosphorus fertilizer additions required to achieve desired soil phosphorus activity, crop uptake, and yield goals; 4) as sand soilization reagents by utilizing their liquid gel-forming activity in the spaces among sand particles to retain water and nutrients and hold the sand particles together; 5) as plant growth stimulants by using the surface-oxygenated biochar humic acids-like substances at proper concentrations; and 6) as carbon sequestration agents to help control climate change for energy and environmental sustainability on Earth.
According to exemplary embodiments, an ozonization-based method is employed as a post-production biochar-surface oxygenation process to improve biochar properties. The ozonization-enabled biochar surface oxygenation process creates a new generation of advanced hydrophilic and clean biochar materials with higher cation exchange capacity, optimized pH and optimized hydrophilicity, and that are free of undesirable potential toxic components, which represents a significant technological improvement. Exemplary embodiments use a single ozonization-enabled biochar surface oxygenation process to achieve at least one of four improvements in the resulting biochar, i.e., enhanced biochar cation exchange capacity, reduced alkaline biochar pH, improved biochar wettability and destruction of potential biochar toxins. Exemplary embodiments can be practiced in a distributed manner at certain biochar-production facilities, biochar-utilizing farm sites, and other industrial sites to convert tons of conventional biochar materials into advanced hydrophilic biochar products for use as soil amendment and other industrial applications.
According to exemplary embodiments, a method for production of an ozonized biochar composition includes reacting a biochar source with an ozone-containing gas stream in a biochar ozonization treatment reactor system using an ozonization-enabled biochar-surface oxygenation operational process. The biochar source is contacted with ozone to (a) enable biochar-surface oxygenation; (b) destruct potential biochar toxins; and (c) produce an ozonized biochar composition having optimal characteristics or an optimal group of characteristics. These characteristics are selected from the group consisting of enhanced cation exchange capacity (CEC), optimal pH value, optimal carboxyl content, optimal hydrophilicity and wettability, optimal water-holding field capacity, optimal oxygen-to-carbon molar ratio, surface area, composition, nutrient contents, biochar particle size, uniformity, and any combination thereof.
Exemplary embodiments are also directed to a method for producing an ozonized biochar material having a higher cation-exchanging property. The cation-exchanging ability of a biochar is predominantly dependent on the density of cation-exchanging groups, mainly carboxyl (—COOH) groups on biochar surface.
In one embodiment, a biochar source is reacted with an injected ozone (O3)-containing stream in a controlled manner such that the biochar source homogeneously acquires carboxy-containing cation-exchanging groups in a post-production biochar-surface oxygenation process that creates carboxyl groups on biochar surfaces even at ambient pressure and temperature. This controlled ozone treatment creates additional oxygen-containing functional groups including, but not limited to, carbonyl (biochar C═O), hydroxyl (—OH) and carboxyl (—COOH) groups, improves biochar surface hydrophilicity and CEC and simultaneously destructs potential toxins.
Exemplary embodiments are also directed to a biochar ozonization treatment reactor system having an air inlet pump or valve, an ozone generator system, an ozone air inlet or tube passing through the biochar ozonization reactor wall near its bottom, an ozone air space at the bottom of the reactor, a porous metal plate, a biochar ozonization reactor chamber space above the porous metal plate, a biochar inlet passing through the biochar ozonization reactor wall at the upper part of the reactor, an ozonized biochar outlet passing through the reactor wall at the lower part of the reactor, a tail gas vent valve and filter at the top of the reactor, a flexible tail gas recycling tube equipped with its filter and valve and pump and valve connecting from the tail gas vent tube to the air inlet, a heat-smoke-sensing sprinkler system passing through the biochar ozonization reactor wall at the upper part of the reactor, and a flexible inlet and outlet valve at the bottom of the reactor.
In one embodiment, the biochar ozonization treatment reactor system comprises an O2/CO2 air inlet pump or valve, an ozone generator system, an ozone air inlet or tube passing through the biochar ozonization reactor wall near its bottom, an ozone O3/CO2 air space at the bottom of the reactor, a W-conical-shaped porous metal plate, a biochar ozonization reactor chamber space above the porous metal plate, a biochar inlet passing through the biochar ozonization reactor wall at the upper part of the reactor, an O3/CO2 gas flowing from O3/CO2 air space at the bottom through the W-conical-shaped porous metal plate and the biochar materials toward the upper part of the reactor, an ozonized biochar outlet passing through the reactor wall at the lower part of the reactor, tail gas vent valve and filter at the top of the reactor, a flexible tail gas recycling tube equipped with its filter and valve and pump and valve connecting from the tail gas vent tube to the air inlet, a heat-smoke-sensing sprinkler system equipped with water inlet and water spray system at the upper part of the reactor, an optional water level and flexible water inlet and outlet valve at the bottom of the reactor, a recycling water pump with a flexible water recycling tube connected with the flexible water inlet and outlet at the reactor bottom and the water inlet at the heat-smoke-sensing sprinkler system.
Exemplary embodiments are directed to a double-wall coolant-jacketed ozone gas biochar reactor system having a heat-conducting reactor inner wall, a reactor outer wall, a coolant chamber space formed between the inner wall and outer wall, a coolant inlet connected with the coolant chamber space at the bottom part of the reactor, a hot coolant outlet connected with the coolant chamber space at the top part of the reactor, an O2/CO2 air inlet pump and valve, an ozone generator system, an ozone air inlet or tube passing through the biochar ozonization reactor wall near its bottom, an ozone O3/CO2 air space at the bottom of the reactor, an inverted-V conical-shaped porous metal plate, a biochar ozonization reactor chamber space above the porous metal plate, a hot biochar inlet passing through the biochar ozonization reactor wall at the upper part of the reactor, an O3/CO2 gas flowing from O3/CO2 air space at the bottom through the conical-shaped porous metal plate and the biochar materials toward the upper part of the reactor, an ozonized biochar outlet passing through the reactor wall at the lower part of the reactor, a tail gas vent valve and filter at the top of the reactor, a flexible tail gas recycling tube equipped with its filter and valve, and pump and valve connected from the tail gas vent tube to the air inlet, a heat-smoke-sensing sprinkler system equipped with water inlet and water spray system at the upper part of the reactor, an optional water level and flexible water inlet and outlet valve at the bottom of the reactor.
In one embodiment, the biochar ozonization treatment reactor system is constructed from special ozone-compatible materials selected from the group consisting of stainless steel, titanium, silicone, glass, polytetrafluoroethylene (PTFE), a perfluoroelastomer polymer, polyether ether ketone (PEEK), polychlorotrifluoroethylene (PCTFE), chlorinated polyvinyl chloride (CPVC), a silicon cast iron, chromium and molybdenum alloy, filled PTFE gasket material, a nickel, molybdenum, chromium and iron alloy, polycarbonate, polyurethane, polyvinylidene difluoride (PVDF), butyl, a heat- and chemical-resistant ethylene acrylic elastomer, a synthetic rubber and fluoropolymer elastomer, ethylene-propylene, a thermoplastic vulcanizate (TPV), flexible polyethylene tubing, commercially available as Flexelene from Eldon James Corporation of Denver, Colo., fluorosilicone, aluminum, copper, and combinations thereof.
Exemplary embodiments are directed to an ozone-enabled biochar-surface oxygenation operational process that is a wet-moisture biochar ozonization treatment operational process that includes the following process steps that may be operated in combination with the use of hydrogen peroxide: a) Loading biochar materials into the reactor through the biochar inlet; b) Monitoring and adjusting (as necessary) biochar temperature; c) Monitoring biochar water content and relative humidity in the reactor, d) Based on the required biochar water content and relative humidity, properly adding water into biochar materials by use of a heat-smoke-sensing sprinkler system with water inlet and water spray system at the upper part of the reactor, and/or introducing at least one of water, steam and water vapor by use of a flexible water inlet and outlet valve and optional water level for vapor and moisture generation at the bottom of the reactor; e) Pumping an oxygen-containing source gas stream such as ambient air oxygen through the ozone generator system to generate ozone; f) Feeding ozone-containing gas stream into the reactor chamber space through the porous metal plate above the ozone air space by controlling the air pump fan speed; g) As necessary, using the flexible inlet and outlet valve at the bottom of the reactor to introduce additional stream or vapor or other gas component(s) of choice into the treating gas stream to manipulate the biochar ozonization process; h) As necessary, using the flexible tail gas recycling tube with its filter and valve and pump and valve to re-use part and/or all of the tail gas for the process; i) Allowing sufficient time for the ozone-containing stream to flow/diffuse through and interact with biochar particles while controlling and monitoring the treatment conditions such as reactor temperature and gas-stream flow rate; j) As necessary, discharging the residual ozonized liquid at the bottom of the reactor through a flexible water inlet and outlet or recycling the residual ozonized liquid stream through a recycling water pump with a flexible water recycling tube connected with the flexible water inlet and outlet and the water inlet to re-use the liquid for the biochar ozonization process; k) Harvesting the ozonized biochar products through the ozonized biochar outlet by use of gravity (with minimal energy cost); and k) repeating steps a) through j) for a plurality of operational cycles to achieve more desirable results.
In one embodiment, the biochar-surface oxygenation and destruction of toxins are accomplished simultaneously by use of an O3-containing gas stream flowing through the biochar ozonization treatment reactor at ambient pressure and temperature with minimal cost.
In another embodiment, the optimized biochar pH value is accomplished through the formation of acidic carboxyl groups at biochar surfaces and by the formation and adsorption of nitrogen oxides/nitric acid during a biochar ozonization process in the presence of N2.
According to yet another embodiment, the ozonized biochar composition has a cation exchange capacity of at least about 200% of that of the untreated biochar and is free of biochar toxins.
Exemplary embodiments are directed to ozonized biochar compositions having a given, exceptional, or optimal set of characteristics, such as enhanced cation exchange capacity, optimal pH value, optimal carboxyl content, optimal hydrophilicity and wettability, optimal water-holding field capacity, optimal oxygen-to-carbon molar ratio, surface area, composition, nutrient contents, biochar particle size, zero toxin content, and/or uniformity in any of these or other characteristics. Exemplary embodiments of methods disclosed herein are suitable for producing these types of advanced hydrophilic biochar products with higher cation exchange capacity and free of potential toxic components, which can be used in many practical applications such as the use of the ozonized biochars as filtration materials and as a biochar soil amendment and carbon sequestration agent.
According to one of the exemplary embodiments, a method for industrial production of surface-oxygenated biochar composition through ozonization in combination with sonication is the method that comprises treating a biochar source with sonication and an ozone-containing gas stream in a biochar sonication-ozonization treatment reactor system using a sonication-ozonization-enabled biochar-surface oxygenation operational process; wherein the treating of the biochar source comprises: a) contacting the biochar source with the ozone-containing gas stream; b) enabling biochar-surface oxygenation; c) destroying a potential biochar toxin; d) producing a surface-oxygenated biochar composition having enhanced cation exchange capacity; e) producing a special surface-oxygenated biochar composition for solubilizing phosphorus from insoluble phosphate materials for producing phosphate fertilizers without using strong industrial acids; f) producing a special surface-oxygenated biochar paste composition for sand soilization; and g) producing a special surface-oxygenated biochar composition having an enhanced filtration property as exemplified in methylene blue adsorption capability for removing at least one contaminant from a medium selected from the group consisting of water and air.
According to one of the exemplary embodiments, the biochar sonication-ozonization treatment reactor system is a sonication-enhanced biochar ozonization treatment reactor system comprising: a sonication control unit which comprises an input end in contact with ultrasonic transducer and a sonication output head in contact with liquid in a biochar ozonization reactor chamber space, a heat-conducting reactor inner wall, a reactor outer wall, a coolant chamber space formed between the inner wall and outer wall, a coolant inlet connected with the coolant chamber space at the bottom part of the reactor, a hot coolant outlet connected with the coolant chamber space at the top part of the reactor, an O2 air inlet pump and valve, an ozone generator system, an ozone air inlet and tube passing through the biochar ozonization reactor out wall and inner wall near its bottom, an ozone O3/water space at the bottom of the reactor, a porous metal plate, a biochar sonication-ozonization reactor chamber space above the porous metal plate, a biochar inlet passing through the biochar ozonization reactor double walls at the upper part of the reactor, an O3 bubble flowing from the O3/water space at the bottom through the porous metal plate and the biochar materials toward the upper part of the reactor, a tail gas vent valve and filter, a flexible tail gas recycling tube equipped with its filter and valve, a pump and valve connected from the tail gas vent tube to the air inlet, a heat-smoke-sensing sprinkler system equipped with water inlet, a water liquid level at the upper part of the reactor, an ozonized biochar outlet passing through the reactor double walls at the lower part of the reactor, and a flexible water inlet and outlet valve at the bottom of the reactor.
According to one of the exemplary embodiments, the sonication-ozonization-enabled biochar-surface oxygenation operational process comprises a liquid biochar sonication-ozonization treatment operational process comprises the following process steps that may be operated in combination with the use of hydrogen peroxide: a) loading biochar materials into a reactor through a biochar inlet; b) monitoring and adjusting biochar temperature; c) monitoring biochar water content and liquid level in the reactor; d) based on a required biochar water content and liquid level, adding at least one of water, steam and vapor into the biochar materials using at least one of a heat-smoke-sensing sprinkler system with a water inlet and water spray system located at a top of the reactor and a flexible water inlet and outlet valve at a bottom of the reactor; e) performing sonication using the sonication control unit which comprises an input end in contact with ultrasonic transducer and a sonication output head in contact with liquid in a biochar ozonization reactor chamber space; f) pumping an oxygen-containing source gas stream through an ozone generator system to generate ozone; g) feeding ozone-containing gas stream into a reactor chamber space through a porous metal plate above an ozone air space by controlling an air pump fan speed; h) using a flexible inlet and outlet valve at the bottom of the reactor to introduce additional gas components into the treating gas stream to manipulate the biochar ozonization process; i) using a flexible tail gas recycling tube having a filter and valve and pump and valve to re-use at least part of tail gas; j) allowing sufficient time for the ozone-containing stream to diffuse through and interact with biochar particles while controlling and monitoring treatment conditions; k) discharging residual ozonized liquid at the bottom of the reactor through a flexible water inlet and outlet; and l) harvesting the ozonized biochar products through an ozonized biochar outlet using gravity.
According to one of the exemplary embodiments, the sonication enhances biochar ozonization process through at least one of the following mechanisms: 1) Sonication force may physically loose up and/or break up biochar materials such as exfoliating graphite-type biochar materials (including graphite and/or graphite oxides) to produce graphene-type of biochar molecules such as fragmented graphene and graphene oxides; 2) Sonication process enhances mixing and mass transfer of ozone gas with liquid water and biochar particles; and 3) Ultra sonication at a frequency of above 15 kHz producing reactive oxygen radical, hydroxyl and peroxyl radicals from the sonochemistry of O2-dissolved water that may also enhance biochar surface oxygenation.
According to one of the exemplary embodiments, the surface-oxygenated biochar composition is a biochar paste product that comprises humic-substances-like surface-oxygenated biochar materials that are selected from the group consisting of surface-oxygenated biochar particles, surface-oxygenated biochar-derived organic matters, surface-oxygenated amorphous carbon particles, surface-oxygenated graphite particles, partially oxygenated graphene, partially oxygenated graphene-like molecules, partially oxygenated graphene molecular fragments, partially oxygenated linear hydrocarbons, partially oxygenated aromatic compounds, partially oxygenated polycyclic aromatic hydrocarbons, dissolved organic carbons including organic acids, and combinations thereof.
According to one of the exemplary embodiments, the surface-oxygenated biochar composition may be used to solubilize phosphorus from insoluble phosphate materials such as hydroxyapatite or fluorapatite for phosphorus sustainability by at least one of the following molecular mechanisms: a) The effect of protons from the organic acid groups of ozonized biochar which can kick phosphate out of the insoluble phosphate materials, resulting in solubilized phosphate; b) The effect of calcium complexation with the deprotonated biochar carboxylate groups that takes calcium away and thus thermodynamically favors the release of phosphate from the insoluble calcium phosphate materials; c) the anion exchange of the deprotonated biochar dissolved organic carboxylate groups (organic anions) with the phosphate in the insoluble phosphate materials favors the release of phosphate from the insoluble phosphate materials; and d) combinations thereof.
According to one of the various embodiments, the surface-oxygenated biochar composition may help to enhance phosphorus availability for plant uptake by helping phosphorus solubilization from insoluble soil phosphate mineral phases comprising at least one of the “insoluble” phosphate materials selected from the group consisting of soil phosphate rock particles and mineral minerals (mostly apatites: Ca10X(PO4)6, where X=F−, Cl−, OH− or CO32−) from parent rocks; the various precipitated Ca-phosphates including Ca(H2PO4)2.H2O (monocalcium phosphate), CaHPO4.2H2O (dicalcium phosphate dihydrate=brushite), CaHPO4 (dicalcium phosphate=monetite), Ca8H2(PO4)6.5H2O (octacalcium phosphate), Ca5(PO4)3OH (hydroxyapatite), and Ca5(PO4)3F (fluoroapatite); precipitated Al- and Fe-phosphates including variscite (AlPO4.2H2O), strengite (FePO4.2H2O), and vivianite [(Fe3(PO4)2.8H2O)]; and combinations thereof.
According to one of the exemplary embodiments, wherein the surface-oxygenated biochar compositions including the biochar paste product may be used for sands soilization by their liquid gel-forming activity in the spaces among sand particles that can retain water and nutrients and hold the sand particles together through at least one of the following noncovalent interactions: 1) the ionic (Coulombic) interactions that are the electrostatic interactions between charged species; 2) the hydrogen bond effects of the surface-oxygenated biochar molecular species with water and sands; 3) the π-π interactions between aromatic structures; and 4) the van der Waals interactions among sands and surface-oxygenated biochar molecular species with water.
According to one of the exemplary embodiments, the surface-oxygenated biochar compositions contain certain amounts of beneficial humic acids-like substances including certain partially oxygenated dissolved organic carbons (DOC) that can stimulate green plant growth when used at a proper DOC concentration selected from the group consisting of: 1 ppm, 2 ppm, 3 ppm, 5 ppm, 8 ppm 10 ppm, 12 ppm, 15 ppm, 20 ppm, 25 ppm, 30 ppm, 40 ppm, 50 ppm, 100 ppm, 200 ppm, 500 ppm, 1000 ppm or a concentration within a particular range bounded by any two of the foregoing values.
Advantages of the materials, methods, and devices described herein are set forth herein and may be learned by practice of the aspects described below. Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive.
Described herein are a series of improved methods for producing and utilizing surface-oxygenated biochar compositions with special sonication-ozonization methods for creating advanced hydrophilic biochar materials are provided with higher cation exchange capacity, optimized pH, improved wettability, and free of potential toxic components. These sonicated and/or ozonized biochar compositions including surface-oxygenated biochar paste products are used for a number of innovative applications including: 1) as filtration materials for clean water and air such as pig manure odor smell removal; 2) as phosphorus solubilizing reagents to mix with phosphate rock materials such as hydroxyapatite or fluorapatite to make a slow-releasing phosphate fertilizer; 3) as biochar soil additives to help solubilize phosphorus (to make it available for plant growth) from the insoluble phosphate materials existed already in certain soils and thus reduce phosphorus fertilizer additions required to achieve desired soil phosphorus activity, crop uptake, and yield goals; 4) as sand soilization reagent by utilizing their liquid gel-forming activity in the spaces among sand particles to retain water and nutrients and hold the sand particles together; 5) as plant growth stimulants by using the humic acids-like surface-oxygenated biochar substances at a proper concentration; and 6) as carbon sequestration agents to help control climate change for energy and environmental sustainability on Earth.
Exemplary embodiments are directed to a systematic method for producing and utilizing a surface-oxygenated biochar composition through ozonization in combination with sonication, the method comprising: treating a biochar source composition with sonication and an ozone-containing gas stream in a biochar sonication-ozonization treatment reactor system using a sonication-ozonization-enabled biochar-surface oxygenation operational process, wherein treating the source biochar composition comprises: a) contacting the source biochar with the ozone-containing gas stream; b) enabling biochar-surface oxygenation; c) destroying a potential biochar toxin; d) producing a surface-oxygenated biochar composition having enhanced cation exchange capacity; e) producing a special surface-oxygenated biochar composition for phosphorus solubilization from insoluble phosphate materials for producing phosphate fertilizers without using strong industrial acids; f) producing a special surface-oxygenated biochar paste composition for sands soilization; and g) producing a special surface-oxygenated biochar composition having an enhanced filtration property as exemplified in methylene blue adsorption capability for removing at least one contaminant from a medium selected from the group consisting of water and air including odor removal.
According to one of the various embodiments, ozonized biochar compositions with unique properties for use as soil amendment or soil additives and as filtration materials, for example, for industrial filtration applications. The methods described herein apply a series of ozone-enhanced biochar-surface oxygenation and cleaning processes to create a new generation of clean biochar materials with higher cation exchange capacity. These clean biochar materials are free of undesirable and potentially toxic substances and represent a major technological improvement. The ozonization chemistry and technologies are employed as a post-production biochar-surface oxygenation process to convert biochar compositions to unique ozonized compositions. Various aspects and embodiments of the methods herein are disclosed below.
According to one of the various embodiments, a method for industrial production of an ozonized biochar composition involves reacting a biochar source with an ozone-containing gas stream in a special biochar ozonization treatment reactor system using a specific ozone-enabled biochar-surface oxygenation operational process. The method utilizes a biochar ozonization treatment reactor system, and the biochar ozonization treatment reactor system in combination with the use of hydrogen peroxide. In one embodiment, the biochar source is contacted with ozone to (a) enable biochar-surface oxygenation; (b) destruct a potential biochar toxin; (c) produce an ozonized biochar composition having an optimal set of characteristics selected from the group consisting of enhanced cation exchange capacity, optimal pH value, optimal carboxyl content, optimal hydrophilicity and wettability, optimal water-holding field capacity, optimal oxygen-to-carbon molar ratio, surface area, composition, nutrient contents, biochar particle size, uniformity, and any combination thereof; and (d) produce a special ozonized biochar composition having an enhanced filtration property for removing at least one contaminant from a medium selected from the group consisting of water and air.
One exemplary embodiment is directed to a method for producing an ozonized biochar material possessing a higher cation-exchanging property. The cation-exchanging ability of a biochar is known to be predominantly dependent on the density of cation-exchanging groups mainly carboxyl (—COOH) groups in the biochar.
Referring to
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Ozone is known to crack rubber and certain elastomers that have C═C double bonds. Cast iron, Steel (Mild, High-strength low-alloy (HSLA)), Zinc, Magnesium, Polypropylene and Nylon are also sensitive to ozone corrosion. Those types of ozone-sensitive materials are not recommended for use in building the reactor and associated parts and joints that may be in contact with ozone. It is a preferred practice to use special ozone-compatible materials that can tolerate the reactive ozone in constructing the ozone biochar reactor system including the associated parts and joints that will be in contact with ozone. According to one of the various embodiments, the ozone-compatible materials for use in the construction of the reactor system are selected from the group consisting of stainless steel, titanium, silicone, glass, polytetrafluoroethylene (PTFE) (commercially available as Teflon® from Chemours of Wilmington, Del.), a perfluoroelastomer polymer (commercially available as Chemraz® from Greene Tweed of Kulpsville, Pa.), polyether ether ketone (PEEK), polychlorotrifluoroethylene (PCTFE) (commercially available as Kel-F® from 3M Corporation of St. Paul, Minn.), chlorinated polyvinyl chloride (CPVC), a silicon cast iron, chromium and molybdenum alloy (commercially available as Durachlor-51 from Duriron Company of Dayton, Ohio), filled PTFE gasket material (commercially available as Durlon® 9000 from Gasket Resources Inc. of Downingtown, Pa.), a nickel, molybdenum, chromium and iron alloy (commercially available as Hastelloy-C™ from All Metals and Forge Group of Fairfield, N.J.), polycarbonate, polyurethane, polyvinylidene difluoride (PVDF) (commercially available as Kynar® from Arkema Inc. of King of Prussia, Pa.), butyl, a heat- and chemical-resistant ethylene acrylic elastomer (commercially available as Vamac® from E. I. du Pont de Nemours and Company of Wilmington, Del.), a synthetic rubber and fluoropolymer elastomer (commercially available as Viton® from DuPont Performance Elastomers L.L.C. of Wilmington, Del.), ethylene-propylene, a thermoplastic vulcanizate (TPV) (commercially available as Santoprene™ from ExxonMobil Chemical of Spring, Tex.), flexible polyethylene tubing (commercially available as Flexelene from Eldon James Corporation of Denver, Colo.), fluorosilicone, aluminum, copper, and combinations thereof.
Ozone is an inorganic trioxygen molecule with the chemical formula O3, and is a pale blue gas with a distinctively pungent smell. Suitable methods for ozone generation include, but are not limited to, the corona discharge method, the cold plasma method, ultraviolet light ozone generation, and electrolytic ozone generation.
In one embodiment, an ozone generator utilizing the corona discharge method with a corona discharge tube is employed as the ozone generator system 102 in the biochar ozonization treatment reactor system 100 illustrated in
Referring now to
According to one embodiment, when desired, the nitrogen oxides and nitric acid formation and adsorption is reduced by use of an air dryer that reduces or eliminates nitric acid formation by removing water vapor, increasing overall ozone production. Use of an oxygen concentrator further increases the ozone production and further reduces the risk of nitric acid formation by removing not only the water vapor, but also the bulk of the nitrogen. Alternatively, at least one of pure oxygen and a mixed oxygen gas such as O2/CO2 gas mixtures (that are completely devoid of N2) are used to generate ozone for the biochar treatment process.
According to one embodiment, an ozone generator based on the cold plasma method is utilized as the ozone generator system 102 in the biochar ozonization treatment reactor system 100 illustrated in
According to one embodiment, the regime of applied ozone concentrations ranges from about 1% to about 5% in air and from about 6% to about 14% in oxygen for older generation methods. New electrolytic methods achieve up about 20% to about 30% dissolved ozone concentrations in output water for biochar treatment.
In operating the ozone biochar treatment reactor system process as provided by the reactor embodiments of one or more of
The most significant reactions of ozone with organic matter are based on the cleavage of the carbon double bond, which acts as a nucleophile having excess electrons. For example, the injected ozone (O3) air stream can, to some extent, lead to the formation of carbonyl and carboxyl groups on biochar surfaces, by reacting with the C═C double bonds (aromatic carbons) of biochar materials at ambient pressure and temperature:
Biochar-CH═CH-Biochar+O3→Biochar-COH+Biochar-COOH [1]
In this aspect, the ozonized biochar product will: 1) become more hydrophilic since both carbonyl and carboxyl groups can attract water molecules; and 2) have higher cation exchange capacity since the carboxyl groups readily deprotonate in water and result in more negative charge (Biochar-COO−) on the ozonized biochar surfaces:
Biochar-COOH→Biochar-COO−+H+ [2]
According to one embodiment, the sources of oxygen gas to generate ozone through the ozone generator system are selected from the group consisting of ambient air oxygen, pure oxygen gas, mixed oxygen and carbon dioxide gas, mixed oxygen and nitrogen gas, residual oxygen-containing flue gas, and combination thereof. Use of pure oxygen gas through the ozone generator can create higher concentration of ozone in the gas stream so that the biochar ozonization reactions are enhanced. Preferably, use of pure oxygen system is limited to well-controlled smaller reactors to ensure operational safety. For better safety and economic considerations, use of ambient air oxygen to generate ozone for biochar ozonization is preferred.
Biochar can also be quite reactive and can ignite itself; therefore, as shown in
In an experimental study utilizing embodiments of the systems and methods in accordance with the present invention, the biochar ozonization process reactions were somewhat exothermic. Therefore, it is preferred to control the biochar ozonization process speed and heat dissipation so that the temperature of the biochar ozonization reactor can be maintained near the ambient temperature. In one embodiment, the reactor wall is preferably made of metals such as stainless steel that tolerate ozone and dissipate heat as necessary or desired.
According to one embodiment, the biochar ozonization process speed is controlled by adjusting compositions including the ozone concentration and the feeding rate and compositions of the treating gas stream. Use of the flexible inlet and outlet valve 106 at the bottom of the reactor enables the introduction of steam and other gases of choice into the ozone-treating gas stream to achieve a more desirable result. Use of the flexible tail gas recycling tube 111 with its filter and valve 112 and pump and valve 113 provides the option to re-use part or all of the tail gas in the process. For example, when ambient air oxygen (typically containing about 21% O2 and 79% N2) is used to generate ozone for the biochar ozonization process, the tail gas is released through the vent or re-used through the flexible tail gas recycling tube 111 with its filter and valve 112 and pump and valve 113 if the tail gas still contains ozone and/or other gas components that may have a value for re-use. When the biochar is desirably ozonized, the ozonized biochar product is harvested through the use of ozonized biochar outlet 109 at the lower part of the reactor by use of gravity as illustrated in
Therefore, according to one embodiment, a dry biochar ozonization treatment operational process includes the following specific process steps: a) Loading biochar materials into the reactor through the biochar inlet; b) Monitoring and adjusting (if/when necessary) biochar temperature, c) Monitoring and adjusting (if/when necessary) biochar water content and relative humidity in the reactor, d) Pumping dry oxygen-containing source gas such as ambient air oxygen with an air dryer through the ozone generator system to generate ozone; e) Feeding dry ozone-containing gas stream into the reactor chamber space through the porous metal plate above the ozone air space by controlling the air pump fan speed without using any water; f) If/when necessary, using the flexible inlet and outlet valve at the bottom of the reactor to introduce other gas component(s) of choice into the treating gas stream to manipulate the biochar ozonization process; g) If/when necessary, using the flexible tail gas recycling tube with its filter and valve and pump and valve to re-use part and/or all of the tail gas for the process; h) Allowing sufficient time for the ozone-containing stream to flow/diffuse through and interact with biochar particles while controlling and monitoring the treatment conditions such as reactor temperature and gas-stream flow rate; i) Harvesting the ozonized biochar products through the ozonized biochar outlet by use of gravity (with minimal energy cost); and j) repeating steps a) through i) for a plurality of operational cycles to achieve more desirable results.
In one embodiment, an exemplary processes in accordance with the present invention uses the biochar ozonization treatment process system for a plurality or series of operational cycles to achieve more desirable results. Any one of the steps a) through j) of this process can be adjusted or modified as desired for certain specific operational conditions. For example, as shown in
Referring to
This biochar ozonization treatment reactor system 200 illustrated in
Referring to
This embodiment of the biochar ozonization treatment reactor system 300 illustrated in
Referring to
The embodiment of the biochar ozonization treatment reactor system 400 illustrated in
Referring to
The embodiment of the biochar ozonization treatment reactor system 500 of
The coolant utilized in this embodiment is a fluid that flows through or around a biochar reactor to prevent its overheating, transferring the heat produced by the biochar reactor to other devices that utilize the waste heat to pre-heat or dry biomass or to dissipate the heat. Suitable coolants have a high thermal capacity, low viscosity and are low-cost. In addition, the coolants are preferably non-toxic and chemically inert, neither causing nor promoting corrosion of the cooling system. Suitable coolants are selected from the group consisting of water, antifreeze liquid, polyalkylene glycol, oils, mineral oils, silicone oils such as polydimethylsiloxane, fluorocarbon oils, transformer (insulating) oil, refrigerants, and combination thereof.
Referring to
The biochar ozonization treatment reactor system 600 embodiment of
In another embodiment, the feeding of an O3-containing gas stream is performed preferably with nearly 30% or above 1% of O3 under a pressure of from about 1 to about 30 atmospheres (atm). The O3-containing gas stream can be an O3/water steam stream, an O3—CO2/water steam stream, an O3—O2—CO2/water steam stream, an O3—O2—CO2—N2/water steam stream, an artificial gas mixture stream including an O3—CO2 mixture, an oxygen (O2)-ozone (O3) mixture, an O3—O2—CO2 mixture, an O3-nitrogen (N2) mixture, an O3—O2—CO2—N2 mixture, an O3—CO2—N2 mixture, an O3-argon mixture, an O3-helium mixture, and any combination thereof. According to one embodiment, one of the O3-containing gas streams listed above is selectively applied in combination with a liquid water spray 218 (
According to one embodiment, a wet-moisture biochar ozonization treatment operational process includes the following process steps that are performed in combination with the use of hydrogen peroxide: a) Loading biochar materials into the reactor through the biochar inlet; b) Monitoring and adjusting (if/when necessary) biochar temperature; c) Monitoring biochar water content and relative humidity in the reactor, d) Based on the required biochar water content and relative humidity, properly adding water into the biochar materials by use of a heat-smoke-sensing sprinkler system with water inlet and water spray system at the upper part of the reactor, and/or introducing water and/or steam/vapor by use of a flexible water inlet and outlet valve and optional water level for vapor/moisture generation at the bottom of the reactor (
In one embodiment, an exemplary process in accordance with the present invention uses the wet biochar ozonization treatment process system for a plurality or series of operational cycles to achieve more desirable results. Any one of the steps a) through k) of the processes as described herein can be adjusted or modified as desired for certain specific operational conditions. For example, as shown in
According to one of the various embodiments, the biochar ozonization treatment process is operated in combination with the use of hydrogen peroxide (H2O2). Suitable overall amounts of hydrogen peroxide include, but are not limited to, about 1, 3, 10, 20, and 30% w/w treatments of H2O2 with or without the use of ozone. Typically, biochar treated with H2O2 show an increase in CEC. This increase in CEC is attributed to an increase in the presence of acidic oxygen functional groups on the surface of the biochar materials. Furthermore, H2O2 treatment causes an overall drop in biochar's capacity for the removal of methylene blue from solution, likely resulting from the weakening of π-π dispersive forces brought about by the introduction of oxygen functionality, which disrupts the overall aromatic structure of the biochar sample. The use of hydrogen peroxide (H2O2) is beneficial especially in combination with the wet biochar ozonization reactor process as illustrated, for example, in
According to one embodiment, the wet biochar ozonization treatment process is operated with biochar completely immersed in liquid water as shown, for example, in
The feeding of an O3-containing gas stream either with or without the use of water spray as shown, for example, in
According to one embodiment, the ozone (O3) treatment destructs potential biochar toxins by selectively attacking their C═C double bounds such as the double bonds in phenolic-type and/or polycyclic aromatic hydrocarbons (R—CH═CH—R) as shown in the following process reaction.
R—CH═CH—R+O3→R—COH+R—COOH [3]
In this example, the potential biochar toxins (R—CH═CH—R) are destructed by the ozonization reaction, forming R—COH and R—COOH species, which are typically benign. Therefore, the biochar ozonization treatment also cleans the biochar products by targeted destruction of potential biochar toxins that contain C═C double bonds, in addition to enhancing biochar-surface oxygenation for better hydrophilicity and cation exchange capacity value. Therefore, the post-production biochar surface-oxygenation-treatment process with ozone can be used, as shown, for example, in
In contrast to the highly uncontrolled biochar production processes known in the art, exemplary embodiments of systems and methods produces a substantially uniform (i.e., substantially homogeneous) surface-oxygenated biochar. By being “substantially uniform”, the resulting biochar contains an absence of regions of non-oxygenated biochar (as commonly found in biochar material formed under uncontrolled conditions, such as in open pits) in the surface-oxygenated biochar. Preferably, a substantially uniform surface-oxygenated biochar possesses different macroscopic regions, e.g., of at least about 100 μm2, 1 mm2, 10 mm2, or 1 cm2 in size, that vary by no more than about 10%, 5%, 2%, 1%, 0.5%, or 0.1% in at least one characteristic, such as CEC, oxygen to carbon molar ratio, and surface area. The substantial uniformity of the surface-oxygenated biochar advantageously provides a user with a biochar material that provides a consistent result when distributed into soil, either packaged or in the ground. Furthermore, a substantial uniformity of the surface-oxygenated biochar ensures that a tested characteristic of the biochar is indicative of the entire batch of biochar.
In one embodiment, a substantially uniform biochar is obtained by an effective level of mixing of the biochar during the surface-oxygenation process. For example, in one embodiment, the biochar is agitated, shaken, or stirred either manually or mechanically during the ozonization and purging process. In another embodiment, the biochar is reacted with ozone in a reactor containing a tumbling mechanism such that the biochar is tumbled during the ozonization reaction.
Suitable biochar sources for use in embodiments of the systems and methods described herein include any biochar material that could benefit by the ozonization process of the inventive method. The biochar source could be, for example, a byproduct of a pyrolysis or gasification process, a material acquired from a biochar deposit and natural coal materials, for example, from coal mines. In one embodiment, the biochar is plant-derived, i.e., derived from cellulosic biomass or vegetation. Suitable biomass materials include, but are not limited to, cornstover, e.g., the leaves, husks, stalks, or cobs of corn plants, grasses, e.g., switchgrass, miscanthus, wheat straw, rice straw, barley straw, alfalfa, bamboo and hemp, sugarcane, hull or shell material, e.g., peanut, rice, and walnut hulls, any woody biomasses including dead trees such as dead pine and dead oak, Douglas fir, woodchips, saw dust, waste cardboard, paper or wood pulp, algae, aquatic plants, food waste, spent mushroom substrate, chicken litters, heifer and cow manure, horse manure, pig manure, agricultural waste, and forest waste. In one embodiment, the biomass material is in its native form, i.e., unmodified except for natural degradation processes, before being converted to biochar. In another embodiment, the biomass material is modified by, for example, adulteration with a non-biomass material, e.g., plastic- or rubber-based materials, or by physical modification, e.g., mashing, grinding, compacting, blending, heating, steaming, bleaching, nitrogenating, oxygenating, or sulfurating, before being converted to biochar.
The one or more surface-oxygenation agents considered herein are ozone and ozone-related compounds or materials known in the art that tend to be reactive by imparting oxygen-containing functional groups into organic materials (including any of the O2 plasma, CO2 plasma, and CO plasma that have been disclosed before). An example of a surface-oxygenating agent is O3 in the gas form in addition to the O3/water vapor stream, O3/water liquid, O3/water liquid-peroxide (H2O2), and O3/carbonated water liquid form. As mentioned before, the O3 gas may also be in the form of an artificial gas mixture, such as an O3-oxygen (O2)-carbon dioxide (CO2), O3—CO2, O3—CO2-peroxide (H2O2), O3—CO2—CO (carbon monoxide), O3—O2-nitrogen (N2), O3—O2—CO2-argon, O3—O2—CO2-helium, or O3—O2—CO2—CO mixture. An artificial gas mixture can be advantageous for the purposes of the invention in that the level of O3 can be precisely controlled, thereby further controlling the pyrolysis and ozonization reactions to optimize the density and kind of oxygen-containing functional groups in the biochar. For example, in different embodiments, it may be preferred to use an O3—CO2-containing gas mixture having at least, less than, or about, for example, 0.1%, 0.5%, 1%, 2%, 3%, 5%, 7%, 10%,15%, 20%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% by the volume of O3, or a range bounded by any two of the foregoing values.
In another embodiment, the biochar source can be treated with O3 for “oxygen-implantation” onto the surfaces of the biochar materials as shown in Equation 1 above. The O3 treatment increases the O:C molar ratios or carboxyl groups at biochar surfaces. The cation exchange capacity increases with the O:C ratio of the biochar materials. Accordingly, use of O3 treatment can enable molecular re-engineering of biochar materials to impart unique surface properties such as the cation exchange capacity, without affecting the bulk properties of the biochar.
Preferably, the O3 treatment is conducted at low or ambient temperature, e.g., from about 15° C. to about 30° C. The O3 treatment process entails subjecting the biochar at ambient pressure to a source of O3-containing gas or liquid. The O3 is typically produced by pumping at least one of pure O2 and ambient air (containing about 21% O2 and 79% N2) through an ozone generator system that utilizes a special electric field under which O2 is converted into O3, which is then fed into the biochar ozone treatment reactor. The particular O3 generating and feeding conditions depend on several factors including the type of ozone generators, gas composition, power source capability and characteristics, operating pressure and temperature, the degree of ozonization required, and characteristics of the particular biochar being treated, i.e., its susceptibility or resistance to oxygenation. Depending on several factors including those mentioned above, the biochar can be exposed to the ozone treatment for at least about 0.1, 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 4, or 5 minutes and up to 6, 8, 10, 12, 15, 20, 30, 40, 50, 60, 90 or 180 minutes. Although the biochar can be ozone treated within a temperature range of about 15° C. to about 30° C., a lower temperature, e.g., less than 15° C., or a higher temperature, e.g., greater than about 30° C., such as 40° C., 50° C., 60° C., 70° C., 80° C., 90° C., 100° C., 110° C., 120° C., 130° C., 140° C., 150° C., 160° C., 170° C., 180° C., 190° C., 200° C., 210° C., 220° C., 230° C., 240° C., 250° C., 260° C., 270° C., 280° C., 290° C., and 300° C., 350° C., 400° C., or a range bounded by any two of the foregoing values, may also be used under controlled conditions where the possibility of combustion is adequately suppressed in the presence of at least one of CO2, water and steam with limited availability of O2/O3.
As shown in
According to one of the various embodiments, after extremely hot biochar is loaded into the biochar ozonization treatment reactor system 500 (
According to one embodiment, the biochar ozonization treatment reactor process is operated at a pressure selected from the group consisting of ambient pressure, 0.1 atm, 0.2, 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 10, 15, 20, 25, 30, 50 or 100 atm ora range bounded by any two of the foregoing values.
Not wishing to be bound by theory, the organic contaminants, i.e., potential toxins, adsorbed on biochar surfaces are removed by oxygenation chemical reactions with highly reactive O3. At the same time, certain O3-enabled oxygenation chemical reactions promote surface carboxylation and sometimes hydroxylation (possibly forming carboxyl COOH groups and hydroxyl OH on the biochar carbon surfaces), which increases surface wettability and cation exchange capacity (CEC). Both the surface wettability and CEC are important properties for biochar soil applications to better retain water and nutrients for improved soil fertility as well as reduction of agricultural chemical runoff.
In one embodiment, ozone is reacted with biochar in a closed system, i.e., a closed container, to ensure that the intended amount of ozonization reactants as measured, and no less and no more, is reacted with the biochar. When an ozonizing gas or liquid (or a solution thereof) is used, a selected volume of the gas or liquid corresponding to a calculated weight or moles of the ozone can be charged into the closed container (reactor) along with the biochar source and the contents homogeneously mixed or blended under conditions suitable for ozonization of the biochar to take place. For example, the temperature of the mixed reactants in the container can be controlled along with proper agitation until the ozone gas or liquid flows and diffuses fully through the biochar materials to promote its reaction with the biochar in a uniform, i.e., homogeneous, manner.
In one embodiment, the moisture level in the ozone treatment reactor can be suitably adjusted, for example, to a humidity level of about, at least, or no more than 1%, 2%, 5%, 10%, 15, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%, or a humidity level within a range bounded by any two of these values.
In another embodiment, ozonization/carboxylation of biochar materials is attained by conducting the ozonization/carboxylation reactions in an open or closed container and by rapidly quenching hot biochar with O3/CO2-containing water (
The methods described herein can also include one or more preliminary steps for producing biochar, i.e., the biochar source or “produced biochar”, from biomass before the biochar is oxygenated/carboxylated. The biomass-to-biochar process can be conducted within any suitable time frame before the produced biochar is oxygenated/carboxylated.
In one embodiment, a biomass-to-biochar process is conducted in a non-integrated manner with the biochar ozonization process as shown, for example, in
In another embodiment, a biomass-to-biochar process is conducted in an integrated manner with a biochar ozonization process. In the integrated process, biochar produced by a biomass-to-biochar process is treated in situ using the double-wall coolant-jacketed ozone gas biochar reactor system 500 (
The biochar ozonization process can be integrated with, for example, a biomass-to-fuel process, such as a low temperature or high temperature pyrolysis/gasification process. In such processes, typically about 40%, 50%, or 60% of the biomass carbon is converted into biochar while the remaining 60%, 50%, or 40% of carbon is converted to fuel (syngas and bio-oils). Furthermore, since it has been found that lower temperature pyrolysis processes generally yield a biochar material with even more improved fertilizer retention properties, in one embodiment, the biochar ozonization process is integrated with a biomass pyrolysis/gasification process conducted at a temperature of about 800° C., 750° C., 700° C., 650° C., 600° C., 550° C., 500° C., 450° C., 400° C., 350° C., or 300° C. or a temperature within a range bounded by any two of these values.
According to one of the various embodiments, the biochar ozonization process is integrated with a biomass pyrolysis process operated at a temperature of about 500° C. to produce a clean hydrophilic biochar product with higher CEC value and minimized potential biochar toxins. Biochar produced from biomass pyrolysis process at around 500° C. is typically already quite clean (with minimized potential biochar toxins); however, its CEC value is often very low due to the loss of its carboxyl groups at such a high pyrolysis temperature (500° C.). In this case, the use of the biochar ozonization process enables creation of oxygen-containing functional groups on biochar surfaces at ambient temperature under ambient pressure, resulting in a better hydrophilic biochar product with higher CEC value and minimized potential toxins.
In one embodiment, an integrated process is configured as a batch process wherein separate batches of produced biochar are ozonized at different times. In another embodiment, the integrated process is configured as a continuous process wherein biochar produced by the biomass-to-biochar process is continuously subjected to an ozonization process as it is produced. For example, produced biochar can be continuously transported either manually or by an automated conveyor mechanism through a biochar ozonization zone. The automated conveyor mechanism can be, for example, a conveyor belt, a gravity-fed mechanism, or an air pressure mechanism.
In another aspect, the ozonized biochar produced herein has a particular, exceptional, or optimal set of characteristics, such as a particular, exceptional, or optimal cation exchange capacity, optimal pH value, optimal carboxyl content, optimal hydrophilicity and wettability, optimal water-holding field capacity, optimal oxygen-to-carbon molar ratio, surface area, nutrient contents, biochar particle size, composition, zero toxin content, and/or uniformity in any of these or other characteristics. The methods described herein are particularly suitable for producing these types of advanced hydrophilic biochars.
According to one of the various embodiments, the biochar ozonization treatment process has a feature that significantly increases the CEC value of biochars often by more than a factor of 2. For example, the biochar ozonization treatment can improve the CEC value of a biochar from its initial value of 80 mmol/kg to as high as 230 mmol/kg after an ozone treatment.
In one embodiment, the CEC of the ozonized biochar is at least moderate, e.g., about or at least 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240 mmol/kg, or within a particular range bounded by any two of the foregoing values. In another embodiment, the CEC of the ozonized biochar is atypically or exceptionally high, e.g., about or at least 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1100, 1200, 1300, 1400, 1500 mmol/kg, or within a particular range bounded by any two of the foregoing values. In another embodiment, the CEC of the ozonized biochar is within a range having a minimum value selected from any of the exemplary moderate CEC values given above and a maximum value selected from any of the exemplary atypically high CEC values given above (for example, 100-1000 mmol/kg or 200-1200 mmol/kg). Preferably, the CEC value is substantially uniform throughout the biochar material.
The density of carboxy-containing cation-exchanging groups is typically proportional to the measured oxygen-to-carbon molar ratio of the biochar, wherein the higher the oxygen-to-carbon molar ratio, the greater the density of cation-exchanging groups in the biochar. In different embodiments, the oxygen-to-carbon molar ratio of the ozonized biochar surface is at least 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.50:1, 0.60:1, 0.70:1, or within a range bounded by any two of the foregoing ratios. Preferably, the ozonized biochar contains a substantially uniform density of the carboxy-containing cation-exchanging groups and a substantially uniform oxygen-to-carbon molar ratio throughout the biochar surface material.
According to another embodiment, the ozone-enabled molecular implantation of oxygen atoms into biochar carbon materials can be used also as a mechanism to remove potential biochar toxins through molecular structural destruction by the ozone-assisted implantation of oxygen atoms into the toxic organic molecules such as phenolic-type phytotoxins and polycyclic aromatic hydrocarbons (PAHs). Therefore, the destruction of potential biochar toxins, the enhancement of biochar cation exchange capacity and hydrophilicity, and the optimization of biochar pH are accomplished simultaneously through the ozone-enabled oxygenation into both the potential toxin molecules and biochar surfaces.
The ozonized biochar can have any suitable specific surface area (SSA), as commonly determined by BET analysis. In different embodiments, the ozonized biochar has an SSA value of about, or at least, or no more than 0.1, 0.5, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 80, 100, 200, 400, 600, or 800 m2/g, or an SSA value within a range bounded by any two of the foregoing values.
The ozonized biochar can also have any suitable charge density. In different embodiments, the ozonized biochar has a surface charge density of about, or at least, or no more than 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, or 120 mmol/m2, or a charge density within a range bounded by any two of the foregoing values.
According to one of the various embodiments, use of a biochar ozonization process can achieve biochar-surface oxygenation to significantly functionalize biochar surface properties such as its cation exchange value and pH without significantly affecting some of the biochar bulk properties such as the biochar core carbon stability and elemental compositions. This feature is explained by the understanding that the biochar surface atomic layer that is accessible to ozone represents only a very small fraction of the total biochar mass. Therefore, a significant biochar-surface oxygenation by ozonization may not significantly alter the bulk properties of the biochar core carbon materials, which is desirable in maintaining biochar carbon stability for biochar soil amendment and carbon sequestration applications.
According to one of the various embodiments, the ozonized biochar can also have any suitable carbon, nitrogen, oxygen, hydrogen, phosphorus, calcium, sulfur, ash, and volatile matter content. The carbon content can be about, at least, or no more than, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95 mole percent, or within a particular range therein. The nitrogen content can be about, at least, or no more than, for example, 0.1, 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 2.5, 2.75, 3.0, 3.25, 3.5, 3.75, 4.0, 4.5, 5.0, 6.0, 7.0, or 8.0 mole percent, or within a particular range therein. The oxygen content can be about, at least, or no more than, for example, 1, 2, 5, 10, 15, 20, 25, or 30 mole percent, or within a particular range therein. The hydrogen content can be about, at least, or no more than, for example, 1, 2, 5, 10, 15, 20, 25, or 30 mole percent, or within a particular range therein. The phosphorus or calcium content can independently be about, at least, or no more than, for example, 5, 10, 25, 50, 100, 500, 1000, 5000, 7500, 10000, 15000, 20000, or 25000 mg/kg, or within a particular range therein. The sulfur content can be about, at least, or no more than, for example, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, or 2000 ppm, or within a particular range therein. The ash content can be about, at least, or no more than, for example, 1, 2.5, 5, 10, 15, 20, 30, 40, 50, 60, or 70%, or within a particular range therein. The volatile matter content can be about, at least, or no more than, for example, 1, 2.5, 5, 10, 15, 20, 25, 30, 35, or 40%, or within a particular range therein.
The ozonized biochar can also have any suitable particle size. In various embodiments, the ozonized biochar can have a particle size of about, at least, or no more than, for example, 50, 100, 250, 500, 750, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, or 5000 μm, or a particle size within a particular range bounded by any two of the foregoing values. In certain applications, e.g., to ensure the biochar materials are resistant to becoming airborne in windy and/or arid regions, larger biochar particle sizes, such as 6000, 7000, 8000, 9000, 10,000, 20,000, 30,000, 40,000, 50,000 μm, or higher (for example, up to 100,000 μm), or a particle size within a particular range bounded by any two of the foregoing values, may be preferred. The biochar materials may also be in the form of an agglomeration, compaction, or fusion of biochar particles, e.g., pellets or cakes, for this type of application as well. The size of the pellets or cakes can correspond, for example, to any of the larger particle sizes given above.
The term “particle size” as used above for a particular value can mean a precise or substantially monodisperse particle size, e.g., within ±0-5% of the value, or a more dispersed particle size, e.g., greater than 5% and up to, for example, about 50% or 100% of the value. In addition, the biochar particles may have a size distribution that is monomodal, bimodal, or higher modal. The term “particle size” may also refer to an average particle size. If desired, the particle size of the ozonized biochar can be appropriately modified by techniques known in the art. For example, the biochar particles may be ground, agglomerated, or sieved by any of the techniques known in the art. Furthermore, when the particles or pellets are substantially or completely spherical, the above exemplary particle or pellet sizes refer to the diameter of the particles or pellets. For particles or pellets that are non-spherical, e.g., elliptical, cylindrical, rod-like, plate-like, disc-like, rectangular, pyramidal, or amorphous, the above exemplary particle or pellet sizes can refer to at least one, two, or three of the dimensional axes of the particles or pellets.
The ozonized biochar can also have any suitable pore size. In various embodiments, the ozonized biochar can have a pore size of about, at least, or no more than, for example, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 100, 250, 500, 750, 1000, 1500, 2000, 2500, 5000, 6000, 7000, 8000, 9000, 10,000, 20,000, 30,000, 40,000, 50,000, 60,000, 70,000, 80,000, 90,000 or 100,000 nm, or a pore size within a particular range bounded by any two of the foregoing values.
The ozonized biochar can also have any suitable pH value. Some of the conventional biochar materials, for example, those made from high-temperature pyrolysis or gasification processes, typically have an alkaline pH ranged from about pH 8.5 up to about pH 12, which are not ideal for use in many regions such as those in the western regions of the United States where the soil pH is already above pH 8.0. According to one of the various embodiments, use of the ozonization treatment can reduce the pH value of biochar through the formation of acidic carboxyl groups at biochar surfaces and/or by the formation and adsorption of nitrogen oxides/nitric acid during a biochar ozonization process in the presence of N2. In various embodiments, depending on biochar ash contents, the ozonized biochar can have an optimized pH value of about, at least, or no more than, for example, 4, 4.5, 5, 6, 7, 8, 9, 10, 11, or a pH value within a particular range bounded by any two of the foregoing values.
The ozonized biochar, such as produced by the method described above, may also be admixed, i.e., enriched, with one or more soil-fertilizing compounds or materials for use as a fertilizing biochar soil amendment or additive and carbon sequestration agent. The soil-fertilizing compounds or materials can be, for example, nitrogen-based, e.g., ammonium-based, carbonate-based, e.g., CaCO3, phosphate-based, e.g., the known phosphate minerals, such as in rock phosphate or triple superphosphate, and potassium-based, e.g., KCl. In one embodiment, the one or more soil-fertilizing compounds or materials include at least one nitrogen-containing, for example, NH4+-containing, compound or material. Some examples of nitrogen-containing fertilizing compounds or materials include, for example, (NH4)2CO3, NH4HCO3, NH4NO3, (NH4)2SO4, (NH2)2CO, biuret, triazine-based materials, e.g., melamine or cyanuric acid, urea-formaldehyde resin, and polyamine or polyimine polymers. The fertilizer material may be inorganic, as above, or alternatively, organic. Some examples of organic fertilizer materials include peat moss, manure, insect material, seaweed, sewage, and guano. The biochar material can be treated by any of the methods known in the art in order to combine the biochar material with a fertilizer. In a particular embodiment, the biochar material is treated with a gas stream of hydrated ammonia to saturate the biochar material. The biochar material may also be coated with fertilizer compounds or materials. The coating may also be suitably modified or optimized as known in the art to adjust the rate of release of one or more fertilizer compounds or materials into soil. In another embodiment, one or more of the above generic or specific soil-fertilizing compounds or materials are excluded from the ozonized biochar composition.
In another embodiment, the invention is directed to a soil formulation containing, at a minimum, soil admixed with the biochar composition described above. The soil can be of any type and composition. For example, the soil can have any of the numerous and diverse proportions of clay, sand, and silt. The sand, silt, and clay components can be independently present in an amount ranging from substantially absent, i.e., zero weight percent or in trace amounts, up to about 100 weight percent, e.g., exactly 100% or at least 98 or 99%. In different embodiments, one or more of the sand, silt, and clay components are in an amount of, independently, about, at least, or no more than, for example, 0.1, 0.5, 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95 weight percent of the total weight of the soil absent the biochar. The soil may also preferably have one or more of the sand, silt, and clay components present in an amount within a range bounded by any two of the foregoing exemplary weight percentages. The soil can also contain any amount of humus and humic substances, i.e., organic matter, humic acid, fulvic acid, cellulose, lignin, peat, or other such component, in any of the exemplary amounts or ranges given above.
According to another embodiment, an ozonized biochar can remove certain industrial organic molecules such as methylene blue dye 5 times better than the untreated biochar.
According to one of the various embodiments, the ozonized biochar can be used as filtration materials to remove various cations and pollutants from fluid streams including water and air. This embodiment is also directed to the use of certain ozonized biochar materials for other environmental or industrial applications such as the formulation and production of ozonized biochar columns or filters for filtration of fluids, including, for example, water, air and other solvents. During the filtration process, various cations and/or pollutants in the medium such as water and air will be in contact with the ozonized biochars in the columns and filters thereby are removed through cation exchange binding and/or physical chemistry adsorption on the ozonized biochar materials. In many cases, the used biochar columns and filters can be readily disposed by combustion cleanly back to air CO2 and H2O. For certain biochar columns and filters after used in removal of certain heavy metal ions such as, for example, Cu2+, they can also be combusted to retain their adsorbed heavy metal content in a relatively small amount of the resultant ash that can also be readily disposed by other proper ways as well. In other aspects, the biochar materials may be disposed by burying into soil at certain proper locations consistent with the practices of both waste disposal and biochar carbon sequestration. Since the biomass-derived and ozonized biochar materials are completely renewable, the use of ozonized biochar materials for filtration applications disclosed herein is another sustainable green-clean technology to remove various cations and pollutants in waters and air. Accordingly, ozonized biochar columns and filters may be used to remove various cations, contaminants, and pollutants selected from the group consisting of ammonium (NH4+), Li+, Ba2+, Fe2+, Fe3+, Cu+, Cu2+, Cd2+, Cs+, Sr2+, Ni2+, Zn2+, Cr3+, Pb2+, Hg2+, other metal ions including uranium ions, plutonium ions, osmium ions, platinum ions, gold ions, iridium ions, ruthenium ions, rhodium ions, cobalt ions, titanium ions, thallium ions, tin ions, indium ions, gallium ions, germanium species and germanium compounds, arsenic species and arsenic compounds, selenium species and selenium compounds, and organic and/or inorganic molecules including certain pollutants in waters, air and other environmental and industrial media as well.
Biochar Ozonization in Combination with Sonication
The present invention here further comprises an improved method for industrial production and utilization of surface-oxygenated biochar composition through ozonization in combination with sonication. The improved method comprises at least one of the following steps: 1) treating a biochar source with sonication and an ozone-containing gas stream in a biochar sonication-ozonization treatment reactor system using a sonication-ozonization-enabled biochar-surface oxygenation operational process, wherein treating the biochar source comprises: 2) contacting the biochar source with the ozone-containing gas stream; 3) enabling biochar-surface oxygenation; 3) destroying a potential biochar toxin; 5) producing a surface-oxygenated biochar composition having enhanced cation exchange capacity; 6) producing a special surface-oxygenated biochar composition for solubilizing phosphorus from insoluble phosphate materials for producing phosphate fertilizers without using strong industrial acids; 7) producing a special surface-oxygenated biochar paste composition for sand soilization; and 8) producing a special surface-oxygenated biochar composition having an enhanced filtration property as exemplified in methylene blue adsorption capability for removing at least one contaminant from a medium selected from the group consisting of water and air including odor removal.
According to one of the various embodiments, the biochar source composition comprises a carbon product or recalcitrant biomass material selected from the group consisting of charcoals from a slow biomass pyrolysis process, charcoals from a fast biomass pyrolysis process, biochar from flash pyrolysis (typically, 815-871° C., residence time about 30 seconds) of biomass, charcoals from a biomass gasification (typically, >700° C.) process, hydrochars from a biomass hydrothermal carbonization process, a material acquired from a biochar deposit, natural coal materials, lignin residues, lignin cellulosic materials, carboxymethyl cellulose, un-hydrolyzed biomass residues such as un-hydrolyzed corn stover residues, recalcitrant biomasses, and a combination thereof.
According to one of the various embodiments, biochar ozonization is performed in combination with sonication. Referring to
According to one of the various embodiments, the sonication-ozonization-enabled biochar-surface oxygenation system (
According to one of the various embodiments, an exemplary process of the sonication-ozonization-enabled biochar-surface oxygenation system (
According to one of the various embodiments, treating the source biochar composition with sonication comprises using a sonication control unit comprising an input end in contact with an ultrasonic transducer and a sonication output head in communication with the ultrasonic transducer and disposed in the volume of liquid to expose the biochar composition to ultrasonic frequencies.
According to one of the various embodiments, sonication enhances biochar ozonization process through at least one of the following three mechanisms: 1) Sonication force may physically loose up and/or break up biochar materials such as exfoliating graphite-type biochar materials (including graphite and/or graphite oxides) to produce biochar-derived organic matters such as the graphene-types of biochar molecules such as fragmented graphene and graphene oxides; 2) Sonication process enhances mixing and mass transfer of ozone gas with liquid water and biochar particles; and 3) Ultra sonication at a frequency of above 15 kHz producing reactive oxygen radical, hydroxyl and peroxyl radicals from the sonochemistry of O2-dissolved water that may also enhance biochar surface oxygenation.
According to one of the various embodiments, ozonization of fragmented graphene and graphene oxides generates partially oxygenated poly aromatic carbon molecules similar to humic acids. Therefore, the sonication-enhanced biochar ozonization process can convert conventional biochar materials into “humic-acids-like” substances and/or biochar paste materials. For an example, the humic-acids-like substances that are produced from this process are partially oxygenated graphene-like molecules and/or partially oxygenated graphene molecular fragments. The biochar “humic-acids-like substances” here are defined as surface-oxygenated biochar derived organic matters that are similar to humic acids in their structures and functions.
According to one of the various embodiments, in addition to biochar surface oxygenation, the processing technology of surface-oxygenation through ozonization in combination with sonication may be applied also to other recalcitrant biomass materials selected from the group consisting of lignin residues, lignin cellulosic materials, carboxymethyl cellulose, un-hydrolyzed biomass residues such as un-hydrolyzed corn stover residues, recalcitrant biomass residues, and combinations thereof.
According to one of the various embodiments, the sonication-ozonization process can be used to treat many different carbon materials including but not limited to hydrochar, slow-pyrolysis biochar, fast pyrolysis biochar, and gasification char.
According to one of the various embodiments, the liquid sonication of biochar materials produces a biochar paste, which is a black viscous fluid of the sonicated fine (mostly sub-millimeter) surface-oxygenated amorphous carbon particles and biochar molecular species including dissolved organic molecular carbons and organic acids in the presence of water. The biochar paste may be ozonized to generate partially oxygenated biochar molecules including biochar molecular carboxylic acids. Again, the sonication-enhanced biochar ozonization process can convert tons of conventional biochar materials into surface-oxygenated biochar-derived organic matters including “humic acids like” substances and/or biochar paste materials that can be immediately applied into soil for agriculture and environmental sustainability.
According to one of the various embodiments, the surface-oxygenated biochar composition produced from the biochar sonication-ozonization reactor process (
According to one of the various embodiments, a significant beneficial feature of the surface-oxygenated biochar paste product is that it is a highly functionalized biochar molecular material which is much more powerful than the conventional biochar for agricultural application. A conventional biochar material in the current market is typically a solid carbon material with a grain size in a range from a few mm to tens of mm, which often has a quite limited cation exchange capacity often not much higher than that of a typical soil. Consequently, it often requires more than ten tons of conventional biochar materials per acre for use as soil amendment since most of the conventional biochar materials as solid carbon grains just sitting there in soil with quite limited functionality to improving soil fertility properties. On the other hand, the sonicated surface-oxygenated biochar paste product as a highly functionalized biochar molecular material can provide much more functionality per carbon mass to improve soil fertility properties. Therefore, the sonicated biochar paste product with fine (mostly sub-millimeter) surface-oxygenated amorphous carbon particles and dissolved organic molecular carbons can significantly reduce the required amount of biochar carbon usage per acre by more than a factor of ten while providing better benefits for sustainable agricultural productivity. This can translate to a significant cost reduction while providing better benefits for the end users such as farmers. For example, the surface-oxygenated biochar paste/liquid is used as part of irrigation into the crop root zones so that it needs less a ton of biochar carbon material per acre to help solubilizing phosphorus from the “insoluble” phosphate material in certain soils for crop to uptake (see more details on surface oxygenated biochar for phosphorus sustainability below).
Phosphorus sustainability has recently been identified as one of the major issues for long-term agricultural and environmental sustainability on Earth. Conventionally, the wet and thermal routes are the main ways to manufacture phosphate fertilizers. The wet route typically requires the use of strong industrial acids such as sulfuric acid, nitric acid, and/or hydrochloric acid to solubilize phosphate from phosphate rock materials such as hydroxyapatite: Ca10(PO4)6(OH)2 and fluorapatite: Ca5(PO4)3F. The thermal route is represented by thermophosphate. Both routes are quite energy intensive and not very environmentally friendly. Any environmentally friendly technology that could solubilize phosphorus from insoluble phosphate materials such as hydroxyapatite without requiring the use of strong industrial acids such as hydrochloric acid would be valuable to addressing the phosphorus sustainability issue for long-term agricultural and environmental sustainability. The present invention here discloses a method on using the green chemistry with ozonized biochar to provide a novel approach to solubilize phosphorus from calcium phosphate rock materials and/or insoluble soil phosphate mineral phases, which may lead to a new technological pathway for producing phosphate fertilizers or making phosphorus available in soils for crop plants to uptake without using strong industrial acids.
According to one of the various embodiments, ozonized biochar (Biochar-COOH) may be used to help solubilize phosphate from “insoluble” phosphate rock materials such as hydroxyapatite, Ca10(PO4)6(OH)2, through a phosphorus solubilization reaction such as:
Ca10(PO4)6(OH)2+Biochar-COOH→HPO42−+Ca9(PO4)5(OH)2++Biochar-(COOCa)+ [4]
For example, this inventive concept has now been experimentally demonstrated: Incubation of hydroxyapatite (0.5 g) in 20 ml water with 1 g of ozonized biochar (Biochar-COOH) for 2 days under ambient pressure and temperature conditions resulted in a solubilized phosphate concentration as high as 272±9 mg/L (equivalent to the phosphorus (P) concentration of 88.7±2.9 ppm or mg P/L), while that of the control mixture of hydroxyapatite and water was 25±1 mg/L (8.2±0.3 mg P/L). The incubation of hydroxyapatite and water with the non-ozonized conventional biochar resulted in a solubilized phosphate concentration of 42±9 mg/L (13.7±2.9 mg P/L).
According to one of the various embodiments, the surface-oxygenated biochar composition may be used to solubilize phosphorus from “insoluble” phosphate materials such as hydroxyapatite or fluorapatite for phosphorus sustainability by at least one of the following molecular mechanisms: a) Protonic effect including the effect of protons from the organic acid groups such as carboxylic acids of ozonized biochar on “insoluble” phosphate rock materials, which for example can kick phosphate out of the hydroxyapatite structure resulting in solubilized phosphate; b) Cation exchange including the effect of calcium complexation with the deprotonated biochar carboxylate groups (such as Biochar-(COOCa)+ and/or Biochar-(COO)2Ca)) on biochar surfaces and/or biochar molecules and its associated dissolved organic acids that takes calcium away from the “insoluble” phosphate rock materials such as hydroxyapatite structure and thus thermodynamically favors the release of phosphate from the “insoluble” phosphate rock materials; c) Anion exchange including the effect of anions such as the deprotonated biochar carboxylate groups and its associated dissolved organic acids in exchange with the phosphate (anion) of the insoluble phosphate materials thus thermodynamically favors its phosphorus release; and d) combinations thereof.
According to one of the various embodiments, the surface-oxygenated biochar composition may help solubilizing phosphorus from at least one of the “insoluble” phosphate rock materials that comprise: ground soft rock phosphate, Ca10(PO4)6(OH)2 (hydroxyapatite), Ca5(PO4)3F (fluorapatite), and phosphorite (also known as phosphate rock or rock phosphate) which typically is a non-detrital sedimentary rock which contains high amounts of phosphate minerals such as the peloidal phosphorite (Phosphoria Formation, Simplot Mine, Idaho) and the fossiliferous peloidal phosphorite (Yunnan Province, China). The phosphate content of phosphorite (or grade of phosphate rock) varies greatly, from 4% to 20% phosphorus pentoxide (P2O5). Marketed phosphate rock is enriched (“beneficiated”) to at least 28%, often more than 30% P2O5. This is achieved typically through washing, screening, de-liming, magnetic separation or flotation.
According to one of the various embodiments, the surface-oxygenated biochar composition may be used to mix with phosphate rock powders and/or ground soft rock phosphate to make slow-releasing phosphorus and calcium fertilizers with surface-oxygenated biochar; wherein the content of phosphate rock powders in the mixture of phosphate rock powers and surface-oxygenated biochar composition can be about, at least, or no more than, for example, 0.00001%, 0.00005%, 0.0001%, 0.0005%, 0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% weight percent, or within a particular range therein.
According to one of the various embodiments, the approach of ozonized biochar for phosphorous sustainability works better than the conventional technology such as the use of strong industrial acids such as chloric acid (HCl) because of the following three reasons. 1) Production and use of ozonized biochar derived from waste biomass represents a renewable green-chemistry process; whereas production and use of strong industrial acids such as HCl is energy intensive and highly hazardous (corrosive); 2) The use of strong industrial acids such as chloric acid (HCl) does not provide the benefit of calcium complexation with an organic acid ligand (deprotonated biochar carboxylate group) on biochar surfaces and/or biochar molecules; And 3) strong industrial acids such as chloric acid (HCl) are so corrosive that typically are not environmentally friendly to use in agriculture soil environment whereas ozonized biochar (Biochar-COOH) that carries gentle carboxyl acid groups are more suitable to agriculture soil application.
Furthermore, many agricultural soils naturally contain significant amounts of “insoluble” phosphate materials which crop plants commonly cannot utilize. The green chemistry of phosphorus solubilization with surface-oxygenated biochar might also have practical implications to helping solubilize some of these “insoluble” phosphate materials in soils and thus reduce phosphorus fertilizer additions required to achieve desired soil phosphorus activity, crop uptake, and yield goals. The present invention on phosphorus solubilization with surface-oxygenated biochar disclosed here has practical implications in achieving phosphorus sustainability and as well as biochar-associated benefits such as helping better retaining soil nutrients and carbon sequestration for agricultural and environmental sustainability.
According to one of the various embodiments, the “insoluble” phosphate materials in soils include (but are not limited to): phosphorus containing minerals (mostly apatites: Ca10X(PO4)6, where X=F−, Cl−, OH− or CO32−) from parent rocks; the various precipitated Ca-phosphates, such as Ca(H2PO4)2.H2O (monocalcium phosphate), CaHPO4.2H2O (dicalcium phosphate dihydrate=brushite), CaHPO4 (dicalcium phosphate=monetite), Ca8H2(PO4)6.5H2O (octacalcium phosphate), Ca5(PO4)3OH (hydroxyapatite), and Ca5(PO4)3F (fluoroapatite); and precipitated Al- and Fe-phosphates such as variscite (AlPO4.2H2O), strengite (FePO4.2H2O), and vivianite [(Fe3(PO4)2.8H2O)].
According to one of the various embodiments, the surface-oxygenated biochar composition may be applied into the root zone of agricultural soils to help solubilize phosphorus from the “insoluble” phosphate material there for crop to uptake with a number of application techniques selected from the group consisting of: 1) mixing surface-oxygenated biochar with soils under wet and calm (non-windy) conditions during plowing of a field and/or tillage practices; 2) mixing and/or coating certain seeds such as wheat, soybean, and peanuts with certain surface-oxygenated biochar composition so that the seeds and surface-oxygenated biochar composition are co-inserted into soil during sowing; 3) placing surface-oxygenated biochar composition into soil during planting of seedlings; 4) using surface-oxygenated biochar paste and/or liquid as an irrigation into the crop root zones; and 5) combinations thereof.
According to one of the various embodiments, the content of the applied surface-oxygenated biochar composition in a soil mixture can be about, at least, or no more than, for example, 0.00001%, 0.00005%, 0.0001%, 0.0005%, 0.001%, 0.002%, 0.005%, 0.01%, 0.02%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 18%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% weight percent, or within a particular range therein.
According to one of the various embodiments, the surface-oxygenated biochar composition may help to enhance phosphorus availability for plant uptake by helping phosphorus solubilization from the soil insoluble phosphate mineral phases comprising at least one of the “insoluble” phosphate materials selected from the group consisting of soil phosphate rock particles and mineral minerals (mostly apatites: Ca10X(PO4)6, where X=F−, Cl−, OH− or CO32−) from parent rocks; the various precipitated Ca-phosphates including Ca(H2PO4)2.H2O (monocalcium phosphate), CaHPO4.2H2O (dicalcium phosphate dihydrate=brushite), CaHPO4 (dicalcium phosphate=monetite), Ca8H2(PO4)6.5H2O (octacalcium phosphate), Ca5(PO4)3OH (hydroxyapatite), and Ca5(PO4)3F (fluoroapatite); precipitated Al- and Fe-phosphates including variscite (AlPO4.2H2O), strengite (FePO4.2H2O), and vivianite [(Fe3(PO4)2.8H2O)]; and combinations thereof.
According to one of the various embodiments, in highly weathered acidic soils rich in Al- and Fe-oxides (e.g., Ferralsols that pre-dominate in subtropical and tropical regions), inorganic phosphorus (Pi) is strongly sorbed onto the edges of silicate clay minerals and to pedogenic Al- and Fe-oxides. Over time, the inorganic phosphorus sorption may become gradually stronger by a slow diffusion of phosphate into micropores forming “occluded P” or even transitions to precipitated Al- and Fe-phosphates. This process, contributing to the low efficiency of fertilizer P in low pH soils, may be partly avoided or reversed by application of surface-oxygenated biochar composition and its dissolved organic carbons including biochar organic acids, low molecular organic anions and higher molecular organic anions such as anions of surface-oxygenated biochar derived fulvic and humic-like acids that can compete with phosphate anions through anion exchange for positively charged binding sites thus favoring phosphorus release. Chelating biochar organic anions may also contribute to the phosphate desorption.
According to one of the various embodiments, phosphorus solubilization in certain acidic soils is accomplished through anion exchange by mixing the soils with surface-oxygenated biochar paste product which comprises surface-oxygenated biochar-derived organic anions such as humic-like substances that are selected from the group consisting of surface-oxygenated biochar particles, surface-oxygenated biochar-derived organic matters, surface-oxygenated amorphous carbon particles, surface-oxygenated graphite particles, partially oxygenated graphene, partially oxygenated graphene-like molecules, partially oxygenated graphene molecular fragments, partially oxygenated linear hydrocarbons, partially oxygenated aromatic compounds, partially oxygenated polycyclic aromatic hydrocarbons, dissolved organic carbons including organic acids, and combinations thereof.
Therefore, according to one of the various embodiments, phosphorus solubilization may be accomplished by application of the surface-oxygenated biochar composition in various soils including certain alkaline soils, pH neutral soils and acidic soils through the effect selected from the group consisting of the protonic effect, cation exchange, anion exchange and combinations thereof.
According to one of the various embodiments, the application of surface-oxygenated biochar composition by mixing with certain soils can result in a solubilized phosphorus concentration that is, at least, 100% higher than the critical P concentration of 0.15 ppm, which is the P concentration in soil solution that is required for crop plant growth (Matula 2011 Plant Soil and Environment, 57(7): p. 307-314).
According to one of the various embodiments, the surface-oxygenated biochar paste materials including the “humic acids like” substances produced from the sonication-enhanced biochar ozonization process can be used to convert desert sands into useful soil, which can help better retain water and nutrients. Sand (silica, silicon dioxide) particles typically have negative surface charges. The principal mechanism by which sand (silica) surfaces acquire a negative charge is the dissociation (deprotonation) of silanol groups:
Sand-SiOH→Sand-SiO−+H+ [5]
Use of “humic acids like” surface-oxygenated biochar organic molecular species that have at least two carboxyl groups per molecule (−COO—R—COO−) in combination with other biomass materials selected from the group consisting of lignin cellulosic materials, carboxymethyl cellulose, un-hydrolyzed biomass residues such as un-hydrolyzed cornstover residues, lignin residues, recalcitrant biomass residues, humic substances, and combinations thereof; and in combination with certain cations selected from the group consisting of Ca2+, Mg2+, Fe2+, and Fe3+ can form a type of ionic cross-linking structures that may create a type of jelly state to better retain water and nutrients and hold sand particles together:
2 Sand-SiO−+−COO—R—COO−+Ca2+→Sand-SiO.Ca.COO—R—COO.Ca.SiO-Sand [6]
Consequently, the surface-oxygenated biochar paste products may act like a gelator or a liquid gel-forming material in the spaces among sand particles that can help to retain much more water (and nutrients) and hold sand particles together, resulting in a novel “sand soilization” effect. The liquid gel-forming activity of surface-oxygenated biochar paste compositions in the spaces among sand particles can retain water and nutrients and hold the sand particles together through at least one of the noncovalent interactions selected from the group consisting of: 1) the ionic (Coulombic) interactions that are the electrostatic interactions between charged species as shown in equation 5 above for example; 2) the hydrogen bond effects of the surface-oxygenated biochar molecular species with water and sands; 3) the π-π interactions between aromatic structures; and 4) the van der Waals interactions among sands and surface-oxygenated biochar molecular species with water.
Therefore, the surface-oxygenated biochar compositions including the biochar paste product may be used for sand soilization by their liquid gel-forming activity in the spaces among sand particles that can retain water and nutrients and hold the sand particles together through at least one of the following noncovalent interactions: 1) the ionic (Coulombic) interactions that are the electrostatic interactions between charged species; 2) the hydrogen bond effects of the surface-oxygenated biochar molecular species with water and sands; 3) the π-π interactions between aromatic structures; and 4) the van der Waals interactions among sands and surface-oxygenated biochar molecular species with water.
According to one of the various embodiments, the surface-oxygenated biochar compositions including the biochar paste product typically has high cation exchange capacity which is the key property that is central to help retain soil water and nutrients. Therefore, the use of surface-oxygenated biochar compositions in mixing with sands for sand soilization also help to better retain water and plant nutrients is fundamentally important to agricultural and environmental sustainability. This “sand soilization” effect, which helps in retaining water and holding sand particles together, may be used as a way to reduce the likelihood of sands becoming airborne with winds and thus may be used also as a way to help minimize desert sand storms.
According to one of the various embodiments, divalent cation solutions such as CaCl2 and/or MgCl2 solution may be used to spray on the surface of sands to anchor the sands and/or soils with and/or without surface-oxygenated biochar paste compositions depending on the consideration of specific environmental conditions.
According to one of the various embodiments, the surface-oxygenated biochar compositions-enhanced sand soilization has a special characteristic that the mixture of sands and surface-oxygenated biochar materials retains much more water and nutrients and hold the sand particles together so that the sands will less likely become airborne with winds than the control sands. As demonstrated experimentally, the surface-oxygenated biochar composition treated sands retain water for much longer time than the control sands so that the surface-oxygenated biochar treated sands will less likely to flow with gravity than the control sands when the sand plates are tilted up to 90 degrees.
According to one of the various embodiments, the content of surface-oxygenated biochar composition in the sands mixture for sand soilization can be about, at least, or no more than, for example, 0.00001%, 0.00005%, 0.0001%, 0.0005%, 0.001%, 0.002%, 0.005%, 0.01%, 0.02%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 18%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% weight percent, or within a particular range therein.
According to one of the various embodiments, the surface-oxygenated biochar compositions comprise certain amounts of beneficial humic acids-like substances including certain partially oxygenated dissolved organic carbons (DOC) that can stimulate green plant growth when used at a proper DOC concentration selected from the group consisting of: 0.1 ppm, 0.2 ppm, 0.5 ppm, 1 ppm, 2 ppm, 3 ppm, 5 ppm, 8 ppm 10 ppm, 12 ppm, 15 ppm, 20 ppm, 25 ppm, 30 ppm, 40 ppm, 50 ppm, 100 ppm, 200 ppm, 500 ppm, 1000 ppm or a DOC concentration within a particular range bounded by any two of the foregoing values.
According to one of the various embodiments, the surface-oxygenated biochar compositions may be used to reduce and/or remove the offensive odor associated with manure applications and to reduce agriculture chemical runoff. The surface-oxygenated biochar compositions can absorb the offensive odor from manures significantly better than conventional biochar. For example, surface-oxygenated biochar can absorb the ammonia (NH3) gas odor through its reaction with the biochar molecular carboxylic acid (Biochar-COOH) to form ammonium carboxylate on ozonized biochar surface (Biochar-COONH4). The surface-oxygenated biochar compositions can be used to reduce the offensive odor associated with manures selected from the group consisting of pig manure, cow manure, buffalo manure, sheep manure, horse manure, donkey manure, camel manure, chicken manure, duke manure, goose manure, turkey manure, human manure, and dog manure, zoo animal manures, and combinations thereof.
According to one of the various embodiments, when the biochar-producing thermal biomass carbonization process is finished, the raw biochar pieces are often too large for practical use so that they are resized at a crushing and screening workstation. The output produces typically five sizes: Chip (size 1″ to 3 mm), Medium (grain size: 3 mm to US Standard 25 mesh (0.71 mm)), Small (25 mesh (0.71 mm) to 50 mesh (0.300 mm)), Powder (50 mesh (0.300 mm) and under), and Fine Power (140 mesh (0.105 mm) and under). Technically, any of these biochar particle sizes may be used in a biochar-surface oxygenation process through sonication and ozonization. Biochar liquid ozonization in combination with sonication can produce liquid biochar paste with fine surface-oxygenated amorphous carbon particles (sizes well below 0.105 mm) plus significant amounts of dissolved organic carbons (DOC) in the presence of water. Each of these biochar products may have its own uses as listed in the Table 1a below.
The following examples illustrate methods and systems for making biochar in accordance with exemplary embodiments of the present invention and also provide an analysis of improved properties of the resulting biochar. These examples are purely exemplary and are not intended to limit the scope of the present invention. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperatures, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in ° C. or is at ambient temperature, and pressure is at or near atmospheric, or in atmospheric pressure units (atm).
Table 1b shows the changed in pH of the biochar samples brought about by treatment with ozone. Overall there is a dramatic decrease in the pH of the biochar samples from untreated at 7.30±0.39 to the sample treated with 90 minutes of ozone at 5.28±0.33. This sharp decrease in pH results from, for example, the addition of acidic functional groups, primarily carboxyl groups on the surface of the biochar. The trend of the drop in pH illustrates a relationship between treatment time and increasing acidity of the biochar samples. This drop in pH is an important characteristic when considering using biochar as a soil amendment. Therefore, exemplary embodiments for ozone treatment of biochar can be used to adjust or to “tune” biochar pH to a desired value for a given soil.
Table 1b also illustrates a significant increase in the measured CEC values of biochar processed in accordance with exemplary embodiments of the ozone treatment. The untreated biochar sample had a CEC of 153.9±15.9, and the sample treated with 90 minutes of ozone had a value of 326.9±25.1 (in units of mmol/kg biochar). In the illustrated example, there is only a small difference between the 30, 60, and 90 minute ozone treated samples, which is potentially due to a saturation of the sites available for alteration by ozone treatment. The increase in CEC is due to an increase in oxygen functionality, as discussed, for example, in Lee et al., Environ. Sci. Technol. 44:7970-7974 (2010) and Matthew et al., Journal of Environmental Management, 146:303-308(2014). Specifically, cation exchange capacity correlates to the availability of oxygen function groups, predominately carboxylic acid groups which carry a negative charge in basic and neutral solutions, making them electrostatically attracted to cations. Table 1 also lists the CEC value of a reference soil sample of 131.8±9.6. From this, it is clear that even untreated biochar has a higher CEC, and treated samples more than double the native CEC of the reference soil sample.
Methylene blue adsorption capacity was measured to evaluate the viability of the biochar for dye-contaminant removal in water systems. As shown in Table 1b, there is a dramatic increase in methylene blue removal capacity resulting from ozone treatment, with the untreated biochar sample only removing 1.79±0.18 mg dye/kg biochar while the 90 minute ozone treated sample removed 9.35±0.04. This significant increase shows the usefulness of ozone treatment when considering biochar amendment for use in contaminated water systems. It is believed that the increase in methylene blue adsorption capacity results from the increase of oxygen functionality on the surface of the biochar, which makes the biochar overall more negatively charged. Methylene blue is natively positive in solution, and therefore is more electrostatically attracted to biochar that has been treated with ozone.
Elemental analysis measures the bulk composition of the biochar and is useful in determining the degree of change brought about by ozone treatments. Overall, there is not a dramatic change through the use of ozone treatments as shown in Table 2. However, there is a clear drop in carbon content from the untreated sample (73.90%±0.06) and the 30 minute ozone treated sample (66.76%±2.77). Additionally, there appears to be an increase in oxygen content of the biochar samples as measured by the difference from the untreated (22.78%) to the 30 minute ozone treated sample (30.07). This data correlates well with the concurrent drop in pH of these samples, as well as the increase in CEC, both owing the change in their properties due to an increase in oxygen functionality. The drop in carbon content across all samples also reveals that ozone treatments selectively attack the carbon bonds in the biochar, which is also shown in the FTIR-ATR data in
In this example, biochar was produced from pinewood biomass by pyrolysis at a highest treatment temperature (HTT) of 400° C. This biochar was then treated with varying concentrations of a H2O2 solution (1, 3, 10, 20, 30% w/w) for a partial oxygenation study. The biochar samples, both treated and untreated, were then tested with a cation exchange capacity (CEC) assay, Fourier Transformed Infrared Resonance (FT-IR), elemental analysis, field water-retention capacity assay, pH assay, and analyzed for their capacity to remove methylene blue from solution. As shown in Table 3, the results demonstrate that higher H2O2 concentration treatments led to higher CEC due to the addition of acidic oxygen functional groups on the surface of the biochar, which also corresponds to the resultant lowering of the pH of the biochar with respect to the H2O2 treatment. Furthermore, it shows that the biochar methylene blue adsorption decreased with higher H2O2 concentration treatments. This is believed to be due to the addition of oxygen groups onto the aromatic ring structure of the biochar which in turn weakens the overall dispersive forces of π-π interactions that are mainly responsible for the adsorption of the dye onto the surface of the biochar. As shown in Table 4, the elemental analysis revealed that there was no general augmentation of the elemental composition of the biochar samples through the treatment with H2O2, which suggests that the bulk property of biochar remains unchanged through the treatment.
The FTIR-ATR spectra as shown in
The Raman spectra as shown in
In this example, sonication of biochar in liquid was conducted with a 750 Watt, 20 KHz Ultrasonic Processor VCX-750 and then followed by ozonization. Briefly, 9.0 g of oven dried biochar P400, which was produced by slow pyrolysis (residence time: 30 min) of pine wood at 400° C., was weighed and placed into an ozone treatment vessel and 50.0 mL of ultrapure water was added into it. The sample mixture was sonicated for 15 minutes with the Ultrasonic Processor set at 50% amplitude. The ozone generator was set to optimum condition for the generation of ozone. The ozone gas stream was bubbled into the liquid sample mixture for 90 min. After 90 min, the mixture was transferred into a Buchner funnel and the filtrate was collected in a vessel for further analysis. The biochar product was then washed with 600 mL of ultrapure water and kept in oven maintained at 105° C. for drying. The biochar was then washed with 1800 mL of ultrapure water and kept in oven maintained at 105° C. for drying. This sonicated-ozonized biochar product is designated as P400 90W+S.
In a related example, liquid sonication was done to the biochar material two times during ozonization treatment. In this double-sonication treatment in combination with wet ozonization, 9.0 g of oven dried biochar was weighed and placed into an ozone treatment vessel and 50.0 mL of ultrapure water was added to it. The sample mixture was sonicated for 15 minutes with the Ultrasonic Processor set at 50% amplitude. The ozone generator was set to optimum condition for the generation of ozone. The ozone was bubbled into the liquid sample mixture for 45 min. The sample mixture was again sonicated for 15 minutes and ozone was bubbled into the sample liquid mixture for next 45 min. The mixture was then transferred into a Buchner funnel and the filtrate was collected in a vessel for further analysis. The biochar was then washed with 1800 mL of ultrapure water and kept in oven maintained at 105° C. for drying. This double-sonicated-ozonized biochar product is designated as P400 90W+2S.
In another related example, the biochar liquid-sonication-ozonization reactor (
In this example, solubilization of phosphorus from hydroxyapatite using a special ozonized biochar was experimentally demonstrated for the first time. The ozonized biochar was specially made from pine wood-derived biochar through slow pyrolysis and followed by a post-production ozonization process. Briefly, pine wood biomass was converted to biochar by slow pyrolysis (residence time 30 min) at a highest treatment temperature of 400° C. The resulting biochar was treated with ozone under wet and dry conditions to add oxygen functional groups on its surface. The pH of the biochar showed a two units decrease when treated with ozone (pH 5.64 for the non-ozonized control biochar versus 3.60 and 3.96 for the wet and dry-ozonized biochar respectively). The biochar cation exchange capacity increased by 50% when the biochar is treated with ozone (14.4 cmol/kg and 13.2 cmol/kg for wet and dry-ozonized biochar respectively) compared to non-ozonized control biochar (10.4 cmol/kg). Incubation of insoluble phosphorus material in the form of hydroxyapatite, with the wet-ozonized biochar together with its filtrate for 2 days resulted in a maximum solubilized phosphate concentration (569.9 mg/L; equivalent to the P concentration of 185.9 ppm), compared to 0.1 mg/L of phosphate when hydroxyapatite was incubated with the non-ozonized control biochar and its filtrate. A similar pattern was observed for the calcium solubilized (Ca 66.0 mg/L) from the hydroxyapatite when the latter was incubated with the wet-ozonized biochar and its filtrate, in comparing to that (Ca 0.4 mg/L) of the hydroxyapatite incubation control with the non-ozonized biochar and its filtrate. These results showed that the surface-oxygenated biochar composition may be used to mix with phosphate rock powders and/or ground soft rock phosphate to make slow-releasing phosphorus and calcium fertilizers.
In a related example, a further experiment was conducted using both dry- and wet-ozonized biochar to incubate with hydroxyapatite in Milli-Q deionized water for periods of 30 minutes, 2 days, and 2 weeks. The phosphate concentration change in the incubation liquid was analyzed using an Ion Chromatograph IPS 5000 Dionex SP.
By integrating for the phosphate peak area under the ion chromatography curve, the amount of solubilized phosphorus and its concentration was calculated according to a phosphate standard ion chromatography curve of known P concentrations. The analyzed results (
Table 5 present the results from a 14-day hydroxyapatite solubilization assay with surface-oxygenated biochar as measured at the end of the incubation experiment. In this experiment, the biochar materials including wet-ozonized biochar and dry-ozonized biochar were washed with water to remove any dissolved organic carbon (DOC) before used in this experiment. The washed clean biochar material is designated as “biochar” to use in the experiment. The DOC liquid resulted from the washing of biochars was designated as “filtrate”. Based on the assay data, use of both the wet-ozonized biochar and the dry-ozonized biochar can significantly solubilize phosphorus from hydroxyapatite and resulted in solubilized P concentrations of 29.26±3.73 and 26.26±0.68 mg/L, which is nearly 10 times better than the control incubation using non-ozonized biochar (3.135±0.198 mg/L).
The incubation treatment of hydroxyapatite with wet-ozonized biochar with its associated filtrate (HA+Biochar+Filtrate wet-ozonized) resulted in the highest solubilized P concentration of 180.6±18.0 mg/L, which is 147 times higher than that (1.228±0.435 mg/L) of the control incubation that used non-ozonized biochar and its filtrate (Table 5). Furthermore, the incubation treatment of hydroxyapatite with the filtrate from the wet-ozonized biochar also resulted in a very high solubilized P concentration (152.0±19.0 mg/L). This result demonstrated that the filtrate including the DOC from the wet biochar ozonization process can play a major role in helping solubilizing phosphorus from phosphate rock materials such as hydroxyapatite.
From the Ca/P molar ratio data listed in Table 5, it is quite clear that the molecular mechanism of cation exchange may play a role in help solubilizing phosphate from hydroxyapatite, since all treatments with biochars and/or their filtrates resulted in a low Ca/P molar ratio in a range from 0.1 to 0.3 that is significantly lower than that of the HA+Water incubation control (1.081) which is somewhat closer to the molar ratio of calcium to phosphate (1.67/1) in the solid hydroxyapatite Ca5(PO4)3(OH). That is, some of the divalent calcium cations may be removed by interacting with the negatively charged surfaces of biochar and/or complexation with the deprotonated carboxylate groups on biochar surfaces and/or with the partially oxygenated biochar molecules and organic acids in the biochar filtrates. As a result, the concentration of Ca++ in the liquid phase was lowered, which is favorable for P solubilization from hydroxyapatite. Alternatively, the deprotonated carboxylate groups (anions) of the partially oxygenated DOC in the biochar filtrates may exchange with phosphate (anions) out of the hydroxyapatite surfaces, which could also explain the observed low molar ratio (0.1˜0.3) of Ca/P in the incubation solutions with surface-oxygenated biochars and filtrates.
The use of ozonized biochars can apparently lowered the final pH of the incubation liquid mixture by nearly 1 pH unit, for example, from the HA+water control pH 6.68 to 5.72 with wet-ozonized biochar and filtrates. The higher solubilized P concentrations in the incubation liquid with wet ozonized biochar and its filtrate apparently correlate well with the observed lower pH. Therefore, it is quite clear that the protonic effect is also in play with the phosphorus solubilization process.
Therefore, the data listed in Table 5 indicated that the phosphorus solubilization with surface-oxygenated biochar is accomplished through at least one of the following molecular mechanisms: a) Protonic effect including the effect of protons from the organic acid groups of ozonized biochar which can kick phosphate out of the insoluble phosphate materials, resulting in solubilized phosphate; b) Cation exchange including the effect of calcium complexation with the deprotonated biochar carboxylate groups on biochar surfaces and/or biochar molecules and its associated dissolved organic acids that takes calcium away and thus thermodynamically favors the release of phosphate from the insoluble phosphate materials; c) Anion exchange including the effect of anions such as the deprotonated biochar molecular carboxylate groups and its associated dissolved organic acids in exchange with the phosphate (anion) of the insoluble phosphate materials thus thermodynamically favors its phosphorus release; and d) combinations thereof.
The soil samples tested included the Portneuf Soil (P-Soil) collected from South Central Idaho and the Bennett Soil (B-Soil) collected from Eastern Colorado. Tests were conducted by mixing 0.5 g of surface-oxygenated biochar with 1 g of soil plus 12 ml of water to incubate for 30 minutes, 2 days, and 14 days and then measuring the solubilized phosphate concentration in the liquid phase using an Ion Chromatograph IPS 5000 Dionex SP. As shown in the ion chromatogram of
These experimental results demonstrated that the use of surface-oxygenated biochar can result in a significantly higher concentration of solubilized phosphate in both of the Portneuf Soil and the Bennett Soil in comparing with the control treatments of these soils using non-ozonized biochar. As listed in Table 6, the concentrations of solubilized phosphorus (P) released through the liquid incubation treatment (with wet-ozonized biochar P400 90W+Water) from each of the P-Soil and the B-Soil reached as high as 4.47 and 5.61 ppm, respectively. These concentrations of solubilized P released from P-Soil and B-Soil with wet-ozonized biochar are nearly four times as high as the controls where non-ozonized biochar “P400 UN+water” was used (1.45 and 0.73 ppm). When dry-ozonized biochar “P400 90D+Water” was used, the concentrations of solubilized phosphorus (P) released from P-Soil and B-Soil were 2.05 and 2.02 ppm, respectively, which are nearly twice as high as those of the controls when non-ozonized biochar “P400 UN+water” was used (1.45 and 0.73 ppm).
These solubilized P concentrations as elevated by the effect of surface-oxygenated biochar in the tested P-Soil and B-Soil water solutions are all well above the critical P concentration of 0.15 ppm that is required in soil solution for crop plant growth as reported by Matula 2011 (Plant Soil and Environment, 57(7): p. 307-314). Therefore, these examples of phosphorus solubilization from soil insoluble phosphate materials with ozonized biochar demonstrated the inventive value of this embodiment.
Note, the soil incubation treatment with 1M HNO3 resulted in the concentrations of solubilized phosphorus (P) of over 600 ppm released from both P-Soil and B-Soil. This indicated that natural soils like P-Soil and B-Soil contain large amounts of “insoluble” phosphate materials that could be potentially solubilized with this new technology using the surface-oxygenated biochar composition. For instance, the amount of phosphorus released from P-Soil with the “wet ozonized biochar P400 90W+water” treatment as demonstrated in this experiment utilized only a very small fraction (4.47/655.53=0.68%) of the total “insoluble” phosphate materials that could be potentially solubilized in the future. Therefore, the technology of phosphorus solubilization from soil insoluble phosphate mineral phases using surface-oxygenated biochar composition may be repeatedly employed in soils well into the future.
In this example, liquid filtrate samples comprising certain partially oxygenated dissolved organic carbons (DOC) were made from liquid ozonization of P400 biochar materials for 90 min. The liquid filtrate DOC concentration was determined to be about 940 ppm. As shown in
In this example, sand soilization was experimentally demonstrated by mixing 10 g of silicon dioxide sand particles with 4 ml of wet-ozonized P400 90W liquid filtrate (shown in
In this example, 3 g of the solid material of un-hydrolyzed corn stover residue was mixed with 50 ml of milli-Q water. The mixture was hand shaken thoroughly. The mixture was then placed into a specialized glass vessel and treated with ozone with a Wellsbach Ozone generator for 90 minutes. The parameters of ozone treatment were as followed: 8 psi for the oxygen pressure, the ozone flow was set to 3 L per minute and the voltage was set to 116 V. The 50 mL filtrate was then collected by vacuum filtration before being stored in a refrigerator at 4° C. The filtrate was filtered through a 0.2-μm pore-size filter and its dissolved organic carbon concentration was determined with a TOC Analyzer. The solid material was further washed with an additional 600 mL of milli-Q water to get rid of the un-bound particles. The solid material was then dried in oven at 105° C.
The pH of the un-hydrolyzed corn stover residue was measured. The effect of ozone treatment caused a dramatic decrease in pH from 4.81±0.0071 (non-ozonized control) to 3.12±0.14 (wet-ozonized sample). The dissolved organic carbon (DOC) was also measured and showed an increase in DOC concentration from 2440.5 mg/L to 2928.3 mg/L (Table 7) by wet ozonization. Both the decrease in pH and the increase in DOC supported the claim that ozonization reaction took effect on the un-hydrolyzed corn stover residue. The un-hydrolyzed corn stover residue, upon being ozonized had a filtrate that had a different color compared to that of the non-ozonized un-hydrolyzed corn stover residue (
In this example, the soilization test of silicon dioxide sands demonstrated that when the sands are mixed with pure water, the sands pile on the Petri dish plate cannot withstand its structure when being tilted at an angle greater than 45 degrees. The addition of 2.5 mM CaCl2 to the sand pile gave a little more holding effect and enabled it to stay intact until a tilt of 90 degrees where the sand pile also falls apart (
In the presence of the filtrate from the un-hydrolyzed corn stover residue, the sand pile is able to maintain its structure when it was tilted at 45 and 90 degrees (
In this example, as shown in
Similarly, a 16-day bioassays of the hydrochar (HTC) liquid from a hydrothermal conversion process using un-hydrolyzed corn stover residues with Synechococcus elongatus PCC 7942 (
In this example, certain partially oxygenated dissolved organic carbons (DOC) from the surface-oxygenated biochar compositions were tested for its biological effect on seedlings from seed germination using commercially available phytotoxkit microbiotest plates with a standard protocol. Briefly, plate 1 contained 300 ppm of DOC material from the hydrochar (HTC) liquid of a hydrothermal conversion process using un-hydrolyzed corn stover residues (UHCSR). One half of test plate column was filled with reference soil. Soil was saturated with 35 ml of UHCSR HTC liquid (4.87 ml UHCSR HTC liquid in 200 ml volumetric flask), was then covered with black filter paper, and followed by the placement of 2 seeds per kind (Sorghum, Lepidium, and Sinapis). The plate was then incubated in the dark for germination. Protocol was repeated for plates 2 (150 ppm) consisting of 35 ml of 2nd serial dilution, plate 3 (75 ppm) consisting of 35 ml of 3rd serial dilution, plate 4 (25 ppm) consisting of 35 ml of 4th serial dilution (3rd serial dilution diluted with 70 ml deionized water), and finally plate 5 (0 ppm) which is just the Control of 35 ml deionized H2O. The results of the assay as observed in 7 days (
In this example, 3 types of biochar were used to compare in the tests are: 1) Pine 400 biochar which was produced from Pinewood biomass through pyrolysis with a high pyrolysis temperature of 400 degrees Celsius (400° C. for 30 min); 2) Dairy manure gasification (>700° C.) biochar (Company biochar 1); and 3) Flash Pyrolysis woody biochar (Company biochar 2) which was produced by 815-871° C. Flash (30 seconds) Pyrolysis using chopped 2-inch chips of softwood including Douglas fir (Oregon pine) and sugar pine with 35% water content. The three different types of biochar were treated with ozone under dry condition (without water) and wet condition (with water) for 90 minutes. The biochar samples were then tested for BET surface area measurements. The Company biochar 2 had a type of “steam activation” effect from the 815-871° C. Flash (30 seconds) Pyrolysis using 35% water content of the chopped softwood (the water content in the biomass quickly turned into steam upon sudden contacting with the high pyrolysis temperature of 815-871° C.) so that its BET surface area was as high as 434.9 m2/g before ozonization. The Pine 400 biochar before ozonization had the lowest BET surface area of 0.7616 m2/g. Ozonization slightly increased the BET surface area under wet conditions for Company biochar 2 giving a BET surface area of 452.7 m2/g. Ozonization caused a drop in pH for all 3 types of biochars; a dramatic pH drop was observed in the Company biochar 2 going from pH 9.835+/−0.028 to 4.65+/−0.071 upon dry ozonization.
Similarly, the cation exchange capacity (CEC) was measured and showed a dramatic increase in the Company biochar 2 upon ozonization: from 14.314 cmol/kg for non-ozonized Company biochar 2 to 84.371 cmol/kg (equivalent to 843.71 mmol/kg) for dry ozonized Company biochar 2. Dry ozonization of Company Biochar 1 also resulted in an improved CEC value, but its improvement was not as big as in Company Biochar 2.
In order to see how efficient the biochars are in adsorbing dyes, a methylene blue adsorption assay was conducted. The results demonstrated that the Company Biochar 2 removed almost all the methylene blue (99.752 percent removal of methylene blue).
Furthermore, the dissolved organic carbon (DOC) concentration was determined for biochar filtrates. Ozonization increased the DOC content for all 3 types of biochar. The DOC production results showed that Pine 400 and Company Biochar 1 were more efficient in the wet ozonization while Company Biochar 2 worked best under dry ozonization.
In this example, bioassay study was conducted using the ozonized biochar filtrates and their respective DOC concentration. The DOC of ozonized Pine 400 biochar showed a greatest beneficial effect on the cyanobacteria Synechococcus elongatus PCC 7942 growth followed by the DOC from ozonized Company Biochar 2.
Overall, Company Biochar 2 is among the best for use with ozonization, which upon dry ozonization yielded the greatest reduction in pH, greatest increase in CEC (by a factor of nearly 5), and greater production of biochar DOC (part of the biochar-derived organic matters). Note, the commercial production capacity of Company Biochar 2 recently reached 3500 tons per year in conjunction with the operation of a 30 MW boiler-based electricity generation power plant, annually utilizing about 250,000 tons of chopped softwood with 35% moisture through 815-871° C. Flash Pyrolysis. The syngas produced from the biomass Flash Pyrolysis was utilized through its clean combustion to heat the boiler for steam turbine electricity generation.
As shown in the experimental data listed in Table 8, the sonication treatment of P400 biochar for 15 minutes (15S) alone resulted in 20.3 ppm of DOC produced in the biochar treatment liquid, which translates to the DOC production yield of 0.34 g per kg biochar. The dry sonication treatment of P400 biochar for 90 minutes (90D) resulted in 214.0 ppm of DOC produced in the biochar treatment liquid with a DOC production yield of 3.57 g/kg biochar. The wet ozonization of P400 biochar for 90 minutes (90W) resulted in 1389.1 ppm of DOC produced in the biochar treatment liquid, which is corresponding to the biochar-derived DOC production yield of 23.15 g/kg biochar. The biochar-derived DOC production yield from 15S+90 W (15-minutes sonication and 90-minutes wet ozonization of P400 biochar) was 40.22 g DOC/kg biochar, resulting in 2413.3 ppm of DOC which was the best in this example. These results demonstrated that the combination of sonication and ozonization is a highly effective method to produce biochar derived organic matters as measured with DOC concentration in the treatment liquid phase.
While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the invention claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant's general inventive concept.
This application is a Continuation-In-Part of co-pending U.S. patent application Ser. No. 15/228,611 that claims priority and benefit from U.S. Provisional Application No. 62/201,870 filed on Aug. 6, 2015, which is incorporated herein by reference in its entirety. This continuation-in-part application also claims the priority and benefit from U.S. Provisional Application No. 62/689,223 filed on Jun. 24, 2018.
| Number | Date | Country | |
|---|---|---|---|
| 62201870 | Aug 2015 | US | |
| 62689223 | Jun 2018 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15228611 | Aug 2016 | US |
| Child | 16104892 | US |
