Solvates and methods for the capture and defluorination of per- and polyfluoroalkyl substances (PFAS).

Abstract

To provide an adsorbent system that can efficiently remove PFAS. [Solution] The system comprises a porous polymer material such as a foam like polyurethane, and may contain nanoparticles and / or active chemical groups. The porous polymer can be activated to improve capture. Captured contaminants can be desorbed using solvents and mechanical methods, and the contaminants can then be concentrated and destroyed by the application of energy, for example, acoustic energy, ultrasound, and / or light such as UV or visible light.

Description

[Background technology]

[0001] Environmental pollution can be caused by industrial processes, fossil fuels, waste disposal, plastics, and other processes and materials. Many pollutants can cause serious harm to people, but once released into the environment, they are extremely difficult to remove. Water pollution is of particular concern because we depend on clean drinking water for survival, and even very low levels of contamination can be harmful. People are increasingly recognizing the need to prevent the release of pollutants into the environment. However, the environment is already contaminated by pollutants released in the past, and harmful pollutants continue to be released or leak into the environment. Therefore, there is a great need to effectively and efficiently remove pollutants from the environment and to manage them after they have been removed.

[0002] One class of chemical contaminants of concern is perfluoroalkyl and polyfluoroalkyl substances (PFAS). PFAS are a broad category of synthetic organic fluorine compounds in which all (per-) or some (poly-) of the hydrogen atoms of the alkyl chain are replaced by fluorine. These C-F groups enable PFAS to have remarkable chemical stability and hydrophobic properties, making them ideal for commercial use in waterproof coatings, fire-fighting foams, and chemical manufacturing. The fluorinated alkyl chains are generally produced with hydrophilic end groups to enable water solubility and enhanced commercial utility. However, these compounds have been shown to be highly mobile and bioaccumulative in the aquatic and marine environments. Because these compounds are very persistent, they have been found in Arctic wildlife and human tissues. The potential toxic effects of PFAS are still being studied, but the prevalence of these chemicals has raised concerns from public health and environmental protection agencies. Due to the increasing regulatory pressure on PFAS in water sources, many industries and public utilities are attempting to upgrade their treatment facilities. Due to the high cost of maintaining and upgrading these facilities, the unstable performance of current processes, and the disposal costs of their hazardous waste, the industry is currently seeking new technologies that can efficiently remove PFAS while reducing capital investment and operating costs.

[0003] Various methods are known for capturing contaminants such as PFAS. However, such methods may be non-selective, have low loading capacity, and carry the risk of re-release or leaching. Furthermore, captured contaminants must be managed to avoid re-contamination of the environment and may need to be treated like toxic or hazardous waste. For example, they may be securely contained, transported, and stored in disposal facilities such as sealed underground storage. Even if captured contaminants can be removed from the sorbent, the result of this process is concentrated waste of released contaminants, typically liquid, which must then be managed further. For example, contaminants in the waste may be treated in a decomposition process. However, the products of this decomposition itself may be harmful to the environment. Another disposal method involves incineration, which involves burning the sorbent material to which the contaminants are bound in an industrial furnace or similar to destroy the contaminants and the sorbent material. However, incineration may release undesirable substances into the air. Thus, each of these disposal methods has its own problems.

[0004] Improved methods are needed to capture pollutants and manage the final products of pollutant capture. [Overview of the project]

[0005] Various embodiments include an sorbent system comprising at least one active chemical group of the porous polymer material bonded to the outer surface and within the porous polymer material. In some embodiments, the porous polymer material is a foam such as polyurethane. In some embodiments, the porous polymer is a fibrous polymer sheet such as polyamide. In some embodiments, the sorbent also comprises at least one active chemical group such as at least one of amines, thiols, and alcohols. The active chemical group may be hydrophobic.

[0006] Other embodiments include an sorbent system comprising a porous polymer material, nanoparticles bonded to the outer surface and within the porous polymer material, and at least one active chemical group bonded to the nanoparticles. The nanoparticles may, for example, comprise one or more metals or metal oxides. In some embodiments, each of the nanoparticles has a diameter between 1 nm and 500 nm. The nanoparticles may comprise one or more of titanium, iron, manganese, zinc, silicon, or their oxides or hydroxides. The at least one active chemical group may be one or more amines, thiols, or alcohols. The active chemical group may be hydrophobic. In some embodiments, the porous polymer material is a foam such as polyurethane. In some embodiments, the porous polymer is a polyamide.

[0007] Other embodiments include a method for desorbing a bound, persistent organic compound from an sorbent. In some embodiments, such a method includes adding an sorbent to a vessel, wherein the sorbent comprises a porous polymer with one or more persistent organic compounds bound to the sorbent; adding a solvent solution comprising an organic solvent and an organic base to the vessel; and passing the solvent solution through the sorbent in the vessel to release the bound, persistent organic compound from the sorbent into the solvent solution. In such embodiments, the persistent organic compound may be, for example, a perfluoroalkyl substance or a polyfluoroalkyl substance. The organic solvent may be an organic acid or an organic alcohol. In some embodiments, the organic solvent may be methanol, ethanol, and isopropanol. The sorbent may be a foam such as polyurethane. The step of passing the solvent through the sorbent in the vessel may include mechanically compressing and releasing the polyurethane foam in the solvent solution. In some embodiments, the vessel has an inner surface coated with long-chain organic molecules such as long-chain aliphatic or branched-chain organic acids or alcohols.

[0008] Other embodiments include methods for destroying captured persistent organic compounds. In some embodiments, such methods include passing a solvent solution through an sorbent having the bound persistent organic compound to release the persistent organic compound into the solvent solution, concentrating the released persistent organic compound, and destroying the released persistent organic compound by applying energy to it. The energy may include acoustic cavitation, which may have frequencies of about 200 kHz to about 1000 kHz, for example, about 850 kHz. The persistent organic compound may be a perfluoroalkyl substance or a polyfluoroalkyl substance. Destroying such persistent organic compounds may include defluorinating the persistent organic compound. The energy may be locally applied energy. Examples of locally applied energy in various embodiments include UV energy, electrical energy, or energy under supercritical conditions. The step of concentrating the released persistent organic compound may include evaporating the solvent solution. For example, evaporating the solvent solution may include at least one of heating the solvent solution and evaporating the solvent solution under vacuum. The method may also involve suspending concentrated, persistent organic compounds in water before applying destructive energy.

[0009] Other embodiments include a method for capturing persistent organic compounds present in a liquid. The method involves passing a contaminated liquid containing the persistent organic compounds through an sorbent, which comprises a porous polymer having active chemical groups bound to its surface and within the porous polymer. The porous polymer may be a polyurethane foam. In some embodiments, the method also includes exposing the polyurethane foam to a solvent before passing the contaminated liquid through the sorbent to increase the binding capacity of the sorbent. The solvent may be, for example, methanol and ammonium hydroxide.

[0010] Further embodiments include a method for activating a porous polymer material, comprising: purifying and activating the porous polymer material by passing it through a first polar protic solvent to remove impurities and liberate existing functional groups before capturing organic contaminants; capturing at least one organic contaminant using the purified and activated porous polymer; passing the porous polymer through a second polar protic solvent to release at least one captured organic contaminant from the porous polymer into the second polar protic solvent; evaporating the polar protic solvent containing the released at least one captured organic contaminant to concentrate at least one organic contaminant; and destroying the concentrated at least one captured organic contaminant. In such embodiments, the first and second polar protic solvents may be the same solvent or different solvents. The porous polymer material may be a foam such as polyurethane. The step of destroying the concentrated at least one captured organic contaminant may include applying acoustic cavitation energy to the at least one captured organic contaminant.

[0011] Other embodiments include devices for destroying captured contaminants. In some such embodiments, the device comprises a vessel wall having an inner surface surrounding an internal space coated with long-chain organic molecules, a vessel having a first inlet in fluid communication with a reagent source, a second inlet in fluid communication with a source of desorbed contaminants in a solvent, and an outlet, and an energy source configured to guide energy into the internal space, the energy including one or more of ultrasonic energy with a frequency of about 200 kHz to about 1000 kHz, UV energy with a frequency of about 100 nm to about 400 nm, and / or visible light with a frequency of about 400 to about 700 nm.

[0012] Other embodiments include a system for destroying captured contaminants. In some such embodiments, the system includes a first vessel comprising a desorption vessel having a vessel wall defining an internal space, one or more inlets configured to receive an sorbent and a solvent containing captured contaminants, an outlet, and one or more mechanical elements for facility desorption of the contaminants from the sorbent to the solvent by causing a flow of solvent through the sorbent; a second vessel comprising a concentration vessel having a vessel wall defining an internal space, an inlet, an outlet, and a device for concentrating or evaporating the solvent in the internal space; and a third vessel comprising a destruction vessel having a vessel wall defining an internal space, an inlet, an outlet, and an energy source configured to direct destruction energy into the internal space. In such embodiments, the first, second, and third vessels can be fluidly connected so that, after the captured contaminants are released from the sorbent in the desorption vessel, they flow from the outlet of the first vessel to the inlet of the second vessel and into the second vessel, and then flow from the outlet of the second vessel to the inlet of the third vessel and into the third vessel.

[0013] In some embodiments, the sorbent system comprises a porous polymer material and a plurality of nanoparticles bonded to the outer surface and within the porous polymer material. The plurality of nanoparticles may have a diameter between 1 nm and 500 nm. The nanoparticles may include titanium, iron, manganese, zinc, silicon, or their oxides and hydroxides. In some such embodiments, the sorbent system further comprises at least one active chemical group bonded to the nanoparticles. The at least one active chemical group may include at least one of amines, thiols, and alcohols. In some embodiments, the active chemical group is hydrophobic.

[0014] This specification will focus on subject matter that is deemed to form various embodiments of the present disclosure and will conclude with the expressly claimed claims, but the present disclosure may be better understood from the following description in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0015] [Figure 1] Methods for capturing and destroying PFAS according to various embodiments.

[0016] [Figure 2] Methods for contaminants, desorption and destruction according to various embodiments.

[0017] [Figure 3] Schematic diagram of a system for contaminants, desorption and destruction according to various embodiments.

[0018] [Figure 4] Schematic diagram of an alternative system for contaminants, desorption and destruction according to various embodiments.

[0019] [Figure 5] Schematic diagram of another alternative system for contaminants, desorption and destruction according to various embodiments.

[0020] [Figure 6] Schematic diagram of another alternative system for contaminants, desorption and destruction according to various embodiments.

[0021] [Figure 7] An example of a system for contaminants, desorption and concentration composed of a solvent extraction vessel and a rotary evaporator.

[0022] [Figure 8] Results of Fourier transform infrared analysis of a polyurethane support material before and after treatment with PFOA.

[0023] [Figure 9] General structure of urethane bonds.

[0024] [Figure 10]This is a photograph showing the measurement of the contact angle of polyurethane foam.

[0025] [Figure 11a] This graph shows the loading capacity of PFOA and PFOS onto activated porous polyurethane nanocomposites.

[0026] [Figure 11b] This graph shows the loading capacity of activated porous polyurethane nanocomposites compared to other sorbent technologies.

[0027] [Figure 11c] This graph shows the dynamic data of experimental sorbation of PFOA and PFOS.

[0028] [Figure 12] This graph shows the breakthrough curves for PFOA in granular activated carbon and activated porous polyurethane nanocomposites.

[0029] [Figure 13] This graph shows the sorption of PFOS from reagent water using unpurified and purified activated porous polyurethane nanocomposites.

[0030] [Figure 14] This is a conceptual diagram of an activated nanocomposite sorbent material.

[0031] [Figure 15] This graph shows the sorption of PFOS and PFOA from reagent water using fibrous polyamide. [Modes for carrying out the invention]

[0032] This invention describes a method by which a material referred to as an sorbent, used to remove contaminants from water by adsorption or other chemical bonding interactions, undergoes desorption and recovery, and the recovered organic contaminant concentrate undergoes a post-treatment destruction process. The systems and methods described herein include the use of sorbents such as polyurethane foams with or without nanocomposites. The sorbent is first used to absorb one or more contaminants from the environment, for example, air or water, so that the contaminants bind to the sorbent. The contaminants can then be released from the sorbent, the sorbent can be recycled, and the contaminants can be destroyed. In some embodiments in which PFAS are captured, the process can break all strong carbon-fluorine bonds so that the PFAS can be generally or completely defluorinated.

[0033] Various types of sorbent systems can be used. In some embodiments, the sorbent includes polyurethane, such as polyurethane foam, where the polyurethane is alone and directly captures contaminants. In other embodiments, the sorbent system also includes nanoparticles. In some such embodiments, the sorbent system includes a polyurethane support, such as polyurethane foam, having nanoparticles on and within the foam matrix as a nanocomposite. In such embodiments, the polyurethane support matrix can directly capture contaminants, while the nanoparticles can also capture the same contaminants and / or other contaminants. In such embodiments, chemical functional groups, such as amines or quaternary ammonium groups, can be directly bonded to the polyurethane support matrix or chemically attached to the surface of the nanoparticles on and within the foam matrix.

[0034] In some embodiments, the sorbent may consist of polymer sheets, including but not limited to electrospun, wet-spun, melt-blown, and extruded films and fibers. Examples of polymers include polyamides, nylons, polystyrenes, polyurethanes, and cellulose, or combinations thereof. In some embodiments, the polymer may be fibers. These fibers may be used for filtration as a curved fiber filter material. In some embodiments, the sorbent comprises two or more polymers.

[0035] In some embodiments, the nanocomposite is a two-phase material comprising metallic or nonmetallic nanoparticles on the surface and within the support matrix. The nanoparticles may have sizes in the nanoscale range, such as approximately 1 nm and approximately 1000 nm, or between approximately 1 nm and approximately 500 nm, or between approximately 100 nm and approximately 700 nm. In some embodiments, the nanoparticles may be metallic. In some embodiments, the nanoparticles may be metal oxides, such as titanium dioxide. The matrix may be, for example, a polymer matrix. The matrix may be porous and have a sponge-like structure, with the nanoparticles bonded to the porous inner and outer surfaces of the matrix throughout the pores. In embodiments where the sorbent system is a nanocomposite, the sorbent, such as a polyurethane matrix, may be a porous matrix that has pores throughout part or all of its sponge-like properties. The matrix may function as a support structure for the metallic or nonmetallic nanoparticles bonded to its surface. In some embodiments, the particles may be one or more metals or metal oxides or hydroxides such as copper, iodine, silver, tin, zinc, titanium, selenium, nickel, iron, cerium, zirconium, magnesium, manganese, silicon, copper oxide, titanium dioxide, iron oxide, and zinc oxide; nonmetals such as selenium and carbon (including graphene, graphite, and their oxides); or two or more combinations of these or other nanoparticles or alloys thereof. Metals, nonmetals, metal oxides, and other compositions may be used alone, in combination, or omitted.

[0036] Adsorbent systems containing nanoparticles useful in various embodiments may be fabricated using a thermal reduction process to create nanocomposites of metallic or nonmetallic nanoparticles bound within a matrix. Specific nanoparticles and matrices used may be selectively tailored to improve the adsorption and diffusion of one or more specific contaminants, such as PFAS, and for their use in the decomposition of captured contaminants.

[0037] In some embodiments, the sorbent system may include active chemical groups bound to the surface and bulk of the sorbent, either through direct interaction with the sorbent or attachment to nanoparticles pre-bound within the matrix. Such chemical groups include, but are not limited to, primary, secondary, tertiary, and quaternary nitrogen-containing (amine) compounds and conjugated polymers containing these compounds, sulfur-containing (thiol) compounds, and oxygen-containing (alcohol) compounds. Other chemical groups include, but are not limited to, compounds having long hydrocarbon chains such as lipids, conjugated sugars, fluorinated hydrocarbon chains, and fatty alcohols, as well as hydrophobic compounds such as alkylbenzenes and aromatic polymers.

[0038] The inclusion of active chemical groups can improve the absorption of PFAS. For example, quaternary ammonium groups provide a stable positive charge on the surface of the sorbent material. This charge attracts negatively charged short-chain PFAS molecules, such as perfluorobutanoic acid, enabling improved capture compared to sorbents that do not contain these groups. By utilizing charge-based interactions in addition to hydrophobic interactions, sorbents can capture a wider range of PFAS compounds, both long-chain and short-chain.

[0039] Figure 1 shows one method for PFAS capture and defluorination according to various embodiments. In this example, Method 10 comprises three main steps. In step 12, PFAS is captured from the stream using an sorbent such as polyurethane. Then, in step 14, the process includes desorbing the captured PFAS from the sorbent to form a concentrated stream. In step 16, the concentrated stream is treated using acoustic cavitation, UV photolysis, supercritical hydroxylation, and / or electrochemical oxidation to defluorinate the PFAS. In this way, the PFAS is captured using an sorbent and removed from the sorbent so that the sorbent can be reused for further PFAS capture. Furthermore, the captured PFAS is defluorinated to eliminate waste disposal concerns. Details of these steps are described further below.

[0040] PFAS are a major environmental concern and are a particular focus of this disclosure; however, the methods described herein are not limited to PFAS and may rather be applicable to other contaminants. Any type of compound that binds to the sorbent system may be bound, removed, and degraded using the sorbent systems and methods described herein. Examples of compounds that can be captured and destroyed include a variety of chemicals, contaminants, or contaminants. These include, for example, organic compounds such as perfluoroalkyl and polyfluoroalkyl substances, biological toxins, polycyclic aromatic hydrocarbons (PAHs), hormones, antibiotic compounds, and volatile organic compounds (VOCs). Some embodiments may be able to absorb two or more contaminants simultaneously. Examples of PFAS that can be bound, removed, and destroyed by various embodiments include synthetic organofluorine compounds in which all or some of the hydrogen atoms in the alkyl chain are replaced by fluorine. Specific examples include perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS).

[0041] Compounds captured by sorbent systems may, for example, be present in water or air in the environment. Soluble systems can be used to remove compounds from water, for example, in water treatment plants, or on the surface or underground of water such as lakes, rivers, groundwater, and wells. However, in some embodiments, the removal of these compounds may be performed before discharge into the environment, for example, in industrial situations such as pre- or during-release influenza gas, or in wastewater before or during discharge from industrial plants, so that the pollutants are never released or their release is minimized, or during manufacturing processes such as chemical manufacturing processes. Therefore, although this disclosure refers to captured compounds as pollutants, it also extends to other compounds that never become pollutants or are not normally pollutants, but which need to be captured and removed from the liquids or gases in which they exist.

[0042] An sorbent system may be placed in a liquid or gas system, such as a water or air system, so that a liquid or gas flows through it or is pumped around and / or through the sorbent, allowing contaminants to bind to the sorbent. While passing through the sorbent system, contaminant molecules are captured and bound to the sorbent. This capture can occur between the contaminant and the sorbent, such as a polymer like polyurethane, and / or by binding to nanoparticles and / or active chemical groups, if present in the sorbent system. For example, electrostatic interactions may exist between contaminants such as PFAS and carboxylic acid functional groups in alcohol and polyurethane matrices or other polymer matrices. Hydrophobic interactions may exist between nonpolar PFAS and nanocomposites, and surface binding to nanoparticles in the composite may exist. Charge-based interactions may exist between negatively charged PFAS compounds and positively charged active chemical groups in the sorbent. Other binding interactions may also occur. Once one or more contaminants are loaded into the sorbent system, the sorbent can be removed from the liquid or gas in which it is placed. The contaminants are now firmly bound to the sorbent. In this way, the contaminant is partially or completely removed from the liquid or gas.

[0043] In some embodiments, the adsorbent may be sealed in a cylindrical cartridge for filtration. Water or air is then introduced into this cartridge in a controlled manner, allowing it to be treated with the adsorbent for a set contact time. In other embodiments, the adsorbent is a flat sheet rolled around a central dispersion point. Water or air is then introduced into the cartridge, thereby flowing radially through the adsorbent for a set contact time.

[0044] In some embodiments, aromatic polyurethane foams can be used as adsorbents. For example, commercially available aromatic polyurethane foams have been found to have a high affinity for the removal of PFAS, particularly perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). Such foams are currently used in bedding materials and interior decoration.

[0045] Polymer foams, such as polyurethane foam, offer several advantages for use in sorption. The foam's open-cell structure features micro-pores that allow water to pass through the material and come into contact with the hydrophobic layer. Furthermore, polymer foams, such as polyurethane foam, have a low density that allows the material to be compressed into reactor vessels, and their lightweight nature keeps disposal costs low. Examples of material properties of polyurethane foams that can be used in various embodiments are shown in Table 1 below.

[0046] [Table 1]

[0047] Chemically, polyurethane foam is an ideal sorbent product for PFAS because it is highly hydrophobic and possesses unique chemical functional groups that enable PFAS bonding, including specific chemical functional groups inherent to urethane bonds, such as amine and carbonyl groups in the urethane bonds. By analyzing the sorbent before and after the addition of the target PFAS compound, information about the adsorption mechanism between the target and the sorbent can be obtained. The experimental results discussed in the experimental section indicate that electrostatic interactions occur between the PFAS compound and the oxygen present in the alcohol and urethane groups, the methyl functional group, and the carbon present in the urethane functional group of the polyurethane support. The sorbent of PFAS compounds by polyurethane also occurs with the formation of CF bonds.

[0048] Polyamide polymers such as nylon are also ideal sorbent products for PFAS because they are highly hydrophobic and possess unique chemical functional groups that enable PFAS bonding, including secondary amines, tertiary amines, and specific chemical functional groups inherent in amide bonds containing carbonyl groups. Furthermore, nylon can be formed into fine fibers with a high reaction surface area. This surface area allows for more bonding sites for PFAS interactions. Other polymers containing amine groups also exhibit preferred bonding to PFAS compounds.

[0049] Adsorbents having hydrophobic surfaces and adsorbents having a contact angle of 90 degrees or greater can be used in various embodiments. Polyurethane foam exhibits an average contact angle of 140 ± 5 degrees. This hydrophobicity is important because PFAS compounds are attracted to the hydrophobic surface. In general, hydrophobic materials with a contact angle of 90 degrees or greater may exhibit preferred sorption for hydrophobic compounds such as PFAS.

[0050] Various embodiments involve the use of adsorbents with high loading capacity. High loading capacity is important because it allows materials to be used for a longer period before they need to be replaced, reducing maintenance costs and the overall footprint of the filtration equipment. Polyurethane has been found to have a particularly high loading capacity for PFOA and PFOS. For example, the loading capacity of polyurethane in mg of PFOA / PFOS adsorbed per 1 mg of adsorbent is almost 30 times that of activated carbon.

[0051] Various foam materials or other porous materials can be used as adsorbents, and the present invention is not limited to polyurethane foam. For example, any foam or porous polymer having a hydrophobic surface with a static water contact angle greater than 90 degrees, preferably greater than 120 degrees, can be used in some embodiments. Compositions of adsorbent materials such as foam that can be used in various embodiments may include one or more combinations of hydrophilic charged functional groups that provide electrostatic interactions with PFAS (e.g., amine-NH, aldehyde-C=O and aromatic groups, urethane-NH-(C=O)-O-); hydrophobic chemical functional groups that capture PFAS by hydrophobic interactions (e.g., methyl-CH2 or ethyl-CH3 groups); and / or aromatic groups that capture PFAS by anion-Pi interactions. In some embodiments, the pore size of the adsorbent may range from about 5 nanometers to about 5 millimeters.

[0052] Other examples of forms that may be used in embodiments of this disclosure include, but are not limited to, foams and porous materials made from or functionalized with melamine, polyamide, nylon, polyester, polystyrene, polyethylene-vinyl acetate foam, ethylene vinyl alcohol, polyvinyl alcohol, polycaprolactone, and / or polylactic acid, lycopodium spores or powder, and other conjugated or composite foams.

[0053] In some embodiments, the adsorbent may be a polymer sheet, for example, a polymer sheet composed of fibers. The fibers may have a size in the range of, for example, about 0.1 to about 5 micrometers. These fibers may include, but are not limited to, one or more of cellulose, polyester, polypropylene, polyamide, nylon, and polyurethane.

[0054] Similar to the polymer foams described above, sheets such as fibrous sheets can be used as adsorbents in adsorbent systems that may contain nanocomposites and / or active chemical groups. Thus, the adsorbent system may contain active chemical groups bound to the surface and bulk of the adsorbent sheet via direct interaction with the adsorbent, or the active chemical groups may adhere to nanoparticles pre-bound on and within the matrix. Such chemical groups include, but are not limited to, amine compounds, including primary, secondary, tertiary, and quaternary amines, and conjugated polymers containing these compounds. For example, a polymer foam may contain an amine as an active chemical group. In some embodiments, a polymer foam may contain a thiol as an active chemical group. In yet another embodiment, a polymer foam may contain an alcohol as an active chemical group. Other chemical groups that may be included in the adsorbent system include, but are not limited to, compounds having long hydrocarbon chains, such as lipids, conjugated sugars, fluorinated hydrocarbon chains, and fatty alcohols, as well as hydrophobic aromatic compounds, such as alkylbenzenes and aromatic polymers. These compounds enable tunable surface interactions driven by hydrophobic interactions between the sorbent and the contaminant.

[0055] Active chemical groups introduce a variable, tunable surface charge into the sorbent material, enabling specific capture of charged contaminants from water. The tunable surface charge is defined here as a charge controlled by the introduction of various active chemical groups. For example, primary amines, when fully protonated, can have a positive charge under certain pH conditions. The surface charge of the sorbent can be controlled by controlling both the positional amounts of these chemical groups.

[0056] Furthermore, the active chemical group provides a tunable surface charge that can be reversed if desired for the recovery and concentration of contaminants. Using primary amines as an example, by increasing the pH around the sorbent using a base, the amine loses a proton and consequently its positive charge. Thus, all bound contaminants, dependent on their positive charge, can be released.

[0057] In some embodiments, adsorbents such as polyurethanes may be treated to improve adsorption, such as through a process that may be called “activation.” This process may allow for the removal of any organic material bound to the adsorbent, including PFAS traces and other hydrophobic compounds, freeing up more adsorption sites for PFAS within the adsorbent and increasing the amount of PFAS that can be captured in the foam. The adsorbent may be activated before its first use for PFAS adsorption and / or the activation may be repeated after PFAS desorption and before reuse of the adsorbent. In various embodiments, activation of polyurethanes may allow for the reduction of PFAS traces and removal of other organic contaminants present in the foam, such as during foam manufacturing or before reuse as an adsorbent. As a result, the activation process frees up new sites for interaction with PFAS contaminants and thus improves the polyurethane's ability to remove PFAS compounds.

[0058] To obtain activated sorbents such as activated polyurethane, the sorbent, for example, a foam such as a sheet or polyurethane foam, can be exposed to a solvent and an organic base, for example, a solvent combination of methanol and ammonium hydroxide. In some embodiments, the solvent is a polar protic solvent. In some embodiments, the sorbent, such as polyurethane foam, can be exposed to about 80-100% methanol and about 0.5-10% ammonium hydroxide by volume. In one example, the sorbent, such as polyurethane foam, can be exposed to 95% methanol and about 5% ammonium hydroxide to form an activated polyurethane for use as an sorbent. The solvent can then be removed from the sorbent, and the activated sorbent can be used (or reused) for PFAS capture. In this way, PFAS capture can be improved compared to the same sorbent that was not activated before PFAS capture.

[0059] In some embodiments, the sorbent system includes a matrix such as a sheet of foam matrix, like a polyurethane foam matrix coated with nanoparticles. One process for fabricating such an sorbent system involves a thermal reduction process, which may be called thermal cress coating, by which nanoparticles can be increased on and throughout a porous support material such as polyurethane foam. In one example, the process may include three steps. The first step may be wet impregnation of a porous or fibrous matrix material with a metallic or non-metallic ionic precursor (e.g., ferrous sulfate, ferric chloride, or titanium chloride) under appropriate conditions such as the concentration, hydration, pH, and zeta of the matrix material. The next step may be evaporation of the solution, such as heating the impregnated matrix in an oven, to initiate thermal reduction and crystallization of nanoparticles on the surface and inside the porous material. The third step may be washing and drying of the sorbent material. This is just one example of a process that may be used, and the process may be modified and / or additional steps may be included as alternatives. The final result of such a process is an sorbent system with a very good surface-to-volume ratio, which allows for a very high contaminant loading capacity and may be further used for efficient contaminant decomposition.

[0060] Active chemical groups can be added to an sorbent by utilizing direct interactions between the functional groups of the sorbent or by interacting with nanoparticles embedded in the sorbent. For example, a molecule containing a primary amine at one end and a linking group at the other can be directly added to the sorbent. Examples of linking groups include siloxanes, which can spontaneously bond to alcohols and carbonyl groups present in the sorbent. Another example of linker chemistry is the use of common linkers such as 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS), which create a bond between the carboxylate group in the molecule and the amide group in the sorbent. Furthermore, many chemical groups, such as siloxanes and thiol groups, can be used as linkers because they can spontaneously bond to the surface of nanoparticles. To facilitate these interactions, the sorbent is added to an aqueous solution or organic solvent solution containing the molecule to be added and a suitable linker group. Depending on the type of linker chemistry used, this solution may then be mixed, heated, or dried.

[0061] Contaminants can be captured by the sorbent in various ways. In some embodiments, a stream of contaminants can be introduced into a column system including an sorbent system. The column system may be gravity-fed or the stream may be introduced using a pump system. In some embodiments, the sorbent may be compressed and released periodically, optionally repeatedly, to allow for faster flow and diffusion of contaminants within the sorbent. If the sorbent is a foam, it may be one or more large foam pieces or a number of small pieces. In some embodiments, a foam sorbent may be shredded into a number of small pieces or in the form of multiple thin films / membranes. In some embodiments, the sorbent may be in the form of a sheet or fibers that can be wrapped around a central water dispersion unit. This central dispersion unit is typically a hollow cylindrical tube with perforations to control porosity and allow water to flow radially outward through the sorbent, which is tightly wrapped around the sorbent to maximize contact time. In some embodiments, the sorbent may be in granular form.

[0062] When PFAS or other target contaminants bind to an sorbent, an sorbent filled with PFAS or other target contaminants may be referred to as a used or depleted sorbent. Captured PFAS can be removed from a used sorbent by various methods. In some embodiments, desorption of PFAS may be induced by a solvent. In some embodiments, such as when polyurethane is used as the sorbent, the interaction between the sorbent and the captured PFAS may be reversible. For example, after capture of PFAS by the sorbent, the sorbent may be washed with a solvent to release the PFAS.

[0063] In various embodiments, such as those using polyurethane for the capture of PFOA and / or PFOS, and other sorbents described herein, the interaction between the sorbent, such as polyurethane, and PFOA / PFOS may be reversible in the presence of high concentrations of organic solvents. In some embodiments, the solvent may be a polar protic solvent. Ideal solvent categories for this process include water-miscible organic solvents. Specific exemplary classes include nitriles, alcohols, and ethers. An example of a water-miscible nitrile is acetonitrile. Water-miscible alcohols that can be used for the desorption of PFOA and / or PFOS include, but are not limited to, methanol, ethanol, and isopropanol. For example, in some embodiments, methanol may be used for the desorption of PFOA and / or PFOS as described herein. In other embodiments, ethanol may be used for the desorption of PFOA and / or PFOS as described herein. In yet another embodiment, isopropanol may be used for the desorption of PFOA and / or PFOS as described herein. Some non-water-miscible solvents, such as hexane, may also be used. For example, after capturing PFAS with an adsorbent such as polyurethane foam, the polyurethane can be thoroughly washed with an organic solvent for 1 to 15 minutes to desorb the PFAS compounds. In some embodiments, the polyurethane may be washed with an organic solvent for approximately 5 minutes. The amount of organic solvent required to remove the captured PFAS from the adsorbent may be the minimum volume required to completely wet the adsorbent. This desorbing process may be performed once or repeated multiple times, such as up to 5 times, to enhance the desorbing performance. In some embodiments, the process is performed twice.

[0064] To improve the removal of PFAS bound by charge-based interactions, inorganic acids or bases such as ammonium hydroxide, sodium hydroxide, hydrochloric acid, and nitric acid may be added to the organic solvent. These acids and bases may also be added directly to the organic solvent and the diluted solution of water. In the case of PFAS bound to the primary amine groups of the sorbent, increasing the pH of the solvent used for extraction effectively deprotonates these chemical groups, removing the positive charge and releasing the bound PFAS.

[0065] Desorption of PFAS from adsorbents remains toxic and produces concentrated streams that must be controlled. In various embodiments, concentrated streams of PFAS can be defluorinated. It is important to distinguish between decomposition and defluorination of PFAS compounds. Decomposition refers to the breakdown of long-chain PFAS compounds, such as PFOA and PFOS, into short-chain fluorocarbons by cleaving carbon-carbon bonds. These short-chain fluorocarbons are problematic because their environmental mobility has not been studied in detail. Furthermore, recent studies by the US National Toxicology Program suggest that PFAS compounds with five or fewer carbon chains present similar liver and thyroid problems as longer-chain PFAS compounds. In contrast, defluorination refers to the decomposition of water, carbon dioxide, and fluoride (F) - This refers to the breakdown of a very strong carbon-fluorine bond, resulting in the final non-toxic product of the ion. Various embodiments include a defluorination process, which involves defluorination for remediation of PFAS compounds, in order to prevent the release of PFAS and potentially toxic short-chain PFAS compounds.

[0066] Destruction includes changes in the identity of a target chemical contaminant through the cleavage of chemical bonds. Destruction that results in complex chemical compounds as end products is referred to as decomposition. In the case of PFAS, decomposition means that larger PFAS compounds consisting of six or more carbon chains are broken down into shorter-chain PFAS compounds consisting of five or fewer carbons. In the case of PFAS compounds, the cleavage of carbon-fluorine bonds to produce carbon dioxide, fluoride, and water is referred to herein as defluorination.

[0067] Destruction involves removing one or more chemical groups to reduce or eliminate toxicity. In some embodiments, the disclosure includes methods and systems in which persistent organic compounds, including per- and polyfluoroalkyl substances, are captured by an sorbent system comprising a porous polymer polyurethane foam and other polymer matrices. Alternatively or additionally, the disclosure includes methods and systems in which compounds captured by an sorbent system comprising a polymer foam matrix are recovered into a stream of concentrated waste using an organic solvent and an organic base. The methods and systems may also include disrupting the stream of concentrated waste by cavitation via an acoustic cavitation device or by a photocatalytic system assisted by ultraviolet light.

[0068] After extracting the target contaminant from the sorbent using a solvent, the extracted target contaminant can be removed by solvent removal to concentrate it. Solvent removal can be achieved by several processes, including but not limited to one or more of heating, pressure, or other evaporation, centrifugation, sedimentation, and / or filtration.

[0069] When PFAS material is concentrated in a small volume stream of waste, methods for defluorinating the PFAS can be put into practice. Various methods can be used to break down concentrated PFAS or other concentrated contaminants. In some embodiments, energy can be applied to concentrated PFAS and / or other concentrated contaminants. For example, ultrasonic energy can be used to break down PFAS and / or other concentrated contaminants. In other embodiments, UV energy can be used to break down PFAS and / or other concentrated contaminants. In other embodiments, electrical energy can be used to break down PFAS and / or other concentrated contaminants. In yet another embodiment, other supercritical conditions can be used to break down PFAS and / or other concentrated contaminants.

[0070] In some embodiments, defluorination of PFAS can be carried out using a free radical generator such as sodium persulfate alone, or in combination with the application of energy such as acoustic cavitation or ultraviolet light in the presence of a catalyst such as a radical generator or hydrate electron generator. Free radical generators promote the generation of radicals, highly reactive atoms containing one or more unpaired electrons. Hydration electrons are highly reactive free electrons surrounded by water molecules. For the breakdown and defluorination of PFAS, both radicals and hydrate electrons attack and cleave the carbon-fluorine bond. In one example, a concentrated volume of PFAS may be placed in a container such as a polypropylene bottle and submerged in an ultrasonic reactor chamber. A free radical generator such as sodium persulfate or hydrogen peroxide may be added to the solution of the PFAS compound. The concentration of the free radical generator can vary. For example, the concentration of sodium persulfate in the mixture may be about 1 g / L to about 5 g / L. This mixture can then be subjected to an energy treatment such as acoustic cavitation. Various parameters can be used. For example, acoustic cavitation energy with sonication frequencies of approximately 200 kHz to 1000 kHz, such as an ultrasonication frequency of approximately 850 kHz, may be applied. In some embodiments, the energy may be applied continuously or intermittently. For example, the ultrasonication frequency used in acoustic cavitation may be 862 kHz for 60 minutes under pulse mode, thereby allowing the sample to be treated intermittently with 100 ms on and 100 ms off. The sample temperature may be maintained between 25 and 40 degrees Celsius. In some embodiments, higher temperatures may be preferred for better performance. In other embodiments, a sweep mode may be used for sonication, such as alternating between high frequencies (e.g., approximately 600 kHz to 1000 kHz) and low frequencies (e.g., 200 kHz to 600 kHz) within a short period of time. For example, a frequency sweep between 862 kHz and 358 kHz within 1000 ms may be used in the procedure. In other embodiments, the reaction parameters may be the same or different, and a gas such as argon may be continuously introduced into the reactor during sonication.Other gases that may be used additionally or alternatively, alone or in combination, include nitrogen and xenon. These gases are added to the reaction to remove oxygen-containing gases that could otherwise consume the radicals or hydrated electrons produced.

[0071] In this embodiment and various other embodiments, acoustic cavitation may be used. In some cases, acoustic cavitation may alternate between high and low frequencies over relatively short periods, such as about 0.05 to about 1 second. In some embodiments, the “high” range may be, for example, about 750 to 900 kHz, and the “low” range may be, for example, about 200 to 350 kHz. In other embodiments, the period may be longer or shorter, the frequency fluctuation may be larger or smaller, or within a larger or smaller range.

[0072] In some embodiments, the breakdown of PFAS can be achieved by applying ultraviolet light to a concentrated solution. The ultraviolet light may be applied in the presence of reagents such as a radical generator such as potassium persulfate, a reducing agent, or a hydrated electron generator such as potassium iodide, which may be referred to as a UV photocatalyst. The breakdown of PFAS can be achieved, for example, by applying ultraviolet light with wavelengths of 100 nm to 400 nm for a period of 10 minutes to 72 hours.

[0073] The defluorination of PFAS is thought to occur as a result of two factors: the reactive oxygen species generated in the solution, and the high temperatures and shock waves generated by cavitation. When exposed to ultrasonic irradiation, the liquid undergoes acoustic cavitation, which is the formation, growth, and implosive collapse of bubbles / vapor bubbles in the liquid. The collapse of bubbles during cavitation creates transient hot spots responsible for the release of light and high-energy chemistry reaching approximately 5000 degrees Celsius (Reference: DOI: 10.1126 / science.253.5026.1397). This high-energy environment facilitates the chemical reaction of PFAS to carbon and fluorine and its defluorination. Furthermore, the photocatalytic process drives the release of radical species containing excited electrons or oxygen. These reactive species then promote the cleavage of chemical bonds.

[0074] The destructive action of contaminants can occur alone or in combination with other treatment methods by applying energy to the contaminants, such as photochemistry, acoustic chemistry, electrochemistry, thermochemistry, supercritical hydroxylation, or plasma treatment. For example, energy may be applied as light such as visible or UV light, plasma, electrons, sonication, heat, or other types of energy. In some embodiments, light in the visible and / or ultraviolet wavelength range, for example between about 180 and about 700 nanometers, or between about 185 and 260 nm, may be applied for a length of time required for the reaction to complete.

[0075] Figures 2–7 show further details of how spent sorbents can be recovered and how contaminants can be concentrated and destroyed by various embodiments. The figures are shown in representative schematic forms. Thus, they include some components of the system, while other components known in the art, such as tubing, pipes, pumps, valves, or other conveyor systems and other equipment, can be used to perform various steps, such as transporting fluids and other materials, or collecting gases, as indicated by the arrows.

[0076] Figure 2 shows method 20 for the desorption of captured and bound contaminants and the destruction of contaminant concentrates. In step 21, the PFAS is captured from the stream using an sorbent. The sorbent may include, for example, polyurethane, polyamide fibers, sheets, or foams. In step 22, an extraction solution is used for the desorption of bound organic contaminants from the sorbent. The extraction solution may include, for example, an organic solvent such as methanol, ethanol, or isopropanol, and a base such as, for example, ammonium hydroxide, sodium hydroxide, or pyridine. Alternatively or additionally, other methods or materials may be used for desorption. After desorption, the contaminants are concentrated in step 24. The contaminants may be concentrated by removing the extraction solution, for example, by evaporation, sedimentation, and / or filtration. The concentrated contaminants are then suspended in water or an appropriate solvent in step 26. In step 28, the contaminants are destroyed by the application of a destruction process such as UV photocatalysis, acoustic cavitation, and / or supercritical water. Contaminants that can be removed and destroyed by this system include, but are not limited to, per- and polyfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), pesticides, cosmetics, pharmaceuticals, and organic contaminants such as 1,4-dioxane. Solubilizing materials that can be used include, but are not limited to, activated carbon, ion exchange resins, or polymer foam-based sorbents such as foam polyurethane.

[0077] Figures 3 to 7 show systems that may be used for contaminant concentration and destruction. In some embodiments, the storage vessels shown in these systems and used in various embodiments may be, but are not limited to, one or more of polyethylene, polypropylene, aluminum, steel, plastic, glass, other metals, nonmetals, or polymer containers.

[0078] In the system shown in Figure 3, used sorbent material with bound contaminants may be placed in a vessel A (desorption vessel) which may have the ability and components to perform compression, depressurization, and / or mixing. An extraction solution containing organic solvents, with or without additives, including but not limited to methanol, isopropyl alcohol, and acetonitrile, may be added to vessel A at a purity of, for example, 20% to 100% (v / v). Additives, including but not limited to ammonium hydroxide, acetic acid, water, and sodium hydroxide, may be added at concentrations of, for example, 0.5% to 50% (v / v). In some embodiments, vessel A may be equipped with a plunger to accelerate the desorption process to several minutes through active compression and release of the compressible sorbent material. In other embodiments, vessel A may be equipped with a mixing or stirring mechanism that enables desorption from compressible sorbents and other sorbent types that may not be compressible.

[0079] The concentration of the target contaminant in the solution of vessel A can be monitored continuously or periodically. For example, vessel A may be equipped with a sampling port, and the desorption process can be monitored by measuring the concentration of the target contaminant.

[0080] Once an appropriate or desired level of contaminant desorption is achieved, the solution can be transferred from vessel A to vessel B. In the embodiment shown in Figure 3, after the desorption process in vessel A, a valve is opened, allowing the spent solvent to pass through vessel B (boiler), as indicated by arrow 1. Vessel B may include a heating device for heating the spent solvent in a controlled manner, and a gas inlet that allows a clean gas, including but not limited to air, nitrogen, and / or argon, to be optionally introduced into vessel B to accelerate the evaporation of the spent solvent. Heating conditions may be, for example, between about 40°C and about 120°C. The system may include a condenser for recovering the evaporated solvent from vessel B by distillation. The recovered solvent may be returned to vessel A for use in subsequent desorption processes, as indicated by arrow 4. The spent solvent containing released PFAS remaining in vessel B after evaporation may be completely or nearly completely dried before the next step.

[0081] Once the distillation of the solvent is complete or has progressed to the desired stage, for example, when vessel B is completely or nearly completely dry, water, including but not limited to distilled water and Grade I reagent water, may be added to vessel B. Other solvents that may be used alternatively or additionally include hydrocarbon solutions containing oil or hexane, octanol, glycerol, and solvent mixtures containing diluted alcohols, such as isopropanol, methanol, and ethanol at concentrations of about 0.5 to about 20% (v / v). These may contain organic or inorganic acids or bases, including but not limited to ammonium hydroxide, sodium hydroxide, hydrochloric acid, and nitric acid. Water and / or other solvents may redissolve and / or dilute any contaminants remaining in vessel B. In some embodiments, the system may be equipped with a stirring or shaking device to facilitate this process.

[0082] When a contaminant dissolves in water and / or other solvents, the water and / or other solvent containing the contaminant can be transferred to vessel C, as indicated by arrow 2. Vessel C may be a pre-coated fracture vessel. The coating may be, but is not limited to, a lipid such as octanoic acid or other non-fluorinated surfactants. Vessel C may be configured in various ways depending on the fracture method used. For example, vessel C may be configured to accommodate various fracture methods that utilize a locally applied energy source. Examples of locally applied energies that may be used include, but are not limited to, sonication-induced cavitation, temperature and pressure changes to induce supercritical hydroxylation, laser ablation, photocatalysis, electrochemistry, plasma and / or bioremediation as alternative mechanisms.

[0083] Similar to vessel C, any other vessel or instrument used in the system may be optionally pre-coated in various embodiments. In some embodiments, the coating may be a coating of long-chain molecules on the inner surfaces of storage vessels, vessels, glassware, plasticware, etc., to prevent the adhesion of per- and polyfluoroalkyl materials to the walls of storage vessels and other instruments. The long-chain molecules may be long-chain organic molecules. In some embodiments, the long-chain organic molecules may be long aliphatic organic acids. In some embodiments, it may be long aliphatic organic alcohols. In other embodiments, it may be branched organic acids. In yet another embodiment, it may be branched organic alcohols.

[0084] One method of destruction that can be used in various embodiments involves ultrasonic-induced cavitation, which can be used to destroy PFAS. In such embodiments, water and / or other solvents containing dissolved PFAS can be subjected to ultrasound at a frequency of about 200 to about 10,000 kHz. Additional chemical additives, including but not limited to peroxides, persulfates, nitrates, metals / metal oxides, and nanoparticles, may be added. This method has been demonstrated to effectively destroy PFOS and PFOA to levels of >90% through the cleavage of carbon-fluorine bonds.

[0085] In other embodiments, UV irradiation may be used to destroy contaminants such as PFAS. In such embodiments, water and / or other solvents containing dissolved PFAS may be subjected to UV irradiation for a period such as about 2 hours to about 72 hours in a wavelength range of about 150 to about 400 nm. Additional chemical additives may be added, including but not limited to radical-generating peroxides, persulfates, nitrates, metals / metal oxides, and nanoparticles such as iron, iron oxide, and titanium dioxide, as well as radical scavenging additives including methanol and isopropanol. Using this methodology, up to 75% of PFAS can be defluorinated.

[0086] The concentration of contaminants in Vessel C can be monitored continuously or intermittently. For example, Vessel C may be equipped with a sampling port for monitoring the breakdown process.

[0087] Once the desired level of breakdown is reached in vessel C, the final product may optionally be transferred to vessel D, which may contain an sorbent, as indicated by arrow 3. The product from vessel C may pass through the sorbent in vessel D before discharge. After absorbing any remaining contaminants, the sorbent in vessel D may be transferred to vessel A. Alternatively, the product from vessel C may be returned to vessel B in one or more additional cycles, as indicated by arrow 5. This may be done if it is determined that the initial treatment has not defluorinated the PFAS to the desired level and another cycle is needed. For example, in one embodiment, another cycle may be needed if the initial treatment has not defluorinated all of the PFAS. Once completed, the product from vessel D may be discharged, and the sorbent in vessel D may be recycled by going through a process again starting from vessel A, as indicated by arrow 6.

[0088] Figure 4 shows an alternative system for decontaminant desorption from the sorbent and contaminant destruction. The system is similar to that shown in Figure 3, except that in this embodiment, vessel B is a concentrator instead of a boiler. In this embodiment, the concentrator may use, for example, reverse osmosis, dialysis, and / or foam fractionation to concentrate the contaminants and separate them from the solvent. The concentrated contaminants can then be destroyed in destruction vessel C, and the separated solvent may be reused after further purification, etc., or disposed of.

[0089] Figure 5 shows another alternative system for decontaminant removal from the sorbent and contaminant destruction. This system is similar to those in Figures 3 and 4, but omits the vessel shown as vessel B in those examples (which was a boiler or concentrator vessel, respectively). In this embodiment, contaminants in the solution from any source are already present at a sufficiently high concentration that a boiler or concentrator is unnecessary. For example, this system can be used for a solution where the contaminant is present at a concentration greater than approximately 1 milligram per liter. This solution can be introduced directly into vessel B, which is the destruction vessel in this example, as described in the other example (which was vessel C). After destruction, the solution may proceed to vessel C containing the sorbent bed, as indicated by arrow 2. Alternatively, after destruction in vessel B, if additional destruction treatment is desired or required, for example, the solution may be optionally returned to vessel A, as indicated by arrow 3. After the solution has passed through vessel C and the sorbent has been sufficiently loaded, the used sorbent may optionally be processed in the process desorption vessel as shown in Figures 3 and 4.

[0090] Figure 6 shows an alternative detoxification system for contaminant destruction that may be used in any of the detoxification and destruction systems described herein. This system is similar to the detoxification systems shown in Figures 3 and 4, except that it combines two destruction methods, specifically UV photocatalysis and acoustic cavitation, in a single detoxification vessel. Although other configurations are possible, the detoxification vessel comprises a UV light source shown inside the vessel along with a mixer, and an acoustic cavitation transducer located at the bottom of the vessel and in communication with a power supply. The two detoxification processes may be performed simultaneously or sequentially.

[0091] Figure 7 illustrates another example of a contaminant concentration system according to various embodiments. This system includes a solvent tank, identified as Vessel A, in which a solvent is stored. A pump transfers the solvent to a material column, identified as Vessel B, containing an sorbent, to desorb bound contaminants. Although other configurations are possible, the shown material column also includes a first inlet for the solvent at the top, a second inlet for water, a rinse solution, or other material, and a filter plate and outlet at the bottom. The second inlet for water or rinse solution allows for rinsing of the sorbent. After releasing the contaminants from the sorbent, the solvent phosphate then flows into a rotary evaporator, identified as Vessel C, where the solvent evaporates by thermal and mechanical action. The evaporated solvent is then re-condensed through a condensing coil equipped with a condenser and then returned to Vessel A, the solvent tank. Vessel C includes a first inlet for the solvent phosphate flowing into the evaporator, and a second inlet for a reagent, a destructive solution, water, or other material. For example, a second inlet to the rotary evaporator allows for the resuspension of contaminants into the concentrate.

[0092] The methods and systems described herein provide efficient methods for activating adsorbents, capturing contaminants, desorbing contaminants, concentrating contaminants, and subsequently destroying contaminants. For example, in some embodiments, the method for capturing and destroying contaminants includes purifying and activating a porous polymer material by passing it through a first solvent, such as a polar protic solvent, to remove impurities and liberate existing functional groups before capturing organic contaminants. Once the porous polymer is purified and activated, the next step may be to capture at least one organic contaminant in the purified and activated porous polymer. The at least one captured organic contaminant can then be released by passing a second solvent, such as a second polar protic solvent, through the porous polymer. The first solvent used for purifying and activating the porous polymer may be the same as or different from the second solvent used to release the captured organic contaminant from the porous polymer. The at least one organic contaminant can then be concentrated by evaporating the second solvent containing the released at least one captured organic contaminant. The concentrated, at least one captured organic contaminant can then be destroyed, for example, by using one of the methods described herein.

[0093] The system provides a complete, versatile, and efficient mode for destroying various contaminants, including PFAS, organic dyes, and organic environmental pollutants such as pesticides, from sorbent media. As an end-of-life solution for the environmental remediation of sorbents, the system avoids secondary contamination. Furthermore, the system can recover and reuse solvents to reduce or eliminate hazardous waste. By design, the modular system can be easily adapted to existing facilities or to meet specific needs. Various solvents, additives, and other components are described, but this disclosure is not limited to those specifically identified. Other purification solutions, including various compounds, combinations of compounds, and solutions of various concentrations, are within the spirit and scope of the invention. For example, in some embodiments, combinations of polar organic solvents and bases may be used. Some solvents that may be used include, but are not limited to, isopropyl alcohol, ethanol, acetone, and acetonitrile. Some bases that may be used include, but are not limited to, potassium hydroxide, sodium hydroxide, and ammonium hydroxide. However, it should be recognized that other solvents and / or bases may be used.

[0094] The example illustrates what desorbing is important for the adsorbent to enable two end-of-life options that may be included in various embodiments. The adsorbent can be regenerated and reused. Furthermore, contaminants such as PFAS can be concentrated for post-treatment and disposal, such as destruction. This process enables end-of-life defluorination and decomposition procedures that are otherwise limited in terms of size and scale, such as sonication, heat treatment, and plasma treatment. Efficient adsorption and subsequent desorbing allow contaminants such as PFAS compounds to be captured and concentrated into small-volume streams of liquid waste. These small-volume streams are much easier to process by the methods described above.

[0095] The mechanical and chemical properties of materials such as polyurethane and nylon make them ideal for both sorption and extraction processes. Firstly, these materials are very mechanically robust and can withstand mixing and compression without losing their structural integrity. Chemically, these materials are stable in the presence of organic solvents and under high pH conditions, both of which are necessary for complete extraction.

[0096] The various embodiments described herein offer many unparalleled advantages. For example, due to faster flow rates, smaller processing systems can be used compared to the large facilities required for activated carbon. Due to the high load capacity of the new sorbent technology, material tannober may be reduced. When activated carbon is used in other systems, it may be disposed of by incineration, which can cause secondary contamination by generating short-chain PFAS. In contrast, according to the various methods described herein, PFAS are recovered using sorbents such as polyurethane and defluorinated by acoustic cavitation, etc., without generating harmful byproducts.

[0097] experiment:

[0098] In the following example, exemplary porous polyurethane nanocomposites were analyzed before and after the addition of a target PFAS compound. In a typical setup, the porous polyurethane nanocomposites were shredded into pieces with a size range of 0.25–3 cm in diameter (1 cm being the ideal size). These pieces were tightly compressed into a column, and water was introduced into the column in a manner that allowed for a contact time of 1–20 minutes (10 minutes being the ideal contact time). A concentration of 100 ppb of PFOA was used for the breakthrough test.

[0099] Example 1

[0100] Fourier transform infrared analysis was performed on polyurethane support materials before and after treatment with PFOA. The results are shown in Figure 8. Peaks characteristic of CF bonds, indicating the presence of PFOA on the sorbent, are labeled. Figure 9 shows the general structure of the urethane skeleton.

[0101] FTIR analysis revealed electrostatic interactions between the PFAS compound and oxygen present in the alcohol and urethane groups, methyl functional groups, and carbon present in the urethane functional groups of the polyurethane support. Since characteristic peaks were observed for CF bonds, FTIR analysis also confirmed the sorption of the PFAS compound.

[0102] Example 2

[0103] The contact angle was measured using a polyurethane foam support material. The contact angle was 140 ± 5 degrees. The hydrophobic surface is shown in the image in Figure 10.

[0104] Example 3

[0105] PFOA and PFOS were removed from the porous polyurethane nanocomposite as a function of target concentration. The resulting graphs were fitted to a Langmuir isotherm model to predict the maximum theoretical "loading capacity" of the polyurethane material, as reported in Table 2. [Table 2]

[0106] The results are shown in Figures 11a to 11c. Figure 11a shows the loading capacity of PFOA and PFOS for an exemplary activated porous polyurethane nanocomposite using Langmuir isotherm fittings. Figure 11b shows the calculated loading capacity of the activated porous polyurethane nanocomposite compared to other available technologies, including ion exchange resins, activated carbon, and metal-organic frameworks (MOFs), using measurements from other available technologies reported in “Adsorption of perfluoroalkyl and polyfluoroalkyl substances (PFASs) from aqueous solution - A review.” Science of The Total Environment 694(2019):133606 by Zhang, DQ, WLZhang, and YNLiang. Figure 11c shows the kinetic data of experimental sorption to PFOA and PFOS.

[0107] Table 3 shows a comparison of the reported loading capacities of granular activated carbon compared to activated porous polyurethane nanocomposites. [Table 3]

[0108] Example 4

[0109] Breakthrough curves were created by comparing granular activated carbon with a bed volume of 1008 ml and activated porous polyurethane nanocomposite with a bed volume of 1950 ml. For granular activated carbon, an inflow concentration of 100 ppb and a 10-minute EBCT were used, while for activated porous polyurethane nanocomposite, a 2-minute EBCT was used. The results are shown in Figure 12, where the breakthrough curves, as a function of time in bed volume, show the inflow and outflow PFOA concentration ratios for activated porous polyurethane nanocomposite and granular activated carbon (GAC). This figure demonstrates the superior performance of activated porous polyurethane nanocomposite compared to commercially available granular activated carbon (GAC). With granular activated carbon, 80% of PFOA breaks through and is not captured after approximately 175 hours. In comparison, with polyurethane, the breakthrough at 325 hours is less than 10%.

[0110] Example 5

[0111] Activated porous polyurethane nanocomposites were rinsed with 95% methanol and 5% ammonium to achieve polyurethane "activation." These activated porous polyurethane nanocomposites were compared to "unactivated" porous polyurethane nanocomposites made from the same material but without activation. Both materials were used to remove PFOS from an aqueous PFOS solution. The results are shown in Figure 13. The "unactivated" porous polyurethane nanocomposites removed 49.9% of PFOS from the original reagent water at an original concentration of approximately 285 ppt (Figure 13). The activated porous polyurethane nanocomposites removed 84.3% of PFOS from the original reagent water.

[0112] Example 6 Small pieces of activated porous polyurethane nanocomposite ranging from 0.08 to 0.09 g were added to a shaker for 10 minutes with approximately 100 parts per billion (ppb) of PFOA and PFOS in 20 mL of water. Desorption was performed by collecting the foam and immersing it in 20 mL of 96% methanol for 5 minutes. The results are shown in Table 4. [Table 4]

[0113] The results demonstrate that over 80% of PFOA and over 97% of PFOS can be recovered in this manner. This allows for the regeneration and reuse of the desorbing sorbent, as well as the concentration of PFAS, for post-treatment and disposal in various embodiments.

[0114] Example 6

[0115] In this example, PFAS was decomposed using sodium persulfate, a free radical generator. A concentrated volume of the PFAS compound in water was placed in a polypropylene bottle and immersed in an ultrasonic reactor chamber (Meinhardt Ultrasonics). Sodium persulfate (1.25 g / L) was added to the PFAS compound solution. This mixture was then subjected to acoustic cavitation by sonication at a frequency of 862 kHz for 60 minutes under pulsed mode, thereby intermittently treating the sample with 100 ms on and 100 ms off intervals. The sample temperature was maintained between 25°C and 40°C. Alternatively, a sweep mode, which alternates between high frequencies (600 kHz to 1000 kHz) and low frequencies (200 kHz to 600 kHz) within short intervals, can be used for sonication. For example, a frequency sweep between 862 kHz and 358 kHz within 1000 ms can be used in the procedure. The results are shown in Table 5.

[0116] [Table 5]

[0117] Example 7

[0118] Coating of PFAS vessels and storage vessels. Experiments were conducted to determine whether coating aluminum reactor vessels with long-chain organic acids is suitable to prevent PFAS loss to the walls of defluorinated vessels. When handling highly concentrated PFAS waste, coating the reactor can be extremely important because loss to the reactor walls can dramatically reduce efficiency and lead to flawed studies. Briefly, an aqueous solution of 0.2% (v / v) hexanoic acid was prepared and added to the vessel. The vessel was placed in an ultrasonic generator and sonication was applied for 40–120 minutes at a sweep frequency of 200–300 kHz to 800–900 kHz. After sonication was complete, the organic acid solution was removed from the vessel and a stable layer of hexanoic acid was observed on the vessel surface. Next, a highly concentrated solution of PFAS was added to the coated vessel. After the incubation period, the concentrated PFAS solution was recovered and analyzed by LC / MS / MS. Table 6 shows the material loss to the reactor walls for a concentrated PFOS solution. The simple addition of organic acids can dramatically reduce PFOS loss. [Table 6]

[0119] Example 8

[0120] One method of destruction that can be used in various embodiments involves ultrasonically induced cavitation, which can be used to destroy PFAS. Water containing dissolved PFAS was subjected to ultrasound at a frequency of 864 kHz. This was achieved by placing PFAS of a known concentration in a 50 mL aluminum bottle coated with hexanoic acid. This bottle was immersed in a water bath connected to an ultrasonic transducer and ultrasonically treated at 864 kHz for 3 hours. The results are shown in Table 6, which indicate that ultrasonic treatment induced cavitation for the destruction of PFAS. The use of ultrasonic treatment effectively destroyed PFOS and PFOA to levels of >90% through the cleavage of carbon-fluorine bonds.

[0121] [Table 7]

[0122] Example 9

[0123] In this example, amine functional groups were introduced into the sorbent material by a process referred to herein as amination. A polyurethane foam was used in this case. An amine-containing polymer having a silane-containing linker molecule at one end, such as (3-aminopropyl)triethoxysilane (APTES), was introduced into the foam. In some cases, the amine-containing polymer was introduced into the foam by direct treatment of raw polyurethane. In other cases, the amine-treated polymer was introduced into the morphology by surface treatment of iron nanomaterials directly bonded to the polyurethane. Briefly, the polyurethane was added to an aqueous solution of aminated silane for 30 minutes. After removal, the saturated polyurethane was removed and dried at room temperature for 12 hours. This process is expected to result in the silane linker bonding to the carbonyl or alcohol groups on the nanoparticle surface and the polyurethane or other support (Figure 14).

[0124] Adsorbent materials containing iron nanomaterials and amine polymers were placed in syringes, and environmental wastewater was repeatedly aspirated and pushed into them to evaluate the capture of short-chain PFAS compounds, particularly perfluorobutanoic acid (PFBA) and perfluorobutanesulfonic acid (PFBS). The procedure was repeated using unprocessed polyurethane, amination polyurethane without iron nanoparticles, and amination polyurethane containing the nanoparticles prepared as described above. This experiment demonstrated that amination of this material improves the removal of PFBA and PFBS (Table 7). [Table 8]

[0125] Example 10

[0126] Small pieces of nylon fiber sheets ranging from 0.08 to 0.1 g were added to a shaker for 24 hours with 10 to 15 parts per billion (ppb) of PFOA and PFOS in 20 mL of water. For comparison, the same procedure was performed using small pieces of activated porous polyurethane nanocomposite in the shaker instead of nylon fiber. The results are shown in the bar graph presented as Figure 15, showing the PFAS capture percentage of each sorbent, including the capture of PFOA and PFOS. As can be understood, as shown in Figure 15, nylon showed similar sorption to activated porous polyurethane nanocomposite in that it removed more than 97% of PFOA and PFOS.

[0127] Example 11

[0128] One method of destruction that can be used in various embodiments involves the cleavage of the carbon-fluorine bond by using a catalyst excited by ultraviolet light, which is referred to herein as a UV photocatalyst. In this example, PFAS, specifically perfluorobutanoic acid (PFBA) at a concentration of 10–15 parts per million (ppm), was added in an oxygen-free environment to a 50 mL quartz test tube containing a reducing agent (e.g., potassium iodide). Ultraviolet light was introduced to the sample at a wavelength of 254 nm for 2 hours. This test resulted in the destruction of >99.0% of PFBA, as measured by liquid chromatography-mass spectrometry.

[0129] Example 12

[0130] In another example, fracture, or cleavage of the carbon-fluorine bond, was achieved using UV photocatalysis. PFAS, specifically PFOS at a concentration of 10–15 parts per million (ppm), was added to a 50 mL quartz test tube containing a reducing agent under oxygen-free conditions. Ultraviolet light was introduced to the sample at a wavelength of 254 nm for 2 hours. The results are shown in Table 8 below. Fracture was measured by determining the initial versus final concentration of PFOS by liquid chromatography-mass spectrometry (LC-MS). To measure defluorination, or cleavage of the carbon-fluorine bond, the sample was sent to total organofluorine analysis to measure the total PFAS before and after treatment. Using these two methods in tandem, the total defluorination efficiency of the process was found to be approximately 80%. [Table 9]

[0131] As used herein, the terms “substantially” or “generally” refer to the degree or extent of complete or near-completeness of an action, feature, characteristic, state, structure, item, or result. For example, an object “substantially” or “generally” included means that the object is either completely included or nearly completely included. The exact acceptable degree of deviation from absolute completeness may, in some cases, depend on the specific circumstances. However, proximity to completion generally results in the same overall outcome as if absolute and complete completion had been achieved. The use of “substantially” or “generally” is equally applicable when used in a negative sense to refer to the complete or near-complete absence of an action, feature, characteristic, state, structure, item, or result. For example, an element, combination, embodiment, or composition that “substantially” or “generally” does not include an element may still actually include such an element, insofar as it does not have a significant effect.

[0132] In the above description, various embodiments of the invention are presented for illustrative and explanatory purposes. They are not intended to be exhaustive or to limit the invention to the exact forms disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments have been selected and described to provide examples of the principles of the invention and their practical applications, and to enable those skilled in the art to utilize the invention in various embodiments with various modifications suitable for the specific use intended. All such modifications and variations are within the scope of the invention as determined by the appended claims, if they are interpreted in accordance with the extent to which they are fairly, legally, and equitably entitled.

Claims

1. Porous polymer materials, and At least one active chemical group bonded to the outer surface of the porous polymer material and within the porous polymer material An adsorbent system, including one.

2. The sorbent system according to claim 1, wherein the porous polymer material comprises a foam.

3. The sorbent system according to claim 2, wherein the foam comprises polyurethane.

4. The sorbent system according to claim 1, wherein the porous polymer material includes a fibrous polymer sheet.

5. The sorbent system according to claim 4, wherein the fibrous polymer sheet contains a polyamide.

6. The sorbent system according to claim 1, wherein the at least one active chemical group comprises at least one of amines, thiols, and alcohols.

7. The sorbent system according to claim 1, wherein the active chemical group is hydrophobic.

8. Porous polymer materials, Nanoparticles bonded to the outer surface of the porous polymer material and to the inside of the porous polymer material, and At least one active chemical group bonded to the nanoparticles An adsorbent system, including one.

9. The sorbent system according to claim 8, wherein the nanoparticles comprise one or more metals or metal oxides.

10. The sorbent system according to claim 8, wherein each of the plurality of nanoparticles has a diameter between 1 nm and 500 nm.

11. The sorbent system according to claim 8, wherein the nanoparticles include one or more of titanium, iron, manganese, zinc, silicon, or their oxides or hydroxides.

12. The sorbent system according to claim 8, wherein the at least one active chemical group comprises one or more amines, thiols, or alcohols.

13. The sorbent system according to claim 8, wherein the active chemical group is hydrophobic.

14. The sorbent system according to claim 8, wherein the porous polymer material comprises a foam.

15. The sorbent system according to claim 14, wherein the foam comprises polyurethane.

16. The sorbent system according to claim 8, wherein the polymer porous polymer material comprises a polyamide.

17. A method for desorbing a bound, persistent organic compound from an sorbent, Adding an sorbent to a vessel, wherein the sorbent comprises a porous polymer containing one or more recalcitrant organic compounds bound to the sorbent, Adding a solvent solution containing an organic solvent and an organic base to the vessel, The solvent solution is passed through the sorbent in the vessel to release the bound, persistently degradable organic compound from the sorbent into the solvent solution. Methods that include...

18. The method according to claim 17, wherein the persistent organic compound comprises a perfluoroalkyl substance or a polyfluoroalkyl substance.

19. The method according to claim 18, wherein the organic solvent comprises an organic acid or an organic alcohol.

20. The method according to claim 19, wherein the organic solvent comprises methanol, ethanol, and isopropanol.

21. The method according to claim 17, wherein the adsorbent comprises a foam.

22. The method according to claim 21, wherein the foam comprises polyurethane.

23. The method according to claim 21, wherein passing the solvent through the sorbent in the vessel comprises mechanically compressing and releasing the polyurethane foam in the solvent solution.

24. The method according to claim 17, wherein the vessel has an inner surface coated with a long-chain organic molecule.

25. The method according to claim 24, wherein the long-chain organic molecule comprises a long-chain aliphatic or branched organic acid or alcohol.

26. A method for destroying captured, persistent organic compounds, The process involves passing a solvent solution through an sorbent having a bound, persistent organic compound to release the persistent organic compound into the solvent solution. Concentrating the aforementioned persistently degradable organic compounds, and Applying energy to the released recalcitrant organic compound to destroy the recalcitrant organic compound. Methods that include...

27. The method according to claim 26, wherein the energy includes acoustic cavitation.

28. The method according to claim 27, wherein the energy of the acoustic cavitation has a frequency of about 200 kHz to about 1000 kHz.

29. The method according to claim 27, wherein the energy of the acoustic cavitation has a frequency of about 850 kHz.

30. The method according to claim 26, wherein the persistent organic compound comprises a perfluoroalkyl substance or a polyfluoroalkyl substance.

31. The method according to claim 30, wherein destroying the persistent organic compound includes defluorinating the persistent organic compound.

32. The method according to claim 31, wherein the energy includes energy to which the energy is locally applied.

33. The method according to claim 32, wherein the locally applied energy includes ultrasonic energy, UV energy, electrical energy, or energy under supercritical conditions.

34. The method according to claim 26, wherein concentrating the released persistent organic compound includes evaporating the solvent solution.

35. The method according to claim 34, wherein evaporating the solvent solution includes at least one of heating the solvent solution and evaporating the solvent solution under vacuum.

36. The method according to claim 34, further comprising suspending the concentrated recalcitrant organic compound in water before applying destructive energy.

37. A method for capturing persistent organic compounds present in a liquid, The process involves passing a contaminated liquid containing a persistent organic compound through an sorbent, wherein the sorbent includes a porous polymer having active chemical groups bonded to the surface and within the porous polymer. Methods that include...

38. The method according to claim 37, wherein the porous polymer includes a polyurethane foam.

39. The method according to claim 37, further comprising exposing the polyurethane foam to a solvent to increase the binding capacity of the sorbent before passing the contaminated liquid through the sorbent.

40. The method according to claim 39, wherein the solvent comprises methanol and ammonium hydroxide.

41. A method for activating a porous polymer material, Before capturing organic contaminants, the porous polymer material is purified and activated by passing it through a first polar protic solvent to remove impurities and liberate existing functional groups. To capture at least one organic contaminant using the purified and activated porous polymer, The method involves passing a second polar protic solvent through the porous polymer to release the at least one captured organic contaminant from the porous polymer into the second polar protic solvent. Evaporating the polar protic solvent containing the released at least one captured organic contaminant to concentrate the at least one organic contaminant, and Destroying the concentrated at least one captured organic pollutant. Includes, The first and second polar protic solvents may be the same solvent or different solvents, in this method.

42. The method according to claim 41, wherein the porous polymer material includes a foam.

43. The method according to claim 42, wherein the porous polymer material includes polyurethane.

44. The method according to claim 43, wherein destroying the concentrated at least one captured organic contaminant includes applying acoustic cavitation energy to the at least one captured organic contaminant.

45. A device for destroying captured pollutants, A vessel wall having an inner surface that encloses an internal space, wherein the inner surface is coated with long-chain organic molecules, The first inlet, which is in fluid communication with the reagent supply source, A second inlet that is in fluid communication with the source of desorbed contaminants in the solvent, and Exit A vessel equipped with, An energy source configured to guide energy into the internal space, wherein the energy includes one or more of the following: ultrasonic energy with a frequency of about 200 kHz to about 1000 kHz, UV energy with a frequency of about 100 nm to about 400 nm, and / or visible light with a frequency of about 400 nm to about 700 nm. A device equipped with the following features.

46. A system for destroying captured pollutants, A first vessel including a detachable vessel, wherein the detachable vessel is A vessel wall defining the internal space, one or more inlets configured to receive sorbents and solvents containing captured contaminants, and an outlet, This causes the flow of the solvent through the sorbent to one or more mechanical elements for facility desorption of the contaminant from the sorbent to the solvent. A first vessel equipped with, A second vessel containing an enriched vessel, A vessel wall defining the interior space, an entrance, and an exit, An apparatus for concentrating or evaporating the solvent in the internal space A second vessel equipped with, A third vessel including a fracture vessel, wherein the fracture vessel is A vessel wall defining the interior space, an entrance, and an exit, An energy source configured to guide destructive energy into the internal space, A third vessel equipped with Equipped with, A system in which the first, second, and third vessels are in fluid communication such that, after the captured contaminant is released from the sorbent in the desorption vessel, it flows from the outlet of the first vessel to the inlet of the second vessel and into the second vessel, and then flows from the outlet of the second vessel to the inlet of the third vessel and into the third vessel.

47. Porous polymer materials, and Multiple nanoparticles bonded to the outer surface and within the porous polymer material An adsorbent system, including one.

48. The adsorbent system according to claim 47, wherein the plurality of nanoparticles have a diameter between 1 nm and 500 nm.

49. The sorbent system according to claim 47, wherein the nanoparticles include titanium, iron, manganese, zinc, silicon, or oxides and hydroxides thereof.

50. The sorbent system according to claim 47, further comprising at least one active chemical group bonded to the nanoparticles.

51. The adsorbent system according to claim 50, wherein the plurality of nanoparticles have a diameter between 1 nm and 500 nm.

52. The sorbent system according to claim 50, wherein the nanoparticles include titanium, iron, manganese, zinc, silicon, or oxides and hydroxides thereof.

53. The sorbent system according to claim 50, wherein the at least one active chemical group comprises at least one of amines, thiols, and alcohols.

54. The sorbent system according to claim 50, wherein the active chemical group is hydrophobic.

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