Abstract: Methods and systems of PFAS destruction in water containing nitrate. The methods and systems include filtering water containing PFAS and nitrate through a membrane selective for PFAS to obtain a membrane reject containing PFAS and nitrate and a filtrate containing nitrate, forming a treatment solution using the membrane reject including diluting the membrane reject and combining the membrane reject with a photosensitizer, a sulfite salt, and a sufficient amount of base such that the treatment solution has a pH of about 10 or more, and irradiating the treatment solution with UV light in a photoreactor to destroy a portion of the PFAS. Before dilution, a concentration of PFAS in the membrane reject may be between about 3 times and about 20 times greater than before the filtering step. Dilution of the membrane reject may include between about a 3 and about a 20 times dilution.

Abstract: Methods, systems and devices for removing iodide from an aqueous solution including submerging an iodophilic electrode in an aqueous solution containing iodide, applying a current to the electrode, and electrochemically oxidizing the iodide to iodine within the electrode. The electrode may include an iodophilic material and an electrically conductive material. It may also include a binder. The iodophilic material may be a starch, chitosan, carboxycellulose, cationic polymer, or an anion exchange membrane material, for example. After oxidizing the iodide to iodine within the electrode, the electrode may be submerged in a second solution and a current may be applied to reduce the iodine and release it from the electrode in the form of iodide into the second solution.

Abstract: Methods, systems and devices for PFAS destruction including removing nitrate from water containing PFAS, combining the water with a sensitizer and a sufficient quantity of base to create a treatment solution having a pH of about 10 or more, and irradiating the treatment solution with UV light in a photoreactor to destroy a portion of the PFAS. The nitrate may be removed electrolytically such as by electrolytically reducing nitrate to nitrogen gas and/or ammonia. The nitrate may be removed by filtration through a selective membrane, such as by reverse osmosis, forward osmosis, nanofiltration, and/or ultrafiltration. The system may include electrolytic cell system including a first cell with a cathode contacting the water containing PFAS in the first cell, a second cell including an anode in an electrolytic solution, a power source, and a salt brine and/or membrane separating the first and second cells.

Abstract: Methods, systems and devices for photo-electrolyitic PFAS destruction including a photoreactor vessel configured to receive an aqueous solution including PFAS, a UV light source configured to direct UV light onto the aqueous solution in the photoreactor vessel, a cathode within the photoreactor vessel configured to contact the aqueous solution, an anode in an electrolyte solution, an electrical power supply configured to provide a voltage difference between the anode and cathode, and a membrane or ionic bridge between the anode and cathode. The cathode may be a mesh and may have a high surface area construction with an electrochemically active surface area that is greater than the geometric surface area.

Abstract: Methods, systems and devices for removing iodide from an aqueous solution including submerging an iodophilic electrode in an aqueous solution containing iodide, applying a current to the electrode, and electrochemically oxidizing the iodide to iodine within the electrode. The electrode may include an iodophilic material and an electrically conductive material. It may also include a binder. The iodophilic material may be a starch, chitosan, carboxycellulose, cationic polymer, or an anion exchange membrane material, for example. After oxidizing the iodide to iodine within the electrode, the electrode may be submerged in a second solution and a current may be applied to reduce the iodine and release it from the electrode in the form of iodide into the second solution.