Patent Application
20240100502
The present invention relates to porous polymeric carbon sorbents, including particularly porous polymeric carbon sorbents for CO2 capture for flue gas from power plants and for gases from other post-combustion CO2 emission outlets, for gas storage, and for direct air capture of CO2, and methods of making and using same.
Plastic pollution and ever-raising carbon dioxide (CO2) levels are among the top environmental concerns of the 21st century. [Modak 2019; Younas 2016; Ramanathan 2009]. The concentration of CO2 in the atmosphere has increased from preindustrial value of ˜280 ppm to 401 ppm in 2018. [Ramanathan 2009]. This increase in CO2 levels is believed to be primarily due to the continuous combustion of fossil fuels and the lack of economical CO2 capture routes. With the slow development of green and renewable energy sources, fossil fuels are expected to remain the least expensive energy source for the next 40 years. [Haszeldine 2009; Pacala 2004]. To lessen the impact caused by fossil fuel consumption, efficient and economic post-combustion CO2 capture technologies are needed to replace the expensive and energy intensive amine-based chemical absorption that has been practiced in industry for years. [Rochelle 2009].
Amine-based technologies for CO2 capture rely on the chemical reaction between amines and CO2 to form a carbamate complex as shown in eq. 1. [Rochelle 2009; Astaria 1983; Rao 2002].
2R—NH2+CO2⇄R—NH3++R—NHCOO− (eq. 1)
Carbamates are stable and require heating to 125° C. to regenerate the amine, making it an extremely energy intensive technology given the high heat capacity of aqueous amine solution. [Camper 2008]. On top of the high regeneration cost, aqueous amines are corrosive and cause continuous equipment failures in the CO2 capture units, degrade upon heating, are expensive to replace, produce large amounts of wastewater and sludge as byproducts, and they occupy a large footprint. Thus, the development of a greener and cheaper technology is sought after. [Dutcher 2008].
Solid sorbents have received more interest in recent years due to their low heat of regeneration and high thermal stability. [Jalilov I 2017; Jung 2013]. Out of all reported solid sorbents, activated carbons are inexpensive, non-toxic and they have a resilient structure [Gray 2008; Jalilov 2015; Sevilla 2018; Siriwardane 2001; Tour 2010; Xu 2018], making them great candidates for applications with severe and harsh conditions as found in crude oil desulfurization [Bandosz 2006; Wang 2007], gas storage [Sun 1996], and high-pressure CO2 capture [Jalilov I 2017]. The surface area and pore volume of carbonaceous materials can be easily tuned and economically generated. Moreover, carbonaceous materials can be synthesized from various feedstocks ranging from a renewable biomass like glucose [Sevilla 2018] to industrial carbon waste like asphalt [Jalilov II 2017], which makes the precursors of carbonaceous material highly abundant.
With the increasing awareness of the harmful effects of microplastics, nanoplastics and other plastic waste [Cox 2019; Tetu 2019], new technologies for plastic waste utilization are being pursued. One of the proposed technologies to treat plastic waste is pyrolysis of plastic, also called chemical recycling. [Al-Salem 2009]. This method involves heating plastics in an inert atmosphere, a process which breaks up the plastic into smaller molecules such as monomers, oligomers, oils and waxes, along with a nonvolatile carbonaceous residue or char. [Al-Salem 2009; Panda 2018]. This process occurs at ˜600° C. [Panda 2018]. The waxes and oil products are further cracked over acidic zeolites or bentonite clay to obtain higher value petrochemicals and fuels. [Nishino 2008; Mani 2011; Budsaereechai 2019]. One of the drawbacks of pyrolysis methods is the formation of large amounts of char that currently has no significant usefulness. [Kiran Ciliz 2004].
Accordingly, there is a need for improved processes to address the large environmental issues that are being faced today, namely plastic waste pollution and the rising CO2 levels in the atmosphere.
Moreover, existing porous sorbent synthesis technologies require heating carbon source with potassium salts (KOH most often used) at 700° C.-900° C., making the process very energy intensive and hard to scale up. Also, at high temperatures and mass quantities there is a risk of formation of potassium metal making the current routes for sorbent synthesis difficult to commercialize because traces of potassium can cause fires, igniting the carbon upon work-up. While in a lab the danger is small, industrially, in large scale, the danger is enormous. Thus an improved process that is safer, less energy intensive, scalable, and commercial is needed.
Furthermore, while the demand for ethylene increases every year, ethylene trade is limited due to challenges in transporting and refrigerating ethylene.
In general, in one embodiment, the invention features a method of synthesizing a rigid porous polymeric carbon sorbent. The method includes the step of mixing a polymer with an additive to form a mixture. The polymer has a polymer chain order including long range order and short range order as detected by powder X-ray diffraction (XRD). The additive is an activation reagent that is selected from the group consisting of metal hydroxide, metal oxalate, metal acetate, metal acetylacetonoate, and mixtures thereof. The method further includes the step of heating the mixture to a temperature to form a porous polymeric carbon sorbent via chemical activation. The chemical activation results in a loss of the long range order and the short range order of the polymer as detected by powder XRD such that the porous polymeric carbon sorbent material is a rigid porous polymeric carbon sorbent. The rigid porous polymeric carbon sorbent is operable for capturing CO2 at a pressure between 0.75 atm to 5 atm. The rigid polymeric carbon sorbent has a selectivity for capturing CO2 over N2 at least 40:1 at 0.15 bar of CO2 in 0.85 bar of N2 at 23° C.
Implementations of the invention can include one or more of the following features:
The polymer can be selected from a group consisting of high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), and combinations thereof.
The polymer can be selected from a group consisting of polyvinyl chloride (PVC), nylon, melamine mixed with HDPE, melamine mixed with LDPE, melamine mixed with PP, melamine-formaldehyde resins, polyethylene imine (PEI), PEI mixed with HDPE, polyurethanes (PU), polyacrylonitrile, (PAN), and polyethyleneteraphthalte (PET) and mixtures therefrom.
The polymer can include nitrogen atoms.
The rigid polymeric carbon sorbent can have a selectivity for capturing CO2 over N2 at least 300:1 in 0.15 bar of CO2 in 0.85 bar N2 at 23° C.
The polymer can include a plastic from a waste plastic source.
The step of heating can be performed at a temperature that is between 550° C. and 700° C.
The step of heating can be performed at a temperature that is between 575° C. and 600° C.
The activation reagent can be an acetate salt of potassium or calcium.
The activation reagent can be potassium acetate.
The activation reagent can be calcium acetate.
The weight ratio of the additive and the polymer in the mixture can be between 0.5:1 and 5:1.
The weight ratio of the additive and the polymer in the mixture can be between 2:1 and 4:1.
The rigid porous polymeric carbon sorbent can be operable for capturing CO2 from a post-combustion CO2 emission outlet gas.
The post-combustion CO2 emission outlet gas can be a flue gas.
The rigid porous polymeric carbon sorbent can be operable for capturing more than 15 wt % CO2 from a post-combustion CO2 emission outlet gas at 25° C. and at 1 atm.
The rigid porous polymeric carbon sorbent can be operable for releasing the CO2 captured from a post-combustion CO2 emission outlet gas by heating the rigid porous polymeric carbon sorbent to at most 110° C. at 1 atm.
The rigid porous polymeric carbon sorbent can be operable for releasing the CO2 captured from a post-combustion CO2 emission outlet gas by heating the rigid porous polymeric carbon sorbent to at most 75° C. at 1 atm.
The rigid porous polymeric carbon sorbent can be operable for capturing more than 18 wt % CO2 from a post-combustion CO2 emission outlet gas at 25° C. and at most 5 atm.
The rigid porous polymeric carbon sorbent can be operable for capturing more than 100 wt % CO2 from a post-combustion CO2 emission outlet gas at 25° C. and at most 300 atm.
The method can further include controlling pore size of the rigid porous polymeric carbon sorbent by controlling pressure during the step of heating.
The step of heating the mixture can be performed at a near vacuum pressure of at least 0.01 bars.
In general, in another embodiment, the invention features a rigid porous polymeric carbon sorbent. The rigid porous polymeric carbon sorbent is operable to capture more than 15 wt % CO2 from a post-combustion CO2 emission outlet gas at 25° C. and at 1 atm. The rigid polymeric carbon sorbent has a selectivity for capturing CO2 over N2 at least 40:1 at 0.15 bar of CO2 in 0.85 bar of N2 at 23° C.
Implementations of the invention can include one or more of the following features:
The rigid porous polymeric carbon sorbent can include a polymer that has no polymeric long range order and no polymeric short range order detectable by powder X-ray diffraction.
The rigid porous polymeric carbon sorbent can include pores having an average pore size of between 2 Å and 100 Å.
The rigid porous polymeric carbon sorbent can include pores having an average pore size of between 5 Å and 20 Å.
The rigid porous polymeric carbon sorbent can be operable for releasing the CO2 captured from post-combustion CO2 emission outlet gas by heating the rigid porous polymeric carbon sorbent to at most 110° C. at about 1 atm pressure.
The rigid porous polymeric carbon sorbent can be operable for releasing the CO2 captured from post-combustion CO2 emission outlet gas by heating the rigid porous polymeric carbon sorbent to at most 75° C. at about 1 atm pressure.
The rigid porous polymeric carbon sorbent can be operable for capturing more than 18 wt % CO2 from post-combustion CO2 emission outlet gas at 25° C. and at 5 atm.
The rigid porous polymeric carbon sorbent can be operable for capturing more than 100 wt % CO2 from post-combustion CO2 emission outlet gas at 25° C. and at 300 atm.
The rigid porous polymeric carbon sorbent can include nitrogen atoms.
The rigid polymeric carbon sorbent can have a selectivity for capturing CO2 over N2 of at least 250:1 at 0.15 bar of CO2 in 0.85 bar of N2 at 23° C.
In general, in another embodiment, the invention features a method that includes selecting a rigid porous polymeric carbon sorbent having a selectivity for capturing CO2 over N2 least 40:1 at 0.15 bar of CO2 in 0.85 bar of N2 at 23° C. The method further includes utilizing the rigid porous polymeric carbon sorbent to capture more than 15 wt % CO2 from post-combustion CO2 emission outlet gas.
Implementations of the invention can include one or more of the following features:
The post-combustion CO2 emission outlet gas can be a flue gas.
The CO2 can be captured from post-combustion CO2 emission outlet gas at atmospheric pressure.
The CO2 can be captured from post-combustion CO2 emission outlet gas at room temperature at around 25° C.
The rigid porous polymeric carbon sorbent can be utilized to capture more than 18 wt % CO2 from post-combustion CO2 emission outlet gas.
The CO2 can be captured from post-combustion CO2 emission outlet gas at a pressure that is at most 5 atm.
The rigid porous polymeric carbon sorbent can be utilized to capture more than 100 wt % CO2 from post-combustion CO2 emission outlet gas.
The CO2 can be captured from post-combustion CO2 emission outlet gas at a pressure that is at most 300 atm.
The method can further include releasing the CO2 captured from post-combustion CO2 emission outlet by heating the rigid porous polymeric carbon sorbent.
The CO2 can be released by heating the rigid porous polymeric carbon sorbent to at most 110° C.
The CO2 can be released by heating the rigid porous polymeric carbon sorbent to at most 75° C.
The method can further include repeating the capture and release of the CO2 by the rigid porous polymeric carbon sorbent for at least 1000 cycles.
The method can further include repeating the capture and release of the CO2 by the rigid porous polymeric carbon sorbent for at least 100,000 cycles.
The rigid porous polymeric carbon sorbent can have a selectivity for capturing CO2 over N2 of at least 70:1 at 0.15 bar of CO2 in 0.85 bar of N2 at 23° C.
The rigid porous polymeric carbon sorbent can include nitrogen atoms.
The rigid porous polymeric carbon sorbent can have a selectivity for capturing CO2 over N2 of at least 300:1 at least 40:1 at 0.15 bar of CO2 in 0.85 bar of N2 at 23° C.
In general, in another embodiment, the invention feature a method of synthesizing a flexible porous polymeric carbon sorbent. The method includes the step of mixing a polymer with an additive to form a mixture. The polymer has a polymer chain order including long range order and short range order as determined by powder X-ray diffraction (XRD). The additive is an activation reagent that is selected from the group consisting of metal hydroxide, metal oxalate, metal acetate, metal acetylacetonoate and mixtures thereof. The method further includes heating the mixture to a temperature to form a porous polymeric carbon sorbent via chemical activation. The chemical activation results in a loss of the long range order while maintaining short range order of the polymer as detected by powder XRD such that the porous polymeric carbon sorbent material is a flexible porous polymeric carbon sorbent. The flexible porous polymeric carbon sorbent is operable for storing 4.5 wt % H2 at room temperature and 100 atm.
Implementations of the invention can include one or more of the following features:
The flexible porous polymeric carbon sorbent gas can be operable for storing each of H2, CO2, O2, methane, natural gas, and combinations thereof.
The flexible porous polymeric carbon sorbent can be independently: (a) operable to store at least 150 wt % of CO2 at room temperature and 50 atm; (b) operable to store at least 140 wt % of O2 at room temperature and 110 atm; and (c) operable to store at least 80 wt % of CH4 at room temperature and 100 atm.
The polymer can be selected from a group consisting of high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), and combinations thereof.
The polymer can be selected from a group consisting of polyvinyl chloride (PVC), nylon, melamine with HDPE, melamine with LDPE, melamine with PP, melamine-formaldehyde resins, melamine resins, urea, polyurethanes (PU), polyacrylonitrile, (PAN), polyethylene imine, polyethylene imine mixed with HDPE, and polyethyleneteraphthalte (PET) and mixtures therefrom.
The polymer can include nitrogen atoms.
The step of heating can be performed at a temperature that is between 400° C. and 525° C.
The step of heating can be performed at a temperature that is between 475° C. and 500° C.
The activation reagent can be an acetate salt of potassium or calcium.
The activation reagent can be potassium acetate.
The activation reagent can be calcium acetate.
The weight ratio of the additive and the polymer in the mixture can be between 0.5:1 and 5:1.
The weight ratio of the additive and the polymer in the mixture can be between 2:1 and 4:1.
The flexible porous polymeric carbon sorbent can be operable for storing more than 5.5 wt % of H2 at room temperature and 100 atm.
The flexible porous polymeric carbon sorbent can be operable for storing more than 8 wt % of H2 at room temperature and 100 atm.
The flexible porous polymeric carbon sorbent can be operable for storing about 13 wt % of H2 at room temperature and 200 atm.
The flexible porous polymeric carbon sorbent can be operable for storing about 15 wt % of H2 at room temperature and 300 atm.
The flexible porous polymeric carbon sorbent can be operable for storing more than 80 wt % of CH4 at room temperature and 100 atm.
The flexible porous polymeric carbon sorbent can be operable for storing more than 150 wt % of CH4 at room temperature and 200 atm.
The flexible porous polymeric carbon sorbent can be operable for storing more than 175 wt % of CH4 at room temperature and 300 atm.
The flexible porous polymeric carbon sorbent can be operable for releasing the stored gas by lowering the pressure back to 1 atm.
The method can further include controlling pore size of the flexible porous polymeric carbon sorbent by controlling pressure during the step of heating.
The step of heating the mixture can be performed at a near vacuum pressure of at least 0.01 bars.
In general, in another embodiment, the invention features a flexible porous polymeric carbon sorbent that is operable for storing 4.5 wt % H2 at room temperature and 100 atm.
Implementations of the invention can include one or more of the following features:
The flexible porous polymeric carbon sorbent can be independently: (a) operable to store at least 150 wt % of CO2 at room temperature and 50 atm; (b) operable to store at least 140 wt % of O2 at room temperature and 110 atm; and (c) operable to store at least 80 wt % of CH4 at room temperature and 100 atm.
The flexible porous polymeric carbon sorbent can include a polymer that has short range order and no long range order by powder X-ray diffraction (XRD).
The flexible porous polymeric carbon sorbent can include pores having an average pore size of between 2 Å and 100 Å.
The flexible porous polymeric carbon sorbent can include pores having an average pore size of between 5 Å and 20 Å.
The flexible porous polymeric carbon sorbent can be operable for storing more than 5.5 wt % of H2 at room temperature and 100 atm.
The flexible porous polymeric carbon sorbent can be operable for storing more than 8 wt % of H2 at room temperature and 100 atm.
The flexible porous polymeric carbon sorbent can be operable for storing more than 13 wt % of H2 at room temperature and 200 atm.
The flexible porous polymeric carbon sorbent can be operable for storing more than 13 wt % of H2 at room temperature and 300 atm.
The flexible porous polymeric carbon sorbent can be operable for storing more than 15 wt % of H2 at room temperature and 300 atm.
The flexible porous polymeric carbon sorbent can be operable for storing about 20 wt % of H2 at 100° C. and 100 atm.
The flexible porous polymeric carbon sorbent can be operable for storing more than 90 wt % of CH4 at room temperature and 100 atm.
The flexible porous polymeric carbon sorbent can be operable for storing more than 150 wt % of CH4 at room temperature and 200 atm.
The flexible porous polymeric carbon sorbent can be operable for storing more than 175 wt % of CH4 at room temperature and 300 atm.
The flexible porous polymeric carbon sorbent can include nitrogen atoms.
In general, in another embodiment, the invention features a method that includes positioning a flexible porous polymeric carbon sorbent in a container that can contain a gas under pressure. The flexible porous polymeric carbon sorbent is operable for storing 4.5 wt % H2 at room temperature and 100 atm. The method further includes storing gas in the container. The container can store more of the gas at room temperature and 100 atm than in the container without the flexible porous polymeric carbon sorbent at the same conditions.
Implementations of the invention can include one or more of the following features:
The flexible porous polymeric carbon sorbent can be independently: (a) operable to store at least 150 wt % of CO2 at room temperature and 50 atm; (b) operable to store at least 140 wt % of O2 at room temperature and 110 atm; and (c) operable to store at least 80 wt % of CH4 at room temperature and 100 atm.
The flexible porous polymeric carbon sorbent can include a polymer that has short range order and no long range order by powder X-ray diffraction (XRD).
The flexible porous polymeric carbon sorbent can include pores having an average pore size of between 2 Å and 100 Å.
The flexible porous polymeric carbon sorbent can include pores having an average pore size of between 5 Å and 20 Å.
The flexible porous polymeric carbon sorbent can store more than 4.5 wt % H2 at room temperature and at most 100 atm.
The flexible porous polymeric carbon sorbent can store more than 13 wt % H2 at room temperature and at most 200 atm.
The flexible porous polymeric carbon sorbent can store more than 15 wt % H2 at room temperature and at most 300 atm.
The flexible porous polymeric carbon sorbent can store at least 8 wt % of H2 at room temperature and at most 100 atm.
The flexible porous polymeric carbon sorbent can store at least 10 wt % of H2 at room temperature and at most 100 atm.
The flexible porous polymeric carbon sorbent can store more than 175 wt % of CH4 at room temperature and at most 300 atm.
The flexible porous polymeric carbon sorbent can store more than 175 wt % of CH4 at room temperature and at most 275 atm.
The flexible porous polymeric carbon sorbent can store more than 150 wt % of CH4 at room temperature and at most 200 atm.
The flexible porous polymeric carbon sorbent can include nitrogen atoms.
In general, in another embodiment, the invention features a vehicle comprising an onboard hydrogen storage container. The container includes a flexible porous polymeric carbon sorbent. The container includes at least 4.5 wt % of H2 at a pressure below 300 atm at room temperature.
Implementations of the invention can include one or more of the following features:
The container can include at least 4.5 wt % of H2 at a pressure below 200 atm at room temperature.
The container can include at least 4.5 wt % of H2 at a pressure below 100 atm at room temperature.
The container can include at least 5.5 wt % of H2 at a pressure below 300 atm at room temperature.
The container can include at least 5.5 wt % of H2 at a pressure below 200 atm at room temperature.
The container can include at least 5.5 wt % of H2 at a pressure below 100 atm at room temperature.
The container can include at least 8 wt % of H2 at a pressure below 300 atm at room temperature.
The container can include at least 8 wt % of H2 at a pressure below 200 atm at room temperature.
The container can include at least 8 wt % of H2 at a pressure below 100 atm at room temperature.
The container can include comprises at least 13 wt % of H2 at a pressure below 300 atm at room temperature.
The container can include at least 13 wt % of H2 at a pressure below 200 atm at room temperature.
The container can include at least 15 wt % of H2 at a pressure below 300 atm at room temperature.
In general, in another embodiment, the invention features a method that includes selecting a flexible porous polymeric carbon sorbent. The flexible porous polymeric carbon sorbent is operable for storing 4.5 wt % H2 at room temperature and 100 atm. The method further includes utilizing the flexible porous polymeric carbon sorbent to capture a gas.
Implementations of the invention can include one or more of the following features:
The gas can be selected from the group consisting of H2, CO2, O2, methane, natural gas, and combinations thereof.
In general, in another embodiment, the invention features a method of synthesizing a porous polymeric carbon sorbent. The method includes the step of mixing a polymer with an additive to form a mixture. The polymer has a polymer chain order comprising long range order and short range order as detected by powder X-ray diffraction (XRD). The additive is an activation reagent that is selected from the group consisting of metal hydroxide, metal oxalate, metal acetate, metal acetylacetonoate, and mixtures thereof. The method further includes the step of heating the mixture to a temperature to form a porous polymeric carbon sorbent via chemical activation. The chemical activation results in a loss of the long range order and the short range order of the polymer as detected by powder XRD such that the porous polymeric carbon sorbent material is a rigid porous polymeric carbon sorbent. The porous polymeric carbon sorbent is operable for direct air capturing of at least 4 wt % of CO2 at room temperature and 4 mbar partial pressure of CO2 in air.
Implementations of the invention can include one or more of the following features:
The polymer can be selected from a group consisting of high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), and combinations thereof.
The polymer can be selected from a group consisting of polyvinyl chloride (PVC), nylon, melamine mixed with HDPE, melamine mixed with LDPE, melamine mixed with PP, melamine-formaldehyde resins, polyethylene imine (PEI), PEI mixed with HDPE, polyurethanes (PU), polyacrylonitrile, (PAN), and polyethyleneteraphthalte (PET) and mixtures therefrom.
The polymer can include a plastic from a waste plastic source.
The step of heating can be performed at a temperature that is between 550° C. and 700° C.
The step of heating can be performed at a temperature that is between 575° C. and 600° C.
The activation reagent can be an acetate salt of potassium or calcium.
The activation reagent can be potassium acetate.
The activation reagent can be calcium acetate.
The weight ratio of the additive and the polymer in the mixture can be between 0.5:1 and 5:1.
The weight ratio of the additive and the polymer in the mixture can be between 2:1 and 4:1.
The porous polymeric carbon sorbent can be operable for releasing the CO2 direct air captured by heating the porous polymeric carbon sorbent to at most 200° C.
The porous polymeric carbon sorbent can be operable for releasing the CO2 direct air captured by heating the porous polymeric carbon sorbent to at most 75° C.
The porous polymeric carbon sorbent can be operable for releasing the CO2 direct air captured by heating the rigid porous polymeric carbon sorbent to at most 100° C.
The porous polymeric carbon sorbent can be operable for releasing the CO2 direct air captured by removing the CO2 with vacuum.
The polymer can include nitrogen atoms.
The porous polymeric carbon sorbent can be operable for direct air capturing of at least 6 wt % of CO2 at 4 mbar partial pressure of CO2 in air.
The porous polymeric carbon sorbent can be operable for releasing the CO2 direct air captured by heating the rigid porous polymeric carbon sorbent to at most 110° C.
The porous polymeric carbon sorbent can be operable for releasing the CO2 direct air captured by removing the CO2 with vacuum.
The method can further include controlling pore size of the porous polymeric carbon sorbent by controlling pressure during the step of heating.
The step of heating the mixture can be performed at a near vacuum pressure of at least 0.01 bars.
In general, in another embodiment, the invention features a rigid porous polymeric carbon sorbent that is operable to direct air capture more than 4 wt % CO2 at room temperature and 4 mbar partial pressure of CO2 in air.
Implementations of the invention can include one or more of the following features:
The rigid porous polymeric carbon sorbent can include a polymer that has no polymeric long range order and no polymeric short range order detectable by powder X-ray diffraction (XRD).
The porous polymeric carbon sorbent can be operable for releasing the CO2 direct air captured by heating the porous polymeric carbon sorbent to at most 200° C.
The porous polymeric carbon sorbent can be operable for releasing the CO2 direct air captured by heating the porous polymeric carbon sorbent to at most 75° C.
The porous polymeric carbon sorbent can be operable for releasing the CO2 direct air captured by heating the rigid porous polymeric carbon sorbent to at most 100° C.
The porous polymeric carbon sorbent can be operable for releasing the CO2 direct air captured by removing the CO2 with vacuum.
The porous polymeric carbon sorbent can include nitrogen atoms.
The porous polymeric carbon sorbent can be operable for direct air capturing of at least 6 wt % of CO2 at 4 mbar partial pressure of CO2 in air.
The porous polymeric carbon sorbent can be operable for releasing the CO2 direct air captured by heating the rigid porous polymeric carbon sorbent to at most 110° C.
The porous polymeric carbon sorbent can be operable for releasing the CO2 direct air captured by removing the CO2 with vacuum.
In general, in another embodiment, the invention features a method that includes selecting a rigid porous polymeric carbon sorbent. The porous polymeric carbon sorbent is operable for direct air capturing of at least 4 wt % of CO2 at room temperature and 4 mbar partial pressure of CO2 in air. The method further includes utilizing the rigid porous polymeric carbon sorbent to direct air capture more than 4 wt % CO2.
Implementations of the invention can include one or more of the following features:
The method can further include releasing the direct air captured CO2 by heating the rigid porous polymeric carbon sorbent.
The CO2 can be released by heating the rigid porous polymeric carbon sorbent to at most 200° C.
The CO2 can be released by heating the rigid porous polymeric carbon sorbent to at most 75° C.
The CO2 can be released by heating the rigid porous polymeric carbon sorbent to at most 100° C.
The method can further include releasing the direct air captured CO2 by applying a vacuum to the rigid porous polymeric carbon sorbent.
The method can further comprising repeating the direct air capture and release of the CO2 by the porous polymeric carbon sorbent for at least 1000 cycles.
The porous polymeric carbon sorbent can include nitrogen atoms.
The porous polymeric carbon sorbent can be operable for direct air capturing of at least 6 wt % of CO2 at 4 mbar partial pressure of CO2 in air.
The rigid porous polymeric carbon sorbent can be utilized to direct air capture more than 6 wt % CO2 at 4 mbar partial pressure of CO2 in air.
The method can further include releasing the direct air captured CO2 by heating the rigid porous polymeric carbon sorbent.
The CO2 can be released by heating the rigid porous polymeric carbon sorbent to at most 200° C.
The CO2 can be released by heating the rigid porous polymeric carbon sorbent to at most 100° C.
The method can further include releasing the direct air captured CO2 by applying a vacuum to the rigid porous polymeric carbon sorbent.
In general, another embodiment, the invention features a method of synthesizing a porous carbon material. The method includes mixing a plastic with an additive. The method further includes heating the plastic and the additive to a temperature in the range of 400° C. and 700° C. to form the porous carbon material.
Implementations of the invention can include one or more of the following features:
The plastic can be selected from a group consisting of HDPE, LDPE, PP, and combinations thereof.
The plastic can be selected from a group consisting of polyvinyl chloride (PVC), nylon.
The plastic can be a polymer that includes nitrogen atoms.
The polymer that includes nitrogen atoms can be a polymer selected from a group consisting of melamine mixed with HDPE, melamine mixed with LDPE, melamine mixed with PP, melamine mixed with other polymers, melamine-formaldehyde resins, urea, polyethylene imine (PEI), PEI mixed with HDPE, PEI mixed with other polymers, polyurethanes (PU), polyacrylonitrile, (PAN), and polyethyleneteraphthalte (PET).
The plastic can be from a mixture of plastic sources.
The plastic can be from at least one waste plastic source.
The plastic can be from plastic waste.
The plastic can be selected from a group consisting of plastics made from chain grow polymerization, vinyl polymerization, step growth polymerization, condensation polymerization, living polymerization, radical polymerization, cationic polymerization, anionic polymerization, synthetic polymers, naturally occurring polymers, and combinations thereof.
The additive can be potassium acetate.
The additive can be calcium acetate.
The additive can be selected from a group consisting of potassium hydroxide, potassium oxalate, potassium acetate, potassium acetylacetonoate, and mixtures thereof.
The additive can be selected from a group consisting of metal hydroxide, metal oxalate, metal acetate, metal acetylacetonoate, and mixtures thereof.
The metal can be selected from a group consisting of Groups 1A, 2A, and 3A of the Periodic Table, transitional metal, lanthanide, and actinide.
The metal can be an alkali-metal.
The metal can be lithium or cesium.
The additive can be a salt.
The weight ratio of the additive to the plastic can be between 0.5:1 and 5:1.
The weight ratio can be between 1:1 and 2:1.
The temperature of heating the plastic and the additive can be greater than about 550° C. The porous carbon material can be a mechanically rigid porous carbon material.
The temperature of heating the plastic and the additive can be at most about 550° C. The porous carbon material can be a mechanically flexible porous carbon material.
The temperature of heating the plastic and the additive can be at most about 500° C.
The temperature of heating the plastic and the additive can be at most about 550° C. The porous carbon material can be a flexible porous carbon material.
The temperature of heating the plastic and the additive can be at most about 500° C.
The diffraction bands in the X-ray diffraction analysis of the porous carbon material that are characteristic of the plastic can be remaining in the porous carbon material.
The method of any of any of the above-described methods can further include controlling pore size of the flexible porous carbon material by controlling the temperature and pressure of the method.
The method of any of the above-described methods can further include controlling pore size of the porous carbon material by controlling the temperature and pressure of the method.
In general, in another embodiment, the invention features a porous carbon material that is made according to the method of one or more of the above-described methods.
In general, in another embodiment, the invention features a porous carbon material that can capture more than 15 wt % CO2 at about 25° C. and at 1 atm.
Implementations of the invention can include one or more of the following features:
The porous carbon material can release the CO2 when heating the porous carbon material to less than 125° C.
The porous carbon material can release the CO2 when heating the porous carbon material to less than 100° C.
The porous carbon material can release the CO2 when heating the porous carbon material to about 70-75° C.
The porous carbon material of any of the above-described porous carbon materials and can be made according to any of the above-described methods.
The porous carbon material can capture more than 15 wt % CO2 at about 25° C. and at a pressure less than 5 atm.
The porous carbon material can capture more than 18 wt % CO2 at about 25° C. and at a pressure less than 5 atm.
The porous carbon material can capture more than 100 wt % CO2 at about 25° C. and at a pressure less than 300 atm.
The porous carbon material can capture more than 100 wt % CO2 at about 25° C. and at a pressure less than 50 atm.
The porous carbon material can capture up to 190 wt % CO2 at about 25° C. and at a pressure less than 50 atm.
The porous carbon material can be any of the above-described porous carbon materials. The porous carbon material can be a flexible porous carbon material made by any of the above-described methods.
In general, in another embodiment, the invention features a method that includes selecting a porous carbon material selected from any of the above-described porous carbon materials. The method further includes utilizing the porous carbon material to capture more than 15 wt % CO2.
Implementations of the invention can include one or more of the following features:
More than 15 wt % CO2 can be captured at about 25° C. and at a pressure less than 5 atm.
More than 18 wt % CO2 can be captured at about 25° C. and at a pressure less than 5 atm.
More than 25 wt % CO2 can be captured at about 25° C. and at a pressure less than 5 atm.
More than 100 wt % CO2 can be captured at about 25° C. and at a pressure less than 300 atm.
More than 100 wt % CO2 can be captured at about 25° C. and at a pressure less than 50 atm.
More than 190 wt % CO2 can be captured at about 25° C. and at a pressure less than 50 atm.
The CO2 can be captured from flue gas.
The CO2 can be captured from a post-combustion process.
The CO2 can be captured from a pre-combustion process.
The pre-combustion process can include separation of the CO2 from natural gas.
The CO2 can be being selectively captured over the capture of N2.
The porous carbon material can be made according to the method of one or more of the above-described methods.
The porous carbon material can be a flexible porous material.
The flexible porous carbon material can be made according to the method of one or more of the above-described methods.
In general, in another embodiment, the invention features a flexible porous carbon material made according to the method of one or more of the above-described methods. The flexible porous carbon materials has tunable pore sizes based upon the gas used, the temperature, the pressure, or a mixture of those conditions.
In general, in another embodiment, the invention features a porous carbon material that can capture O2, methane, or natural gas at about 25° C. and at 100 atm.
Implementations of the invention can include one or more of the following features:
The porous carbon material can be a flexible porous material.
The flexible porous carbon material can be made according to the method of one or more of the above-described methods.
In general, in another embodiment, the invention features a storage container that includes a flexible porous carbon material. The storage container can store more H2, O2, methane, or natural gas at about 25° C. and about 100 atm to 300 atm than in the storage container without the flexible porous carbon material at the same conditions.
In general, in another embodiment, the invention features a method that includes feeding plastic bags into a chopper. The method further includes sheering the plastic bags in the chopper to produce flakes. The method further includes utilizing a sizing mesh to allow flakes below a pre-determined size to flow out of the chopper. The flakes that are above the pre-determined size remain in the chopper for further sheering. The method further includes gathering the flakes in a receptacle.
Implementations of the invention can include one or more of the following features:
The flakes can be utilized in a flash graphene process.
The flakes can be utilized in method to synthesize a porous carbon material.
The present invention relates to porous polymeric carbon sorbents for CO2, H2, and other gases and methods of making and using same. For instance, the present invention relates to a cost-effective way to process plastic waste (such as, for example, waste plastic milk jugs, which are high density polyethylene, HDPE) to produce value added chemicals and products that can capture >17 wt % CO2 at room temperature and 1 atm. Such processes easily release the captured CO2 at 70° C. and are reversible in this capture and release cycling.
Embodiments of the present invention encompass an alternative approach to plastic pyrolysis of the prior art, which alternative approach results in obtaining a porous carbon that has high CO2 capture capacity. The developed approach also results in thermal cracking of the polymer, yielding the typical chemicals and fuels that are usually produced with the conventional pyrolysis including monomers and oligomers. The advantage of this technology over conventional pyrolysis, is the elimination of an unusable char by simply adding potassium acetate (or other metal salt, such as an alkali-metal salt) to the process. The process produces a high surface area carbonaceous residue that is an effective CO2 sorbent. This addresses two enormous environmental issues, namely the reuse of waste plastics and the capture of post-combustion or pre-combustion CO2 from a single new technological approach.
In embodiments of the present invention, thermal cracking of polymers and plastic waste is used to emit chemicals including monomers, oligomers and high surface porous carbon. While thermal cracking of plastic waste is known in the prior art, the prior art processes do not produce the porous carbon like obtained using embodiments of the present invention when cracking the plastic waste over potassium acetate and/or other potassium salt additives like potassium hydroxide, potassium oxalate, potassium acetylacetonoate, etc. In lieu of (or in addition to) such additives, the additives include other metal hydroxides, metal oxalates, metal acetates, metal acetylacetonoates, and mixtures thereof (including those in which the metal is one or more of Group 1A, 2A, and 3A from the periodic table, transitional metals, lanthanide, and actinide). A particular good one is calcium acetate.
The porous carbon can be used as a CO2 sorbent while it has a much higher sorbing affinity to CO2 than to N2, thus making it useful to even capture CO2 from flue gas, such as the evolved CO2 from a power plant stack (such as the scheme of the post-combustion process and CO2 capture unit shown in
Since the cracking temperature is maintained below 700° C. (and typically below 600° C., and even more typically at or below 500° C.), the potassium in the additive (i.e., the potassium salt) does not reduce to potassium metal. So, there is little, if any, risk of generating H2 gas with ignition upon washing with water to remove the remaining additive after the cracking process. Hence, this has an additional benefit of lessening production costs.
In embodiments of the present invention the same porous carbon generated via the process can also sorb H2 gas. A goal is to make a material that is both dense (i.e., density ˜1 g/cc) and can sorb 5.5 wt % H2 at room temperature and 100 atm of pressure. In this invention, the carbon materials have a density greater than 1.5 g/cc and even 1.7 g/cc. So unlike an aerogel which is too low density and therefore voluminous to be easily used in mobile tanks, the carbon material here, though porous, is high density so low in overall volume. The material porous carbon made using embodiments of the present invention captures ˜7 wt % to 8 wt % H2 at room temperature and 100 atm and ˜15 wt % at room temperature and 300 atm, and oddly ˜20 wt % H2 at 100° C. and 100 atm. This is counterintuitive since most materials capture less gas at higher temperature. But this goes back to the interesting behavior of the materials of the present invention, as described and discussed below. The 5.5 wt % is an essential goal set by the US Department of Energy to make hydrogen fuel cell vehicles widely available. Presently they can only use H2 tanks that are 5000-10,000 psi (340-680 atm) to provide the range needed in a car. But those tanks are spherical to handle the high pressures, and therefore hard to fit in vehicles, and considered dangerous. If H2 is liquefied, the density is low and 30% of the energy content is lost in the liquefaction process. So to be able to store H2 at 100 atm (1470 psi) is a huge advance since light weight composite tanks can be used. Although the results here can be advantageous even up to 300 atm where the H2 storage starts to saturate at ˜13 wt %.
Moreover, embodiments of the present invention shows that the properties of the resultant material can be tunable by simply controlling the activation temperature or the pressure or a combination of both temperature and pressure. For example, a porous carbon obtained by activating high density polyethylene (HDPE plastic at ˜475-500° C. shows properties that are similar to porous polymers (rather than porous carbons) where they are mechanically flexible in that the pores can vary in sizes depending upon the pressure and temperature used during the sorption process. This allows the polymer to tune its pore sizes for a particular gas at a particular pressure and temperature. So at 500° C., the material has both the properties of a porous carbon and the properties of a porous polymer. If however, a higher temperature is utilized (such as ˜575-600° C.), the resulting materials is stiff, rather than flexible.
Further embodiments include sorbing of other gases, such as O2 and methane. O2 sorbing can be very useful in that if one can add even obtain 20% more O2 to a compressed cylinder, at the same pressure, then it would enormously reduce the price of O2 gas cylinder deliveries. But since this material can be flexible like a polymer, it can sorb most any gas since it can accommodate variable size molecules due to its mechanical flexibility. The sorption of methane has also been seen with the flexible porous polymer here, and that could increase the amount of methane that can be contained in a methane or natural gas tank. Again, lowering cost of deliver per amount of gas in the cylinder and making the use of natural gas more attractive for vehicular (car and truck) and maritime (boat and ship) use.
Embodiment of the present invention encompass a one-step activation method of plastic waste to produce a solid sorbent with high CO2 capacity at room temperature and pressure along with monomer and oligomer that can be recycled or used for other chemical applications. See
The ability to synthesize sorbent <700° C. eliminates the possibility of potassium metal formation, making the scale up of this process highly attractive since there is no formation of potassium metal at these temperatures. The nature of the sorbent can be manipulated by changing the activation temperature. For example, activating at around 600° C. can yield a rigid porous carbon while activating below 550° C., and more preferably 475 to 500° C., can yield an sorbent with porous polymer-like properties. TG-MS data of the evolved gases during the synthesis of the sorbent showed that the predominant product in the gas phase is propylene and ethylene, which are monomers that can potentially be used to synthesize fresh plastics. The synthesized sorbent has a selectivity of CO2 over N2 of 230 at 0.1 bar, and the sorbent is stable upon cycling. The sorbent has low heat of sorption, making it possible to regenerate at 70 to 75° C. using waste heat from power plants and refineries. In comparison, one of the dominant technologies used today for CO2 capture at 1 bar is aqueous amine towers. These trap 13 wt %, they are corrosive, require a large footprint, and they need to be heated to 120-140° C. to yield the CO2. Moreover, since aqueous amine towers have a high heat capacity (water), the amount of energy needed to heat them to 120-140° C. is exceedingly high.
Porous sorbents were prepared by carbonization of plastic waste (polyolefins) at below 700° C. under inert atmosphere (such as argon or nitrogen) in the presence of activation reagents. High density polyethylene (HDPE) was utilized. It was found that the same conditions can be used to activate plastic cups (PP) and plastic bags (LDPE), the latter being one of the most challenging materials to recycle and is one of the main sources of microplastics after polyethylene terephthalate (PET). Samples were named so that the first two numbers represent the activation reagent to polymer ratio followed by the plastic type and the numbers after the plastic type represents the activation temperature. I.e., “2-1-A-HDPE-500” represents a 2:1 activation reagent to polymer ratio, “A” for thermally activated, a plastic type of HDPE, and an activation temperature of 500° C. In some cases the “A” is not used since “activation” can be understood in the context here.
Different activation agents can be utilized, including potassium hydroxide, potassium oxalate, potassium acetate, and calcium acetate. See
This adsorption capacity surpasses amine scrubbing which has 13 wt % CO2-capacity at 1 bar at 25° C. While KOH is commonly reported in literature as an effective activation reagent for high surface area porous carbon synthesis [He 2016; Otowa 1997]; it is corrosive, hard to handle in large quantities and can have detrimental human health effects. The utilization of potassium acetate or calcium acetate as an activation reagent in embodiments of the present invention is highly advantageous because potassium acetate is a greener and nontoxic activation reagent and calcium salts are green and even less toxic that most other metal salts. In fact, potassium acetate is commonly used as food additive as acidity regulator and flavor enhancer.
Synthesis was carried at different temperatures (
In exemplar methods of the present invention, plastic waste was chemically activated using potassium acetate. 8 grams of plastic cups and milk bottles were cut into small 2 cm2 pieces and the plastic mixture was processed at 160° C.-180° C. in a Brabender melt mixer (model type 808-400-DTI). Once melted, potassium acetate was added to the polymer melt at salt: plastic weight ratio of 0.5-2. After adding potassium acetate to the polymer melt, the mixture was mixed in the Brabender at 50 RPM for 15 min to form a homogenous blend. The mixture was cool before transferring the polymer-based mixture to a ceramic boat and heating in a tube furnace at rate of 20° C./min under argon atmosphere. Once the targeted temperature was reached, the temperature was held for 50 min to obtain 6 grams of product. The mixture was washed with DI water to obtain 0.8 g of porous carbon. While heating, the polymer was observed to crack and some liquids distilled out into the cool region of the tube. These are the volatile fractions that have ancillary commercial value in the pyrolysis.
The structural and chemical properties of the synthesized sorbent is presented in TABLE I.
The Brunauer-Emmett-Teller (BET) surface area were characterized via N2 physisorption analysis at 87 K. The results show that the surface area and total pore volume decrease as temperature increase indicating a collapse in the pore structure as temperature increase (TABLE I). Pore size distribution was studied via DFT theory to find that sorbents activated 600° C. have pores diameter of 10, 25 and 30 Å. Samples activated at higher temperatures have larger pore diameter that could go up to 100 Å. While larger pore diameter is favorable for high pressure CO2 capture, narrow pore diameter is better for CO2 capture at 1 bar.
The morphology of the sorbent was studied using environmental scanning electron microscope (ESEM).
XRD and TGA were utilized to study the activation mechanism of the sorbent. XRD of the unwashed sorbent after synthesis at 600° C. indicates the formation of potassium carbonate (
2CH3COO−K+→K2CO3+CH3COCH3↑T=˜450-520° C. (1)
At 400° C., while some of the polymer decomposes to monomers, the carbon material is oxidized, and the formed CO is subsequently oxidized to generate CO2 and H2 gas (2-3).
C+H2O→CO+H2↑T=˜400° C.-460° C. (2)
CO+H2O→CO2+H2↑T=˜400° C.-460° C. (3)
This process occurs from −400° C.-460° C. in the carbon material (
K2CO3+2C→2K+3CO T>700° C. (4)
Therefore, synthesizing an sorbent at temperatures lower 700° C. is highly advantageous because it eliminate the risk forming potassium metal, (potassium is flammable and can even be explosive upon contact with air or water), which is one of the biggest challenges standing before commercializing the synthesis of porous carbon. Moreover, the use of potassium acetate instead of potassium hydroxide as an activation reagent is advantageous because potassium acetate is non-corrosive. Unlike potassium hydroxide, potassium acetate is easy to handle and will not cause continuous corrosion in the scale-up rector. Moreover, the use of potassium acetate is environmentally favorable because it is non-toxicity and the byproduct of the activation reaction is potassium carbonate, which is non-toxic, too, making it simple to deal with the waste product of this reaction.
Embodiments of the present invention (and its method of activation) can utilize different plastic types, including LDPE and PP (see
As shown in
Post-combustion streams are made of around 10% CO2 and 90% N2. Therefore, selectivity is an important parameter for sorbent quality.
where,
The LAST selectivity of the sorbent was found to be 150 at 0.1 bar and 58 at 1 bar (
To understand the nature of interactions between the CO2 gas and the sorbent, isosteric heat of absorption (Qst) was calculated using Clausius-Clapeyron equation (eq.3) using the isotherms collected at 20° C. and 25° C. (
where,
The sorbent has a maximum heat of adsorption of 51 kJ/mol (
Byproducts of Reaction when Making the Carbon Materials.
The prior art shows the feasibility of cracking plastic waste over zeolites or bentonite clay to get liquid fuels and an ash that has no significant use. [Budsaereechai 2019; Kumar 2011]. The activation process disclosed and taught herein allows one to produce monomers as a gas and oligomers as solid, waxy or oily deposits in the cool regions of the furnace without the generation of the undesirable ash that is usually obtained in conventional methods of plastic pyrolysis.
Ethylene can be reacted with other chemical feedstocks to produce polyvinyl chloride, polystyrene, and polyester resin. Therefore, the demand of ethylene is high worldwide. Currently, large-scale production of ethylene is carried in steam cracker where naphtha and paraffin hydrocarbon are pyrolyzed in the presence of steam. The temperatures in a typical steam cracker that could reach 850° C. and the yield of ethylene is only 30% ethylene when naphtha is cracked at high severity. While the demand for ethylene increases every year, ethylene trade is limited due to challenges in transporting and refrigerating ethylene. The pyrolysis method disclosed and taught herein is simple and allows for ethylene production on site using plastic waste, making ethylene production not limited to large petrochemicals companies. The beauty of this process is what can be done with the remaining carbon when it is mixed with an additive that will make the carbon porous while remaining flexible in desired cases.
While activating plastic waste at 600° C. yields rigid porous carbon that is attractive for CO2 capture at low pressure, it was found that activating the plastic waste at temperatures around 500° C. yields carbon materials that behave like a metal organic framework (MOF) and porous polymers.
The CO2 sorption process was evaluated at different temperatures and it was found that high temperatures increased the CO2 uptakes at lower pressure, as shown in
The scale up of the synthesis process was considered.
As the synthesis process disclosed and taught herein involve synthesis of high surface area sorbent at 475-600° C., this eliminate the risk of forming undesired materials, such as potassium metal. For instance, in embodiments of the present invention, potassium acetate can be utilized. Potassium acetate is non-toxic and cheap as compared to potassium, which is corrosive and has determine health effects.
Embodiments of the present invention can be used as a technology for chemical recycling of plastics via thermal cracking of plastic wastes to get oligomers, monomers and porous sorbent. Furthermore, the resultant sorbent has properties, such as the high porosity and electrical conductivity, which can be utilized.
Batteries/Cathodes
The porous carbon obtained from the processes described herein is a good CO2 sorbent and has high capacity when used as a anode or cathode for batteries.
Hydrogen Storage
The porous carbon can be utilized for hydrogen storage. The low activation temperature of 2,1-HDPE-500 allows for the formation of micropores that are ideal for hydrogen storage at 100 bar.
Methane and Mix Gases Storage
As show in
Oxygen Storage Tanks
The flexible sorbent shows high oxygen capacity reaching an uptake of 155 wt % oxygen at 125 bars as shown in
The sorbent described herein can be nitrogen-doped (N-doped) for further uses.
Differential scanning calorimetry was used to determine the glass-transition temperature of the sorbent 2,1-HDPE-500.
It is standard in the practice of gas uptake measurement to subject the material to an absolute pressure of at around 0.00013 bar (0.1 mmHg) or lower absolute pressure. This is done to remove any remaining sorbates from the material in order to get an accurate uptake of gas in the subsequent experiment. This is also done in BET surface area determination equipment before the surface area is determined. While low absolute pressure activation is fine for the rigid carbon materials that were prepare at around 600° C., it is destructive to the flexible carbons made at around 500° C. The applicants discovered that these low absolute pressures cause destruction of this flexible carbon material presumably by collapse of the framework. One needs to exercise extreme care in the pressure control of these carbon frameworks in order to preserve their structure. The uptake capacity of the flexible sorbent is dependent on the level of vacuum applied as a pre-treatment to activate the materials by removing the traces of sorbates like water, i.e. the absolute pressure before the sorbent gas is introduced. If the sample is subjected to even slightly more vacuum (lower absolute pressure), then the capacity to sorb the gas is drastically reduced since the material undergoes a catastrophic change in structure wherein its density lessens (from about 1.5 g/cc to less than 1.0 g/cc) and its gas uptake capacity plummets. The absolute pressure (or level of vacuum) during this pretreatment where the failure occurs is also temperature dependent. However, when the quality of the vacuum is poorer (i.e. at slightly higher absolute pressure) then the uptake is high when the gas is introduced.
Collapse upon drying or removal of sorbates is a known phenomenon with some metal organic frameworks (MOFs). MOF is an example of a sorbent with pores that have unique interaction with the solvent. Complete removal of the solvent from pores results, in some cases, in pore collapse. The pore collapse and interactions between the different MOFs and solvents has been studied extensively. [Hisaki 2018; Dodson 2018]. To prevent the MOFs pore collapse the pores must be supported with polymer or covalent interactions. [Peng 2019]. Furthermore, porous polymeric membranes have been reported to demonstrate unique solvent-pores interactions. It has been shown that solvent choice, heating time and temperature affect the pores interconnectivity. [Lu 2018]. Moreover, the interactions between the polymers strands also plays a role in preserving the porous structure. Strong polymer-polymer interaction may lead to pore collapse. [Lu 2018; Bhattacharjee 2018]. Pore collapse in carbon materials: (A) Cellulose cell wall pore collapse in wood derived porous structure upon drying; some work shows that drying water from the nanopores in wood leads to the collapse of the pores. [Papadopoulos 2018]. (B) Templated porous carbon can collapse upon drying. Thus, cationic polyelectrolyte template or surfactant must be used to stabilize the porous structure. [Dutta 2014]. The “pore collapse during the drying step due to large capillary forces imposed at the liquid-vapor interface” is known. [Lee 2002]. Functionalized pores collapse due to drying is known. Some structural deterioration of functionalized porous carbon is known when a hydrophilic porous carbon is dried. The work shows a decrease in the surface area and pore volume upon drying water or solvent exchange with ethanol. Freeze drying was found to be effective at preserving the porous structure. Hydrophobic porous carbons were found to remain intact upon drying and are not affected by water removal. [Zhang 2019]. Note that the porous carbons in that work by Zhang 2019 was prepared by a silicon templating method. This is distinct from embodiments of the present invention which were porous carbon that was hydrophobic with very little non-carbon content. Further, there are no known reports of porous carbon collapse in carbons prepared by potassium salt activation.
The results as described herein show that higher vacuum (lower absolute pressure) pre-treatment could alter the structure of the sorbent material and lowering its uptake capacity. Three possible mechanisms are suggested below:
First possible mechanism: after the starting polymer has been subject to partial thermal decomposition at elevated temperatures in argon, when the tube furnace is opened, room air displaces the argon. Atmospheric moisture is likely to be strongly sorbed into the pores. The material was further submersed in water to remove excess salts after the carbonization step, then the material is put in an oven at 100° C. to give it a dry surface appearance. Yet sorbed water will remain in the pores. Upon lowering the absolute pressure, the nitrogen, oxygen, argon, and similar non-polar species will be quickly pumped away, whereas water is quite “sticky,” meaning that its polar interactions keep to sorbed to the carbon. This makes water the overwhelming favorite as the sorbed species that give rise to this observation. Inside the pores, the water has a vapor pressure, but is much lower than liquid water because the water molecules are sorbed onto the surface. Let us assume for this argument that the average vapor pressure of the sorbed water in the sample is 7 mbar. If the needle valve is used to keep the pressure at 10 mbar in the pre-treatment chamber, then little water vapor escapes from the sample because there is not enough pressure to displace the external surrounding gas. A small amount will be lost due to diffusion, but nearly all water molecules that desorb will just re-sorb. When the pressure is reduced to 4 mbar (well below the internal vapor pressure), it is believed that the 7-mbar internal vapor pressure can displace the lower external pressure, and water molecules will freely escape from the sample into the chamber. The sample is quickly dehydrated, and the nano-sized pores collapse once the sorbed water is gone and cannot be re-opened.
The second possible mechanism is similar to the first: the polymer is partially decomposed, will likely leave many reactive sites, with radicals and multiple bond structures. The highly polar water molecule will adhere due to van der Waals attractions of the water to these sites. So, water is keeping the reactive sites from binding to each other. However, if the water is completely removed, then these nanoscale pores are likely to collapse, and gas species cannot pry the pores open again. In effect, this becomes a new material, with the partially decomposed hydrocarbon chains that are propped apart by water molecule.
A third possible mechanism is that at the lower absolute pressures, the flexible domains from the remaining short range polymer order (as described in
External Vacuum Control System
The Rubotherm system determines gas uptake by weight increase. As is the case for most gas uptake measuring systems, it is designed to evacuate the sample to a low absolute pressure of 0.1 mmHg or less, which has the built-in assumption that vacuum will not alter the material morphology. Hence, the sample is exposed to the best vacuum (lowest absolute pressure) that the pump can generate. For a mechanical pump, this is 0.1 mmHg (0.13 mbar) and likely lower. The limit of resolution of the Rubotherm gauge is 0.01 bar, which does not allow useful pressure measurements in the range of interest when the water is outgassing. A high vacuum gauge can be installed on the pumpout line, but the many tubes, valves, and fittings in the control box will have a low gas conductance, whereas the tube connecting to the vacuum pump has a high gas conductance. Therefore, the gauge is measuring the pressure of the pump, not the sample, which could be one to two orders of magnitude higher than the gauge reading. Since it is not feasible to connect directly to the sample chamber, which is designed for greater than 200 bar, then the gauge system must necessary be mounted external to the Rubotherm control box.
In order to measure the sample pressure so far from the gauge, it is necessary to introduce a restricted conductance with an external vacuum manifold.
In embodiments of the present invention, ball valve 2304a can be main pumpout valve, ¼ turn, ½ inch tube (Swagelok B-8P6T). Ball valve 2304a can be open for total pumpdown and closed for measurements. Ball valve 2304b can be a three-way ¼ turn valve (Swagelok SS-41-XS2 or SS-41-GSX2). The middle position with the handle perpendicular to the tubing is the off position, ¼ turn up to open to the manifold, and ¼ turn down to vent absolute pressure gauge 2303. This isolates and protects absolute pressure gauge 2303 until conditions are appropriate for a measurement. Needle valve 2305a can be a regulating needle valve in parallel (Swagelok SS-ORS2) and can be a multi-turn adjustable valve. This valve provides fine control on pumpout rate when ball valve 2304a is closed. Ball valve 2305b can be a vent valve for absolute pressure gauge 2303. Needle valve 2305b is typically barely open. When the handle for ball valve 2304b is turned to the down position, needle valve 2305b lets air in slowly to bring the needle for absolute pressure gauge 2303 to full scale in about 5 seconds. Then ball valve 2304b is closed. Needle valve 2305c is a manifold vent valve that is normally kept closed.
Vacuum gauge 2302 can be a Bourdon tube gauge, which measures pressure relative to atmospheric pressure. “0” is the reading when open to air. −30 inches Hg is full vacuum, and 15 psi about 1 atmosphere above room pressure. This is termed a combination gauge. A conventional Bourdon-tube gauge is used to measure from atmosphere to vacuum and it is not suitable for an accurate measure of the absolute pressure. The term “vacuum gauge” implies that the gauge is measuring a decrease in pressure relative to atmospheric pressure and the numerals have a minus (−) sign. When the vacuum gauge 2302 goes below −25 inches Hg (≈130 Torr remaining) then the 3-way valve can be switched to absolute pressure gauge 2303. The reason for using a combination gauge rather than vacuum only, is that this provides a check to see if the Rubotherm is venting to the pump while under pressure. Since this gauge is referenced to atmospheric pressure (which changes with the weather) it is not suitable for low-pressure measurements. Absolute pressure gauge 2303 (Edwards Vacuum) has an internal evacuated “can” with a “lid” that is mechanically connected to the pointer. This reference is sealed high vacuum, and it is unaffected by the barometric pressure or temperature. The gauge glass is much thicker since the entire volume of the gauge is evacuated. The absolute pressure gauge 2303 used can be a 25 mbar (absolute) full scale, which is the most sensitive available. This type of gauge is easily damaged by the shock wave if atmospheric pressure is allowed to rush in when it is evacuated. The needle will move with extreme speed and can bend or break off. The Rubotherm pumpout valve just pops open, which will ruin the gauge, as a discussion with the manufacturer confirmed. Hence there are protective devices incorporated in the design. The connecting tube can be at least 3/16 inch OD, which can be shaped by hand. ¼ inch SS tube needs a tube bender. 40 mbar and 100 mbar ranges can alternatively utilized.
The first level of protection for the absolute pressure gauge is ball valve 2304b that has two quarter turn motions. The protective air inlet needle valve 2305b is used to control the air inlet to the absolute pressure gauge 2303 when the 3-way valve is switched to the vent position; this low-flow needle valve is the primary protection for absolute pressure gauge 2303. One position vents absolute pressure gauge 2303 to air, the opposite position connects to the vacuum manifold, with off in the middle position. Needle valve 2305b attached to the vent connection restricts the airflow to the absolute pressure gauge 2303. The absolute pressure gauge 2303 is vented through needle valve 2305b to reach full scale (but does not need to be more than 25 mbar); and then shut off ball valve 2304b. When the Rubotherm has opened to the pump, and vacuum gauge 2302 is below 25 inches Hg (typical units for Bourdon vacuum gauges) or about 100 Torr, then ball valve 2304b can be switched to connect to the manifold and measure the absolute pressure, and comes on scale at 25 mbar absolute.
Snubber 2307 (such as McMaster-Carr 4072K6 with the most restrictive “A” piston) provides a second layer of protection. There is a small piston that is pushed upward into an orifice to restrict flow when there is a fast inrush of air and protects the absolute pressure gauge 2303. With the piston engaged, it typically takes about 2 seconds for absolute pressure gauge 2303 to go to the peg at 25 mbar. A simple version of a snubber is a fitting with a pinhole passage, but this also restricts pump down rate. The largest orifice available from McMaster-Carr is 0.015″, which is too small, and it was drilled out to 0.025″ with a #72 drill in a hand-held pin vise (an electric drill would break the bit). The second option is a piston snubber that must be mounted in the vertical direction. When the airflow is too fast, it lifts the piston and plugs the orifice.
However, the surface of the orifice apparently was not smooth and did not seal well, allowing the gauge to move too fast. Since the orifice is brass and the piston is steel, a pin punch and hammer were used to gently flatten the brass orifice for a better seal. With this modified piston snubber, the evacuated gauge can be switched suddenly to atmospheric pressure without damage. When the piston is in the lower (normal) position, the pump down rate of the gauge is adequate. This piston “vibration damper” is also available from McMaster Carr (which is what is used in the described system). Normally, the 3-way valve is turned off once the needle reaches the 25 mbar peg, leaving the gauge under partial vacuum. It is kept in the off position until the manifold pumpout pressure is below 25 inches Hg and then switched to the manifold to read the decreasing pressure. For pressures below 2 mbar, it may take the gauge a minute or more to settle down. Also, it is beneficial to gently tap the gauge after a minute to help it settle. The absolute pressure is controlled with needle valve 2305a. The desired pressure can be approached gradually to allow equilibration between the sample and the absolute pressure gauge 2303. For lower pressures in the range of a few mbar, more time is needed because the pressure drop is so small and the flow rates are likewise small. Gently tap the gauge to help it settle. If the pressure rises when the bypass valve is closed, this indicates outgassing of the sample and the rise will slow down. In contrast, if there is a leak the pressure will rise at a steady rate until the gauge reaches its maximum. When the pressure is steady for 30 seconds to a minute, then this is also the pressure of the sample.
For pressure control manifold 2300, a ½ inch tube goes to the oil-type rotary vacuum pump, and the manifold is fitted with a ¼-turn ball valve 2304a for unrestricted pumping and will achieve <0.1 mbar in seconds when opened. Since needle valve 2305a bypasses ball valve 2304a, when ball valve 2304a is closed, needle valve 2305a can then be used to reduce conductance or even stop pumping action altogether to control the pressure in the sample. As needle valve 2305a is closed down and the conductance becomes much less than that through the control box, vacuum gauge 2302 will come into equilibrium with the sample. Outgassing may cause the pressure to drift upwards, and a slight opening of needle valve 2305a can compensate to keep the pressure stable. While ball valve 2304a can be used for quick pump down, needle valve 2305a is normally used to slowly approach the desired manifold pressure, and because the pressure is approached slowly, it is also close to the sample pressure.
For water outgassing, all manifold components can be brass with copper tubing. However, other polar molecules may be introduced as proppants. Ammonia, NO2 and halogen acids will attack copper and brass, and in this case, stainless steel is preferred. All fittings are Swagelok fittings.
Embodiments of the present invention can encompass converting plastic bags to flakes for use in the synthesis processes described herein or for use to make in other synthesis process, such as in the flash Joule heating synthesis method described in PCT International Patent Appl. Serial No. PCT/US19/47967, filed Aug. 23, 2019, to Tour et al. (which describe and teach among other things, methods for making flash graphene). Of the many problems with recycling plastic, plastic shopping bags are among the worst of the problems. Conventional recycling machines cannot handle the bags because they get entangled in the slow turning shredders that are made for harder plastics. And bags left in the open are degraded by sunlight and air, and because they are lightweight, can easily be dispersed by wind. Unfortunately, the bags do not break down completely but instead photo-degrade, becoming microplastics that absorb toxins and continue to pollute the environment. Microplastics and nanoplastics adversely affect the food chain and they degrade the immune system. [Allen 2019].
A bag flaker device utilizing the processes of the present invention can be located at a store entry to minimize employee work and allow the customer to know that the customer's efforts are directly contributing to the recycling effort.
As shown in
In step 2602, the bags 2617 are feed into the chopper 2618 using rollers 2611, which feed the bags 2617 into the chopper 2618 at a constant feed rate.
In step 2603, chopper 2618 is used to sheer the bags to plastic flakes 2619. The chopper 2618 includes a high speed rotor with rotating knives 2613, which are close in tolerance to fixed knives 2614.
In step 2604, the smaller flakes 2619 will pass through sizing mesh 2614 located at the bottom of chopper 2618. The larger flakes 2619 (too big to pass through sizing mesh 2614) will circulate in chopper 2618 so that they can be cut smaller.
In step 2605, the flakes 2619 (that pass through sizing mesh 2614) will fall by gravity into a receptacle, such as barrel 2615. A bag 2616 is lined inside barrel 2615.
In step 2606, once barrel 2615 is full, the bag 2616 is removed with the flakes 2619 (and replaced with a new bag 2616). The flakes 2619 can then be utilized in a synthesis process as described above.
For safety and other reasons, equipment may be added to prevent/avoid customers (and especially children) from throwing foreign objects into the device.
In step 2701, the store employee/customer/etc. feeds the plastic bags 2617 into the inverted funnel 2720.
In step 2702, bag sensors 2721 search for foreign objects. Bag sensors 2721 may use light scattering, radio waves, ultrasound and/or millimeter waves to determine that the item is a bag and does not contain foreign objects.
In step 2703 after determining that the bag 2617 is empty and there are no foreign objects, controls 2722 turn on the suction. Controls 2722 do not switch on the suction until the bag is positively identified.
In step 2704, suction pulls the bag 2617 into and through pipe 2723, and the bag is carried by the air flow to the rollers 2611.
In step 2705, the bags 2617 are feed into the chopper 2618 using rollers 2611, similar as described above in step 2602 for
In step 2706, chopper 2618 is used to sheer the bags to plastic flakes 2619, similar as described above in step 2603 for
In step 2707, the smaller flakes 2619 will pass through sizing mesh 2614 located at the bottom of chopper 2618, similar as described above in step 2604 for
In step 2708 a suction pipe (or exit hose) 2724 is utilized to deliver the flakes 2619 to a receptacle, such as vacuum canister 2725, which can be nearby. (Alternatively, the vacuum canister 2725 can be located at a remote location, such as in the stockroom at the back of the store. The latter case will reduce employee time and could allow central collection for several bag cutters if the store has multiple entries). The vacuum canister 2725 is lined with a bag, similar to as shown in
In step 2709, vacuum canister 2725 collects flakes 2619.
In step 2710, the bag is removed from the vacuum canister 2725 (such as by an employee removing it and tying it off).
The bagged flakes (such as produced from the above systems/methods of
Further advantages for the store (as well as other similarly situated users) include:
As discussed above, the present invention relates to porous polymeric carbon sorbents for CO2 capture and methods of making and using same. The porous polymeric carbon sorbent is rigid and the CO2 captured from the flue gas and for gases from other post-combustion CO2 emission outlets can be released at low temperature (such as around 70° C. to 75° C.) when there are no nitrogen atoms as part of the polymeric carbon sorbant and at around 110° C. when there are nitrogen atoms as part of the polymeric carbon sorbent. Or one can reduce the pressure to release the captured CO2 from the porous polymeric carbon sorbent. The term “post-combustion CO2 emission outlet gas” refers to the exhaust gases (which include CO2) that evolved from any combustion process, such as industrial applications, like flue gas from a power plant or other fossil fuel-based large point source, from a factory, exhaust from a vehicle, and the burning of oil, natural gas, gasoline, diesel, etc.) The term “rigid” as used herein when referring to the porous polymeric sorbent refers to that the polymer of the sorbent having lost its long range order and short range order as detected by powder X-ray diffraction (XRD). The term “flexible” as used herein when referring to the porous polymeric sorbent refers to the polymer of the sorbet having lost its long range order while retaining its short range order as detected by powder XRD.
HDPE, PP and LDPE may be used for this rigid polymer system.
In an example utilizing a melt mixing procedure, 8 g of plastic was cut into small 2 cm2 pieces and melted at 150° C.-170° C. in a Brabender melt mixer (model type 808-400-DTI). This took less than 5 minutes. Once melted, potassium acetate was added to the polymer melt as salt: plastic weight ratio of 4:1 (salt to polymer) and was mixed at 50 RPM for 10 min at 150° C. to form a homogenous blend. Then, 2 g of the polymer-based mixture was transferred to a ceramic boat and heated in a tube furnace at a rate of 25° C./min under argon atmosphere. The temperature was held at 620° C. for 45 min to carbonize the plastic and get porous carbon. After cooling down, 1.5 g of sorbent/salt product was recovered. The product was washed with DI water and filtered using a 0.22 μm PTFE filter to obtain 0.07 g of porous carbon after drying at 100° C. overnight.
In an example that utilized an alternative approach using powdered plastic, to make plastic powder, plastic waste was chilled in liquid nitrogen before it was ground using a commercial mill. After that, 8 g of plastic powder was mixed with potassium acetate at salt: plastic weight ratio of 4:1. Using a mortar and pestle, the plastic/salt mixture was mixed until a homogeneous blend is formed. Then, 2 g of the polymer-based mixture was transferred to a ceramic boat and heated in a tube furnace at rate of 25° C./min under argon atmosphere. The temperature was held at 600° C. for 45 min to carbonize the plastic and get porous carbon. After cooling down, 1.5 g of sorbent/salt product was recovered. The product was washed with DI water and filtered using a 0.22 μm PTFE filter to obtain 0.07 g of porous carbon after drying at 100° C. overnight.
To activate the sorbent, heat the sample at a temperature of 120° C. and pressure of 1 mbar (full vacuum) for at least 1 hour.
As shown in
Calcium acetate can be utilized in lieu of potassium acetate to make the rigid sorbets.
In some embodiments, the rigid sorbet can be N-doped by adding N-containing polymers to the HDPE (or other polymer).
N-doped sorbent can also be synthesized from different N-containing polymers to have an uptake of 20 wt % at 1 bar.
N-doping further allows for tuning heat of adsorption and will lead to higher regeneration temperature.
Because the rigid sorbent material can release the captured CO2 at low temperature, waste heat or recycle streams can then be utilized.
As discussed above, the present invention relates to flexible porous polymeric carbon sorbents for gas storage. The gas can be, for example, H2, CO2, O2, methane, and natural gas. The gas can be contained in containing that includes the flexible sorbent, and an increased amount of gas can be stored in the container as compared to the container without the flexible sorbent. I.e., the storage container can store more H2, O2, methane, or natural gas at about 25° C. and about 100 atm than in the storage container without the flexible porous carbon material at the same conditions. For instance, the container can be a hydrogen storage vessel to contain H2 for an automobile that runs on H2. And even much more storage can be achieved at 300 atm.
In example utilizing HDPE, 8 g of plastic was cut into small 2 cm2 pieces and melted at 150-170° C. in a Brabender melt mixer (model type 808-400-DTI). This took less than 5 minutes. Once melted, potassium acetate was added to the polymer melt at salt: plastic weight ratio of 4:1 and was mixed at 50 RPM for 10 min at 150° C. to form a homogenous blend. Then, 2 g of the polymer-based mixture was transferred to a ceramic boat and heated in a tube furnace at rate of 25° C./min under argon atmosphere. The temperature was held at 500° C. for 40 min to carbonize the plastic and get porous carbon. After cooling down, 1.5 g of sorbent/salt product was recovered. The product was washed with DI water and filtered using a 0.22 μm PTFE filter to obtain 0.08 g of porous carbon after drying at 100° C. overnight.
To activate the sorbent, one of the following can be performed:
The United States Department of Energy (DOE) goal for 2020 for onboard hydrogen storage for light-duty vehicles is 4.5 wt % at 100 atm and room temperature. The DOE's goal for 2025 is 5.5 wt % at 100 atm, with an ultimate goal of 6.5 wt % at 100 atm and room temperature. [DOE Technical Targets]. Embodiments of the present invention have already exceeded the 2025 goal and the ultimate goal with their 8 wt % capture at 100 atm and room temperature, thereby underscoring the novelty of the advance described here.
The present invention relates to porous polymeric carbon sorbents for direct air capture (DAC). The results reveal that the porous polymeric carbon sorbents perform better than sorbents with metal-organic framework (MOF), but with none of the high-cost, water instability, and volumetric problems associated with MOFs. Direct air capture of CO2 (and other gases) from air is a technological goal important to large-scale industrial processes such as gas purification and the mitigation of carbon emissions. Moreover, the porous polymeric carbon sorbents can selectively sorb the gases from air.
In example utilizing HDPE and/or LDPE, to make plastic powder, plastic waste was chilled in liquid nitrogen before it was grounded using a commercial mill. After that, 1 g of plastic powder was mixed with potassium acetate at salt: plastic weight ratio of 4:1. For N-doping, 1 g of N-containing feedstock was added to the plastic/salt mixture. Using a mortar and pestle, the plastic/salt mixture was mixed until a homogeneous blend is formed. Then, 2 g of the polymer-based mixture was transferred to a ceramic boat and heated in a tube furnace at rate of 25° C./min under argon atmosphere. The temperature was held at 620° C. for 45 min to carbonize the plastic and get porous carbon. After cooling down, 1.5 g of sorbent/salt product was recovered. The product was washed with DI water and filtered using a 0.22 μm PTFE filter to obtain 0.07 g of porous carbon after drying at 100° C. overnight.
To activate the sorbent, heat the sample at 120° C. under vacuum (1×10−3 mbar) for at least 4 hours. Possible N-containing chemicals include melamine resin, polyethylenimine (most effective), urea, nylon, and NH3 gas (during the furnace stage).
Additional variations of these embodiments will be obvious to those of ordinary skill in the art. Therefore, the spirit and scope of the appended claims should not be limited to the foregoing description. Only those claims specifically reciting “means for” or “step for” should be construed in the manner required under the sixth paragraph of 35 U.S.C. § 112.
While embodiments of the invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. The embodiments described and the examples provided herein are exemplary only, and are not intended to be limiting. Many variations and modifications of the invention disclosed herein are possible and are within the scope of the invention. The scope of protection is not limited by the description set out above, but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims.
The disclosures of all patents, patent applications, and publications cited herein are hereby incorporated herein by reference in their entirety, to the extent that they provide exemplary, procedural, or other details supplementary to those set forth herein.
Amounts and other numerical data may be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a numerical range of approximately 1 to approximately 4.5 should be interpreted to include not only the explicitly recited limits of 1 to approximately 4.5, but also to include individual numerals such as 2, 3, 4, and sub-ranges such as 1 to 3, 2 to 4, etc. The same principle applies to ranges reciting only one numerical value, such as “less than approximately 4.5,” which should be interpreted to include all of the above-recited values and ranges. Further, such an interpretation should apply regardless of the breadth of the range or the characteristic being described. The symbol “—” is the same as “approximately”.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently disclosed subject matter belongs. Although any methods, devices, and materials similar or equivalent to those described herein can be used in the practice or testing of the presently disclosed subject matter, representative methods, devices, and materials are now described.
Following long-standing patent law convention, the terms “a” and “an” mean “one or more” when used in this application, including the claims.
Unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification are approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter.
As used herein, the term “and/or” when used in the context of a listing of entities, refers to the entities being present singly or in combination. Thus, for example, the phrase “A, B, C, and/or D” includes A, B, C, and D individually, but also includes any and all combinations and subcombinations of A, B, C, and D.
This application is a 35 U.S.C § 371 national application of PCT Application No. PCT/US20/55637, filed on Oct. 14, 2020, entitled “Porous Polymeric Carbon Sorbents For Co2 Capture And Methods Of Making And Using Same”, which claims priority to U.S. Patent Appl. Ser. No. 62/914,826, filed Oct. 14, 2019, entitled “Method To Convert Plastic Waste To Porous Polymeric Carbon Sorbents And Compositions Thereof,” which patent applications are commonly owned by the owner of the present invention. This application relates to PCT Appl. No. PCT/US20/55638 (Attorney Docket No. 072174-01201), filed concurrent herewith, entitled “Porous Polymeric Carbon Sorbents For Gas Storage And Methods Of Making And Using Same,” and PCT Int'l Appl. No. PCT/US20/55639 (Attorney Docket No. 072174-01301), filed concurrent herewith, entitled “Porous Polymeric Carbon Sorbents For Direct Air Capture Of CO2 And Methods Of Making And Using Same,” which patent applications are commonly owned by the owner of the present invention. These patent applications are incorporated herein in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US20/55637 | 10/14/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62914826 | Oct 2019 | US |
