Polymeric beads bearing charged functional groups that exchange ions with a passing water stream. PFAS-selective anion exchange resins remove both long- and short-chain PFAS to sub-part-per-trillion levels, but like GAC they concentrate rather than destroy the contaminant.
Ion exchange has been used in water treatment for over a century, but the modern PFAS-selective anion exchange resins developed by Purolite, Evoqua, and DuPont (PFA694E, PSR2 Plus, AmberLite PSR2 Plus) are a recent advance. They use a strong-base quaternary ammonium functional group on a styrene-divinylbenzene matrix tuned for hydrophobic uptake of perfluorinated tails.
Compared with GAC, PFAS-selective IX achieves longer bed life, smaller vessel footprints, and stronger short-chain capture, including GenX, PFBS, and PFBA. Single-use resins are common: they are run to exhaustion and incinerated, transferring PFAS to a destruction step. Regenerable resins exist but produce a concentrated brine that itself requires destruction.
The same containment-and-transfer logic that governs GAC applies to IX. The destruction obligation does not disappear at the resin vessel; it is consolidated into a smaller, higher-concentration waste stream that is then routed to high-temperature thermal treatment or to an emerging destruction technology such as SCWO or electrochemical oxidation.
Also known as: IX, ion exchange, anion exchange resin, PFAS-selective resin.
PFAS (Per- and Polyfluoroalkyl Substances): treatment approach
A family of thousands of synthetic fluorinated organics — including PFOA, PFOS, GenX, PFHxS, and AFFF constituents — defined by C-F bonds that resist conventional treatment and require destruction technologies to close a site.
An ex-situ soil treatment process that heats contaminated soil to volatilize and separate organic contaminants from the soil matrix, after which the liberated vapors are captured and treated, usually in a high-temperature oxidizer.
A thermal desorption configuration where the heat source contacts the soil directly inside the rotary unit, delivering high heat-transfer efficiency and supporting higher treatment temperatures.
A thermal desorption configuration where heat is conducted through the wall of the treatment vessel without combustion gases contacting the soil, producing a concentrated, lower-volume vapor stream suitable for condensation and recovery.
Treatment that heats contaminated soil and groundwater in place, typically with electrical resistance, thermal conduction, or steam injection, to volatilize and recover contaminants without excavation. Used where excavation is impractical or where the contaminant zone sits beneath active infrastructure.