Removing Poly- and Perfluoroalkyl Substances (PFAS) with Ion Exchange Resins

Many municipalities discovered that levels of perfluorinated and poly-fluorinated chemicals in their water systems exceed new Federal Health Advisory levels. These chemicals are collectively known as PFASs and are commonly referred to as PFCs. Although the current health advisory levels vary throughout the world, in May 2016, the US EPA issued Health Advisory (HA) levels of 70 parts per trillion (ppt) for two of these chemicals, PFOS and PFOA (perfluorooctane sulfonic acid and perfluorooctanoic acid, respectively). When both PFOS and PFOA are present at the same time in the water, the recommended combined health advisory level is 70 ppt.

Purolite has designed, developed and commercially tested a special ion exchange resin with high selectivity for poly- and perfluoroalkyl substances (PFAS). Purofine® PFA694E resin is a proprietary, uniform particle size resin with the dual removal mechanisms of ion exchange and adsorption technology built into each bead for maximum uptake of PFAS. Water treated with this resin will consistently achieve non-detectable levels of both short- and long chain PFAS—including PFOA, PFOS, PFNA, PFHxA, PFHxS, PFHpA, PFBS and PFBA.

​Advantages of Purofine PFA694E:

  • Can reduce both short and long chain PFAS to non-detectable (ND) levels (< 1 to 2 ppt depending on lab accuracy)
  • Can achieve > 99.99% reduction for high concentrations (e.g. 770,000 ppt to < ND)
  • Displays at least 5 to 10 times higher PFAS capacity vs.  granular activated carbon (GAC)
  • Is economical for single-use application followed by high-temperature incineration
  • Requires shorter contact times of 1.5 – 5 mins. vs. 12 – 25 mins. for GAC and is ideal for municipal as well as POE and POU applications
  • Capital equipment / installation cost is about ½ that for GAC
  • Operating cost typically lower than GAC (inclusive of cost for extraction/refill/ trucking/profiling and high temperature incineration)
  • Can be used either for primary removal of PFAS or as polisher to GAC
  • Is compliant with: –21 CFR §173.25 and NSF/ANSI 61
For convenience, PFCs are divided into two groups – “long chain” and “short chain” PFCs. Long chain includes carboxylic types such as PFOA and PFNA with ≥ 8 carbons and sulfonic type PFOS with≥ 6 carbons. 

Due to the shorter contact time, Purofine PFA694E is advantageous for industrial Point of Entry (POE) and Point of Use (POU) systems, and Purolite offers design guidelines for developing these systems.

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