PFAS decomposition system and apparatus

Abstract

This specification discloses catalytic systems for decomposing PFAS flows. The process includes a PFAS decomposition system integrating an upstream aqueous PFAS decomposition technique with a downstream gas-phase flue gas oxidation catalyst. Methods for implementing the PFAS decomposition system are also provided herein.

Description

[Technical Field]

[0001] This application claims priority based on International Application No. PCT / CN2023 / 102712, filed on 27 June 2023. The entire contents of that application are incorporated therein.

[0002] This disclosure relates in general to the field of catalysts for the decomposition of perfluoroalkyl and polyfluoroalkyl substances ("PFAS"). More specifically, it relates to the use of aqueous PFAS decomposition techniques in combination with gas-phase flue gas oxidation catalysts. [Background technology]

[0003] As understood in the art, PFAS refers to perfluoroalkyl and polyfluoroalkyl substances, a group of artificial fluorine chemicals. PFAS are known to possess strong carbon-fluorine bonds that can cause long-term sustainability problems. For example, sustainability issues include long-term persistence in the natural environment, bioaccumulation along the food chain, and adverse health effects on humans. Therefore, effective degradation (destruction) of PFAS is needed to prevent PFAS contamination. [Overview of the project] [Problems that the invention aims to solve]

[0004] Currently, PFAS degradation strategies are primarily water-based, including electrochemical oxidation, supercritical hydroxide oxidation, and sonication-induced cavitation. These water-based methods generate harmful byproducts such as CF4, C2F6, perfluoropropionic acid (PFPrA), and perfluorobutanesulfonic acid (PFBS), which have fewer than four carbon atoms and can be released into the atmosphere, water, or soil. Due to their mobility in air, water, and soil, these gaseous short-chain PFAS species can further diffuse, potentially exacerbating PFAS pollution in the natural environment. Therefore, improvements to PFAS degradation processes are needed in this field to reduce PFAS pollution levels. [Means for solving the problem]

[0005] In embodiments of this disclosure, a system is provided. The system may include a source of PFAS; an aqueous PFAS decomposition section configured to perform electrochemical oxidation, supercritical hydrooxidation, sonication-induced cavitation, or a combination thereof; and a vapor PFAS decomposition catalytic section. In some embodiments, the PFAS may include perfluorooctanoic acid ("PFOA"), perfluorooctanesulfonic acid ("PFOS"), perfluorobutanesulfonate ("PFBS"), perfluorobutanoic acid ("PFBA"), perfluoroalkyl sulfonic acid ("PFSA"), perfluoroalkyl carboxylic acid ("PFCA"), perfluoroalkyl acid ("PFAA"), perfluoroheptanesulfonate ("PFHpS"), perfluorohexanesulfonate ("PFHxS"), perfluoropentanesulfonic acid ("PFPeS"), perfluorovaleric acid ("PFPeA"), perfluorohexanoic acid ("PFHxA"), or a combination thereof.

[0006] In some embodiments, the vapor PFAS decomposition catalyst section is located in parallel with the aqueous PFAS decomposition section or downstream of the aqueous PFAS decomposition section.

[0007] In some embodiments of the method, a PFAS-free liquid is formed after the aqueous PFAS decomposition section. In other embodiments of the method, a PFAS-containing solution is formed after the aqueous PFAS decomposition section.

[0008] In some embodiments, the vapor PFAS decomposition catalyst section may be configured to receive PFAS-containing vapor from the aqueous PFAS decomposition section.

[0009] In some embodiments, the vapor PFAS decomposition catalyst treatment section may include an exhaust gas oxidation catalyst. In some embodiments, the exhaust gas oxidation catalyst may include zirconium oxide, vanadium oxide, and at least one oxide selected from the group consisting of manganese oxide, cerium oxide, and cobalt oxide. In some embodiments, the exhaust gas oxidation catalyst may include zirconium oxide in an amount of about 40% to about 90% by mass based on the total mass of the catalyst.

[0010] In some embodiments, the exhaust gas oxidation catalyst may include a wash coat. The wash coat may include zirconium oxide and one or more oxides of manganese, cerium, or cobalt. In some embodiments, vanadium oxide is dispersed on the wash coat in an amount of about 0.1% to about 20% by mass, based on the total mass of the wash coat. In some embodiments, zirconium oxide is dispersed on the wash coat in an amount of about 10% to about 90% by mass, based on the total mass of the wash coat. In some embodiments, manganese oxide is dispersed on the wash coat in an amount of about 10% to about 80% by mass, based on the total mass of the wash coat. In some embodiments, the wash coat material may consist of zirconium oxide and manganese oxide.

[0011] In some embodiments, the exhaust gas oxidation catalyst may further contain tungsten oxide, tin oxide, or a mixture thereof. In some embodiments, the tungsten oxide is dispersed on the wash coat of the exhaust gas oxidation catalyst in an amount of about 5% to about 20% by mass based on the total mass of the wash coat. In some embodiments, the catalyst may further contain one or more platinum group metals in an amount of about 0.01% to about 5% by mass based on the total mass of the wash coat.

[0012] In some embodiments, the surface area of ​​the washcoat material of the exhaust gas oxidation catalyst is approximately 25 m². 2 / g ~ approx. 275m 2 / g is also acceptable.

[0013] In some embodiments, emissions that do not contain PFAS may be formed downstream of the vapor PFAS decomposition catalyst treatment unit. In another embodiment, emissions that substantially do not contain PFAS may be formed downstream of the vapor PFAS decomposition catalyst treatment unit. In some embodiments, vapor that does not contain PFAS may be formed downstream of the vapor PFAS decomposition catalyst treatment unit. In another embodiment, vapor that substantially does not contain PFAS may be formed downstream of the vapor PFAS decomposition catalyst treatment unit.

[0014] In some embodiments, the system may further include a gas / liquid separator.

[0015] In some embodiments, the gas / liquid separator may be configured to receive vapor that does not contain PFAS.

[0016] In some embodiments, vapor that does not contain PFAS is converted by the gas / liquid separator into emissions that do not contain PFAS and a liquid that does not contain PFAS.

[0017] In some embodiments, air may be applied to the vapor PFAS decomposition catalyst treatment unit.

[0018] In another embodiment of the present disclosure, a method is provided. The method includes supplying a PFAS-containing fluid to an aqueous PFAS decomposition section of a system; performing aqueous PFAS decomposition in the aqueous PFAS decomposition section, the aqueous PFAS decomposition including any one of electrochemical oxidation, supercritical water oxidation, ultrasonic-induced cavitation, or a combination thereof; receiving PFAS-containing vapor after the aqueous PFAS decomposition; and flowing the PFAS-containing vapor into a vapor PFAS decomposition catalyst treatment unit.

[0019] In some embodiments, electrochemical oxidation may be performed. Electrochemical oxidation can include applying an electric current to the PFAS-containing fluid.

[0020] In some embodiments, supercritical water oxidation may be carried out.

[0021] In some embodiments, ultrasonic induced cavitation can be carried out. Ultrasonic induced cavitation can include applying ultrasonic waves to a PFAS-containing fluid.

[0022] In some embodiments, the vapor PFAS decomposition catalyst treatment unit can include reacting an exhaust gas oxidation catalyst with PFAS-containing vapor.

[0023] In some embodiments, the vapor PFAS decomposition catalyst treatment unit can include an exhaust gas oxidation catalyst. In some embodiments, the exhaust gas oxidation catalyst can include at least one oxide selected from the group consisting of zirconium oxide, vanadium oxide, and manganese oxide, cerium oxide, and cobalt oxide. In some embodiments, the exhaust gas oxidation catalyst can include zirconium oxide in an amount of about 4 wt% to about 90 wt% based on the total mass of the catalyst washcoat.

[0024] In some embodiments, the exhaust gas oxidation catalyst can include a washcoat. The washcoat can include zirconium oxide and one or more oxides of manganese, cerium, or cobalt. In some embodiments, vanadium oxide can be dispersed on the washcoat in an amount of about 0.1 wt% to about 20 wt% based on the total mass of the washcoat. In some embodiments, zirconium oxide can be dispersed on the washcoat in an amount of about 10 wt% to about 90 wt% based on the total mass of the washcoat. In some embodiments, manganese oxide can be dispersed on the washcoat in an amount of about 10 wt% to about 80 wt% based on the total mass of the washcoat. In some embodiments, the washcoat material can consist of zirconium oxide and manganese oxide.

[0025] In some embodiments, the exhaust gas oxidation catalyst may further contain tungsten oxide, tin oxide, or a mixture thereof. In some embodiments, tungsten oxide is dispersed in the wash coat of the exhaust gas oxidation catalyst in an amount of about 5% to about 20% by mass, based on the total mass of the wash coat. In some embodiments, the catalyst may further contain one or more platinum group metals in an amount of about 0.01% to about 5% by mass, based on the total mass of the wash coat.

[0026] In some embodiments, the surface area of ​​the washcoat material of the exhaust gas oxidation catalyst is approximately 25 m². 2 / g ~ approx. 275m 2 It may also be / g. In some embodiments, the vapor PFAS decomposition catalytic treatment may be carried out at a temperature of about 45°C to about 700°C.

[0027] In some embodiments, the method may further include supplying air to the vapor PFAS decomposition catalyst section.

[0028] In some embodiments, after performing vapor PFAS decomposition catalytic treatment, vapor free of PFAS is formed.

[0029] In some embodiments, the method may further include supplying PFAS-free vapor to a gas / liquid separator.

[0030] In some embodiments, the gas / liquid separator can produce PFAS-free emissions and PFAS-free liquids.

[0031] In some embodiments, PFAS-free emissions can be formed after catalytic treatment of vapor PFAS decomposition.

[0032] In some embodiments, a PFAS-free liquid is formed after the aqueous PFAS decomposition treatment.

[0033] In another embodiment, another method is provided, which comprises the steps of: performing aqueous PFAS decomposition on a PFAS-containing fluid to produce PFAS-containing vapor, wherein the aqueous decomposition includes electrochemical oxidation, supercritical hydroxide oxidation, ultrasonically induced cavitation, or a combination thereof; and contacting the PFAS-containing vapor with a PFAS decomposition catalyst.

[0034] In one embodiment of this method, electrochemical oxidation may be carried out. In some embodiments, electrochemical oxidation includes applying a high current density to the PFAS-containing fluid in an aqueous PFAS decomposition section. In other embodiments, supercritical hydroxide oxidation may be carried out. In some embodiments, supercritical hydroxide oxidation is carried out at a temperature of about 450 to 600°C and a pressure greater than about 100 kPa. In yet another embodiment, ultrasonic cavitation may be carried out. In some embodiments, ultrasonic cavitation includes applying an ultrasonic frequency of about 15 kHz to about 1100 kHz to the PFAS-containing fluid.

[0035] In some embodiments, the PFAS decomposition catalyst includes an exhaust gas oxidation catalyst. In some embodiments, the exhaust gas oxidation catalyst may include zirconium oxide, vanadium oxide, and at least one oxide selected from the group consisting of manganese oxide, cerium oxide, and cobalt oxide. In some embodiments, the exhaust gas oxidation catalyst may contain zirconium oxide in an amount of about 30% to about 90% by mass based on the total washcoat mass.

[0036] In some embodiments, the exhaust gas oxidation catalyst may include a wash coat. In some embodiments, the wash coat may include zirconium oxide and one or more oxides of manganese, cerium, or cobalt. In some embodiments, vanadium oxide may be dispersed on the wash coat in an amount of about 0.1% to about 20% by mass based on the total mass of the wash coat. In some embodiments, zirconium oxide is dispersed on the wash coat in an amount of about 30% to about 90% by mass based on the total mass of the wash coat. In some embodiments, manganese oxide is dispersed on the wash coat in an amount of about 10% to about 80% by mass based on the total mass of the wash coat.

[0037] In other embodiments, the wash coat may include zirconium oxide and manganese oxide. In some embodiments, the exhaust gas oxidation catalyst may further include tungsten oxide, tin oxide, or a mixture thereof. In some embodiments, tungsten oxide may be dispersed on the wash coat of the exhaust gas oxidation catalyst in an amount of about 5% to about 20% by mass, based on the total mass of the wash coat. In some embodiments, the exhaust gas oxidation catalyst may include one or more platinum group metals in an amount of about 0.01% to about 5% by mass, based on the total mass of the wash coat. In some embodiments, the wash coat may be about 25 m 2 / g ~ approx. 275m 2 It can have a surface area of ​​ / g. [Brief explanation of the drawing]

[0038] The disclosures described herein are illustrated by the accompanying drawings and are not limited thereto. [Figure 1] Figure 1 shows a schematic diagram of an integrated PFAS decomposition system comprising a separate aqueous PFAS decomposition section and a vapor PFAS decomposition catalyst section. [Figure 2]Figure 2 shows a schematic diagram of an integrated PFAS decomposition system that integrates vapor PFAS decomposition catalytic treatment as a subsection of an aqueous PFAS decomposition section equipped with a gas / liquid separator. [Modes for carrying out the invention]

[0039] Currently, industry strategies for PFAS degradation are primarily water-based, including electrochemical oxidation, supercritical hydroxide oxidation, and sonication-induced cavitation. These methods can generate harmful byproducts such as CF4, C2F6, perfluoropropionic acid (PFPrA), and perfluorobutanesulfonic acid (PFBS) into the surrounding air. Due to their mobility in air, water, and soil, these gaseous short-chain PFAS species can further diffuse, potentially exacerbating PFAS contamination in the natural environment.

[0040] In embodiments of this disclosure, a system has been developed for applying an exhaust gas oxidation catalyst to a PFAS source to decompose PFAS and prevent PFAS pollution in the environment. In one embodiment, the system is provided. This system includes a PFAS source which may include perfluorooctanoic acid ("PFOA"), perfluorooctanesulfonic acid ("PFOS"), or a combination thereof. In another embodiment, the PFAS may include PFOA, PFOS, PFBS, PFBA, PFSA, PFCA, PFAA, PFHpS, PFHxS, PFPeS, PFPeA, PFHxA, or a combination thereof. Furthermore, the system may include an aqueous PFAS decomposition section. The aqueous PFAS decomposition section is configured to perform electrochemical oxidation, supercritical hydroxylation, sonication-induced cavitation, or a combination thereof. In some embodiments, the aqueous PFAS decomposition system may decompose long-chain PFAS species having more than four carbon atoms, such as PFOA and PFOS, into short-chain PFAS species. In some embodiments, the aqueous PFAS decomposition section can decompose PFAS species into hydrogen fluoride, short-chain PFAS species such as CF4, C2F6, PFPrA and PFBS having fewer than four carbon atoms, or combinations thereof. The system may further include a vapor PFAS decomposition catalytic treatment. The vapor PFAS decomposition catalytic treatment may be an independent unit following the aqueous PFAS decomposition section, or a subunit within the aqueous PFAS decomposition section.

[0041] In some embodiments, the source of PFAS may be a PFAS-containing liquid or PFAS-containing fluid. In some embodiments, the PFAS-containing liquid or PFAS-containing fluid may include PFOA, PFOS, PFBS, PFBA, PFSA, PFCA, PFAA, PFHpS, PFHxS, PFPeS, PFPeA, PFHxA, or a combination thereof.

[0042] In some embodiments, the PFAS source is received into an aqueous PFAS decomposition section. In some embodiments, this section is configured to perform either electrochemical oxidation, supercritical hydroxide oxidation, sonication-induced cavitation, or a combination thereof.

[0043] In some embodiments, electrochemical oxidation involves applying an electric current to a source of PFAS. In some embodiments, electrochemical oxidation involves cleaving and oxidizing the carbon-fluorine bonds of the PFAS species using a high current density. In some embodiments, electrochemical oxidation involves the use of boron-doped diamond electrodes.

[0044] In some embodiments, supercritical hydroxide oxidation may include solvation of PFAS and accelerated oxidation of PFAS by oxygen in a supercritical state. In this specification, supercritical refers to oxidation carried out at a temperature greater than about 700°C, a pressure greater than about 100 kPa, or a combination thereof. In some embodiments, supercritical hydroxide oxidation may involve heating of the PFAS-containing fluid. In some embodiments, supercritical hydroxide oxidation may involve pressurizing of the PFAS-containing fluid.

[0045] In some embodiments, ultrasonic cavitation involves applying ultrasound to a PFAS to decompose it. In some embodiments, ultrasonic cavitation refers to cavitation initiated directly or indirectly by an ultrasonic energy source, such as an ultrasonic transducer. In some embodiments, the ultrasonic frequency range may include the ranges of about 15 kHz to about 1100 kHz, about 50 kHz to about 1050 kHz, about 100 kHz to about 1000 kHz, about 150 kHz to about 950 kHz, about 200 kHz to about 900 kHz, about 250 kHz to about 850 kHz, about 300 kHz to about 800 kHz, about 350 kHz to about 750 kHz, about 400 kHz to about 700 kHz, about 450 kHz to about 650 kHz, or about 500 kHz to about 600 kHz. In some embodiments, ultrasonic cavitation can be performed under ambient conditions without the use of chemical additives.

[0046] In certain embodiments, a PFAS-free liquid is formed after the PFAS decomposition section. In some embodiments, the PFAS-free liquid from the aqueous PFAS decomposition section is recycled back into the aqueous PFAS decomposition section. In another embodiment, the PFAS-free liquid is released into the atmosphere.

[0047] In certain embodiments, PFAS-containing vapor is generated after the PFAS decomposition section. In some embodiments, the PFAS-containing vapor is introduced into a vapor PFAS decomposition catalytic treatment. The vapor PFAS decomposition catalytic treatment is arranged in parallel with the aqueous PFAS decomposition section or after the aqueous PFAS decomposition section.

[0048] In some embodiments, the vapor PFAS decomposition catalytic treatment may include an exhaust gas oxidation catalyst. In some embodiments, the exhaust gas oxidation catalyst may include zirconium oxide, vanadium oxide, and at least one oxide selected from the group consisting of manganese oxide, cerium oxide, and cobalt oxide.

[0049] In some embodiments, the exhaust gas oxidation catalyst may contain zirconium oxide in amounts of about 40% to about 90% by mass, about 45% to about 85% by mass, about 50% to about 80% by mass, about 55% to about 75% by mass, or about 60% to about 70% by mass, based on the total mass of the catalyst.

[0050] In some embodiments, the exhaust gas oxidation catalyst may include a wash coat. The wash coat may include zirconium oxide and one or more oxides of manganese, cerium, or cobalt. In some embodiments, vanadium oxide is dispersed on the core in amounts of about 0.1% to about 20% by mass, about 0.5% to about 18% by mass, about 1% to about 15% by mass, about 2% to about 12% by mass, about 5% to about 10% by mass, or about 7% to about 8% by mass, based on the total mass of the wash coat. In some embodiments, zirconium oxide may be dispersed on the wash coat in amounts of about 10% to about 90% by mass, about 15% to about 85% by mass, about 20% to about 80% by mass, or about 25% to about 75% by mass, based on the total mass of the wash coat. In some embodiments, manganese oxide can be dispersed on the wash coat in amounts of about 10% to about 80% by mass, about 15% to about 75% by mass, about 20% to about 70% by mass, or about 25% to about 65% by mass, based on the total mass of the wash coat. In some embodiments, the wash coat material can consist of zirconium oxide and manganese oxide.

[0051] In some embodiments, the exhaust gas oxidation catalyst may further include tungsten oxide, tin oxide, or a mixture thereof. In some embodiments, tungsten oxide is dispersed on the washcoat of the exhaust gas oxidation catalyst in an amount of about 5 wt% to about 20 wt%, or about 10 wt% to about 15 wt%, based on the total mass of the washcoat. In some embodiments, the catalyst may further include one or more platinum group metals in an amount of about 0.01 wt% to about 5 wt%, about 0.1 wt% to about 4 wt%, about 0.5 wt% to about 3 wt%, or about 1 wt% to about 2 wt%, based on the total mass of the washcoat.

[0052] In some embodiments, the surface area of the washcoat material of the exhaust gas oxidation catalyst is about 25 m 2 / g to about 275 m 2 / g, about 50 m 2 / g to about 250 m 2 / g, about 75 m 2 / g to about 225 m 2 / g, about 100 m 2 / g to about 200 m 2 / g, about 125 m 2 / g to about 175 m 2 / g.

[0053] In some embodiments, the vapor PFAS decomposition catalyst treatment may be performed at a temperature of about 45°C to about 700°C, about 70°C to about 675°C, about 100°C to about 650°C, about 125°C to about 625°C, about 150°C to about 600°C, about 175°C to about 575°C, about 200°C to about 550°C, about 225°C to about 525°C, about 250°C to about 500°C, about 275°C to about 475°C, about 300°C to about 450°C, about 325°C to about 425°C, or about 350°C to about 400°C. In some embodiments, the system may further include supplying air to the vapor PFAS decomposition catalyst treatment.

[0054] In some embodiments, PFAS-free steam is produced after vapor PFAS decomposition catalytic treatment. In another embodiment, substantially PFAS-free steam is produced after vapor PFAS decomposition catalytic treatment. In yet another embodiment, PFAS emissions are produced after vapor PFAS decomposition catalytic treatment. In yet another embodiment, substantially PFAS-free emissions are formed after vapor PFAS decomposition catalytic treatment. In this specification, “steam” means ____. In this specification, “emissions” means ____. In this specification, “substantially free” means a composition containing less than about 1% by mass, less than about 0.5% by mass, less than about 0.25% by mass, less than about 0.1% by mass, less than about 0.05% by mass, less than about 0.01% by mass, or 0% by mass of the component.

[0055] In some embodiments, PFAS-free steam, substantially PFAS-free steam, PFAS emissions, or substantially PFAS-free emissions obtained from the steam PFAS decomposition catalytic treatment may be recycled through the steam PFAS decomposition catalytic treatment.

[0056] In some embodiments, the PFAS-containing vapor is received by a gas / liquid separator. In some embodiments, the gas / liquid separator is a condenser that condenses the PFAS-containing vapor. In some embodiments, the gas / liquid separator is a heat exchanger that recovers heat from the PFAS-containing vapor.

[0057] In some embodiments, PFAS-containing vapor is converted into PFAS-free emissions and PFAS-free liquids by a gas / liquid separator.

[0058] In some embodiments, the PFAS-free vapor is received by a gas / liquid separator. In some embodiments, the gas / liquid separator is a condenser that condenses the PFAS-free vapor. In some embodiments, the gas / liquid separator is a heat exchanger that recovers heat from the PFAS-free vapor.

[0059] In some embodiments, substantially PFAS-free vapor is converted by a gas / liquid separator into substantially PFAS-free emissions and substantially PFAS-free liquids.

[0060] Another embodiment of this disclosure provides a method for applying an exhaust gas oxidation catalyst to a PFAS source to decompose PFAS and prevent PFAS contamination in the environment. This method may include leading the PFAS source described herein to an aqueous PFAS decomposition section. The aqueous PFAS decomposition section may perform electrochemical oxidation, supercritical hydrooxidation, sonication-induced cavitation, or a combination thereof. In some embodiments, the aqueous PFAS decomposition system may decompose long-chain PFAS species, such as PFOA and PFOS having more than four carbon atoms, into short-chain PFAS species. In some embodiments, the aqueous PFAS decomposition section may decompose PFAS species into hydrogen fluoride, short-chain PFAS species, such as CF4, C2F6, PFPrA and PFBS having fewer than four carbon atoms, or a combination thereof. Furthermore, the method may include performing a vapor PFAS decomposition catalytic treatment. The vapor PFAS decomposition catalytic treatment may be performed in parallel with or after the aqueous PFAS decomposition section.

[0061] In some embodiments, the source of PFAS may include a PFAS-containing liquid or PFAS-containing fluid. The PFAS-containing liquid or PFAS-containing fluid may include PFOA, PFOS, PFBS, PFBA, PFSA, PFCA, PFAA, PFHpS, PFHxS, PFPeS, PFPeA, PFHxA, or a combination thereof.

[0062] In some embodiments, when the PFAS source is received into the aqueous PFAS decomposition section, various treatments may be performed. In some embodiments, the PFAS decomposition section is configured to perform electrochemical oxidation, supercritical hydroxide oxidation, sonication-induced cavitation, or a combination thereof.

[0063] In some embodiments, electrochemical oxidation involves applying an electric current to a PFAS-containing fluid. In some embodiments, high current densities can be used to cleave and oxidize the carbon-fluorine bonds in the PFAS-containing fluid. In some embodiments, the products expected from this process include carbon dioxide, fluorine gas, and short-chain PFAS species, such as CF4, C2F6, PFPrA and PFBS having fewer than four carbon atoms, or combinations thereof. In some embodiments, electrochemical oxidation may involve the use of boron-doped diamond electrodes.

[0064] In some embodiments, supercritical hydroxide oxidation may include solvation of PFAS and accelerated oxidation of PFAS by oxygen in a supercritical state. In some embodiments, supercritical hydroxide oxidation may involve heating of the PFAS-containing fluid. In some embodiments, supercritical hydroxide oxidation may involve pressurizing the PFAS-containing fluid. In some embodiments, supercritical hydroxide oxidation may produce short-chain PFAS species, such as CF4, C2F6, PFPrA and PFBS having fewer than four carbon atoms, or combinations thereof.

[0065] In some embodiments, ultrasonic cavitation involves applying ultrasound to a PFAS-containing fluid to decompose the PFAS. In some embodiments, ultrasonic cavitation refers to cavitation initiated directly or indirectly by an ultrasonic energy source, such as an ultrasonic transducer. In some embodiments, the ultrasonic frequency range may include the ranges of about 15 kHz to about 1100 kHz, about 50 kHz to about 1050 kHz, about 100 kHz to about 1000 kHz, about 150 kHz to about 950 kHz, about 200 kHz to about 900 kHz, about 250 kHz to about 850 kHz, about 300 kHz to about 800 kHz, about 350 kHz to about 750 kHz, about 400 kHz to about 700 kHz, about 450 kHz to about 650 kHz, or about 500 kHz to about 600 kHz. In some embodiments, treatment of PFAS species by cavitation can be achieved under ambient conditions without the use of chemical additives.

[0066] In some embodiments, a PFAS-free liquid is formed after electrochemical oxidation, supercritical hydroxide oxidation, sonication-induced cavitation, or a combination thereof, in the aqueous PFAS decomposition section.

[0067] In some embodiments, the PFAS-free liquid from the aqueous PFAS decomposition section is recycled through the aqueous PFAS decomposition section.

[0068] In some embodiments, in the aqueous PFAS decomposition section, electrochemical oxidation, supercritical hydroxide oxidation, ultrasonic cavitation, or a combination thereof is performed on the PFAS-containing liquid or PFAS-containing fluid to generate PFAS-containing vapor.

[0069] In some embodiments, PFAS-containing vapor is introduced into a vapor PFAS decomposition catalytic treatment. In some embodiments, the vapor PFAS decomposition catalytic treatment is arranged in parallel with or after the aqueous PFAS decomposition section.

[0070] In some embodiments, the vapor PFAS decomposition catalytic treatment may include an exhaust gas oxidation catalyst. In some embodiments, the exhaust gas oxidation catalyst may include zirconium oxide, vanadium oxide, and at least one oxide selected from the group consisting of manganese oxide, cerium oxide, and cobalt oxide. In some embodiments, the exhaust gas oxidation catalyst may contain zirconium oxide in amounts of about 40% to about 90% by mass, about 45% to about 85% by mass, about 50% to about 80% by mass, about 55% to about 75% by mass, or about 60% to about 70% by mass, based on the total mass of the catalyst washcoat.

[0071] In some embodiments, the exhaust gas oxidation catalyst may include a wash coat. The wash coat may include zirconium oxide and one or more oxides of manganese, cerium, or cobalt. In some embodiments, vanadium oxide is dispersed on the core in amounts of about 0.1% to about 20% by mass, about 0.5% to about 18% by mass, about 1% to about 15% by mass, about 2% to about 12% by mass, about 5% to about 10% by mass, or about 7% to about 8% by mass, based on the total mass of the wash coat. In some embodiments, zirconium oxide may be dispersed on the wash coat in amounts of about 10% to about 90% by mass, about 15% to about 85% by mass, about 20% to about 80% by mass, or about 25% to about 75% by mass, based on the total mass of the wash coat. In some embodiments, manganese oxide can be dispersed on the core in amounts of about 10% to about 80% by mass, about 15% to about 75% by mass, about 20% to about 70% by mass, or about 25% to about 65% by mass, based on the total mass of the wash coat. In some embodiments, the core material can consist of zirconium oxide and manganese oxide.

[0072] In some embodiments, the exhaust gas oxidation catalyst may further include tungsten oxide, tin oxide, or a mixture thereof. In some embodiments, the tungsten oxide is dispersed on the core of the exhaust gas oxidation catalyst in an amount of about 5% to about 20% by mass, or about 10% to about 15% by mass, based on the total mass of the core. In some embodiments, the catalyst may further include one or more platinum group metals in an amount of about 0.01% to about 5% by mass, about 0.1% to about 4% by mass, about 0.5% to about 3% by mass, or about 1% to about 2% by mass, based on the total mass of the wash coat.

[0073] In some embodiments, the surface area of ​​the washcoat material of the exhaust gas oxidation catalyst is approximately 25 m². 2 / g ~ approx. 275m 2 / g, approx. 50m 2 / g ~ approx. 250m 2 / g, approx. 75m 2 / g ~ approx. 225m 2 / g, about 100m 2 / g~about 200m 2 / g, approx. 125m 2 / g~approx. 175m 2 It is / g.

[0074] In some embodiments, the vapor PFAS decomposition catalytic treatment may be carried out at temperatures of approximately 45°C to approximately 700°C, approximately 70°C to approximately 675°C, approximately 100°C to approximately 650°C, approximately 125°C to approximately 625°C, approximately 150°C to approximately 600°C, approximately 175°C to approximately 575°C, approximately 200°C to approximately 550°C, approximately 225°C to approximately 525°C, approximately 250°C to approximately 500°C, approximately 275°C to approximately 475°C, approximately 300°C to approximately 450°C, approximately 325°C to approximately 425°C, or approximately 350°C to approximately 400°C. In some embodiments, the system may further include supplying air to the vapor PFAS decomposition catalytic treatment.

[0075] In some embodiments, PFAS-free steam is produced after the steam PFAS decomposition catalytic treatment. In some embodiments, substantially PFAS-free steam is produced after the steam PFAS decomposition catalytic treatment. In some embodiments, PFAS emissions are produced after the steam PFAS decomposition catalytic treatment. In some embodiments, substantially PFAS-free emissions are produced after the steam PFAS decomposition catalytic treatment.

[0076] In some embodiments, PFAS-free steam from the steam PFAS decomposition catalytic treatment may be recycled through the steam PFAS decomposition catalytic treatment. In another embodiment, substantially PFAS-free steam from the steam PFAS decomposition catalytic treatment may be recycled through the steam PFAS decomposition catalytic treatment. In yet another embodiment, PFAS-free emissions from the steam PFAS decomposition catalytic treatment may be recycled through the steam PFAS decomposition catalytic treatment. In yet another embodiment, substantially PFAS-free emissions from the steam PFAS decomposition catalytic treatment can be recycled back into the steam PFAS decomposition catalytic treatment.

[0077] In some embodiments, PFAS-free vapor is received by a gas / liquid separator. In some embodiments, the gas / liquid separator is a condenser that condenses the PFAS-free vapor. In some embodiments, the gas / liquid separator is a heat exchanger that recovers heat from the PFAS-free vapor.

[0078] In some embodiments, PFAS-free vapor is converted into PFAS-free emissions and PFAS-free liquids by a gas / liquid separator.

[0079] In some embodiments, the PFAS-free vapor is received by a gas / liquid separator. In some embodiments, the gas / liquid separator is a condenser that condenses the PFAS-free vapor. In some embodiments, the gas / liquid separator is a heat exchanger that recovers heat from the PFAS-free vapor.

[0080] In some embodiments, substantially PFAS-free vapor is converted by a gas / liquid separator into substantially PFAS-free emissions and substantially PFAS-free liquids.

[0081] Referring to the figures, Figure 1 shows a PFAS decomposition system 100 according to an embodiment of the present disclosure. As is clear from Figure 1, a PFAS-containing fluid 105 is supplied to an aqueous PFAS decomposition section 110. The PFAS-containing fluid 105 may contain any of the PFAS species described herein, including, but not limited to, PFOA, PFOS, PFBS, PFBA, PFSA, PFCA, PFAA, PFHpS, PFHxS, PFPeS, PFPeA, PFHxA, or combinations thereof.

[0082] Once the PFAS-containing fluid 105 enters the aqueous PFAS decomposition section 110, various treatments can be performed. These treatments include, as previously described, electrochemical oxidation, supercritical water oxidation, sonication-induced cavitation, or a combination thereof. After treatment in the aqueous PFAS decomposition section 110, PFAS-containing vapor 120 and PFAS-free liquid 115 are produced. The PFAS-free liquid 115 is released into the environment, and its impact is limited because it is PFAS-free or substantially PFAS-free. On the other hand, the PFAS-containing vapor 120 requires further treatment in the vapor PFAS decomposition catalyst section 130.

[0083] The vapor PFAS decomposition catalyst section 130 is arranged in parallel with the aqueous PFAS decomposition section 110, as shown in Figure 1. The vapor PFAS decomposition catalyst section 130 may be located elsewhere, but it is understood that it is placed downstream of the aqueous PFAS decomposition section 110 in order to receive the PFAS-containing vapor 120. The vapor PFAS decomposition catalyst section 130 includes the exhaust gas oxidation gas catalyst described above.

[0084] As shown in Figure 1, air 125 is supplied to the vapor PFAS decomposition catalyst treatment unit 130. The air 125 helps activate the exhaust gas oxidation gas catalyst. The catalyst treatment 130 is carried out at a temperature of approximately 45°C to approximately 700°C and a pressure of over approximately 100 kPa. After the catalyst treatment 130, PFAS-free emissions 135 are produced and released into the atmosphere.

[0085] Figure 2 shows a PFAS decomposition system 200 according to another embodiment of the present disclosure. The PFAS decomposition system 200 includes supplying a PFAS-containing fluid 205 to an aqueous PFAS decomposition section 210. The PFAS-containing fluid includes, but is not limited to, PFOA, PFOS, PFBS, PFBA, PFSA, PFCA, PFAA, PFHpS, PFHxS, PFPeS, PFPeA, PFHxA, or combinations thereof.

[0086] Various treatments can be performed in the aqueous PFAS decomposition section 210. These treatments include electrochemical oxidation, supercritical water oxidation, ultrasonic cavitation, or a combination thereof, as described above. After treatment in the PFAS decomposition section 210, PFAS-containing vapor 215 is generated. This PFAS-containing vapor 215 is supplied to the vapor PFAS decomposition catalyst treatment section 220. The vapor PFAS decomposition catalyst treatment section 220 includes the exhaust gas oxidation gas catalyst described above.

[0087] As shown in Figure 2, air 225 is supplied to the steam PFAS decomposition catalyst treatment unit 220. The steam PFAS decomposition catalyst treatment unit 220 includes an exhaust gas oxidation gas catalyst, as described above. After catalytic treatment, PFAS-containing steam 230 is generated and supplied to the gas / liquid separator 235. The gas / liquid separator 235 generates PFAS-free emissions 240 and PFAS-free liquid 245, which are released into the atmosphere.

[0088] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as those generally understood by those skilled in the art in which this disclosure pertains. Furthermore, terms as defined in commonly used dictionaries should be interpreted in a sense consistent with their meaning in the relevant technical field and the context of this disclosure, and not in an idealized or overly formal sense unless expressly defined herein.

[0089] In this specification, the term "of" may mean "containing". For example, "liquid dispersion of" is interpreted as "liquid dispersion containing".

[0090] In this specification, "a" or "an" refers to one or more such entities. For example, "a" or "compound" refers to one or more compounds or at least one compound unless otherwise specified. Therefore, in this specification, the terms "a" (or "an"), "one or more," and "at least one" are used interchangeably.

[0091] In this specification, the term "and / or" encompasses any combination that includes one or more of the related enumerated items. Furthermore, in this specification, "or" means "and / or".

[0092] Furthermore, the term “approximately” in this specification is used to describe and account for small variations. For example, “approximately” refers to any value within a range of ±10% variation, and “approximately 10” includes the range from 9 to 11.

Claims

1. Sources of perfluoroalkyl and polyfluoroalkyl substances ("PFAS"), including perfluorooctanoic acid ("PFOA"), perfluorooctanesulfonic acid ("PFOS"), perfluorobutanesulfonate ("PFBS"), perfluorobutanoic acid ("PFBA"), perfluoroalkyl sulfonic acid ("PFSA"), perfluoroalkyl carboxylic acid ("PFCA"), perfluoroalkyl acid ("PFAA"), perfluoroheptanesulfonate ("PFHpS"), perfluorohexanesulfonate ("PFHxS"), perfluoropentanesulfonic acid ("PFPeS"), perfluorovaleric acid ("PFPeA"), perfluorohexanoic acid ("PFHxA"), or combinations thereof; Aqueous PFAS decomposition sections configured to perform electrochemical oxidation, supercritical hydroxide oxidation, sonication-induced cavitation, or a combination thereof; Steam PFAS decomposition catalyst processing unit A system that includes this.

2. The system according to claim 1, wherein the vapor PFAS decomposition catalyst processing unit is arranged in parallel with the aqueous PFAS decomposition section.

3. The system according to claim 1, wherein the vapor PFAS decomposition catalyst processing unit is located downstream of the aqueous PFAS decomposition section.

4. The system according to claim 1, wherein a PFAS-free liquid is formed in a subsequent step of the aqueous PFAS decomposition section.

5. The system according to claim 1, wherein PFAS-containing vapor is formed downstream of the aqueous PFAS decomposition section.

6. The system according to claim 5, wherein the vapor PFAS decomposition catalyst processing unit is configured to receive the PFAS-containing vapor from the aqueous PFAS decomposition section.

7. The system according to claim 1, wherein the steam PFAS decomposition catalyst processing unit can include an exhaust gas oxidation catalyst.

8. The system according to claim 6 or 7, wherein after the vapor PFAS decomposition catalyst treatment, PFAS-free waste is formed.

9. The system according to claim 6 or 7, wherein after the vapor PFAS decomposition catalyst treatment, an exhaust product substantially free of PFAS is formed.

10. The system according to claim 6 or 7, wherein after the vapor PFAS decomposition catalyst treatment, vapor that does not contain PFAS is formed.

11. The system according to claim 6 or 7, wherein after the vapor PFAS decomposition catalyst treatment, a vapor substantially free of PFAS is formed.

12. The system according to claim 7, wherein the exhaust gas oxidation catalyst comprises zirconium oxide, vanadium oxide, and at least one oxide selected from the group consisting of manganese oxide, cerium oxide, and cobalt oxide.

13. The system according to claim 12, wherein the exhaust gas oxidation catalyst contains zirconium oxide in an amount of about 30% to about 90% by mass based on the total mass of the wash coat.

14. The system according to claim 12, wherein the exhaust gas oxidation catalyst includes a wash coat.

15. The system according to claim 14, wherein the wash coat comprises zirconium oxide and one or more oxides of manganese, cerium, or cobalt.

16. The system according to claim 14, wherein the vanadium oxide is dispersed on the wash coat in an amount of about 0.1% by mass to about 20% by mass, based on the total mass of the wash coat.

17. The system according to claim 15, wherein the zirconium oxide is dispersed on the wash coat in an amount of about 30% to about 90% by mass, based on the total mass of the wash coat.

18. The system according to claim 15, wherein the manganese oxide is dispersed on the wash coat in an amount of about 10% to about 50% by mass, based on the total mass of the wash coat.

19. The system according to claim 12, wherein the wash coat comprises zirconium oxide and manganese oxide.

20. The system according to claim 7, wherein the exhaust gas oxidation catalyst further comprises tungsten oxide, tin oxide, or a mixture thereof.

21. The system according to claim 20, wherein the tungsten oxide is dispersed on the wash coat of the exhaust gas oxidation catalyst in an amount of about 5% to about 20% by mass based on the total mass of the wash coat.

22. The system according to claim 7, wherein the exhaust gas oxidation catalyst contains one or more platinum group metals in an amount of about 0.01% by mass to about 5% by mass, based on the total mass of the wash coat.

23. The core is approximately 25m ２ / g ~ approx. 275m ２ The system according to claim 12, having a surface area of ​​ / g.

24. The system according to claim 11, further comprising a gas / liquid separator.

25. The system according to claim 24, wherein the gas / liquid separator is configured to accept vapor that does not contain PFAS.

26. The system according to claim 25, wherein the PFAS-free steam is converted by the gas / liquid separator into a PFAS-free discharge and a PFAS-free liquid.

27. The system according to any one of claims 1 to 7, wherein air is applied to the vapor PFAS decomposition catalyst section.

28. A step of supplying a PFAS-containing fluid to the aqueous PFAS decomposition section of the system; A step of carrying out aqueous PFAS decomposition in the aqueous PFAS decomposition section, wherein the aqueous PFAS decomposition includes electrochemical oxidation, supercritical hydroxide oxidation, ultrasonic cavitation, or a combination thereof; The process of receiving PFAS-containing steam after the aqueous PFAS decomposition; The process of introducing the PFAS-containing steam into a vapor PFAS decomposition catalyst treatment. Methods that include...

29. The method according to claim 28, wherein electrochemical oxidation is carried out.

30. The method according to claim 29, wherein the electrochemical oxidation comprises applying a high current density to the PFAS-containing fluid in the aqueous PFAS decomposition section.

31. The method according to claim 28, wherein supercritical hydroxide oxidation is carried out.

32. The method according to claim 31, wherein the supercritical hydroxide oxidation is carried out at a temperature of about 450 to 600°C and a pressure of more than about 100 kPa.

33. The method according to claim 28, wherein ultrasound-induced cavitation is performed.

34. The method according to claim 33, wherein the ultrasonic cavitation is performed by applying an ultrasonic frequency of about 15 kHz to about 1100 kHz to the PFAS-containing fluid.

35. The method according to claim 28, wherein the vapor PFAS decomposition catalyst treatment includes applying an exhaust gas oxidation catalyst to the PFAS-containing vapor.

36. The method according to claim 35, wherein the exhaust gas oxidation catalyst comprises zirconium oxide, vanadium oxide, and at least one oxide selected from the group consisting of manganese oxide, cerium oxide, and cobalt oxide.

37. The method according to claim 36, wherein the exhaust gas oxidation catalyst contains zirconium oxide in an amount of about 30% to about 90% by mass based on the total mass of the wash coat.

38. The method according to claim 36, wherein the exhaust gas oxidation catalyst includes a wash coat.

39. The method according to claim 38, wherein the wash coat comprises zirconium oxide and one or more oxides of manganese, cerium, or cobalt.

40. The method according to claim 38, wherein the vanadium oxide is dispersed on the wash coat in an amount of about 0.1% by mass to about 20% by mass, based on the total mass of the wash coat.

41. The method according to claim 39, wherein the zirconium oxide is dispersed on the wash coat in an amount of about 30% to about 90% by mass, based on the total mass of the wash coat.

42. The method according to claim 39, wherein the manganese oxide is dispersed on the wash coat in an amount of about 10% to about 80% by mass, based on the total mass of the wash coat.

43. The method according to claim 38, wherein the wash coat material comprises zirconium oxide and manganese oxide.

44. The method according to claim 35, wherein the exhaust gas oxidation catalyst further comprises tungsten oxide, tin oxide, or a mixture thereof.

45. The method according to claim 44, wherein the tungsten oxide is dispersed in the wash coat of the exhaust gas oxidation catalyst in an amount of about 5% to about 20% by mass, based on the total mass of the wash coat.

46. The method according to claim 35, wherein the exhaust gas oxidation catalyst contains one or more platinum group metals in an amount of about 0.01% by mass to about 5% by mass, based on the total mass of the wash coat.

47. The aforementioned wash coat is approximately 25m ２ / g ~ approx. 275m ２ The method according to claim 38, having a surface area of ​​ / g.

48. The method according to any one of claims 28 to 47, wherein the vapor PFAS decomposition catalyst treatment is carried out at a temperature of about 45°C to about 700°C.

49. The method according to any one of claims 28 to 47, further comprising supplying air to the vapor PFAS decomposition catalyst treatment.

50. The method according to any one of claims 28 to 47, wherein vapor free of PFAS is formed after vapor PFAS decomposition catalyst treatment.

51. The method according to claim 50, further comprising supplying steam that does not contain the PFAS to a gas / liquid separator.

52. The method according to claim 51, wherein the gas / liquid separator produces a PFAS-free discharge and a PFAS-free liquid.

53. The method according to any one of claims 28 to 36, wherein after vapor PFAS decomposition catalytic treatment, PFAS-free emissions are formed.

54. The method according to any one of claims 28 to 36, wherein a liquid free of PFAS is formed after carrying out an aqueous PFAS decomposition treatment.

55. A step of performing aqueous PFAS decomposition on a PFAS-containing fluid to generate PFAS-containing vapor, wherein the aqueous decomposition includes electrochemical oxidation, supercritical hydroxide oxidation, ultrasonic cavitation, or a combination thereof; and The process of contacting the PFAS-containing vapor with a PFAS decomposition catalyst. Methods that include...

56. The method according to claim 55, wherein electrochemical oxidation is carried out.

57. The method according to claim 56, wherein the electrochemical oxidation comprises applying a high current density to the PFAS-containing fluid in the aqueous PFAS decomposition section.

58. The method according to claim 55, wherein supercritical hydroxide oxidation is carried out.

59. The method according to claim 58, wherein the supercritical hydroxide oxidation is carried out at a temperature of about 450 to 600°C and a pressure of more than about 100 kPa.

60. The method according to claim 55, wherein ultrasound-induced cavitation is performed.

61. The method according to claim 60, wherein the ultrasonic cavitation is performed by applying an ultrasonic frequency of about 15 kHz to about 1100 kHz to the PFAS-containing fluid.

62. The method according to claim 55, wherein the PFAS decomposition catalyst includes an exhaust gas oxidation catalyst.

63. The method according to claim 62, wherein the exhaust gas oxidation catalyst comprises zirconium oxide, vanadium oxide, and at least one oxide selected from the group consisting of manganese oxide, cerium oxide, and cobalt oxide.

64. The method according to claim 63, wherein the exhaust gas oxidation catalyst contains zirconium oxide in an amount of about 30% to about 90% by mass based on the total mass of the wash coat.

65. The method according to claim 63, wherein the exhaust gas oxidation catalyst includes a wash coat.

66. The method according to claim 65, wherein the wash coat comprises zirconium oxide and one or more oxides of manganese, cerium, or cobalt.

67. The method according to claim 63, wherein the vanadium oxide is dispersed on the wash coat in an amount of about 0.1% by mass to about 20% by mass, based on the total mass of the wash coat.

68. The method according to claim 66, wherein the zirconium oxide is dispersed on the wash coat in an amount of about 30% to about 90% by mass, based on the total mass of the wash coat.

69. The method according to claim 66, wherein the manganese oxide is dispersed on the wash coat in an amount of about 10% by mass to about 80% by mass, based on the total mass of the wash coat.

70. The method according to claim 65, wherein the wash coat material comprises zirconium oxide and manganese oxide.

71. The method according to claim 63, wherein the exhaust gas oxidation catalyst further comprises tungsten oxide, tin oxide, or a mixture thereof.

72. The method according to claim 71, wherein the tungsten oxide is dispersed in the wash coat of the exhaust gas oxidation catalyst in an amount of about 5% to about 20% by mass, based on the total mass of the wash coat.

73. The method according to claim 62, wherein the exhaust gas oxidation catalyst contains one or more platinum group metals in an amount of about 0.01% by mass to about 5% by mass, based on the total mass of the wash coat.

74. The aforementioned wash coat is approximately 25m ２ / g ~ approx. 275m ２ The method according to claim 65, having a surface area of ​​ / g.

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