Patent Application
20240376292
This invention relates to the field of water treatment and in particular to the removal of boron from aqueous solution.
Boron compounds have been detected in natural water at concentration levels of 0.3-100 mg/L (Bonilla-Petriciolet, A., et al. (2017) Adsorption Processes for Water Treatment and Purification. Springer). Excessive concentrations of boron are damaging and even lethal to plants (Bonilla-Petriciolet, A., et al. (2017) Adsorption Processes for Water Treatment and Purification. Springer). Therefore, boron concentration in water and wastewater is regulated in many countries (Bonilla-Petriciolet, A., et al. (2017) Adsorption Processes for Water Treatment and Purification. Springer).
When dissolved in water, boron can form multiple species which complicate its removal. At pH<9, boron exists primarily as boric acid [B(HO)3). At pH>9, boron primarily exists as the borate anion [B(HO)4−] (Bonilla-Petriciolet, A., et al. (2017) Adsorption Processes for Water Treatment and Purification. Springer). Boric acid and the borate anion are highly soluble and difficult to precipitate as metal salts from solution. Furthermore, due to boric acid's low degree of polarity and small size, it has a tendency to permeate reverse osmosis membranes and is poorly separated from aqueous solutions by anion exchange resins (Bonilla-Petriciolet, A., et al. (2017) Adsorption Processes for Water Treatment and Purification. Springer). To combat these challenges in separation in membrane processes, solution pH is generally raised to shift composition of boron species in solution to the borate form, which can then be removed in an additional membrane separation step after other dissolved constituents which are sensitive to elevated pH have been removed (2-PASS RO) (Imbernón-Mulero, A. et al. (2022) ‘Boron Removal from Desalinated Seawater for Irrigation with an On-Farm Reverse Osmosis System in Southeastern Spain’, Agronomy, p. 611. doi:10.3390/agronomy12030611). An additional strategy is to utilize ion exchange resins (IX) which specifically remove boron. Boron specific ion exchange resins generally contain a cis-diol functional group affixed to a porous substrate. Boron is able to covalently bind with the cis-diol groups of the resin at narrow pH ranges, and can be eluted from the resins upon acidification. While capable of selective removal of boron, solid media ion exchange resins suffer from very low loading capacities (0.1-10 mg Boron/g resin), and carry a high operating cost due to the regeneration of the resin (Ezechi, E. H., Isa, M. H. and Kutty, S. R. B. (2012) ‘Boron in Produced Water: Challenges and Improvements: A Comprehensive Review’, Journal of Applied Sciences, pp. 402-415. doi:10.3923/jas.2012.402.415). The low loading capacities and high regeneration costs of boron specific ion exchange resins make them very useful for removal of low quantities of boron from solution at low flow rates. However, as flow rates or boron loading rates increase the amount of resin and frequency of cleaning make boron specific resins uneconomical. Processes combining reverse osmosis, followed by ion exchange process have also been proposed (RO-IX) (Imbernón-Mulero, A. et al. (2022) ‘Boron Removal from Desalinated Seawater for Irrigation with an On-Farm Reverse Osmosis System in Southeastern Spain’, Agronomy, p. 611. doi:10.3390/agronomy12030611). In an RO-IX process the bulk of boron (50-70%) is removed during the filtration step, followed by a polishing step with a specific boron ion exchange resin. The advantage of this process is that a second RO unit is not required, decreasing engineering CAPEX and system complexity. A major downside to an RO-IX process is that an ion exchange resin capacity decreases with boron concentration in solution. As a result, high volumes of water still require excessively large media beds and frequent regeneration cycles. The end result is a high OPEX cost, although the total treatment cost can still be less than a 2-PASS RO system.
The above methods (2-PASS RO, IX, RO-IX) are potential solutions for removal of boron from water when boron is present at levels from 1-10 ppm. However, as boron concentrations increase above this level the operating costs and efficacy of these systems become challenging to operate. Elevated boron concentrations (above 10 ppm), are often encountered when concentrated saline solutions, particularly from ground water, leachates or evaporative processes, must be treated. In these cases, 2 PASS-RO, RO-IX, and IX methods are unable to economically remove the boron present in solution. One growing industrial application for the removal of boron that is not effectively treated by membranes or ion exchange resins is in the preparation of commercial brines. Examples of brine production impacted by boron contamination include lithium brines, magnesium brines, and potassium brines. During the concentration process, water is removed from solution by evaporation and contaminating ions by precipitation. However, boron will remain in solution and concentrate along with the commercially relevant salt during evaporation. To remove the concentrated boron, which can range from 50 ppm up to 5000 ppm, a liquid-liquid organic phase extraction process must be utilized. IX processes are far too expensive due to the low loading capacities, and membrane processes are unable to effectively separate the boron ions from the target salt.
In general, two main approaches have been studied for removal of boron by enhanced ultrafiltration: micellar enhanced and polymer enhanced. In polymer enhanced filtration, large water soluble polymers covalently bind borate ions in solution, and the resulting complex is filtered (Yürüm, A. et al. (2013) ‘High performance ligands for the removal of aqueous boron species by continuous polymer enhanced ultrafiltration’, Desalination, pp. 33-39. doi:10.1016/j.desal.2013.04.020). In micellar enhanced ultrafiltration, surfactants containing boron binding headgroups are utilized to form large macromolecular assemblies containing bound boron (U.S. Pat. No. 8,357,300), which are unable to pass through the membrane pores. While both of these approaches have shown boron removal rates in excess of 90%, two significant barriers to their commercial adoption are fouling and attrition. Addition of large organic molecules to ultrafiltration is known to lead to pronounced decreases in membrane flux due to membrane fouling and concentration polarization (Schwarze, M. (2017) ‘Micellar-enhanced ultrafiltration (MEUF)—state of the art’, Environmental Science: Water Research & Technology, pp. 598-624. doi:10.1039/c6ew00324a). In particular, cake layer formation or irreversible fouling of the membranes can be extremely limiting and make the process uneconomical due to effective flux rates of <1 L/m2 h and filter replacement costs. Large polymers and large surfactant aggregates are particularly susceptible to membrane fouling. Attrition of the binding component through the membrane is a significant issue for micellar enhanced ultrafiltration; micelle formation is governed by surfactant solubility and a critical micelle concentration (CMC) of surfactant being present in solution. Above the CMC surfactants will form micelles, but a significant amount of monomeric surfactant still exists in solution (Schwarze, M. (2017) ‘Micellar-enhanced ultrafiltration (MEUF)—state of the art’, Environmental Science: Water Research & Technology, pp. 598-624. doi:10.1039/c6ew00324a). These monomeric surfactants are able to permeate the membrane pore, leading to boron leakage and a constant loss of surfactant. Surfactant micelles are in an equilibrium with the surfactant monomer in solution, therefore as monomer concentrations decrease, micelle concentration will decrease to maintain a constant concentration of monomeric surfactant. As a result, a supplemental amount of surfactant must be constantly injected into the process, leading to high chemical costs. In summary, enhanced ultrafiltration requires a solute complexing agent that has 1) low fouling characteristics at high concentrations, and 2) low attrition rates (Schwarze, M. (2017) ‘Micellar-enhanced ultrafiltration (MEUF)—state of the art’, Environmental Science: Water Research & Technology, pp. 598-624. doi:10.1039/c6ew00324a).
U.S. Pat. No. 8,357,300, describe a method for reducing a boron concentration in a boron-containing aqueous liquid involves administering micelle(s) for selective boron adsorption to the boron-containing aqueous liquid to produce boron-bonded micelle(s), wherein the micelle(s) comprise a reaction product of an N-substituted-glucamine and a glycidyl ether; passing the micelle-containing aqueous liquid through a membrane to separate the boron-bonded micelle(s) from the aqueous liquid; and recovering a permeate having a reduced boron concentration from the membrane. A material capable of selectively adsorbing boron from a boron-containing aqueous liquid contains at least one micelle having a hydrophobic tail and a head comprising a hydrophilic functional group having formula (I): R1-O-A (I) R1 represents a hydrocarbon group selected from the group consisting of substituted and unsubstituted aromatic, linear aliphatic, and branched aliphatic hydrocarbon groups and mixtures thereof, and A contains hydroxyl and amine groups.
This invention is based, at least in part, on the elucidation of compositions of particular polymers and surfactants that are suitable for use in removing boron from aqueous solutions. More particularly, the use of the compositions in existing infrastructure and equipment for treating aqueous solutions.
The present invention is directed, at least in part, to enhanced ultrafiltration methods. In enhanced ultrafiltration methods, boron is complexed with a soluble organic molecule of high molecular weight, allowing for separation of the boron in an ultrafiltration process with a pore size cut off below the molecular weight of the complexing molecule. In contrast to conventional IX resins, enhanced ultrafiltration has the benefits of being entirely liquid based, meaning there are no resin beds to maintain and boron binding speed and capacity is not limited by solid-liquid diffusion kinetics. Relative to RO processes, enhanced ultrafiltration can be run at significantly lower pressures, the membranes are cheaper to replace and more robust, and higher boron rejection rates can be achieved at near neutral pH.
The present invention is directed, at least in part, to the formation of NanoNets™; soluble, self-assembling complexes of surfactant and amphiphilic block co-polymers. The self-assembly of NanoNets™ is primarily governed by hydrophobic balance of the polymer chain and target surfactant, length of the polymer chain, size of the polymer only micelle, size of the surfactant only aggregate, and alkyl chain length of the surfactant monomers. In comparison to other surfactant-polymer complexes targeted at water treatment, NanoNet™ self-assembly is guided by association of the hydrophobic components of the surfactant and block-copolymer; this leaves the hydrophilic groups of the surfactant and polymer available for complexation of dissolved constituents in the bulk water phase. NanoNet™ formation occurs at surfactant concentrations far below the CMC of pure surfactant micelles, making them excellent candidates for attrition free enhanced ultrafiltration due to low or functionally non-existent concentrations of free monomer. Furthermore, in contrast to small micelles, NanoNets™ can be formed with large apparent diameters (10-100 nM), while maintaining full solubility and high homogeneity. The ability to formulate NanoNets™ at low aggregation concentrations and large molecular weights makes them suitable for the high flux, low fouling and low attrition rates required for economical enhanced ultrafiltration.
This invention is based, at least in part, on development of boron removal from aqueous environments based on the integration of boron binding chemistry with conventional ultrafiltration system. Compositions of the present invention may be separated out by conventional ultrafiltration membrane.
Compositions are described herein with various alkyl chain lengths to optimize filtration performance of the compositions. Brine stable surfactant scaffolds are provided and support higher boron binding, filterability, and aid in reducing attrition rates of compositions described herein. Compositions described herein have a polymer scaffold that sequesters free surfactant monomers into larger overall particles, minimizing attrition through the ultrafiltration membrane. The compositions described herein may provide for better boron binding capacity, high flux in cross-flow ultrafiltration system, high stability in media with various salinities and pH, faster binding kinetics than solid phase ion exchange resins and minimal chemical attrition (often about 0.1-0.3%).
The attrition rate of the chemical during filtration may be further improved by stacking membrane filters in a batch mode. Binding isotherms may be used to improve boron binding in a batch mode with stacked filters of 2, 3, 4, 5, 6, 7, 8, 9, or 10 filters. With these modifications, the attrition of compositions of the present invention may become negligible. Further modifications may be applied to the filtration system by including a solid-liquid separation step in the regeneration protocol, followed by a polishing filtration step to reduce loss of compositions of the present invention during regeneration. The membrane pore size of each filter and inventive composition micelle size may be optimized to achieve improved flux across the membrane, and by extension an improved concentration factor. Minimal waste streams (often about 10%) may be provided when compared with waste streams generated by ion exchange resins (often about 30%).
Further, decreased acid consumption of inventive compositions, as well as recaptured and re-cycled unused inventive compositions during a regeneration process are also provided. Additionally, the waste stream may be neutralized with a caustic agent to generate a non-hazardous waste (non-acidic). Hence, inventive composition waste may be disposed of as non-hazardous waste and favours economics in comparison to the waste from ion-exchange resins, which is acidic and hazardous waste.
In illustrative embodiments of the present invention there is provided a composition comprising: (a) compound of formula (I):
and (b) a compound of formula (II):
wherein G1 is
G2, G3, and G6 are each independently a straight, saturated, unsubstituted C5 to C20 alkyl; a branched, saturated, unsubstituted C5 to C20 alkyl; a straight, saturated, substituted C5 to C20 alkyl; a branched, saturated, substituted C5 to C20 alkyl; a straight, unsaturated, unsubstituted C5 to C20 alkyl; a branched, unsaturated, unsubstituted C5 to C20 alkyl; a straight, unsaturated, substituted C5 to C20 alkyl; or a branched, unsaturated, substituted C5 to C20 alkyl; G4 is
G5 is H, or a straight, saturated, unsubstituted C1 to C6 alkyl; and n+m is in the range of from 20 to 600 and the ratio of n:m is in the range of from 1:1 to 3:1.
In illustrative embodiments of the present invention, there is provided a composition comprising: (a) compound of formula (I):
and (b) a compound of formula (II):
wherein G1 is:
G2, G3, and G6 are each independently a straight, saturated, unsubstituted C5 to C20 alkyl; a branched, saturated, unsubstituted C5 to C20 alkyl; a straight, saturated, substituted C5 to C20 alkyl; a branched, saturated, substituted C5 to C20 alkyl; a straight, unsaturated, unsubstituted C5 to C20 alkyl; a branched, unsaturated, unsubstituted C5 to C20 alkyl; a straight, unsaturated, substituted C5 to C20 alkyl; or a branched, unsaturated, substituted C5 to C20 alkyl; G4 is
G5 is H, a straight, saturated, unsubstituted C1 to C6 alkyl, or
and n+m is in the range of from 20 to 600 and the ratio of n:m is in the range of from 1:1 to 3:1.
In illustrative embodiments, there is provided a composition described herein, wherein G5 is H, a straight, saturated, unsubstituted C1 to C6 alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G4 is
In illustrative embodiments, there is provided a composition described herein, wherein G1 is
In illustrative embodiments, there is provided a composition described herein, wherein G2 is a C5 to C20 straight, saturated, unsubstituted alkyl; or a C5 to C20 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G2 is a C8 to C18 straight, saturated, unsubstituted alkyl; or a C8 to C18 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G2 is a C9 to C12 straight, saturated, unsubstituted alkyl; or a C9 to C12 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G2 is a C9 straight, saturated, unsubstituted alkyl; or a C9 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G2 is a C12 straight, saturated, unsubstituted alkyl; or a C12 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G1 is
In illustrative embodiments, there is provided a composition described herein, wherein G3 is a C5 to C20 straight, saturated, unsubstituted alkyl; or a C5 to C20 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G3 is a C8 to C18 straight, saturated, unsubstituted alkyl; or a C8 to C18 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G3 is a C9 to C12 straight, saturated, unsubstituted alkyl; or a C9 to C12 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G3 is a C9 straight, saturated, unsubstituted alkyl; or a C9 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G3 is a C12 straight, saturated, unsubstituted alkyl; or a C12 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G1 is
In illustrative embodiments, there is provided a composition described herein, wherein G6 is a C5 to C20 straight, saturated, unsubstituted alkyl; or a C5 to C20 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G6 is a C8 to C18 straight, saturated, unsubstituted alkyl; or a C8 to C18 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G6 is a C9 to C12 straight, saturated, unsubstituted alkyl; or a C9 to C16 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G6 is a C16 straight, saturated, unsubstituted alkyl; or a C16 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G6 is a C12 straight, saturated, unsubstituted alkyl; or a C12 straight, unsaturated, unsubstituted alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G4 is
In illustrative embodiments, there is provided a composition described herein, wherein G4 is
In illustrative embodiments, there is provided a composition described herein, wherein G4 is
In illustrative embodiments, there is provided a composition described herein, wherein G4 is
In illustrative embodiments, there is provided a composition described herein, wherein G4 is
In illustrative embodiments, there is provided a composition described herein, wherein the counter ion is a halogen.
In illustrative embodiments, there is provided a composition described herein, wherein the counter ion is chloride.
In illustrative embodiments, there is provided a composition described herein, wherein G5 is H.
In illustrative embodiments, there is provided a composition described herein, wherein G5 is a straight, saturated, unsubstituted C1 to C6 alkyl.
In illustrative embodiments, there is provided a composition described herein, wherein G5 is CH3.
In illustrative embodiments, there is provided a composition described herein, wherein G5 is
In illustrative embodiments, there is provided a composition described herein, wherein n+m is in the range of from 100 to 600.
In illustrative embodiments, there is provided a composition described herein, wherein n+m is in the range of from 200 to 600.
In illustrative embodiments, there is provided a composition described herein, wherein n+m is in the range of from 300 to 600.
In illustrative embodiments, there is provided a composition described herein, wherein the ratio of n:m is 1:1.
In illustrative embodiments, there is provided a composition described herein, wherein the ratio of n:m is 2:1.
In illustrative embodiments, there is provided a composition described herein, wherein the ratio of n:m is 3:1.
In illustrative embodiments, there is provided a composition described herein, wherein the wt % ratio of the compound of formula (I):the compound of formula (II) is in the range of 0.5:1 to 2:1.
In illustrative embodiments, there is provided a composition described herein, wherein the wt % ratio of the compound of formula (I):the compound of formula (II) is 0.5:1.
In illustrative embodiments, there is provided a composition described herein, wherein the wt % ratio of the compound of formula (I):the compound of formula (II) is 1:1.
In illustrative embodiments, there is provided a composition described herein, wherein the wt % ratio of the compound of formula (I):the compound of formula (II) is 2:1.
In illustrative embodiments, there is provided a composition comprising: a) 6-((2-hydroxydodecyl)(methyl)amino)hexane-1,2,3,4,5-pentaol; and b) Poly(styrene)-co-(4-oxo-4-((2-sulfoethyl)amino)but-2-enoic acid, in a wt % ratio of 1.5:1.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
In drawings which illustrate embodiments of the invention,
As used herein, exemplary surfactants may be referred to using interchangeable terminology. In particular, the WB-S surfactants may be referred to as WB-S surfactants, WB-S-[number] surfactants or WB-S surfactants, which refers to weak base surfactants. Further, in some cases the phrase WB-S (WB-S [number]) refers to the specific surfactant having an alkyl chain of the number. Further SB-S12 refers to a C12 epoxide surfactant and the term SB-S20 refers to a C16 glycidyl ether surfactant.
As used herein, the term “moiety” refers to the radical of a molecule that is attached to another moiety. As used herein, the symbol
indicates the point at which the displayed moiety is attached to the remainder of the molecule. This is sometimes referred to as a point of attachment. For example, NH2-(moiety), wherein moiety is
would mean NH2—CH2—CH2—CH3.
As used herein, the phrases “Cx to Cy”, and/or “Cx-Cy” where x and y are integers refers to the number of carbon atoms in the main carbon chain (i.e. without regard to any substituent groups that may be present) of a particular moiety and means that the particular moiety has as few as x carbon atoms and as many as y carbon atoms. For example, the phrase “C5 to C20” refers to a moiety having as few as 5 carbon atoms and as many as 20 carbon atoms in its main carbon chain. The phrase encompasses all integers and ranges within the broad range as if each individual integer and range were explicitly recited. For example, the term “C5 to C20” explicitly teaches and describes moieties having 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 5-20, 5-19, 5-18, 5-17, 5-16, 5-15, 5-14, 5-13, 5-12, 5-11, 5-10, 5-9, 5-8, 5-7, 5-6, 6-20, 6-19, 6-18, 6-17, 6-16, 6-15, 6-14, 6-13, 6-12, 6-11, 6-10, 6-9, 6-8, 6-7, 7-20, 7-19, 7-18, 7-17, 7-16, 7-15, 7-14, 7-13, 7-12, 7-11, 7-10, 7-9, 7-8, 8-20, 8-19, 8-18, 8-17, 8-16, 8-15, 8-14, 8-13, 8-12, 8-11, 8-10, 8-9, 9-20, 9-19, 9-18, 9-17, 9-16, 9-15, 9-14, 9-13, 9-12, 9-11, 9-10, 10-20, 10-19, 10-18, 10-17, 10-16, 10-15, 10-14, 10-13, 10-12, 10-11, 11-20, 11-19, 11-18, 11-17, 11-16, 11-15, 11-14, 11-13, 11-12, 12-20, 12-19, 12-18, 12-17, 12-16, 12-15, 12-14, 12-13, 13-20, 13-19, 13-18, 13-17, 13-16, 13-15, 13-14, 14-20, 14-19, 14-18, 14-17, 14-16, 14-15, 15-20, 15-19, 15-18, 15-17, 15-16, 16-20, 16-19, 16-18, 16-17, 17-20, 17-19, 17-18, 18-20, 18-19, and 19-20 carbon atoms.
As used herein, the term “alkyl” by itself or as part of another substituent, means, unless otherwise stated, a straight or branched chain, or cyclic hydrocarbon radical, or combination thereof, which may be fully saturated, mono- or polyunsaturated and can include di- and multivalent radicals, having the number of carbon atoms designated (e.g. C1-C10 or 1- to 10-membered means one to ten carbons). Examples of saturated hydrocarbon radicals include, but are not limited to, groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, isobutyl, sec-butyl, cyclohexyl, (cyclohexyl)methyl, cyclopropylmethyl, homologs and isomers of, for example, n-pentyl, n-hexyl, n-heptyl, n-octyl, and the like. An unsaturated alkyl group is one having one or more double bonds or triple bonds. Examples of unsaturated alkyl groups include, but are not limited to, vinyl, 2-propenyl, crotyl, 2-isopentenyl, 2-(butadienyl), 2,4-pentadienyl, 3-(1,4-pentadienyl), ethynyl, 1- and 3-propynyl, 3-butynyl, and the higher homologs and isomers. The term “alkyl” is meant to include both substituted and unsubstituted forms of the indicated radical, unless otherwise clear from context. Preferred substituents are provided below.
As used herein, the term “substituted” refers to the replacement of a hydrogen atom on a compound with a substituent group. A substituent may be a non-hydrogen atom or multiple atoms of which at least one is a non-hydrogen atom and one or more may or may not be hydrogen atoms. For example, without limitation, substituted compounds may comprise one or more substituents selected from the group consisting of: R″, OR″, NR″R′″, SR″, halogen, SiR″R′″R″″, OC(O)R″, C(O)R″, CO2R″, CONR″R′″, NR′″C(O)2R″, S(O)R″, S(O)2R″, CN, PO4R, and NO2.
As used herein, each R″, R′″, and R″″ may be selected, independently, from the group consisting of: hydrogen, halogen, oxygen, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkyl, alkoxy or thioalkoxy groups, and arylalkyl groups.
As used herein the term “Nanonet™” and/or “NanoNet™” (used interchangeably) refers to a particle that is a formed by an association between a polymer and surfactant aggregate. The NanoNet™ self-assembles in an aqueous environment, is stable in aqueous solution, and is comprised of i) a polymer and ii) a surfactant aggregate. NanoNets™ remain associated at lower concentrations relative to surfactant aggregates in the absence of the polymer. The solution stability of NanoNets™ may be disrupted by the addition of a suitable destabilization material. Without being limited by theory, it is believed that NanoNets™ are the result of interactions between the alkyl chains of the surfactants and the alkyl chains of the hydrophobic portions of the polymer. Often, NanoNets™ are colloidal particles comprising amphipathic block co-polymers and surfactants. The amphipathic block co-polymers often comprise a hydrophilic functional group and a hydrophobic functional group.
As used herein, the term “aqueous solution” refers to a liquid environment in which water is a major component. Examples of aqueous solutions include, but are not limited to, wastewater, aqueous material recovered from a process, (such as sewage sludge, animal manure, food processing waste), oil and gas wastewater, used fracking fluid, industrial effluent, ground water, brine, and the like.
In illustrative embodiments, there is provided a composition comprising:
In formula (I), G1 may be
In some embodiments, G1 is preferably
In other embodiments, G1 is preferably
In other embodiments, G1 is preferably
In formula (I) G2, when present, may be a straight, saturated, unsubstituted C5 to C20 alkyl; a branched, saturated, unsubstituted C5 to C20 alkyl; a straight, saturated, substituted C5 to C20 alkyl; a branched, saturated, substituted C5 to C20 alkyl; a straight, unsaturated, unsubstituted C5 to C20 alkyl; a branched, unsaturated, unsubstituted C5 to C20 alkyl; a straight, unsaturated, substituted C5 to C20 alkyl; or a branched, unsaturated, substituted C5 to C20 alkyl. As set out above, the range of C5 to C20 encompasses all integers and ranges of integers, inclusively. In some preferred embodiments, G2 is a C5 to C20 straight, saturated, unsubstituted alkyl; or a C5 to C20 straight, unsaturated, unsubstituted alkyl. In some other preferred embodiments, G2 is a C8 to C18 straight, saturated, unsubstituted alkyl; or a C8 to C18 straight, unsaturated, unsubstituted alkyl. In other preferred embodiments, G2 is a C9 to C12 straight, saturated, unsubstituted alkyl; or a C9 to C12 straight, unsaturated, unsubstituted alkyl. In other preferred embodiments, G2 is a C9 straight, saturated, unsubstituted alkyl; or a C9 straight, unsaturated, unsubstituted alkyl. In other preferred embodiments, G2 is a C12 straight, saturated, unsubstituted alkyl; or a C12 straight, unsaturated, unsubstituted alkyl. In some preferred embodiments, G2 is a C18 saturated or unsaturated alkyl.
In formula (I) G3, when present, may be a straight, saturated, unsubstituted C5 to C20 alkyl; a branched, saturated, unsubstituted C5 to C20 alkyl; a straight, saturated, substituted C5 to C20 alkyl; a branched, saturated, substituted C5 to C20 alkyl; a straight, unsaturated, unsubstituted C5 to C20 alkyl; a branched, unsaturated, unsubstituted C5 to C20 alkyl; a straight, unsaturated, substituted C5 to C20 alkyl; or a branched, unsaturated, substituted C5 to C20 alkyl. As set out above, the range of C5 to C20 encompasses all integers and ranges of integers, inclusively. In some preferred embodiments, G3 is a C5 to C20 straight, saturated, unsubstituted alkyl; or a C5 to C20 straight, unsaturated, unsubstituted alkyl. In some other preferred embodiments, G3 is a C8 to C18 straight, saturated, unsubstituted alkyl; or a C8 to C18 straight, unsaturated, unsubstituted alkyl. In some other preferred embodiments, G3 is a C9 to C12 straight, saturated, unsubstituted alkyl; or a C9 to C12 straight, unsaturated, unsubstituted alkyl. In some other preferred embodiments, G3 is a C9 straight, saturated, unsubstituted alkyl; or a C9 straight, unsaturated, unsubstituted alkyl. In some other preferred embodiments, G3 is a C12 straight, saturated, unsubstituted alkyl; or a C12 straight, unsaturated, unsubstituted alkyl.
In formula (I) G6, when present, may be a straight, saturated, unsubstituted C5 to C20 alkyl; a branched, saturated, unsubstituted C5 to C20 alkyl; a straight, saturated, substituted C5 to C20 alkyl; a branched, saturated, substituted C5 to C20 alkyl; a straight, unsaturated, unsubstituted C5 to C20 alkyl; a branched, unsaturated, unsubstituted C5 to C20 alkyl; a straight, unsaturated, substituted C5 to C20 alkyl; or a branched, unsaturated, substituted C5 to C20 alkyl. As set out above, the range of C5 to C20 encompasses all integers and ranges of integers, inclusively. In some preferred embodiments, G6 is a C5 to C20 straight, saturated, unsubstituted alkyl; or a C5 to C20 straight, unsaturated, unsubstituted alkyl. In some other preferred embodiments, G6 is a C8 to C18 straight, saturated, unsubstituted alkyl; or a C8 to C18 straight, unsaturated, unsubstituted alkyl. In some other preferred embodiments, G1 is a C9 to C12 straight, saturated, unsubstituted alkyl; or a C9 to C12 straight, unsaturated, unsubstituted alkyl. In some other preferred embodiments, G6 is a C9 straight, saturated, unsubstituted alkyl; or a C9 straight, unsaturated, unsubstituted alkyl. In some other preferred embodiments, G6 is a C12 straight, saturated, unsubstituted alkyl; or a C12 straight, unsaturated, unsubstituted alkyl. In some preferred embodiments, G6 is a C16 alkyl.
In formula (II), G4 is
In some preferred embodiments, G4 is
In some preferred embodiments, G4 is
In some other preferred embodiments, G4 is
In some other preferred embodiments, G4 is
In some other preferred embodiments, G4 is
In some other preferred embodiments, G4 is
As used here, the term “C-Ion” refers to a counter ion. A counter ion is any suitable ion or ions that have the equal and opposite charge to the moiety to which it is associated. In some embodiments, the counter ion is a halogen. In some preferred embodiments, the counter ion is chloride.
In formula (II), G5 is H, a straight, saturated, unsubstituted C1 to C6 alkyl, or
As set out above, the range of C1 to C6 encompasses all integers and ranges of integers, inclusively. In some preferred embodiments, G5 is H, or a straight, saturated, unsubstituted C1 to C6 alkyl. In some embodiments, G5 is preferably a C1 or C2 alkyl. In some other preferred embodiments, G5 is methyl (i.e. a C1 alkyl). In some preferred embodiments G5 is H. In some preferred embodiments, G5 is
In Formula (II), n+m is a number that provides a polymer having an average molecular weight of from about 5 KDa to about 130 KDa. This means that n+m is in the range of from 20 to 600. In some preferred embodiments, n+m is in the range of from 100 to 600. In some other preferred embodiments n+m is in the range of from 200 to 600. In some other preferred embodiments, n+m is in the range of from 300 to 600. The ratio of n:m is in the range of from 1:1 to 3:1. Preferably, n:m is in a ratio of 1:1. More preferably, n:m is in the ratio of 2:1. More preferably, n:m is in the ratio of 3:1.
As is often the case with polymers, the composition of bulk polymer comprises individual polymers having different molecular weights and are often obtained and/or sold as an average molecular weight, meaning that some of the individual polymers within the bulk polymer may have above or below the average molecular weight and many of the individual polymers will have the average molecular weight. It is acceptable in embodiments of the present invention that bulk polymers having individual polymers with different molecular weights from each other are used. It is also acceptable in embodiments of the present invention that bulk polymers having only individual polymers with the same molecular weight as each other are used. A person of skill in the art of polymers will be familiar with this approach to average molecular weights of polymers and will readily be able to identify polymers, both bulk polymers and individual polymers that are suitable for use in compositions of the present invention based on this teaching.
Compositions of the present invention often have a wt % ratio of the compound of formula (I):the compound of formula (II) in the range of 0.5:1 to 2:1. In some preferred embodiments, the wt % ratio of the compound of formula (I):the compound of formula (II) is in the range of 1:1 to 2:1. In some other preferred embodiments, the wt % ratio of the compound of formula (I):the compound of formula (II) is 2:1. In some other preferred embodiments, the wt % ratio of the compound of formula (I):the compound of formula (II) is 1:1. In some other preferred embodiments, the wt % ratio of the compound of formula (I):the compound of formula (II) is 0.5:1.
Boron complexation as boric acid and borate ion has been demonstrated to occur with cis-diols. A common functional group utilized for boron complexation is N-methyl glucamine. Attachment of hydrocarbon chains of varying lengths to the nitrogen on the N-methylglucamine (NMG) was generally prepared using two separate approaches (scheme 1 and scheme 2 below). NanoNet™ formation requires an alkyl chain length of >6. Accordingly, NMG-based surfactants with varying alkyl chain lengths (see examples) were prepared via an epoxide (EPOX) and acyl chloride (WB-S) synthesis routes. To facilitate additional boron binding, the scaffold polymer (Styrene Maleic Anhydride) was reacted with additional NMG to form SMA-NMG (
Scheme 1: N-methyl glucamine (NMG) was reacted with acyl chlorides containing from 8 to 18 aliphatic carbons in methanol. The resulting WB-S surfactant was formed by linkage of the secondary amine to the carbonyl containing carbon via amide bond formation.
Specific examples of how to make specific compounds for use in the present invention are provided in the Examples section below. Once the compounds are made, they may be mixed together (where specific examples of such mixing are given in the Examples section below) and the compositions may be added to an aqueous solution for which boron treatment is desired. Specific examples of using the invention are provided in the Examples section below.
NanoNets™ according the present invention may be made by mixing, in an aqueous environment, a polymer and a surfactant, and then added to an aqueous solution for treatment. In illustrative embodiments, there is provided a method of treating an aqueous solution using NanoNets™ described herein. An example of such a method is injecting a solution of NanoNets™ into a liquid flow. The manner of injection may be through any method known to a person of skill in the art, and is often through a pump, such as a diaphragm pump. The NanoNet™ solution may be injected into the fluid flow alone, or concurrently with a gas or other water chemicals. The NanoNet™ solution may also be injected through an injection coil followed by a static mixer. In such a case it may be necessary to first dilute the NanoNet™ solution to facilitate mixing in a pipe.
Tables 3 and 4 below show some examples of some compounds suitable for use in compositions of the present invention.
The following examples are illustrative of some of the embodiments of the invention described herein. These examples do not limit the spirit or scope of the invention in any way.
In the following examples, the following methods, reagents, equipment and protocols were used:
To probe the stability/solubility of the surfactants in the presence of SMA-Taurine polymers (SMAT), boron binding surfactant SB-S12 (2% solutions, 0.02 g/mL) were combined with a various ratio of SMA-Taurine polymer (4% solutions, 0.04 g/mL). All components were mixed in a 200 microL centrifuge tube or a skirted 96-well PCR plate. The total tube volume was 200 microL, except when conditions at pH 2 were employed, in which case the total volume was 220 microL. The mixtures were sealed and heated in an Applied Biosystems Veriti 96 well Thermal cycler for 30 minutes at 90° C., quickly cooled to 25° C. and held for 10 minutes. All samples were pipetted into a 96 well plate and absorbance at 540 nm was measured after desired times. Data points represent average values of replicate samples and error bars represent standard deviation values. It should be noted that when no error bars are present, one measurement was deemed an outlier and the highest turbidity measurement was kept.
Poly(styrene-co-maleic acid) polymer, SMA130, SMA125, SMA230, and SMA150 were purchased from Jiaxing Huawen Chemical Co., Ltd. N-methyl-D-glucamine (CAS no. 6284-40-8), N-nonanoyl-N-methylglucamine (WB-S 9, CAS no. 85261-19-4), N-decanoyl-N-methylglucamine (WB-S 10, CAS no. 85261-20-7), octanoyl chloride (CAS no 111-64-8), lauroyl chloride (CAS no. 112-16-3), oleoyl chloride (CAS no. 112-77-6), hexadecyl glycidal ether (CAS no 15965-99-8), 1,2-epoxydodecane (CAS no 2855-19-8), 2-Aminoethanesulfonic acid (CAS no 107-35-7) were purchased from Sigma Aldrich™. Amberlite IRA-743™ was purchased from DOW Chemicals™. Methanol (BioShop, CAS no. 67-56-1, reagent grade) and acetonitrile (Fisher Scientific, CAS no. 75-05-8, HPLC grade 99.9%) were used as solvents. Polymers and surfactants were characterized by Fourier transform infrared (FT-IR) spectrometry. Vivaspin 500, Vivaspin 2 spin filters with MWCO of 5 kDa, 10 kDa, 30 kDa, 50 kDa, 100 kDa were purchased from Sigma Aldrich™. A Molecular Devices SpectraMax M2 microplate reader was used to measure absorbance of samples.
Fourier-transform infrared spectroscopy was performed on NMG functionalized poly(styrene-co-maleic acid) polymers, TAU functionalized poly(styrene-co-maleic acid) polymers, NMG based WB-S surfactants, and SB-S surfactants using an Agilent Technologies Cary 630 spectrometer equipped with a diamond ATR (attenuated total reflectance). Spectra were recorded in the range of 400-4000 cm−1 with an average of 4 scans and a resolution of 1 cm−1.
Flux as a function of concentration was found for WB-S, SMA130NMG polymer and the NanoNet™ made up of these materials at a 1:1 weight ratio polymer to surfactant. Vivaspin filters of 5 kDa, 10 kDa, 50 kDa and 100 kDa MWCO were used. Before testing, all filters were treated with deionized water and spun for 10 minutes. Each filter was pre weight on an analytical balance. 400 microL of solution at the desired concentration was pipetted into the filter. The filter is centrifuged until sufficient volume has passed through the membrane (10-120 microL). The tube containing the filtrate was weighed on the analytical balance to determine the mass permeate. The filtrate was then pipetted back into the filter, and the process was repeated. Three readings were recorded for each process. The mass permeate was converted to volume under the presumption that the solution has the density of water. The flux was calculated by using the area of the membrane. See equation 1.
Flux between different filters of the same pore size was not always consistent, therefore all flux values were reported relative to the flux of water through that filter. Flux of other polymers and NanoNets™ at 10,000 ppm or 20,000 ppm (1% and 2%, respectively) were measured through 10 kDa, 50 kDa and 100 kDa filters following the same process.
WB-S and SB-S12 surfactants were prepared as 2.5% (w/v) solutions in deionized water and sonicated at 50° C. with frequent vortexing until solutions were clear (approximately 1 hour). To the warm SB-S12 solution was added dropwise 6 M HCl until neutral pH was attained and the solution was soluble at ambient temperature. The 2.5% WB-S suspension at ambient temperature was prepared in deionized water at pH 6 with no pH adjustment.
A boron stock solution was prepared using 99.9% boric acid (Factory Direct Chemicals) at 45,760 ppm (8,000 ppm total boron) in deionized water. Working stock solutions were prepared by further diluting to the appropriate concentrations needed for spiked solutions.
The synthetic water was centrifuged at 4,000 rpm for 4 minutes to pelletize any undissolved calcium carbonate and decanted for experimental use. Vivaspin 2 PES filters with a 30 kDa molecular weight cut-off (GE Healthcare) were pre-treated with deionized water for 60 minutes and centrifuged prior use. Synthetic water at pH 5 was prepared following salt concentrations listed in Table 1.
Boron Removal Assay with Varying Boron Concentration from 0 ppm-400 ppm: Sample Preparation:
For both assays at pH 8 and pH 5, respectively, 550 microL of 1M Tris HCl buffer pH 8 and 550 microL of synthetic water were added to 1.5 mL Eppendorf centrifuge tubes. Following the buffer, 50 microL of boric acid solution at a suitable concentration was added (i.e. 200 ppm boron binding: 50 microL of 4,000 ppm boron stock solution was added into 1000 microL total binding solution). Finally, 400 microL of 2.5% adsorbent at ambient temperature was added to achieve 1% adsorbent in binding solution, and vortexed before placing on an Eppendorf Thermomixer at 600 rpm mixing speed for 30 minutes. The pH of the binding solutions was verified to ensure neither the adsorbent nor boric acid effected the final pH.
Amberlite™ 743 beads were hydrated overnight at pH 5 and pH 8, respectively. 10 mg wet Amberlite™ 743 beads were weighed into 1.5 mL Eppendorf centrifuge tubes. Following the beads, 110 microL of pH 8 Tris HCl buffer pH 8 or pH 5 synthetic water was added into their respective centrifuge tubes. To each tube, was added 80 microL of deionized water and 10 microL of boric acid solution at a suitable concentration and mixed for 30 minutes. A pH 10 Amberlite™ 743 resin control sample was set for binding overnight (approximately 17 hours). The sample was prepared by adding 10 mg of pH 10 hydrated beads, 183 microL deionized water, 7 microL 0.5 M KOH, and 10 microL of a suitable concentration of boric acid.
After 30 minutes mixing at ambient temperature, the binding solutions of the soluble adsorbents were transferred into Vivaspin 2 PES filter and centrifuged for 10 minutes at 4,000 rpm. 150 microL filtrate was collected for each sample. Filtrates containing unbound boron were diluted where necessary to attain concentrations between 0.5 ppm and 35.0 ppm that are within the linear region of the carminic acid assay. Amberlite™ 743 binding solutions were diluted directly without centrifuging. A total of 50 microL of each filtrate was analyzed using the carminic acid assay. Centrifuge filters were reused where possible by washing profusely with distilled water after use, centrifuging through with deionized water multiple times, and storing at 4° C. overnight.
Separate calibration curves at pH 5 and pH 8 were prepared and analyzed for all different spiked boron concentrations. Control stock solutions were prepared in a similar way to the samples by adding 550 microL of 1M Tris HCl buffer pH 8 or synthetic water, 50 microL of the appropriate concentration of boric acid solution, and 400 microL of distilled water. The stock solution was diluted to achieve concentrations appropriate for the solution being analyzed (between 0.5 ppm and 35.0 ppm).
The carminic acid assay was applied to determine boron concentration in aqueous solution. The following method was adapted from the reference: Floquet, C. F. A.; Sieben, V. J., MacKay, B. A., Mostowfi, F., Talanta, 2016, 150, 240-252 (https://doi.org/10.1016/j.talanta.2015.12.010).
In a 2 mL microcentrifuge tube was added 5 microL of 4M HCl solution and 50 microL supernatant from the sorption experiment followed by the slow addition of 250 microL of sulphuric acid (99.99%). After 5 minutes, 250 microL of 0.1% carminic acid solution was added. The mixture was vortexed for 10 seconds. After 30 minutes at ambient temperature, the samples were transferred into a 96-well plate and absorbance was measured at 610 nm.
Boron Removal Assay with Boron Concentration at 9 ppm and 200 ppm at Varying Time Points:
Separate calibration curves at 9 ppm and 200 ppm boron at pH 8 were prepared and analyzed. Binding experiments were performed with 10,000 ppm SB-S12, a 20,000 ppm complex of SB-S12 and SMA150T (SMA150T-SB-S1), and 20,000 ppm Amberlite™ 743. Binding tests were performed with PES filters with 30 kDa molecular weight cut-off. Each time point (1 minute, 3 minute, 5 minute, 10 minute, 15 minute, 20 minute, 25 minute, and 30 minute) represents a separate binding experiment.
Vivaspin 2 PES filters with a MWCO of 5 kDa were pre-treated with 200 microL of 10,000 ppm SB-S12 and 20,000 ppm SMA150T-SB-S 1 solution, respectively. The samples were centrifuged for 45 min at 4,000 rpm to a final volume of 50 microL. To the retentate was added 1 mL deionized water and the sample was centrifuged for 30 min at 4,000 rpm. The wash cycle was repeated.
Binding Experiment with 52 ppm Total Boron Concentration:
In one instance 160 microL of 1.25% surfactant solution was added to a Vivaspin 2 filter along with 10 microL 0.6% boric acid and 30 microL 1M Tris HCl buffer pH 8. In another instance, 80 microL of 5% SMA150T-SB-S 1 solution was added to a filter along with 80 microL deionized water, 10 microL 0.6% boric acid, and 30 microL 1M Tris HCl buffer pH 8. The samples were vortexed for 10 seconds to form a clear solution and placed on an Eppendorf Thermomixer R mixer shaker for 5 minutes at 400 rpm. The samples were centrifuged for 45 min at 4,000 rpm until a final volume of 50 microL retentate remained. 50 microL of the filtrate was used for the carminic acid assay for quantification of unbound boron.
To the 50 microL retentate was added 145 microL of deionized water and 5 microL 4 M HCl. After 5 min contact time of surfactant and NanoNet™ solution with 0.1 M HCl, respectively, the solutions were centrifuged to a final retentate volume of 50 microL. To each filter was added 150 microL deionized water and the samples were centrifuged. In each step, 50 microL filtrate was collected to perform the carminic acid assay.
Boron Elution from Amberlite™ IRA-743™ Particles:
10 mg of pre-soaked Amberlite™ 743 beads at pH 10 were added to a mixture of 190 microL Tris HCl buffer pH 8 and 10 microL 0.6% boric acid. This sample represents an Amberlite™ 743 resin concentration of 20,000 ppm and 52 ppm total boron concentration. The mixture was vortexed for 17 hours and 50 microL of this solution was collected for determining the boron content via carminic acid assay. The remaining 150 microL solution was discarded and 175 microL deionized water and 25 microL 4M HCl were added to the resin beads to prepare a 0.5M HCl solution to elute boron from Amberlite™ 743. The samples were vortexed for 10 seconds and placed on an Eppendorf Thermomixer R mixer shaker for 60 minutes at 400 rpm. After an hour elution time, 50 microL supernatant was collected to perform the carminic acid assay to quantify unbound boron. The remaining solution was discarded and 150 microL of 1M NaOH was added to the beads and the mixture was vortexed for one hour. Finally, the solution was replaced with 190 microL Tris HCl buffer pH 8 and 10 microL 0.6% boric acid in preparation to start another binding cycle.
To assess efficacy of the synthesized boron binding surfactants, a boron solution containing 8.72 ppm boron was incubated at room temperature with varying concentrations of each surfactant. Boron binding of the surfactants occurred for 2 hours at a solution pH of 8. After equilibration of the boron-binding surfactant, the formed surfactant-boron complex was subsequently removed from solution by ultrafiltration with a pore-size of 5 kDa. After ultrafiltration, any unbound or non-complexed boron remained in the filtrate, while surfactant-boron complex remained in the retentate. The binding capacity was also measured for a solid-phase ion exchange resin (Amberlite™-743) after equilibrating for 24 hours at pH 10 in the boron containing solutions. The total boron concentration of the filtrate was subsequently measured by carminic acid assay, and the total boron removal per gram of added surfactant calculated (
To assess the ion exchange capability of the boron binding surfactants, WB-S9 and WB-S12 and Amberlite™-743 resins preloaded with boron at varying concentrations were treated with acidic elution solutions. After addition of acid, the mixtures were allowed to incubate for 30 minutes to facilitate release of boron from the NMG groups, and eluted boron separated from the surfactant solutions by ultrafiltration. Each binding media was treated with propionic, hydrochloric, or phosphoric acids at 1M concentrations, and the eluted boron quantified relative to the starting binding media mass loading (
Cis-diol complexation with boron is known to occur more favourably with the Borate anion than boric acid. As a result, ion exchange processes with Amberlite™-743 resins typically occur at pH 9-10 for maximal binding efficiency. To measure the effect of pH on the WB-S9 surfactant boron binding, 10,000 ppm solutions of WB-S9 was added to solutions containing 8.72 ppm boron at varying pH and the boron binding capacity measured. Consistent with a cis-diol mechanism of boron complexation, boron uptake was maximal at pH 10 (
In boron treatment applications, boron is rarely the only ion present in solution. However, competition with other ions on the binding media can result severe decreases in binding efficiency for ion exchange processes. To investigate the effect of alternative ions in solution for Boron binding capacity, boron removal experiments were conducted with WB-S 9 and Amberlite™-743 with increasing concentrations of either NaCl or CaCl2) (
A limiting factor for solid phase extraction media are the rate of complexation of the ligand to the functional group, and diffusion of the ligand onto the surface of the ion exchange resin. As the WB-S surfactants behave as soluble colloids when associated as micelles, boron removal should theoretically not be governed by liquid-solid diffusion kinetics. Therefore the rate of boron complexation was measured for both WB-S surfactants and Amberlite™-743 resin from a solution containing 8.72 ppm boron at pH 8. Interestingly, the boron complexation rate of the WB-S surfactant was faster than the assay could measure, with 100% of complexation occurring in under 1 minute of contact time (
To improve boron binding surfactant stability in solution, the surfactants were formulated into NanoNets™. WB-S12 and SB-S12 were resuspended in solution and mixed with varying ratios of SMA-NMG derivatives to form NanoNets™. After mixture, the solutions were heated at 60, 70, 80 or 90° C. to allow for solubilization of the aggregates and self-assembly into NanoNets™ or individual micelles, followed by cooling to 4° C. (
To apply surfactant enhanced ultrafiltration, the surfactant aggregates present must be filterable while maintaining low attrition. NanoNet™ formation stabilizes the surfactant in solution into mixed-polymer surfactant micelles. Often, these micelles should be retained in an ultrafiltration apparatus without significant fouling occurring. To measure the effect of NanoNet™ formation on filterability, varying concentrations of 1:1 wt % SMA130NMG and WB-S12 were filtered at low applied pressure (10 PSI) on PES membranes with MWCO of 5 kDa, 10 kDa, 50 kDa, and 100 kDa and compared to flux rates of equivalent concentrations of polymer alone and surfactant alone (
To form a cost-effective enhanced ultrafiltration process, the ion exchange media must be retained during the ultrafiltration step. Those skilled in the art will recognize that larger pore sizes can allow higher flux rates, however the loss of the binding media through the pores can quickly eliminate any economic gains of higher flow rates and less filter washing cycles by chemical replacement costs. Therefore, the attrition of a 10,000 ppm solution of SMA130NMG-WB-S12 was measured through a 100 kDa membranes at an applied pressure of 10 PSI (
After synthesis of the WB-S, SB-S, and SMA-NMG variants and confirmation of their purities performance for boron removal was measured. The results are depicted graphically in
To assess the potential for micelle enhanced removal of boron from aqueous solutions, boron binding isotherms were generated with two candidate surfactants and compared to a gold-standard ion exchange resin control (
To improve the solution stability of the selected boron binding surfactants, complexation with amphipathic block co-polymers was measured. Derivatization of SMA150 and SMA130 with Taurine through amide formation of the maleic anhydride block on the polymers was utilized to create salt and acid stable polymers SMA150T and SMA130T, respectively. The polymers were then mixed with SB-S12 at varying ratios, heated to 90 degrees to facilitate dissolution and cooled to 25° C. to facilitate complexation. The polymer-surfactant complexes were then monitored for 90 hours for destabilization and aggregation, which occurred as a white precipitate that could be quantitatively measured by light scattering induced absorbance at 540 nm (
Micelle enhanced ultrafiltration is a promising approach for water treatment, but carries significant barriers to adoption. A primary barrier is attrition of the surfactant; micelle formation is governed by the critical micelle concentration of the surfactant. Below this concentration, surfactants exist as free monomers and will permeate and ultrafiltration membrane. Polymer surfactant complexes described here form at substantially lower concentrations than surfactant micelles alone. By substantially decreasing the aggregation concentration of the micelle, less monomer will be available to permeate the membrane. To investigate this property, surfactant WB-S12 was concentrated through a 100 kDa MWCO PES membrane filter, subsequently re-diluted and filtered again. This process was repeated 5 times and the concentration of WB-S12 in the filtrate determined (
A limiting factor of ion exchange resins is they are kinetically limited; soluble contaminants must diffuse within the porous matrix of the ion exchange resin and contact the functional groups to be removed from solution. This often necessitates larger bed volumes at higher flow rates, dramatically increasing regeneration costs, infrastructure, and initial set-up cost. To compare the kinetic limitations of the boron binding surfactants, boron binding capacity over time at low boron concentrations (10 ppm), and high boron concentrations (200 ppm), was measured (
To function as an effective ion exchange method, stable regeneration is required. To test the efficacy of regeneration, surfactant SB-S12 was measured for boron binding removal after multiple cycles of acid elution in the presence and absence of stabilizing polymer (
To a 250 ml round bottom flask was added taurine (3 g, 0.024 mol), 5 M NaOH (4.8 mL, 0.024 mol), 15 mL deionized water, and 45 mL acetone. The reaction mixture was stirred until the taurine completely dissolved. To the resulting clear solution was added SMA150 (4.85 g, 0.024 mol) at ambient temperature. The yellow suspension was refluxed for 3 hours. After the allotted reaction time a viscous precipitate was isolated. The reaction solution was decanted, reduced by ca. 80% volume, and the desired product was precipitated out using methanol. Both precipitates were combined and dried in vacuo. The isolated polymer was washed with methanol (2×10 mL), collected via centrifugation for 5 min at 4,000 rpm, and dried in vacuo at 50° C. Yield: 3.22 g, 41%. FT-IR (SMA-Taurine 150, ATR, cm−1): 3382, 2924, 2850, 1695, 1636, 1558, 1492, 1450, 1399, 1185, 1044, 737, 698.
To a 500 ml round bottom flask was added taurine (7 g, 0.056 mol), 5 M NaOH (11.2 ml, 0.056 mol), 50 ml deionized water, and 150 mL acetone. The reaction mixture was stirred until the taurine completely dissolved. To the resulting clear solution was added SMA130 (17.14 g, 0.056 mol) at ambient temperature. The yellow suspension was refluxed for 3 hours. After the allotted reaction time a viscous precipitate was isolated. The reaction solution was decanted, reduced by ca. 80% volume, and the desired product was precipitated out using methanol (30 mL). Both precipitates were combined and dried in vacuo. The isolated polymer was washed with methanol (2×10 mL), collected via centrifugation for 5 min at 4,000 rpm, and dried in vacuo at 50° C. Yield: SMA-130: 20.21 g, 83%; SMA-230: 18.49 g, 77%. FT-IR (SMA-Taurine 130, ATR, cm−1): 3386, 3022, 2925, 1698, 1653, 1570, 1526, 1491, 1451, 1387, 1175, 1042, 960, 736, 698. FT-IR (SMA-Taurine 230, ATR, cm−1): 3364, 3026, 2927, 1651, 1557, 1492, 1450, 1398, 1317, 1194, 1045, 842, 744, 697.
To a 250 ml round bottom flask was added N,N′-dimethylformamide (100 mL) and SMA-130 (10 g, 0.033 mol) and refluxed until the polymer dissolved, resulting in a yellow solution. To the warm solution was added n-methyl-D-glucamine (9.55 g, 0.049 mol, 1.48 equiv. relative to maleic anhydride) and refluxed for 4 hours. The reaction mixture was concentrated to approximately half the volume and stirred overnight at ambient temperature. The product was precipitated out by slow addition of 100 mL 1M HCl and filtered. The crude product was dried in vacuo at 50° C. The resulting colourless, viscous material was transferred to a 50 ml centrifuge tube to which methanol was added (2×20 mL) and centrifuged for 5 minutes at 4,000 rpm. The supernatant was decanted, and the isolated product was dried in vacuo at 50° C. Yield: 12.68 g, 86%. FT-IR (SMA-NMG-130, ATR, cm−1): 3025, 2925, 1777, 1717, 1652, 1646, 1580, 1492, 1451, 1386, 1251, 1153, 1090, 1027, 758, 698, 658.
To a stirring suspension of N-methyl-D-glucamine (100.0 g, 0.51 mol) in methanol (1000 mL) was added DIPEA (1 eq, 89 mL). Lauroyl chloride (1 eq, 118 mL) was added slowly over 5 minutes. Upon addition, the mixture became a clear and colourless solution and HCl gas was observed. The mixture was stirred, uncovered, overnight. After the allotted reaction time, the mixture was transferred to pre-weighed 50 mL falcon tubes and centrifuged for a minimum of 12 minutes at 2500 rpm. The liquid was decanted, and the colourless solid washed repeatedly with acetonitrile and dried via centrifugation. The isolated product was dried overnight in a vacuum oven at 50° C. Yield: 136 g, 70%. 1H (400 MHz, DMSO-de) NMR spectrum: 8.50 (br s, 1H), 5.35-427 (m, 1H), 4.73-4.27 (m, 4H), 3.85-3.16 (m, 8H), 2.95-2.76 (m, 3H), 2.33-2.19 (m, 2H), 1.41 (br s, 2H), 1.19 (m, 16H), 0.81 (t, 3H). 13C (75 MHz, DMSO-de) NMR spectrum: δ 172.66, 172.49, 72.58, 71.66, 71.52, 71.45, 71.39, 71.35, 70.90, 70.35, 70.26, 69.88, 69.37, 68.41, 63.37, 63.35, 63.32, 51.94, 50.95, 50.86, 36.72, 33.57, 33.00, 32.74, 32.23, 31.36, 29.12, 29.09, 29.06, 29.03, 28.98, 28.88, 28.78, 25.00, 24.65, 22.15, 13.98.
FT-IR (cm−1): 3395, 3327, 3101, 3010, 2916, 2848, 1742, 1623, 1493, 1413, 1376, 1322, 1301, 1256, 1230, 1206, 1167, 1105, 1079, 1067, 1031, 1008, 954, 931, 907, 884, 866, 844, 769, 680.
To a 250 mL round-bottom flask was added n-methyl-D-glucamine (10.0 g, 51.2 mmol) and 1,2-epoxydodecane (1 eq, 51.2 mmol, 9.4 g, 11.2 mL). Methanol (150 mL) was added and the reaction mixture was refluxed for 20 h. After the allotted time, the reaction mixture was cooled in a freezer and a colourless solid precipitated out. The solid was isolated by filtration, washed with cold methanol and dried in vacuo. Subsequent crystallizations of the filtrate were performed, the isolated solids were combined, washed with cold methanol, and dried in vacuo. Yield: 14.5 g, 80% Alternatively, the reaction mixture can be concentrated on a rotary evaporator to reveal a colourless product in quantitative yield.
1H (400 MHz, DMSO-de) NMR spectrum: 4.50-4.23 (m, 5H), 3.62-3.29 (m, 8H), 2.46-2.15 (overlapped m, 8H), 1.38-1.15 (m, 17H), 0.81 (t, 3H). 13C (75 MHz, DMSO-de) NMR spectrum: 72.05, 71.97, 71.45, 71.40, 70.60, 70.26, 70.19, 70.01, 67.25, 67.14, 64.98, 64.46, 63.52, 63.47, 61.19, 60.54, 43.58, 42.91, 40.43, 35.05, 34.96, 31.32, 29.29, 29.12, 29.07, 29.04, 28.74, 25.25, 25.23, 22.11, 13.96. FT-IR (ATR, cm−1): 3460, 3322, 2956, 2915, 2847, 1454, 1366, 1341, 1251, 1191, 1157, 1133, 1092, 1082, 1040, 9645, 925, 862, 839, 792, 721.
To a 250 mL round-bottom flask was added n-methyl-D-glucamine_(10.0 g, 51.2 mmol) and hexadecyl glycidal ether (1 eq, 51.2 mmol, 15.3 g). Methanol (150 mL) was added, and the mixture refluxed for 5 h. After the allotted time, the flask was cooled in a freezer to precipitate out a colourless solid. The solid was isolated by filtration, washed with cold methanol and dried in vacuo. Yield: 14.0 g, 55%. Increased yields can be obtained upon successive crystallizations of the filtrate or reducing all volatiles on a rotary evaporator.
1H (400 MHz, DMSO-de) NMR spectrum: 4.42 (br s, 5H), 3.60-3.25 (m, 12H), 2.51-2.21 (m, 7H) 1.46 (m, 2H), 1.23 (m, 26H), 0.85 (t, 3H). 13C (75 MHz, DMSO-de) NMR spectrum: 73.55, 73.48, 72.19, 72.08, 71.45, 71.40, 70.59, 70.49, 70.23, 70.17, 70.13, 67.10, 67.05, 63.53, 63.50, 61.70, 61.33, 61.17, 60.65, 43.61, 43.09, 31.35, 29.26, 29.12, 29.09, 29.08, 28.97, 28.78, 25.70, 22.13, 13.91. FT-IR (ATR, cm−1): 3442, 3272, 2912, 2847, 1469, 1347, 1249, 1121, 1100, 1040, 1023, 927, 876, 841, 776, 715.
A 1 L Erlenmeyer flask was charged with SMA 230 (2:1. 50 g) and acetone (500 mL). The mixture was heated gently using a hot plate and stirred using a magnetic stirrer until a colourless or light-yellow solution was observed. The heating was stopped, and the mixture was allowed to cool to ambient temperature. While stirring, 3-(dimethylamino)-1-propylamine (1.1 eq relative to maleic anhydride, 18.4 g, 22.6 mL) was added dropwise via pipette causing a white solid to precipitate. The mixture was allowed to stir for 3 hours before collecting the solid via gravity filtration. The white product was washed repeatedly with cold acetone (3×25 mL) and dried in a vacuum oven under reduced pressure at 60° C. yielding 62.5 g of product (94%). Characterization by IR spectroscopy shows conversion of the SMA starting material maleic anhydride carbonyl (1770 cm−1) to the desired ring-opened product with carbonyl resonances at 1630 cm−1 and 1552 cm−1.
IR (ATR, cm−1): 3306, 2929, 1699, 1638, 1582, 1560, 1490, 1451, 1379, 1300, 1221, 1155, 1028, 760, 697.
Synthesis of the following product was carried out using a procedure modified from the literature (Tzong-Liu Wang, Hung-Ming Lee, Ping-Lin Kuo, Journal of Applied Polymer Science, Vol 78, 592-602 (2000)).
A 500 mL Erlenmeyer flask was charged with ring-opened SMA-2301 (25.0 g) and 100 mL 1M NaOH to bring the pH to ca. 11. The suspension was stirred at ambient temperature using a magnetic stir bar for 1 hour before chloroacetic acid (8.5 g) was added in one portion. The mixture was allowed to stir overnight at room temperature. The next morning, a clear colourless solution was observed. The reaction mixture was frozen and dried using a lyophilizer for 3 days revealing a solid, white product, 20.0 g (74.6%). Reactions conducted at elevated temperatures in organic solvent led to ring-closure, so ensuring low to moderate temperatures and aqueous conditions were used to discourage maleimide formation.
IR (ATR, cm−1): =3322, 2920, 1666, 1621, 1558, 1450, 1405, 1394, 1152, 895, 710, 699.
Tg=85.15° C.
Synthesis of sultone-derivitized amine polymers were conducted using a method modified from the following literature procedure: Chunhau Wang, Chunfeng Ma, Changdao Mu, and Wei Lin, Langmuir, 2014, 30, 12860-12867.
A 500 mL Erlenmeyer flask was charged with intermediate SMA-2301 polymer (10 g) and 100 mL DI H2O. The pH was adjusted to ca. 11 using 1M NaOH to give a total volume of 175 mL. The mixture was let stir for 1 h after which time the majority of polymer dissolved to form a light-yellow suspension. 1,3-propanesultone (1 eq. relative to maleic anhydride comonomer, 4.4 g) was added in one portion and the mixture allowed to stir for 4 days. All polymer dissolved and a light-yellow solution was observed. After the allotted time, the reaction mixture was purified by dialysis using 3,500 g/mol snakeskin dialysis bags over 2 days. The contents of the dialysis bags were frozen and lyophilized to reveal a white solid, 7.8 g, 54%.
IR (ATR, cm−1): 3356, 2922, 1696, 1646, 1569, 1491, 1450, 1394, 1172, 1034, 699.
Tg=85.15° C.
In a 500 mL Erlenmeyer flask, SMA230T (9.8 g) was dissolved in 200 mL of hot DMF while stirring using a magnetic stir bar. The light-yellow solution was allowed to cool to ambient temperature and further to 0° C. in an ice bath. 4-Dimethylaminopyridine (10 mol %, 0.30 g) was added to the mixture in one portion and the mixture allowed to stir for 5 minutes. Benzyl alcohol (4 eq relative to functionalized maleic anhydride comonomer, 10.6 g) was added in one portion. The mixture was allowed to stir for 5 minutes before DCC (1 eq, 5.06 g) was added in one portion. The ice bath was removed, and the mixture was stirred overnight at room temperature. The next morning, a white precipitate (DCU) was observed in the flask and removed via vacuum filtration using a medium porosity, glass fritted funnel. The filtrate was added dropwise to a vortex of cold diethyl ether (150 mL) causing a gel-like precipitate to form. This precipitate was isolated via gravity filtration and was redissolved in a minimum amount of hot DMF (60 mL) before being re-precipitated using cold diethyl ether (150 mL). The colourless precipitate was stirred vigorously for 1 hour and the white solid precipitate was collected via gravity filtration and dried in vacuo, 8.3, 67%.
IR (ATR, cm−1): 2924, 1867, 1491, 1437, 1385, 1161, 1053, 1040, 740, 699.
The binding capacity of a SMA230T-SB-S12 was determined by combining a known amount of NanoNet™ solution and boron at pH 9, followed by a filtration of the solution through a Vivaspin centrifuge PES membrane with a 30 kDa MWCO. The boron concentration in the filtrate was measured by an Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Any boron in the filtrate is considered as unbound boron. Equation 1 is used to calculate the bound boron in the sample. Equation 2 is used to determine mass of boron and Equation 3 is used to determine mass of adsorbent, respectively. With the mass of bound boron and mass of adsorbent, equation 4 is used to calculate the binding capacity. Equation 5 is used to calculate the ratio of total boron to adsorbent in the sample.
Utilizing these equations, binding curves were developed. These curves typically fit a logarithmic regression and allow the prediction of the binding capacity at any given boron to adsorbent ratio. Binding capacity may depend on pH, temperature, and salinity of a sample.
Binding isotherms of the NanoNets™ were generated in synthetic water matrices and deionized waters containing high (>150 ppm) and low (5 ppm) boron concentrations.
To access the boron removal efficacy of NanoNet™ with boron binding surfactant SB-S12, a boron solution containing 5.4 ppm boron was incubated with varying concentrations of adsorbent at 40° C. Boron binding occurred for 5 minutes at pH 9. After equilibration of boron-binding surfactant, the surfactant-boron complex was subsequently removed from solution by ultrafiltration with a PES filter with a pore-size of 30,000 Da. After ultrafiltration any unbound or non-complexed boron remained in the filtrate. The total boron concentration was measured by ICP-OES analysis and the total boron removal per gram of added surfactant (adsorbent) was calculated.
The maximal boron uptake occurred at lower surfactant dosing (0.01% surfactant with high loading capacity of 30.7 mg B/g adsorbent). The loading capacity decreased at higher adsorbent concentration. A full boron removal was achieved at highest surfactant dosing (5.28 ppm boron removal at 0.1% surfactant concentration).
The synthetic brine composition was:
To access the boron removal efficacy of NanoNet™ with boron binding surfactant SB-S12 a boron solution containing 150 ppm boron was incubated with varying concentrations of adsorbent at 40° C. Boron binding occurred for 5 minutes at pH 9. After equilibration of boron-binding surfactant, the surfactant-boron complex was subsequently removed from solution by ultrafiltration with a PES filter with a pore-size of 30 kDa. After ultrafiltration any unbound or non-complexed boron remained in the filtrate. The total boron concentration was measured by ICP-OES analysis and the total boron removal per gram of added surfactant (adsorbent) was calculated. The theoretical maximum binding isotherm is 28 mgB/g adsorbent.
The maximal boron uptake occurred at lower surfactant dosing (0.08% adsorbent with a binding isotherm of 32.3 mg B/g adsorbent; 0.18% surfactant with high loading capacity of 23.5 mg B/g adsorbent). Larger error bars were due to low volume dosing of adsorbent. The loading capacity decreased at higher adsorbent concentration. Full boron removal was achieved at highest surfactant dosing (148.7 ppm boron removal at 1.76% surfactant concentration).
Boron binding occurred for 5 minutes at pH 9 at ambient temperature. After equilibration of boron-binding surfactant, the surfactant-boron complex was subsequently removed from solution by ultrafiltration with a PES filter with 30 kDa MWCO. After ultrafiltration any unbound or non-complexed boron remained in the filtrate. The total boron concentration was measured by ICP-OES analysis and the total boron removal per gram of added surfactant (adsorbent) was calculated. From the binding capacity results, it can be concluded that with increasing boron to adsorbent ratio the binding capacity increases reaching near theoretical maximum binding capacity.
To decrease chemical consumption during the elution and regeneration step, various polymers used in NanoNet™ formulation were tested for acid consumption.
To enhance the binding capacity, boron binding surfactant SB-S12 was complexed with different polymers. A boron solution containing 100 ppm boron was incubated with a NanoNet™ solution containing 1% adsorbent. Boron binding occurred for 5 minutes at pH 9 at ambient temperature. After equilibration of boron-binding surfactant, the surfactant-boron complex was subsequently removed from solution by ultrafiltration with a 30 kDa PES MWCO filter. After ultrafiltration any unbound or non-complexed boron remained in the filtrate. The total boron concentration was measured by ICP-OES analysis and the total boron removal per gram of added surfactant (adsorbent) was calculated. The theoretical maximum binding isotherm is 28 mg B/g adsorbent.
The maximal boron uptake occurred with NanoNet SMA230CIAA-SB-S12 with a binding capacity of 16.3 mg B/g adsorbent, followed by SMA230S-SB-S12 (binding capacity of 15.2 mgB/g), SMA230T-Protected-SB-S12 (binding capacity of 13 mg B/g), and SMA230T-SB-S12 (binding capacity of 13 mg B/g).
The 3 step- and 4-Step regeneration processes were developed as a method to regenerate a NanoNet™ while minimizing NanoNet™ chemical loss during bench scale filtration. This process takes advantage of rapid self-assembly of micelles through boron binding surfactant SB-S12 and polymer SMA230T complexation. The 4 steps refer to (i) precipitation of the NanoNet™ during elution, (ii) neutralization of the supernatant, (iii) NanoNet™ addition to the supernatant and (iv) filtration of the supernatant. To test the efficacy of regeneration and reduce chemical attrition and acid consumption during the regeneration process, surfactant SB-S12 was measured for boron binding removal after multiple cycles of acid elution in the presence of stabilizing polymer (
It was found that after the first cycle, the surfactant polymer complex was able to remove 95% of the boron from solution equally for the 3-step and 4-step regeneration process and was able to maintain 100-99% removal over the first 3 cycles, and 96% boron removal in cycles 4 and 5 during the 4-step regeneration. The 3 step regeneration process demonstrated a 95% boron removal for the first 3 cycles and >85% boron removal for cycles 4 and 5. (
Isotherms may be used to maximize binding of element of interest in a batch mode with 1 filter and stacked filters of 2, 3, 4, 5, 6, 7, 8, 9, or 10 filters, respectively. An example of two stacked filters is illustrated in the
In the first binding event, boron-containing influent and partially saturated NanoNet™ solution are combined and filtered through filter 1. Filter 1 contains a flat-sheet membrane with a large membrane pore size. The membrane pore size can range from 50 kDa to 100 kDa MWCO. The NanoNet™ is concentrated by a concentration factor of 14. Filtration step 1 demonstrates a high boron to adsorbent ratio and a high binding capacity. The partially depleted boron-containing water from the first binding event along with regenerated NanoNet™ pass-through a second filter. This event results in a lower binding capacity. Filter 2 has a tight pore size of 10 kDa MWCO to 30 kDa MWCO. The NanoNet™ solution is further concentrated by a concentration factor of 7.5. By stacking filters with different membrane pore size attrition of polymer-surfactant complex will become negligible.
The filtrate from the second binding step is depleted of boron, while the retentate containing partially saturated NanoNet™ is combined with incoming boron-rich influent.
The first few cycles of the process involve certain boron accumulation. To determine the NanoNet™ dosing requirements for a given influent, a binding curve is used to model the cycles until the system reaches steady state. The NanoNet™ dosing is adjusted until the model shows that the filtrate of the second binding event contains <1 ppm boron.
The concentrated NanoNet™ solution is then regenerated. The in-situ regeneration of the NanoNet™ chemical leads to a minimal waste stream of 9%-11.5%. The waste stream is neutralized with caustic and becomes non-hazardous waste in comparison to IEX that generates an acidic waste stream of >25%.
Micellar and polymer enhanced ultrafiltration are current methods used in water treatment. However, these methods are prone to attrition of surfactant and polymer components. The surfactant micelle formation is directed by the critical micelle concentration of the surfactant. Below this concentration, surfactants exist as free monomers and will permeate through an ultrafiltration membrane. Polymer surfactant complexes described here form at lower concentrations than surfactant micelles alone. By substantially decreasing the aggregation concentration of the surfactant micelle, less monomer will be available to permeate the membrane. To investigate the attrition of NanoNet™ surfactant and polymer components in enhanced ultrafiltration, the polymer attrition was measured by HPLC. Total organic carbon (TOC) analysis was utilized to measure the total concentration of NanoNet™ chemical.
A NanoNet solution containing 5% SB-S12 and 7.5% SMA130T solution was prepared and concentrated to 10% and 15%, respectively, through a 30 kDa MWCO PES membrane filter at 60 PSI. The retentate was subsequently re-diluted to the initial concentration and filtered again. This process was repeated 4 times and the concentration of SB-S12 in the filtrate determined (
The experiment was repeated with polymer alone, and the concentrations of stabilizing polymer were examined in the filtrate (
Although various embodiments of the invention are disclosed herein, many adaptations and modifications may be made within the scope of the invention in accordance with the common general knowledge of those skilled in this art. Such modifications include the substitution of known equivalents for any aspect of the invention to achieve the same result in substantially the same way. Numeric ranges are inclusive of the numbers defining the range. Furthermore, numeric ranges are provided so that the range of values is recited in addition to the individual values within the recited range being specifically recited in the absence of the range. The word “comprising” is used herein as an open-ended term, substantially equivalent to the phrase “including, but not limited to”, and the word “comprises” has a corresponding meaning. As used herein, the singular forms “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. Thus, for example, reference to “a thing” includes more than one such thing. Citation of references herein is not an admission that such references are prior art to the present invention. Furthermore, material appearing in the background section of the specification is not an admission that such material is prior art to the invention. Any priority document(s) are incorporated herein by reference as if each individual priority document were specifically and individually indicated to be incorporated by reference herein and as though fully set forth herein. The invention includes all embodiments and variations substantially as hereinbefore described and with reference to the examples and drawings.
This application is a National Phase entry of PCT Application No. PCT/CA2022/050523 filed Apr. 6, 2022, which claims benefit to U.S. Provisional Application No. 63/171,553 filed Apr. 6, 2021, the entire disclosures of which are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CA2022/050523 | 4/6/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63171553 | Apr 2021 | US |
