Systems and methods for controlling emissions in aqueous effluent streams of proton exchange membrane cells

Abstract

Disclosed herein are a proton exchange membrane (PEM) system, a fuel cell system, and a water electrolysis system, each of which are operable to remove residuals including at least one organic residual from an effluent stream of water before discharging the water. Also disclosed herein is a method of operating the proton exchange membrane (PEM) system.

Description

FL0715-W001TITLESYSTEMS AND METHODS FOR CONTROLLING EMISSIONS IN AQUEOUS EFFLUENT STREAMS OF PROTON EXCHANGE MEMBRANE CELLSCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of U.S. Provisional Application No. 63 / 733,150 filed December 12, 2024, the disclosures of which are incorporated herein by reference in its entirety.FIELD

[0002] The present disclosure relates to systems and methods for controlling emissions in an aqueous effluent stream discharged from a proton exchange membrane cell (e.g., a fuel cell or a water electrolysis cell).BACKGROUND

[0003] Proton exchange membrane (PEM) cells, also referred to as polymer electrolyte membrane cells or membrane electrode assemblies (MEAs), are used in electrochemical and energy conversion applications and are becoming more widely used as an efficient and clean energy source. Two example PEM cell applications include PEM fuel cells (PEMFC), which are becoming popular in the automotive industry, and PEM water electrolyzers (PEMWE), which are used to produce hydrogen as an energy source. PEM fuel cells generate electricity from electrochemical reactions between a fuel (e.g., hydrogen or methanol) at an anode of the cell and an oxidant (e.g., oxygen, O2, or air) at a cathode of the cell. In operation, the fuel is split at the anode into electrons and protons (e.g., positively charged hydrogen ions, H+), with the electrons being directed along an external circuit to create an electrical current and the protons permeating through the proton exchange membrane towards the cathode. The protons and the electrons are combined at the cathode with the oxidant, forming water as a byproduct which is subsequently discharged from the fuel cell. PEM water electrolyzers operate in reverse, and decompose water into hydrogen gas, H2, and oxygen gas, O2. The water is split into electrons, positively charged hydrogen ions, and oxygen at the anode. The hydrogen ions permeate through the proton exchange membraneFL0715-W001 towards the cathode, where they are re-combined with the electrons to produce the hydrogen gas. The hydrogen gas is separated from excess water exiting the cell and collected, while the excess water is discharged.SUMMARY

[0004] Depending on the manufacturer, PEM fuel cells and PEM water electrolyzers can operate at a variety of temperatures, pressures, relative humidity, and with a variety of potential scavengers and catalyst coatings. As this is still an emerging field, the impact of these individual operating variables is still being understood as to its impact to impurities and degradation potential to be measured in effluent streams. It is believed, however, that rigorous operating conditions have the potential to cause accelerated degradation of various components of fuel cells or water electrolyzers.

[0005] To this end, if there were impurities or degradations from the various components of the PEMFC and / or PEMWE, the device according to the present disclosure would be able to abate those potential emissions. The goal of the invention is to reduce the potential emissions in the water that exits the electrochemical cells and enters the environment.

[0006] One aspect is a proton exchange membrane (PEM) system. The PEM system includes a PEM cell including a cathode, an anode, and a PEM positioned between the cathode and the anode, wherein the PEM cell is operable to consume and / or produce water; a discharge line connected to the PEM cell that receives an effluent stream of the water exiting the PEM cell; and an effluent treatment apparatus positioned on the discharge line, wherein the effluent treatment apparatus is operable to remove residuals including at least one organic residual from the effluent stream of the water before discharging the water from the PEM system.

[0007] Another aspect is a fuel cell system. The fuel cell system includes a fuel cell including a cathode, an anode, and a membrane positioned between the cathode and the anode, wherein the fuel cell is operable to produce electrical power and water as a reaction byproduct; a discharge line connected to the fuel cell that receives an effluent stream of the water exiting the fuel cell; and an effluent treatment apparatus positioned on the discharge line, wherein the effluent treatmentFL0715-W001 apparatus is operable to remove residuals including at least one organic residual from the effluent stream of the water before discharging the water from the fuel cell system.

[0008] Another aspect is a water electrolysis system. The water electrolysis system includes a water electrolyzer including a cathode, an anode, and a membrane positioned between the cathode and the anode, wherein the water electrolyzer is operable to produce hydrogen by decomposing water; a discharge line connected to the fuel cell that receives an effluent stream of the water exiting the water electrolyzer; and an effluent treatment apparatus positioned on the discharge line, wherein the effluent treatment apparatus is operable to remove residuals including at least one organic residual from the effluent stream of the water before discharging the water from the water electrolysis system.

[0009] Yet another aspect is a method of operating a proton exchange membrane (PEM) system. The method includes operating a PEM cell to consume and / or produce water; receiving an effluent stream of the water exiting the PEM cell in a discharge line; removing residuals including at least one organic residual from the effluent stream of the water using an effluent treatment apparatus positioned on the discharge line; and discharging the water from the PEM system.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic diagram of a proton exchange membrane (PEM) cell.

[0011] Figure 2 is a schematic diagram of a PEM fuel cell system that includes an effluent treatment apparatus in accordance with the present disclosure.

[0012] Figure 3 is a schematic diagram of a PEM water electrolyzer system that includes an effluent treatment apparatus in accordance with the present disclosure.

[0013] Figure 4 represents an effluent treatment apparatus filled with a treatment material and showing the flow of effluent through the apparatus.

[0014] Figure 5 represents a cross-sectional view of an effluent treatment apparatus having radial effluent flow.FL0715-W001

[0015] Figure 6 represents an effluent treatment apparatus filled with multiple treatment materials and showing the flow of effluent through the apparatus.

[0016] Figure 7 represents a cross-sectional view of an effluent treatment device having multiple mixed treatment materials and having radial effluent flow.

[0017] Figure 8 represents a cross-sectional view of an effluent treatment device having multiple sequential treatment materials and having radial effluent flow.

[0018] Figure 9 represents an effluent treatment device having different treatment materials in sequence within a single device.

[0019] Figure 10 represents an effluent treatment device made from two sequential devices having different treatment materials.

[0020] Figure 11 represents reported and interpolated isotherm data for C4-C8 perfluorocarboxylic acids on granular activated carbon.DETAILED DESCRIPTION OF THE INVENTION

[0021] Advantages of the present disclosure include, but are not limited to including, abating residuals from an effluent stream of water that is discharged from PEM cells, and / or improving safe and environmentally friendly operation of PEM cells with well-controlled emissions, and doing so in an efficient, cost-effective manner.

[0022] As used herein, the term “discharge line” refers to a flow line connected to a PEM cell that receives an effluent stream of the water exiting the PEM cell and outputs a stream of water that is discharged from the system after processing. The discharge line optionally further outputs a stream of water that is recirculated back into the system after processing. A discharge line is distinguishable from a recirculation line, where a recirculation line is part of a recirculation loop for recirculating a portion of the effluent stream to the PEM cell and does not output a stream of water that is discharged from the system after processing.

[0023] The effluent stream of water exiting the PEM cell is in the form of liquid water, steam, or a combination thereof. When steam is present, a gas-liquid separator optionally serves as a pass-through exhaust for the steam. In some embodiments, a portion of the steam naturally condenses as it moves through theFL0715-W001PEM cell. In some embodiments, the PEM cell further comprises a condenser for condensing steam. Figure 1 schematically depicts an example proton exchange membrane (PEM) cell 100. The PEM cell 100 includes a cathode 102, an anode 104, and a semi-permeable proton exchange membrane (PEM) 106 positioned between the cathode 102 and the anode 104. The cathode 102 and the anode 104 are each constructed of a suitable conductive (e.g., metal or metal alloy) material. The cathode 102 and / or the anode 104 may include a catalytically active surface that is effective to catalyze an electrochemical reaction. The catalytically active surface may include a metal, metal salt, or metal oxide catalyst.

[0024] The cathode 102 and the anode 104 are connected by an external circuit 120 through which electrons 110 flow as current between the cathode and anode during operation of the PEM cell 100. Depending on the intended application of the PEM cell 100, the circuit 120 includes an electrical source 122 that provides power to the cell 100 or a load 122 that consumes power generated by the cell 100. For example, in some embodiments, the PEM cell 100 operates as a PEM fuel cell, such as the PEM fuel cell 202 described below with reference to Figure 2. In such embodiments, the PEM cell 100 includes the load 122. In other embodiments, the PEM cell 100 operates as a PEM water electrolyzer, such as the PEM water electrolyzer 302 described below with reference to Figure 3.

[0025] The PEM 106 positioned between the cathode 102 and the anode 104 includes an ion exchange polymer or an ionomeric material, that is, a polymeric material having a pendant group with a terminal ionic group. The terminal ionic group may be an acid or a salt thereof. The ion exchange polymer of the PEM 106 enables transporting protons or cations 112 across the PEM. In embodiments, the ionomer may include cation exchange groups that are acids such as, for example, sulfonic, carboxylic, boronic, phosphonic, imide, methide, sulfonimide and / or sulfonamide groups. In certain embodiments, the ionomer has sulfonic acid and / or carboxylic acid groups. Various known cation exchange ionomers can be used including ionomeric derivatives of trifluoroethylene, tetrafluoroethylene, styrene-divinylbenzene, alpha, beta, beta-trifluorostyrene, etc., in which cation exchange groups have been introduced.FL0715-W001

[0026] In preferred embodiments, the PEM 106 includes highly fluorinated ionomers. In other embodiments, the PEM 106 includes other ionomers such as partially fluorinated ionomers including ionomers based on trifluorostyrene, ionomers using sulfonated aromatic groups in the backbone, non-fluorinated ionomers including sulfonated styrenes grafted or copolymerized to hydrocarbon backbones, and polyaromatic hydrocarbon polymers possessing different degrees of sulfonated aromatic rings to achieve desired range of proton conductivity in the membrane. “Highly fluorinated” ionomers have at least 90% of the total number of univalent atoms in the polymer are fluorine atoms.

[0027] Ionomers used in the PEM 100 may include sulfonate ion exchange groups. In certain embodiments, the PEM 106 is made from perfluorosulfonic acid (PFSA) / tetrafluroethylene (TFE) copolymer. The term “sulfonate ion exchange groups” as used herein means either sulfonic acid groups or salts of sulfonic acid groups, typically alkali metal or ammonium salts. In some embodiments of the PEM cell 100, the sulfonic acid form of the PEM 106 is used. In some embodiments, the PEM 106 is subjected to a post treatment acid exchange step can be used to convert the ionomer to acid form. Suitable perfluorinated sulfonic acid polymer membranes in acid form are available from The Chemours Company, Wilmington, Del., under the NAFION trademark.

[0028] Reinforced ion exchange polymer membranes can also be utilized. Such membranes are typically reinforced with a porous support such as a microporous film or a woven or nonwoven fabric. A porous support may improve mechanical properties for some applications and / or decrease costs. The porous support can be made from a wide range of materials, including hydrocarbons and polyolefins (e.g., polyethylene, polypropylene, polybutylene, and copolymers of these materials) and porous ceramic substrates. Reinforced membranes can be made by impregnating a porous, expanded polytetrafluoroethylene film (ePTFE) with ion exchange polymer. ePTFE is available under the trade name “Gore-Tex” from W. L. Gore and Associates, Inc., Elkton, Md., and under the trade name “Tetratex” from Tetratec, Feasterville, Pa. The catalytically active component particles can be incorporated into the ionomer before the porous support is impregnated with the ionomer.Alternatively, a reinforced membrane can be imbibed with a solution containing the catalytically active component.FL0715-W001

[0029] In operation of the PEM cell 100, a voltage is applied across the anode 102 and cathode 104, and a first fluid 108 (e.g., water, methanol, or hydrogen) is introduced into the anode-side of the cell 100 and contacts the catalytically active surface of the anode 102. A half-reaction occurs at the anode 102, causing the first fluid 108 to split into the electrons 110, protons 112, and, in some instances, an electrochemical byproduct that is carried out of the cell in a first effluent stream 114. The electrons 110 travel across the external circuit 120 to the cathode 104, and the protons 112 permeate through the PEM 106 towards the cathode 104. A second fluid 116, such as an oxidant (e.g., water, air or O2), is introduced into the cathode-side of the cell 100 and contacts the catalytically active surface of the cathode 104 and is combined with the electrons 110 and protons 112. A half-reaction occurs at the cathode 104, producing an electrochemical reaction product 118 such as water or hydrogen.

[0030] Figure 2 is a schematic diagram of a fuel cell system 200 in which the PEM cell 100 of Figure 1 is implemented as a PEM fuel cell 202 which generates electrical power 205. In this embodiment, hydrogen, H2, is supplied as the first fluid 108 to the anode-side of the PEM fuel cell 202 via line 204 and air, containing oxygen, O2, is supplied as the second fluid 116 to the cathode-side of the PEM fuel cell 202 via line 206. The half-reaction at the anode 102 generates the electrons 110 and the protons 112 (positively charged hydrogen ions, H+), with the electrons 110 travelling across the external circuit 120 to the cathode 102, generating the electrical power 205 to be consumed by the load 122, and the H+ions 112 permeating through the PEM 106 towards the cathode 102. The half-reaction at the cathode 104, between O2, the electrons 110, and the H+ions 112, produces water, H2O, which is subsequently discharged from the PEM fuel cell 202 in an effluent stream with excess of the first fluid 108 (e.g., H2) and excess of the second fluid 116 (e.g., air) via discharge lines 208, 210, respectively.

[0031] The PEM fuel cell 202 is connected with a cooling loop 212 that circulates a cooling fluid (e.g., water) for cooling the anode 102 and / or cathode 104 during operation. The cooling loop 212 includes a cooling fluid supply line 214 for introducing the cooling fluid into the loop 212 and towards the PEM fuel cell 202. The cooling fluid circulates through the PEM fuel cell 202 and exits via a line 216 of the loop 212. The line 216 is connected to a chiller 218, or any other suitable fluid cooler,FL0715-W001 that operates to cool the cooling fluid after it has passed through the PEM fuel cell 202. The cooling fluid exits the chiller 218 and may be recirculate back into the line 214 and towards the PEM fuel cell 202.

[0032] The system 200 also includes components downstream from the PEM fuel cell 202 that operate to treat the effluent streams in the discharge lines 208, 210. In the example system 200, gas-liquid separators 220, 222 are respectively positioned on one of the discharge lines 208, 210. A first gas-liquid separator 220 is positioned on the discharge line 208 and operates to separate the excess first fluid 108 (e.g., H2) from the water in the effluent stream. The separated first fluid 108 may be recirculated back to the PEM fuel cell 202 via the recirculation loop 226. The separated water exiting the first gas-liquid separator 220 is routed towards a collector 224 (e.g., a liquid receiver, accumulator, storage tank, and the like). A second gas-liquid separator 222 is positioned on the discharge line 210 and operates to separate the excess second fluid 116 (e.g., air) from the water in the effluent stream. The separated second fluid 116 is routed to the outside environment via an exhaust line 228. Alternatively, the separated second fluid 116 may be recirculated back to the PEM fuel cell 202. The separated water exiting the second gas-liquid separator 222 is routed towards the collector 224 where it combines with the water exiting the first gas-liquid separator 220 into an effluent stream of water.

[0033] The effluent stream of water exits the water collector 224 via a line 230 and enters an effluent treatment apparatus 232. The effluent treatment apparatus 232 operates to remove residuals from the effluent stream of water, as described below, producing a treated stream of water 234 that can be safely discharged (e.g., drained) from the system into the environment or another storage site. In embodiments, the effluent treatment apparatus 232 includes any one or more of an adsorbent contacting device (e.g., a packed bed of adsorbent particles or monolithic adsorbent media that include granular activated carbon or non-traditional adsorbents), an activated carbon filter, a reverse osmosis system, an ion exchange resin or polisher, and combinations thereof. The one or more of an adsorbent contacting device, activated carbon filter, reverse osmosis system, ion exchange resin or polisher, and combinations thereof are made of one or more treatment materials. In one aspect, a portion of the water exiting the effluent treatment apparatus 232 may be recirculated via a recirculation loop back into the PEM cell 202.FL0715-W001

[0034] Figure 3 is a schematic diagram of a water electrolysis system 300 in which the PEM cell 100 of Figure 1 is implemented as a PEM water electrolyzer 302 which uses electrical power 305 to generate H2 gas using water. In this embodiment, water, H2O, is supplied as the first fluid 108 to the anode-side of the PEM electrolyzer 302 and as the second fluid 116 to the cathode-side of the PEM electrolyzer 302 via line 304. The half-reaction at the anode 102 generates the electrons 110 and the protons 112 (positively charged hydrogen ions, H+), with the electrons 110 travelling across the external circuit 120 to the cathode 102, and the H+ions 112 permeating through the PEM 106 towards the cathode 102. The half-reaction at the cathode 104, between the electrons 110 and the H+ions 112, produces hydrogen, H2, which is subsequently discharged from the PEM electrolyzer 302 in an effluent stream with excess of the water via a discharge line 308. Oxygen, O2, is generated as a reaction byproduct and is discharged from the PEM electrolyzer 302 with excess of the water via a discharge line 310.

[0035] The system 300, like the system 200 of Figure 2, also includes components downstream from the PEM electrolyzer 302 that operate to treat the effluent streams in the discharge lines 308, 310. In the example system 300, gas-liquid separators 320, 322 are respectively positioned on one of the discharge lines 308, 310. A first gas-liquid separator 320 is positioned on the discharge line 308 and operates to separate the hydrogen, H2, from the water in the effluent stream. The separated hydrogen may be collected via a line 325 and stored for use as an energy source. A portion of the water exiting the first gas-liquid separator 320 may be recirculated back to the PEM electrolyzer 302 via a recirculation loop. Another portion, or all, of the water exiting the first gas-liquid separator 320 is routed towards a collector 324 (e.g., a liquid receiver, accumulator, storage tank, and the like). A second gas-liquid separator 322 is positioned on the discharge line 310 and operates to separate the oxygen, O2, from the water in the effluent stream. The separated oxygen is routed to the outside environment via an exhaust line 328. A portion of the water exiting the second gas-liquid separator 322 may be recirculated back to the PEM electrolyzer 302 via a recirculation loop. Another portion, or all, of the water exiting the second gas-liquid separator 322 is routed towards the collector 224 where it combines with the water exiting the first gas-liquid separator 320 into an effluent stream of water. AFL0715-W001 portion of the water exiting water collector 324 may be recirculated back to the PEM electrolyzer 302 via a recirculation loop 326.

[0036] In one aspect, the PEM system exemplified as fuel cell system 200 or water electrolysis system 300 may further comprise a second treatment apparatus to remove other types of residuals, including for example, fluoride ions or other anions. Such a second treatment apparatus may be positioned at any point in the system, such as between the water collector (224 or 324) and the effluent treatment apparatus (232 or 332); between the gas-liquid separator (220 or 320) and the PEM cell (202 or 302) in a recycling loop; between the water collector (224 or 324) and the PEM cell (202 or 302) in a recycling loop; or between the effluent treatment apparatus (232 or 332) and the drain to the environment. The positioning of the second treatment apparatus and the effluent treatment apparatus may influence the active life of the apparatuses. For example, reducing anions in the water prior with a second treatment apparatus prior to contact with the effluent treatment apparatus may extend the life of the effluent treatment apparatus, and positioning the effluent treatment apparatus before the second treatment apparatus may extend the life of the second treatment apparatus. The second treatment apparatus may comprise a treatment material capable of treating anions including fluoride ions, such as an ion exchange membrane, activated alumina, clays, hydroxyapatite, or molecular sieves.

[0037] Optimal residuals reduction can be achieved by controlling the contact time of the effluent water with the treatment material, and thus, the effluent treatment apparatus. The optimal contact time depends on the treatment material and design of the effluent treatment apparatus. In one aspect, the effluent water contacts the treatment material, and thus the effluent treatment apparatus, for a minimum of 1 minute; in another aspect, a minimum of 2 minutes; in another aspect, a minimum of 5 minutes; and in another aspect, a minimum of 10 minutes. For optimizing efficiency, a maximum contact time may also be desired. In one aspect, the effluent water may contact the treatment material for at most 20 minutes; in another aspect, at most 15 minutes; in another aspect, at most 12 minutes; and in another aspect, at most 10 minutes. In one aspect, the PEM system exemplified as fuel cell system 200 or water electrolysis system 300 may further comprise a means of forcing water through the effluent treatment apparatus 232 or 332 and / or through the second treatment apparatus. This can be done, for example, by using a pump or pressure-FL0715-W001 regulation device. Means to monitor and / or control water flow may also be used to optimize the contact time of the effluent water with the effluent treatment apparatus and thus the treatment material.

[0038] The effluent stream of water exits the water collector 324 via a line 330 and enters an effluent treatment apparatus 332. The effluent treatment apparatus 332, like the effluent treatment apparatus 232, operates to remove residuals from the effluent stream of water, as described below, producing a treated stream of water 334 that can be safely discharged (e.g., drained) from the system into the environment or another storage site. In embodiments, the effluent treatment apparatus 332 includes any one or more of an adsorbent contacting device (e.g., a packed bed of adsorbent particles or monolithic adsorbent media that include granular activated carbon or non-traditional adsorbents), an activated carbon filter, a reverse osmosis system, an ion exchange resin or polisher, and combinations thereof. The one or more of an adsorbent contacting device, activated carbon filter, reverse osmosis system, ion exchange resin or polisher, and combinations thereof are made of one or more treatment materials. In one aspect, a portion of the water exiting the effluent treatment apparatus 332 may be recirculated via a recirculation loop back into the PEM cell 302.

[0039] In operation of the fuel cell system 200 and the water electrolysis system 300, there is a risk that the PEM 106 of the PEM cell 100 will degrade and materials from the PEM 106 will enter the discharge streams, and ultimately, the water that is discharged from the system 200, 300. The residuals include at least one organic residual and optionally at least one inorganic residual. The residuals include, for example, organic compounds. The residuals include, for example, polyaromatic hydrocarbons (PAHs); per- and polyfluoroalkyl substances (PFASs) such as perfluoroalkyl carboxylic acids (PFCAs); monoether carboxylic acids; monoether sulfonic acids; perfluoroalkane sulfonic acids (PFSA); perfluoroalkane sulfonyl-based substances; fluorotelomer saturated and unsaturated carboxylic acids; polyether carboxylic acids; polyether sulfonic acids; and combinations thereof. Optionally, the residuals additionally include inorganic fluorides. These residuals may be difficult to treat because the highly stable bonds (e.g., carbon-fluorine bonds) are very difficult to break down.FL0715-W001

[0040] Advantageously, the effluent treatment apparatus 232, 332 control (reduce) a level of the residuals in the effluent stream of water that is discharged from the system 200, 300 and, in particular, operate to separate or capture the residuals from the effluent stream of water.

[0041] In embodiments where the effluent treatment apparatus 232 and / or 332 includes an adsorbent contacting device (e.g., a packed bed of adsorbent particles or monolithic adsorbent media that include granular activated carbon or non- traditional adsorbents), and / or an activated carbon filter, the effluent treatment apparatus 232 and / or 332 may operate to remove neutrally charged, non-polar organic species from water, as well as charged species with a sufficient amount of highly non-polar character (e.g., perfluorinated carbon chains). The contacting device and / or filter allows for uniform passage of the water through the adsorbent material (e.g., activated carbon or non-traditional adsorbents) at appropriate contact times. In some embodiments, the adsorbent material includes non-traditional adsorbents that possess optimized ion exchange properties, physical adsorption properties, or a combination of the two for targeting and removing the residuals from the water. The adsorbent contacting device and / or activate carbon filter may have finite capacity require periodic replacement.

[0042] In embodiments where the effluent treatment apparatus 232 and / or 332 includes a reverse osmosis system, the effluent treatment apparatus 232 and / or 332 can effectively remove charged species from discharge water, both organic and inorganic, using sufficient pressure to overcome the prevailing osmotic pressure of the water being purified across an appropriate membrane material. Reverse osmosis systems generally require pressurizing contaminated water against an appropriate membrane material to effect the separation. Unlike adsorbents, reverse osmosis systems do not have finite capacities, but produce an impurity-rich retentate stream that must be collected and, at some point, handled and / or disposed of. Fouling and / or slow deterioration of the reverse osmosis membrane may require very infrequent replacement.

[0043] In embodiments where the effluent treatment apparatus 232 and / or 332 includes an ion exchange resin or polisher, the effluent treatment apparatus 232 and / or 332 operates to remove organic and inorganic anionic or cationic species, orFL0715-W001 both in the case of mixed resin beds. In some embodiments, in addition to the ion exchange mechanism, physical adsorption of molecules having some hydrophobic character may occur on the resin’s polymer backbone.

[0044] The effluent treatment apparatus 232 and / or 332 can include any one or more of the above-described treatment systems, in any combination. The abovedescribed treatment systems are provided by way of example only. The effluent treatment apparatus 232 and / or 332 includes any suitable device or system that operates to remove targeted residuals from water exiting the system 200 and / or 300. Typically, effluent treatment apparatus 232 and / or 332 has an inlet in a first location, an outlet in a second location, and it contains a treatment material.

[0045] For example, the effluent treatment apparatus 232 and / or 332 can include a treatment material inside the effluent treatment apparatus, where the treatment material is in the form of particles, beads, monolithic shapes of porous material, films, or other shapes, as long as water can flow through the effluent treatment apparatus in one location, contact the treatment material, and exit in another location. The treatment materials for the effluent treatment apparatus make up the one or more of an adsorbent contacting device (e.g., a packed bed of adsorbent particles or monolithic adsorbent media that include granular activated carbon or non-traditional adsorbents), an activated carbon filter, a reverse osmosis system, an ion exchange resin or polisher, and combinations thereof. The treatment material for the effluent treatment apparatus may comprise, for example, anion exchange resins, such as resins with quaternary amines or tertiary amines; activated carbon; or combinations thereof. Non-limiting examples of resins with quaternary amines include resins functionalized with trimethylamine, dimethylethanolamine, tributyl ammonium compounds, or combinations thereof.

[0046] The treatment material may fill the entire space inside the effluent treatment apparatus, or it may only partially fill the space inside the effluent treatment apparatus provided the water makes contact with the treatment material without circumventing it. For example, in a radial configuration, water may flow into a central porous chamber prior to flowing outward into the treatment material. The effluent treatment device may further comprise inert materials, such as glass wool or containment devices, to secure the treatment material in a desired location.FL0715-W001

[0047] Figure 4 represents an effluent treatment apparatus 400 filled with a treatment material 406 and showing the flow of effluent through the apparatus. Effluent treatment apparatus 400 can be used as an effluent treatment apparatus 232 in a PEM fuel cell system and / or an effluent treatment apparatus 332 in a PEM water electrolyzer system. The effluent water flows through inlet 402, through the treatment material 406, and exits the outlet 404 as a treated water. The inlet 402 and outlet 404 may be in any location on the effluent treatment apparatus, as long as the effluent water can flow through the effluent treatment apparatus in one location, contact the treatment material, and exit in another location. In one aspect, the inlet 402 may be at one end of the effluent treatment apparatus 400, and the outlet 404 may be at an end opposite the effluent treatment apparatus, such that the water flows from one end to the other. In another aspect, the inlet 402 may be at one end of the effluent treatment apparatus 400, leading to a central porous chamber within the effluent treatment apparatus, such that the water flows radially from the center of the effluent treatment apparatus to the treatment material housed in the outer portion of the effluent treatment apparatus. The outlet 404 may be on any location of the effluent treatment apparatus such that it connects to the outer portion of the apparatus. Figure 5 represents a cross-sectional view of such an effluent treatment apparatus having radial effluent flow. Effluent water would enter the central porous chamber 414 through an inlet, travel radially to the outer portion of the effluent device through pores in the chamber, contact the treatment material 406, and flow out the outlet 404 as a treated water. Central porous chamber 414 is optional but may be used to control water flow rate.

[0048] In some cases, two or more treatment materials may be used within one effluent treatment apparatus. For example, multiple treatment materials may be present as a mixture of materials or as a sequence of materials within the same space. Figure 6 represents an effluent treatment apparatus 400 filled with multiple treatment materials and showing the flow of effluent through the apparatus. The effluent water flows through inlet 402, contacts both a treatment material 406 and a second treatment material 408, and exits through outlet 404 as a treated water. The outlet 404 may be on any location of the effluent treatment apparatus such that it connects to the outer portion of the apparatus. Figure 7 represents a cross-sectional view of such an effluent treatment apparatus having radial effluent flow. EffluentFL0715-W001 water would enter the central porous chamber 414 through an inlet, travel radially to the outer portion of the effluent device through pores in the chamber, contact the treatment material 406 and second treatment material 408, and flow out the outlet 404 as a treated water. Figure 8 represents a cross-sectional view of an effluent treatment apparatus having radial effluent flow with a different configuration. In Figure 8, effluent water would enter the central porous chamber 414 through an inlet, travel radially to the outer portion of the effluent device through pores in the chamber, contact the second treatment material 408, then contact treatment material 406, and flow out the outlet 404 as a treated water. Again, the central porous chamber 414 is optional but may be used to control water flow rate. Figure 9 represents an effluent treatment device 400 having different treatment materials in sequence within a single device. In Figure 9, effluent water would flow through an inlet 402, contact the second treatment material 408, then contact treatment material 406, and flow out the outlet 404 as a treated water. A porous barrier may be used to separate the two treatment materials and / or control the water flow rate.

[0049] In another aspect, the effluent treatment apparatus 400 may comprise two or more effluent treatment devices used in sequence. The two or more effluent treatment devices may have the same or different treatment materials, and each device may comprise one or more treatment materials. A simple configuration, containing two devices, each device containing one treatment material, is shown in Figure 10. Here, the effluent water flows through inlet 402, contacts second treatment material 408, flows through port 412 into a second device 410, contacts a treatment material 406, and exits through outlet 404 as a treated water.

[0050] When two or more treatment materials are used, they are different in chemical or physical composition. For example, two different forms of a chemically similar treatment material may be used, or similar forms / shapes of chemically different treatment materials may be used. The second treatment material may be selected to treat organic species or inorganic species, such as fluoride anions and may be selected, for example, from any of the treatment materials mentioned above.

[0051] The effluent treatment apparatus 232 and / or 332 and / or 400 may take any shape capable of housing the treatment material and / or capable of housing the one or more of an adsorbent contacting device (e.g., a packed bed of adsorbent particlesFL0715-W001 or monolithic adsorbent media that include granular activated carbon or non- traditional adsorbents), an activated carbon filter, a reverse osmosis system, an ion exchange resin or polisher, and combinations thereof. For example, the effluent treatment apparatus can have a cylindrical shape.

[0052] The size of the effluent treatment apparatus depends on the desired residual reduction and treatment material used. In one aspect, the effluent treatment apparatus has a total volume of treatment material of at least 500 mL for a light-duty vehicle; in another aspect, at least 750 mL; in another aspect, at least 1000 mL; and in another aspect, at least 1200 mL. In one aspect, the effluent treatment apparatus has a total volume of treatment material of at least 5,000 mL for a heavy-duty vehicle; in another aspect, at least 7,500 mL; in another aspect, at least 10,000 mL; and in another aspect, at least 12,000 mL. Total volume of treatment material includes all treatment material regardless of how many devices compose the effluent treatment device. For example, the effluent treatment apparatus may comprise one device having at least 500 mL in a light-duty vehicle, or it may comprise two devices having 250 mL of treatment material in each device.

[0053] The embodiments described herein enable controlling (reducing) emissions in effluent streams of water produced from proton exchange membrane cells, such as fuel Cells and water Electrolyzers. Aspects of the present disclosure are particularly advantageous where fluoropolymer membranes are used. In the described embodiments, an effluent treatment apparatus is provided downstream from the FEM cell and separates or captures residuals from the effluent stream of water (e.g., residuals that are introduced into the water via degradation of the exchange membrane). The residuals include, for example, organic compounds such as polyaromatic hydrocarbons (PAHs); per- and polyfluoroalkyl substances (PFASs) such as perfluoroalkyl carboxylic acids (PFCAs); monoether carboxylic acids; and combinations thereof. The water exiting the PEM cell can therefore be drained. In various embodiments, the separation or capture of fluorinated residuals from effluent streams of water from PEM cells is achieved using (separately or a combination of) granular activated carbon adsorbent, reverse osmosis, non-traditional adsorbents and / or ion exchange resin or polisher. In one aspect, the invention relates to a lightduty vehicle or heavy-duty vehicle comprising the PEM system, fuel cell system, or water electrolysis system described herein. In one aspect, the invention relates to aFL0715-W001 method of operating a PEM system, where the method is performed inside a lightduty vehicle or heavy-duty vehicle.

[0054] Some examples of residuals to be treated are described in Table 1 of Lange, T. et al, Journal of Power Sources Advances, v. 32 (2025), “Investigating PFAS emissions of light- and heavy-duty fuel cell electric vehicles”, herein incorporated by reference.Exemplary Light-duty Vehicle Effluent Treatment Systems

[0055] In one aspect, the proton exchange membrane system is housed in a lightduty vehicle, which is defined by the United States Environmental Protection Agency as a vehicle weighing less than 10,000 pounds having one axle and fewer than 6 tires. In one example, an effluent treatment apparatus may be formed having a cylindrical canister shape and containing carbon treatment material (such as Filtrasorb® F400 granular activated carbon, available from Calgon Carbon Corporation in Pittsburgh, PA, USA), with a 5.1 -cm (2-inch) diameter and 20.3-cm (8- inch) length. Assuming a water generation rate of the PEM fuel cell of 90 mL / km and an average speed of 80 km / hour (50 miles / hour), the water generation rates can be converted to a flow rate of 120 mL / minute.

[0056] Adsorber life can be estimated by calculating annual carbon required based on the average concentration of residual compounds and equilibrium loading of those compounds on carbon. The Average Concentration of light-duty residual compounds are shown in Table 1 below, based on information from Table 1 of Lange, T. et al, Journal of Power Sources Advances, v. 32 (2025), “Investigating PFAS emissions of light- and heavy-duty fuel cell electric vehicles”. In the reference, light-duty vehicle data is shown as FCEV 1 and FCEV 2. Equilibrium Loading data of perfluorobutanoic acid (PFBA, C4), perfluorohexanoic acid (PFHxA, C6), and perfluorooctanoic acid (PFOA, C8) in water on granular activated carbon can be found in EPA-published adsorption isotherm data. Isotherm data for perfluoropentanoic acid (PFPeA, C5) and perfluoroheptanoic acid (PFHpA, C7) can be estimated based on data for PFBA, PFHxA, and PFOA. Reported and interpolated isotherm data can be found in Figure 11 . The Equilibrium Loading for the residuals is shown in Table 1 below.FL0715-W001

[0057] In Table 1 below, the Mass Generation was calculated using the Average Concentration and the water generation rate of 90 mL / km; the Minimum Carbon Required was calculated as the quotient of Equilibrium Loading divided by Mass Generation; and the Minimum Annual Carbon Required was calculated by multiplying the Minimum Carbon Required by an assumed 10,000 miles (16,100 km) in annual driving distance.Table 1. Light-Duty Carbon Consumption of Residuals

[0058] Given an annual driving distance of 10,000 miles (16,100 km), an effluent treatment apparatus could treat the highest measured amount of residual compounds for 16 months. The life of the cartridge could last longer, since typical proton exchange membrane systems are expected to produce less than the highest measured amount of PFAS, sometimes in amounts below detection limits.

[0059] An optimal adsorber volume for a given effluent treatment apparatus can be estimated using a desired empty-bed contact time for the treatment material (EBCT) and water flow rate of the PEM system. The EBCT is the quotient of the volume of adsorbent present divided by the water flow rate. Assuming the water flow rate of 120 mL / minute and the desired EBCT of 10 minutes, the optimal volume of adsorbent is 1200 mL. For example, a cylinder having a diameter of 8.0 cm (3.1 inches) and length of 24.0 cm (9.4 inches) could be used.

[0060] For a 1200-mL cylinder, given a bulk density of granular activated carbon of 0.47 g / cm3, the mass of fresh activated carbon available is 560 g. Using the Minimum Annual Carbon Required and the amount of fresh activated carbon available, this effluent treatment apparatus could have a life of over 8 years.FL0715-W001Exemplary Heavy-duty Vehicle Effluent Treatment Systems

[0061] In one aspect, the proton exchange membrane system is housed in a heavy-duty vehicle, which is defined herein as a vehicle weighing at least 10,000 pounds or weighing less than 10,000 pounds but having more than one axle or at least 6 tires. In one example, an effluent treatment apparatus may be formed having a cylindrical canister shape and containing carbon treatment material (such as Filtrasorb® F400 granular activated carbon, available from Calgon Carbon Corporation in Pittsburgh, PA, USA).

[0062] Using the water generation rate of the PEM fuel cell of 900 mL / km and an average speed of 80 km / hour (50 miles / hour), the water generation rates can be converted to a flow rate of 1200 mL / minute. Optimal adsorber volume can be estimated as described above at 12,000 mL. For example, a cylinder having a diameter of 17.2 cm (6.8 inches) and length of 51 .6 cm (20.3) can be used.

[0063] Adsorber life can be estimated by calculating annual carbon required based on the average concentration of residual compounds and equilibrium loading of those compounds on carbon, as described above. The Average Concentration of heavy-duty residual compounds are shown in Table 2 below, based on information from Table 1 of Lange, T. et al, Journal of Power Sources Advances, v. 32 (2025), “Investigating PFAS emissions of light- and heavy-duty fuel cell electric vehicles”. In the reference, heavy-duty vehicle data is shown as FCEV 3. The Equilibrium Loading for the residuals is shown in Table 2 below.

[0064] In Table 2 below, the Mass Generation was calculated using the Average Concentration and the water generation rate of 900 mL / km; the Minimum Carbon Required was calculated as the quotient of Equilibrium Loading divided by Mass Generation; and the Minimum Annual Carbon Required was calculated by multiplying the Minimum Carbon Required by an assumed 50,000 miles (80,500 km) in annual driving distance.FL0715-W001Table 2. Heavy-Duty Carbon Consumption of Residuals

[0065] Given an annual driving distance of 50,000 miles (80,500 km), an effluent treatment apparatus could treat the highest measured amount of residual compounds for 16 months. The life of the cartridge could last longer, since typical proton exchange membrane systems are expected to produce less than the highest measured amount of PFAS, sometimes in amounts below detection limits.

[0066] For a 12,000-mL cylinder, given a bulk density of granular activated carbon of 0.47 g / cm3, the mass of fresh activated carbon available is 5,600 g. Using the Minimum Annual Carbon Required and the amount of fresh activated carbon available, this effluent treatment apparatus could have a life of over 7 years.

[0067] While the invention has been described with reference to one or more embodiments, it will be understood by those skilled in the art that various changes may be made, and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention is not limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. In addition, all numerical values identified in the detailed description shall be interpreted as though the precise and approximate values are both expressly identified.

Claims

FL0715-W001CLAIMSWhat is claimed is:1 . A proton exchange membrane (PEM) system comprising: a PEM cell including a cathode, an anode, and a PEM positioned between the cathode and the anode, wherein the PEM cell is operable to consume and / or produce water; a discharge line connected to the PEM cell that receives an effluent stream of the water exiting the PEM cell; and an effluent treatment apparatus positioned on the discharge line, wherein the effluent treatment apparatus is operable to remove residuals comprising at least one organic residual from the effluent stream of the water before discharging the water from the PEM system.

2. The PEM system of claim 1 , wherein the PEM cell is a fuel cell.

3. The PEM system of claim 1 , wherein the PEM cell is a water electrolyzer.

4. The PEM system of any one of the preceding claims, wherein the residuals include at least one organic residual and at least one inorganic residual.

5. The PEM system of any one of the preceding claims, wherein the residuals include a material selected from the group consisting of polyaromatic hydrocarbons (PAHs), per- and polyfluoroalkyl substances (PFASs), perfluoroalkyl carboxylic acids (PFCAs), monoether carboxylic acids, monoether sulfonic acids, perfluoroalkane sulfonic acids (PFSA), perfluoroalkane sulfonyl-based substances, fluorotelomer saturated and unsaturated carboxylic acids, polyether carboxylic acids, polyether sulfonic acids, and combinations thereof, and, optionally, wherein the residuals include a material selected from the group consisting of inorganic fluorides.

6. The PEM system of any one of the preceding claims, wherein the PEM is a fluoropolymer membrane.

7. The PEM system of any one of the preceding claims, wherein the effluent treatment apparatus includes an adsorbent contacting device, an activated carbon filter, a reverse osmosis system, an ion exchange resin or polisher, or any combination of two or more thereof.FL0715-W0018. The PEM system of any one of claims 1 to 7, wherein the effluent treatment apparatus includes an adsorbent contacting device, the adsorbent contacting device being one of a packed bed of adsorbent particles, a monolithic adsorbent media, or an adsorbent filter.

9. The PEM system of claim 8, wherein the effluent treatment apparatus includes an adsorbent material selected from granular activated carbon and non- traditional adsorbents.

10. The PEM system of any one of the preceding claims, further comprising a recirculation loop for recirculating a portion of the effluent stream to the PEM cell.11 . The PEM system of any one of the preceding claims, where the effluent treatment apparatus comprises an inlet, one or more treatment materials, and an outlet.

12. The PEM system of any one of the preceding claims, where the effluent treatment apparatus comprises at least two treatment materials.

13. The PEM system of any one of the preceding claims, where the effluent treatment apparatus comprises two or more effluent treatment devices in sequence.

14. The PEM system of any one of the preceding claims, where the effluent treatment apparatus comprises a treatment material selected from anion exchange resins, activated carbon, or combinations thereof.

15. The PEM system of any one of the preceding claims, further comprising a second treatment apparatus.

16. The PEM system claim 15, where the second treatment apparatus removes anions from water.

17. A fuel cell system comprising: a fuel cell including a cathode, an anode, and a membrane positioned between the cathode and the anode, wherein the fuel cell is operable to produce electrical power and water as a reaction byproduct;FL0715-W001 a discharge line connected to the fuel cell that receives an effluent stream of the water exiting the fuel cell; and an effluent treatment apparatus positioned on the discharge line, wherein the effluent treatment apparatus is operable to remove residuals comprising at least one organic residual from the effluent stream of the water before discharging the water from the fuel cell system.

18. The fuel cell system of claim 17, wherein the residuals include a material selected from the group consisting of polyaromatic hydrocarbons (PAHs), per- and polyfluoroalkyl substances (PFASs), perfluoroalkyl carboxylic acids (PFCAs), monoether carboxylic acids, monoether sulfonic acids, perfluoroalkane sulfonic acids (PFSA), perfluoroalkane sulfonyl-based substances, fluorotelomer saturated and unsaturated carboxylic acids, polyether carboxylic acids, polyether sulfonic acids, and combinations thereof, and, optionally, wherein the residuals include a material selected from the group consisting of inorganic fluorides.

19. The fuel cell system of claim 17 or 18, wherein the PEM is a fluoropolymer membrane.

20. The fuel cell system of any one of claims 17 to 19, wherein the effluent treatment apparatus includes an adsorbent contacting device, an activated carbon filter, a reverse osmosis system, an ion exchange resin or polisher, or any combination of two or more thereof.21 . The fuel cell system of any one of claims 17 to 20, wherein the effluent treatment apparatus includes an adsorbent contacting device, the adsorbent contacting device being one of a packed bed of adsorbent particles, a monolithic adsorbent media, or an adsorbent filter.

22. The fuel cell system of claim 21 , wherein the effluent treatment apparatus includes an adsorbent material selected from granular activated carbon and non-traditional adsorbents.

23. The fuel cell system of any one of claims 17 to 22, wherein the fuel cell is operable to produce the electrical power using a first fluid supplied to the anode and a second fluid supplied to the cathode.

24. The fuel cell system of claim 23, wherein the first fluid is hydrogen and the second fluid is oxygen or air.FL0715-W00125. The fuel cell system of claim 23 or claim 24, further comprising a first discharge line connected to the fuel cell that receives the effluent stream of the water exiting the fuel cell with excess first fluid, and a second discharge line connected to the fuel cell that receives the effluent stream of the water exiting the fuel cell and excess second fluid.

26. The fuel cell system of claim 25, further comprising a first gas-liquid separator positioned on the first discharge line and operable to separate the water and the first fluid, and a second gas-liquid separator positioned on the second discharge line and operable to separate the water and the second fluid.

27. The fuel cell system of claim 26, further comprising a collector downstream from each of the first and second gas-liquid separators for collecting and combining the water exiting each of the separators upstream from the effluent treatment apparatus.

28. The fuel cell system of claim 26 or 27, further comprising a recirculation loop for recirculating at least a portion of the first fluid exiting the first gas-liquid separator to the fuel cell.

29. The fuel cell system of any one of claims 17 to 28, further comprising a cooling loop connecting to the fuel cell for circulating a cooling fluid through the fuel cell.

30. The fuel cell system of any one of claims 17 to 29, where the effluent treatment apparatus comprises an inlet, one or more treatment materials, and an outlet.31 . The fuel cell system of any one of claims 17 to 30, where the effluent treatment apparatus comprises at least two treatment materials.

32. The fuel cell system of any one of claims 17 to 31 , where the effluent treatment apparatus comprises two or more effluent treatment devices in sequence.

33. The fuel cell system of any one of claims 17 to 32, where the effluent treatment apparatus comprises a treatment material selected from anion exchange resins, activated carbon, or combinations thereof.

34. The fuel cell system of any one of claims 17 to 33, further comprising a second treatment apparatus.FL0715-W00135. The fuel cell system claim 34, where the second treatment apparatus removes anions from water.

36. A water electrolysis system comprising: a water electrolyzer including a cathode, an anode, and a membrane positioned between the cathode and the anode, wherein the water electrolyzer is operable to produce hydrogen by decomposing water; a discharge line connected to the fuel cell that receives an effluent stream of the water exiting the water electrolyzer; and an effluent treatment apparatus positioned on the discharge line, wherein the effluent treatment apparatus is operable to remove residuals comprising at least one organic residual from the effluent stream of the water before discharging the water from the water electrolysis system.

37. The water electrolysis system of claim 36, wherein the residuals include a material selected from the group consisting of polyaromatic hydrocarbons (PAHs), per- and polyfluoroalkyl substances (PFASs), perfluoroalkyl carboxylic acids (PFCAs), monoether carboxylic acids, monoether sulfonic acids, perfluoroalkane sulfonic acids (PFSA), perfluoroalkane sulfonyl-based substances, fluorotelomer saturated and unsaturated carboxylic acids, polyether carboxylic acids, polyether sulfonic acids, and combinations thereof, and, optionally, wherein the residuals include a material selected from the group consisting of inorganic fluorides.

38. The water electrolysis system of claim 33 or 37, wherein the PEM is a fluoropolymer membrane.

39. The water electrolysis system of any one of claims 36 to 38, wherein the effluent treatment apparatus includes an adsorbent contacting device, an activated carbon filter, a reverse osmosis system, an ion exchange resin or polisher, or any combination of two or more thereof.

40. The water electrolysis system of any one of claims 36 to 39, wherein the effluent treatment apparatus includes an adsorbent contacting device, the adsorbent contacting device being one of a packed bed of adsorbent particles, a monolithic adsorbent media, or an adsorbent filter.FL0715-W00141 . The water electrolysis system of claim 40, wherein the effluent treatment apparatus includes an adsorbent material selected from granular activated carbon and non-traditional adsorbents.

42. The water electrolysis system of any one of claims 36 to 41 , wherein the water electrolyzer is operable to produce the hydrogen and oxygen by decomposing the water.

43. The water electrolysis system of claim 41 , further comprising a first discharge line connected to the water electrolyzer that receives the effluent stream of the water exiting the water electrolyzer and the hydrogen, and a second discharge line connected to the water electrolyzer that receives the effluent stream of the water exiting the water electrolyzer and the oxygen.

44. The water electrolysis system of claim 43, further comprising a first gas-liquid separator positioned on the first discharge line and operable to separate the water and the hydrogen, and a second gas-liquid separator positioned on the second discharge line and operable to separate the water and the oxygen.

45. The water electrolysis system of claim 44, further comprising a collector downstream from each of the first and second gas-liquid separators for collecting and combining the water exiting each of the separators upstream from the effluent treatment apparatus.

46. The water electrolysis system of any one of claims 36 to 45, further comprising a recirculation loop for recirculating a portion of the water in the effluent stream to the water electrolyzer.

47. The water electrolysis system of any one of claims 36 to 51 , where the effluent treatment apparatus comprises an inlet, one or more treatment materials, and an outlet.

48. The water electrolysis system of any one of claims 36 to 47, where the effluent treatment apparatus comprises at least two treatment materials.

49. The water electrolysis system of any one of claims 36 to 48, where the effluent treatment apparatus comprises two or more effluent treatment devices in sequence.FL0715-W00150. The water electrolysis system of any one of claims 36 to 49, where the effluent treatment apparatus comprises a treatment material selected from anion exchange resins, activated carbon, or combinations thereof.51 . The water electrolysis system of any one of claims 36 to 50, further comprising a second treatment apparatus.

52. The water electrolysis system claim 51 , where the second treatment apparatus removes anions from water.

53. A method of operating a proton exchange membrane (PEM) system, method comprising: operating a PEM cell to consume and / or produce water; receiving an effluent stream of the water exiting the PEM cell in a discharge line; removing residuals comprising at least one organic residual from the effluent stream of the water using an effluent treatment apparatus positioned on the discharge line; and discharging the water from the PEM system.

54. The method of claim 53, wherein the PEM cell is a fuel cell.

55. The method of claim 53, wherein the PEM cell is a water electrolyzer.

56. The method of any one of claims 53 to 55, wherein the residuals include a material selected from the group consisting of polyaromatic hydrocarbons (PAHs), per- and polyfluoroalkyl substances (PFASs), perfluoroalkyl carboxylic acids (PFCAs), monoether carboxylic acids, monoether sulfonic acids, perfluoroalkane sulfonic acids (PFSA), perfluoroalkane sulfonyl-based substances, fluorotelomer saturated and unsaturated carboxylic acids, polyether carboxylic acids, polyether sulfonic acids, and combinations thereof, and, optionally, wherein the residuals include a material selected from the group consisting of inorganic fluorides.

57. The method of any one of claims 53 to 56, wherein the PEM cell includes a fluoropolymer membrane.

58. The method of any one of claims 53 to 57, wherein the effluent treatment apparatus includes an adsorbent contacting device, an activated carbonFL0715-W001 filter, a reverse osmosis system, an ion exchange resin or polisher, or any combination of two or more thereof.

59. The method of any one of claims 53 to 58, wherein the effluent treatment apparatus includes an adsorbent contacting device, the adsorbent contacting device being one of a packed bed of adsorbent particles, a monolithic adsorbent media, or an adsorbent filter.

60. The method of claim 59, wherein the effluent treatment apparatus includes an adsorbent material selected from granular activated carbon and non- traditional adsorbents.61 . The method of any one of claims 53 to 60, further comprising recirculating a portion of the effluent stream to the PEM cell.

62. The method of any one of claims 53 to 61 , where the effluent treatment apparatus comprises an inlet, one or more treatment materials, and an outlet.

63. The method of any one of claims 53 to 62, where the effluent treatment apparatus comprises at least two treatment materials.

64. The method of any one of claims 53 to 63, where the effluent treatment apparatus comprises two or more effluent treatment devices in sequence.

65. The method of any one of claims 53 to 64, where the effluent treatment apparatus comprises a treatment material selected from anion exchange resins, activated carbon, or combinations thereof.

66. The method of any one of claims 53 to 65, further comprising a second treatment apparatus.

67. The PEM system claim 66, where the second treatment apparatus removes anions from water.

68. A light-duty vehicle or heavy-duty vehicle comprising the PEM system of any one of claims 1 to 16.

69. A light-duty vehicle or heavy-duty vehicle comprising the fuel cell system of any one of claims 17 to 35.

70. A method of any one of claims 53 to 66, where the method is performed inside a light-duty vehicle or heavy-duty vehicle.

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