Process for removing perfluoroalkyl substances and process for regenerating adsorbents used therewith - Patent Application 20070122997

Abstract

A process and apparatus for decomposing PFAS into calcium fluoride, carbon dioxide, and water. The PFAS is heated and introduced into a calcium base, which decomposes the PFAS. The PFAS may be present in a PFAS-enriched stream formed by desorbing PFAS from a sorbent that has removed the PFAS from a contaminated stream. The PFAS may be desorbed in the presence of a calcium base. The calcium base may be calcium hydroxide, calcium oxide, calcium carbonate, or a combination thereof.

Description

[Technical Field]

[0001] (Statement of priority) This application claims the benefit of and priority to U.S. Patent Application No. 18 / 064,025, filed December 9, 2022, which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE INVENTION The present invention relates generally to a process and apparatus for removing and decomposing perfluoroalkyl materials, and more particularly to a process and apparatus that utilizes a calcium base to convert perfluoroalkyl materials to calcium fluoride, carbon dioxide, and water. [Background technology]

[0003] Perfluoroalkyl substances (PFAS) are "forever chemicals" that are highly stable and persistent in the environment. PFAS have been linked to harmful effects on the kidneys, liver, blood, and immune system. Examples of PFAS are surfactants in industrial and consumer products, such as firefighting foam, alkaline cleaners, paints, nonstick cookware, carpets, upholstery, shampoos, floor polishes, fume suppressants, semiconductors, photographic film, pesticide formulations, food packaging, masking tape, and denture cleaners.

[0004] Typical PFAS concentrations are pg / L to ng / L. The EPA recommends that PFAS be <70 ppt, so sites require remediation. The EPA has a list of over 179 PFASs that are toxic.

[0005] Although it is known to use sorbent materials to adsorb and remove PFAS, there is still a possibility that adsorbed PFAS may leach into the environment from discarded sorbents.

[0006] Therefore, it is desirable to have more effective and efficient processes for removing and destroying PFAS. Summary of the Invention

[0007] The present invention provides for the removal and destruction of PFAS. PFAS are decomposed with calcium base to form calcium fluoride. The reaction with calcium base avoids the generation of light fluorinated hydrocarbons, which can occur when PFAS compounds are incompletely incinerated. Mineralization minimizes the emission of light fluorinated hydrocarbons, which have a significantly higher global warming potential compared to carbon dioxide.

[0008] Furthermore, it has been found that sorbents that remove PFAS from contaminated streams can be regenerated by desorbing the PFAS from the sorbent with a thermal or liquid-phase desorbent, such as water, methanol, or a hydrocarbon, to produce a PFAS-rich effluent stream. The liquid desorbent may be separated from the PFAS before thermal treatment in the presence of a calcium base, or the entire effluent may be sent to a reactor for thermal treatment.

[0009] Thus, the invention, in at least one embodiment, can be characterized as providing a process for decomposing PFAS by heating PFAS to provide a heated PFAS stream and introducing the heated PFAS stream into a vessel containing a calcium base to convert the PFAS to calcium fluoride, carbon dioxide, and water.

[0010] The PFAS may have a temperature of 400°C to 925°C when the heated PFAS stream is introduced into the vessel. The temperature may be 525°C to 825°C.

[0011] The molar ratio of calcium to fluoride in the container may be 0.5-10.

[0012] The calcium base may include calcium hydroxide, calcium oxide, calcium carbonate, or a combination thereof. Alternatively, the calcium base may consist of calcium oxide.

[0013] The heated PFAS stream may be introduced into the vessel for a time period ranging from 0.5 seconds to 10 minutes.

[0014] The process may also include separating the calcium fluoride, carbon dioxide, and water into a stream containing carbon dioxide and water and solid calcium fluoride. The carbon dioxide may be removed in a carbon dioxide scrubber.

[0015] The PFAS may be heated in the absence of a calcium base.

[0016] In a second aspect, the invention may be broadly characterized as providing a process for removing PFAS from a contaminated stream by removing PFAS from the contaminated stream with a sorbent configured to selectively retain PFAS and provide a treated stream; desorbing the PFAS from the sorbent by heating the sorbent in a reaction zone with or without a calcium base, wherein the desorbed PFAS is converted to calcium fluoride, carbon dioxide, and water; separating a vapor portion from an effluent from the reaction zone; and recovering calcium fluoride from a solid portion of the effluent.

[0017] The adsorbent may include granular activated carbon, ion exchange resin, aluminosilicate, or a combination thereof.

[0018] The adsorbent may be a microporous aluminosilicate having an atomic ratio of silicon to aluminum greater than 50 or greater than 100.

[0019] The adsorbent may be a mesoporous aluminosilicate having an atomic ratio of silicon to aluminum greater than 50 or greater than 100.

[0020] The adsorbent may be an essentially aluminum-free microporous silicate.

[0021] The adsorbent may be an essentially aluminium-free mesoporous silicate.

[0022] The process may further include recycling at least a portion of the vapor fraction to the reaction zone.

[0023] The desorbed PFAS may have a temperature of 525°C to 825°C.

[0024] The molar ratio of calcium to fluoride in the reaction zone may be from 0.5 to 10.

[0025] The calcium base may include calcium hydroxide, calcium oxide, calcium carbonate, or a combination thereof.

[0026] The calcium base may comprise calcium oxide.

[0027] The process may further include separating the calcium fluoride, carbon dioxide, and water into a stream comprising carbon dioxide and water and solid calcium fluoride. The carbon dioxide may be removed in a carbon dioxide scrubber.

[0028] The PFAS may be heated in the absence of a calcium base.

[0029] In a third aspect, the invention may generally be characterized as providing an apparatus for decomposing PFAS, the apparatus comprising: a vessel configured to receive a heated PFAS stream having a calcium base and including the PFAS, the calcium base configured to convert the PFAS to calcium fluoride, carbon dioxide, and water; and a heater configured to heat the PFAS-including stream in the absence of the calcium base to provide a heated PFAS stream.

[0030] Further aspects, embodiments and details of the invention, all of which may be combined in any manner, are set out in the detailed description of the invention below. [Brief explanation of the drawings]

[0031] One or more exemplary embodiments of the invention are described below in conjunction with the following drawing figures. [Figure 1]FIG. 1 is a process flow diagram according to one or more embodiments of the present invention. [Figure 2] 1 is a graph showing experimental data comparing calcium fluoride yield versus reaction time. [Figure 3] 1 is a graph showing experimental data comparing calcium fluoride yield versus reaction time. [Figure 4] 1 is a graph showing experimental data comparing calcium fluoride yield versus calcium to fluoride ratio. DETAILED DESCRIPTION OF THE INVENTION

[0032] As described above, the present invention addresses the decomposition of PFAS and the regeneration of adsorbents used to remove PFAS from contaminated streams. Generally, PFAS is heated and then introduced into a calcium base, which decomposes the PFAS into calcium fluoride, carbon dioxide, and water. By first heating the PFAS and then introducing the heated PFAS, the process is believed to be more energy efficient. Furthermore, interactions between solids and gases can lead to further efficiency in the process.

[0033] Furthermore, in some embodiments, the present invention provides for the regeneration of PFAS-loaded sorbents, for example, to remove PFAS from contaminated streams. The sorbents may be heated to desorb or release the PFAS, which are decomposed in the presence of a calcium base. A liquid-phase desorbent, such as water, methanol, or a hydrocarbon, can be used to desorb the PFAS and produce a PFAS-rich effluent stream. The liquid desorbent may be separated from the PFAS before thermal treatment, or the entire effluent may be sent to a reactor.

[0034] After the PFASs are desorbed, the adsorbent can be reused to remove PFASs. Unlike conventional processes that discard contaminated adsorbents, this process allows the adsorbent to be reused, so PFASs are not stored or disposed of in locations where they may still pose a threat to the environment.

[0035] PFAS should be understood to include compounds such as perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), GenX, perfluorobutane sulfonic acid (PFBS), perfluoropentanesulfonic acid (PFPS), perfluorohexane sulfonic acid (PFHxS), perfluoroheptanesulfonic acid (PFHpS), perfluorononanesulfonic acid (PFNS), or perfluorodecanesulfonic acid (PFDS), hexafluoropropylene oxide dimer acid (HFPO-DA), etc. This list is not intended to be exhaustive, but merely illustrative. Additional PFA compounds can be found, for example, in the definition provided by the EPA.

[0036] With these general principles in mind, one or more embodiments of the invention are described below with the understanding that the description is not intended to be limiting.

[0037] As shown in FIG. 1 , in various embodiments of the present invention, a PFAS10 stream is heated to provide a heated PFAS stream 12. The PFAS10 stream is heated, for example, in heater 14. In the PFAS stream, the PFAS is heated in the absence of a calcium base. For example, the PFAS10 stream may be heated before moving to reaction zone 16, which includes reactor vessel 18. The PFAS10 may be heated to a temperature such that when the heated PFAS contacts or is introduced into the calcium base, the PFAS has a temperature of 400°C to 925°C or 525°C to 825°C. Without being bound by theory, it is believed that the PFAS may partially decompose during initial heating before entering the reactor. These partially decomposed molecules may have increased reactivity within the reactor.

[0038] The heated PFAS stream 12 may be introduced into a vessel 18 containing a calcium base. In the presence of the calcium base, the PFAS is converted to calcium fluoride, carbon dioxide, and water. The calcium base may include calcium hydroxide, calcium oxide, calcium carbonate, or a combination thereof. In some embodiments, the calcium base comprises calcium oxide. The molar ratio of calcium to fluoride in vessel 18 may be from 0.5 to 10 or from 0.5 to 2. The PFAS may have a residence time in vessel 18 and / or in the presence of the calcium base of from 0.5 seconds to 10 minutes.

[0039] Effluent 20 from vessel 18 contains calcium fluoride, carbon dioxide, and water. Accordingly, effluent 20 may be separated in separation zone 22 into a stream 24 containing carbon dioxide and water and solid calcium fluoride 26. A centrifuge 28 may be used in separation zone 22, although other separation devices, such as a baghouse, may also be used. Additionally, carbon dioxide may be removed in carbon dioxide scrubber 30. A portion of effluent 20 may be returned to vessel 18 to minimize release of undecomposed PFAS.

[0040] The PFAS 10 stream may be a PFAS-enriched stream generated by removing PFAS from a contaminated stream 32. In this application, "PFAS-enriched stream" means that at least 0.1% of the stream contains PFAS.

[0041] For example, the contaminated stream 32 may be transferred to a purification zone 34 including a vessel 36 containing a sorbent configured to selectively retain PFASs and provide a treated stream 38. The sorbent may be granular activated carbon, an ion exchange resin, or an aluminosilicate. For example, the sorbent may be a microporous aluminosilicate having an atomic ratio of silicon to aluminum greater than 50 or greater than 100. The sorbent may also be a mesoporous aluminosilicate having an atomic ratio of silicon to aluminum greater than 50 or greater than 100. The sorbent may also be a microporous silicate or a mesoporous silicate that is essentially aluminum-free. While only one vessel 36 is shown, it is contemplated that more than one vessel 36 containing sorbent may be provided. The sorbents in multiple vessels 36 may be regenerated at various times.

[0042] The PFASs can be desorbed from the adsorbent to provide a PFAS-enriched stream. Depending on the adsorbent, the PFASs can be desorbed with a solvent or heat. In some embodiments, this can be a batch process. In some embodiments, this can be a continuous process. For example, a liquid-phase desorbent, such as water, methanol, or a hydrocarbon, can be used to desorb the PFASs and produce a PFAS-enriched effluent stream. The liquid desorbent can be separated from the PFASs before thermal treatment, or the entire effluent can be sent to the reactor.

[0043] Alternatively, the PFASs can be concentrated by adsorption onto a sorbent, and the sorbent can then be mixed with the calcium base along with the PFASs.

[0044] Thus, an apparatus for decomposing PFAS may include a first vessel 36 that receives a contaminated stream 32 containing PFAS. The first vessel 36 includes a sorbent configured to selectively retain PFAS. Under suitable conditions, the sorbent can desorb the PFAS and provide a PFAS10 stream. The second vessel 18 includes a calcium base that converts the PFAS to calcium fluoride, carbon dioxide, and water. A heater 14 is provided to heat the PFAS10 stream in the absence of the calcium base.

[0045] In embodiments, instead of desorbing PFAS into a PFAS stream, the present invention contemplates a mixture of PFAS-containing sorbent that is heated in the presence of a calcium base. The heat desorbs the sorbent, thus regenerating the desorption. At the same time, the calcium base decomposes the PFAS.

[0046] experiment PFOA (0.15 g) was dissolved in water (15 g) and UZM-50 (0.98 g) was added. UZM-50 was prepared according to the method described in U.S. Patent No. 1,063,2454. The mixture was stirred at room temperature for 1 day. The solid was separated from the liquid by centrifugation. The UZM-50 was combined with water and centrifuged to wash away any unadsorbed PFAS. The PFOA-loaded UZM-50 was dried in a rotovap at 80°C. PFOA-loaded UZM-50 (1.0 g) was combined with calcium oxide (1.42 g) and crushed with a mortar and pestle. The solid mixture was then slowly poured into a glass reactor and heated in an oven at 525°C for 20 minutes. After cooling, the solid was analyzed by XRD. XRD indicated the formation of calcium fluoride. It is believed that similar results would be observed when PFAS is desorbed, heated, and then introduced into a calcium base.

[0047] Temperature, Ca / F ratio, and time for decomposition Additionally, PFAS (PFOA, PFOS, or HFPO-DA) was mixed with calcium base (0.6-5 mol Ca / F) using a mortar and pestle. The solid mixture was poured into a glass reactor and heated in a furnace at temperatures ranging from 200°C to 525°C for 5-60 minutes. The solid was cooled and subjected to XRD, which showed the presence of calcium fluoride.

[0048] In Figure 2, a graph is depicted showing the relationship between calcium fluoride yield and reaction time of PFAS and calcium base. In the experiment in Figure 2, the Ca / F molar ratio was 1.3 and the PFAS had a temperature of 525°C.

[0049] In Figure 3, a graph is depicted showing the relationship between calcium fluoride yield and temperature of PFAS when exposed to calcium base. In the experiment in Figure 3, the Ca / F molar ratio was 1.3 and the PFAS was exposed to calcium base for 20 minutes.

[0050] In Figure 4, a graph is depicted showing the relationship between calcium fluoride yield and the molar ratio of Ca / F. In the experiment of Figure 3, the PFAS had a temperature of 525°C and was exposed to calcium base for 20 minutes.

[0051] As can be seen from Figures 2 to 4, PFAS was successfully decomposed by changing the conditions.

[0052] Desorption of PFAS from GAC and treatment with calcium oxide GAC was shaken with PFOA (2.18 g) in water (200 mL) at room temperature for 3 hours. The GAC mixture was filtered to isolate the PFOA-loaded GAC. The GAC was washed with water and dried on a rotovap to remove excess water. GAC (10 g) was loaded into the upper heating zone of a quartz reactor using a nitrogen flow (150 cc / min). Two beds of calcium oxide (2.3 g each) were loaded into the lower heating zone of the reactor. The upper heating zone reached 325°C, and the lower heating zone reached 425°C. After heating for 1 hour, the reactor was cooled. XRD of the CaO bed detected CaF2.

[0053] Those skilled in the art should appreciate and understand that various other components, such as valves, pumps, filters, coolers, etc., are not shown in the drawings because their details are well within the knowledge of those skilled in the art and their description is not necessary to practice or understand embodiments of the present invention.

[0054] Any of the above lines, conduits, units, devices, vessels, ambient environments, zones, or the like may be equipped with one or more monitoring components, including sensors, measurement devices, data acquisition devices, or data transmission devices. Signals, process, or condition measurements and data from the monitoring components may be used to monitor conditions in, around, and on the process equipment. Signals, measurements, and / or data generated or recorded by the monitoring components may be collected, processed, and / or transmitted over one or more networks or connections, which may be private or public, general or specific, direct or indirect, wired or wireless, encrypted or unencrypted, and / or combinations thereof. This specification is not intended to be limiting in this respect.

[0055] Signals, measurements, and / or data generated or recorded by the monitoring components may be transmitted to one or more computing devices or systems. The computing devices or systems may include at least one processor and memory storing computer-readable instructions that, when executed by the at least one processor, cause the one or more computing devices to perform a process, which may include one or more steps. For example, the one or more computing devices may be configured to receive data related to at least one piece of equipment associated with the process from one or more monitoring components. The one or more computing devices or systems may be configured to analyze the data. Based on the analysis of the data, the one or more computing devices or systems may be configured to determine one or more recommended adjustments to one or more parameters of one or more processes described herein. The one or more computing devices or systems may be configured to transmit encrypted or unencrypted data including one or more recommended adjustments to one or more parameters of one or more processes described herein.

[0056] Specific Embodiments While the following will be described in conjunction with specific embodiments, it will be understood that this description is illustrative, but not intended to limit the scope of the preceding description and appended claims.

[0057] A first embodiment of the invention is a process for decomposing PFAS, the process comprising: heating PFAS to provide a heated PFAS stream; and introducing the heated PFAS stream into a vessel containing a calcium base to convert the PFAS to calcium fluoride, carbon dioxide, and water. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the PFAS has a temperature of 400°C to 925°C when the heated PFAS stream is introduced into the vessel. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the temperature is 525°C to 825°C. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the molar ratio of calcium to fluoride in the vessel is 0.5 to 10. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the calcium base comprises calcium hydroxide, calcium oxide, calcium carbonate, or a combination thereof. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the calcium base consists of calcium oxide. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the heated PFAS stream is introduced into the vessel for a time period of 0.5 seconds to 10 minutes. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, further comprising separating the calcium fluoride, carbon dioxide, and water into a stream comprising carbon dioxide and water and solid calcium fluoride. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, further comprising removing carbon dioxide in a carbon dioxide scrubber. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the PFAS is heated in the absence of a calcium base.

[0058] A second embodiment of the present invention is a process for removing PFASs from a contaminated stream, the process comprising: removing PFASs from the contaminated stream using a sorbent configured to selectively retain PFASs and provide a treated stream; desorbing the PFASs from the sorbent in a reaction zone by heating the sorbent in the presence or absence of a calcium base, whereby the desorbed PFASs are converted to calcium fluoride, carbon dioxide, and water; separating a vapor portion from an effluent from the reaction zone; and recovering calcium fluoride from a solid portion of the effluent. An embodiment of the present invention is one, any, or all of the preceding embodiments in this paragraph through the second embodiment of this paragraph, in which the sorbent comprises granular activated carbon, an ion exchange resin, or an aluminosilicate. An embodiment of the present invention is one, any, or all of the preceding embodiments in this paragraph through the second embodiment of this paragraph, in which the sorbent is a microporous aluminosilicate having an atomic ratio of silicon to aluminum greater than 50. An embodiment of the invention is one, any, or all of the preceding embodiments in this paragraph through the second embodiment of this paragraph, in which the adsorbent is a microporous aluminosilicate having an atomic ratio of silicon to aluminum greater than 100. An embodiment of the invention is one, any, or all of the preceding embodiments in this paragraph through the second embodiment of this paragraph, in which the adsorbent is a mesoporous aluminosilicate having an atomic ratio of silicon to aluminum greater than 50. An embodiment of the invention is one, any, or all of the preceding embodiments in this paragraph through the second embodiment of this paragraph, in which the adsorbent is a mesoporous aluminosilicate having an atomic ratio of silicon to aluminum greater than 100. An embodiment of the invention is one, any, or all of the preceding embodiments in this paragraph through the second embodiment of this paragraph, in which the adsorbent is a microporous silicate essentially free of aluminum. An embodiment of the invention is one, any, or all of the preceding embodiments in this paragraph through the second embodiment of this paragraph, in which the adsorbent is a mesoporous silicate essentially free of aluminum.An embodiment of the invention is any one, any, or all of the preceding embodiments of this paragraph through the second embodiment of this paragraph, further comprising recycling at least a portion of the vapor fraction to the reaction zone. An embodiment of the invention is any one, any, or all of the preceding embodiments of this paragraph through the second embodiment of this paragraph, wherein the desorbed PFAS has a temperature of 525°C to 825°C. An embodiment of the invention is any one, any, or all of the preceding embodiments of this paragraph through the second embodiment of this paragraph, wherein the molar ratio of calcium to fluoride in the reaction zone is 0.5 to 10. An embodiment of the invention is any one, any, or all of the preceding embodiments of this paragraph through the second embodiment of this paragraph, wherein the calcium base comprises calcium hydroxide, calcium oxide, calcium carbonate, or a combination thereof. An embodiment of the invention is any one, any, or all of the preceding embodiments of this paragraph through the second embodiment of this paragraph, wherein the calcium base consists of calcium oxide. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the second embodiment of this paragraph, further comprising separating the calcium fluoride, carbon dioxide, and water into a stream comprising carbon dioxide and water and solid calcium fluoride. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the second embodiment of this paragraph, further comprising removing carbon dioxide in a carbon dioxide scrubber. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the second embodiment of this paragraph, wherein the PFAS is heated in the absence of a calcium base.

[0059] A third embodiment of the invention is an apparatus for decomposing PFAS, the apparatus comprising: a vessel comprising a calcium base and configured to receive a heated PFAS stream comprising PFAS, wherein the calcium base is configured to convert the PFAS to calcium fluoride, carbon dioxide, and water; and a heater configured to heat the PFAS-containing stream in the absence of the calcium base to provide a heated PFAS stream.

[0060] Without further elaboration, it is believed that, using the preceding description, one skilled in the art can utilize the present invention to its fullest extent and easily ascertain the essential characteristics of the present invention, and can make various changes and modifications to the present invention to adapt it to various uses and conditions, without departing from the spirit and scope of the present invention. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way, and are intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0061] Above, all temperatures are set forth in degrees Celsius and all parts and percentages are by weight unless otherwise indicated.

[0062] While at least one exemplary embodiment has been presented in the foregoing detailed description of the present invention, it should be understood that numerous variations exist. It should also be understood that the exemplary embodiment(s) are merely examples and are in no way intended to limit the scope, applicability, or configuration of the present invention. Rather, the foregoing detailed description provides those skilled in the art with a convenient guide for implementing exemplary embodiments of the present invention, and it should be understood that various changes can be made in the functions and arrangement of elements described in the exemplary embodiment without departing from the scope of the present invention as set forth in the appended claims and their legal equivalents.

Claims

1. 1. A process for decomposing PFAS, comprising: heating the PFAS to provide a heated PFAS stream; introducing said heated PFAS stream into a vessel containing a calcium base to convert said PFAS to calcium fluoride, carbon dioxide, and water.

2. 10. The process of claim 1, wherein the PFAS has a temperature of from 400°C to 925°C or from 525°C to 825°C when the heated PFAS stream is introduced into the vessel.

3. 10. The process of claim 1, wherein the molar ratio of calcium to fluoride in the vessel is 0.5 to 10.

4. 10. The process of claim 1, wherein the calcium base comprises calcium hydroxide, calcium oxide, calcium carbonate, or a combination thereof.

5. 10. The process of claim 1, wherein the calcium base comprises calcium oxide.

6. The process of any one of claims 1 to 5, wherein the heated PFAS stream is introduced into the vessel for a time period of from 0.5 seconds to 10 minutes.

7. 6. The process of any one of claims 1 to 5, further comprising separating the calcium fluoride, the carbon dioxide, and the water into a stream comprising carbon dioxide and water and solid calcium fluoride.

8. 8. The process of claim 7, further comprising removing the carbon dioxide in a carbon dioxide scrubber.

9. The process of any one of claims 1 to 5, wherein the PFAS is heated in the absence of the calcium base.

10. An apparatus for decomposing PFAS, comprising: a vessel (18) configured to receive a heated PFAS stream (12) containing a calcium base and containing PFAS, the calcium base configured to convert the PFAS to calcium fluoride, carbon dioxide, and water; a heater (14) configured to heat a stream (10) comprising PFAS in the absence of said calcium base to provide said heated PFAS stream.

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