Residual organic fluorinated compounds from thermal treatment of PFOA, PFHxA and PFOS adsorbed onto granular activated carbon (GAC)

Comparison of Activated Carbons for Removal of Perfluorinated Compounds From Drinking Water

“…On the basis of the age of the custom reactivation pool, it was estimated that the CMR carbon used in this study had undergone three reactivation cycles. Custom reactivation is conducted with steam at approximately 800°C, well above the 700°C threshold reported by Watanabe et al (). The direct activated coconut carbons selected for inclusion in the comparison study described here were an 8 × 30 mesh product 13 and a 12 × 40 mesh product.…”

“…In the reactivation process, the activated carbon is heated to temperatures of at least 800°C using steam as a selective oxidant. It should be noted that in testing of activated carbons containing PFCs, Watanabe et al () found no residual perfluoroalkyl substances on activated carbon when heated to 700°C in nitrogen. During reactivation, the adsorbed organic material either boils off the activated carbon or is broken down to a char in the carbon pores.…”

Understanding and Managing the Potential By‐Products of PFAS Destruction

“…Multiple studies on thermal destruction of a specific list of PFAS were conducted using solid phases, such as pure PFOS or PFOA as a crystalline powder (Yamada and Taylor ; Krusic and Roe ; Krusic et al ), polyester/cellulose fabric (Yamada et al ), fluorotelomer‐based polymers (Taylor et al ), solid polytetrafluoroethylene polymer pellets (Aleksandrov et al ), or during the reactivation of GAC (Watanabe et al ; Watanabe et al. ).…”

“…Incomplete mineralization as a result of inadequate temperatures or insufficient residence times can create various short‐chain PFAAs and fluoro‐organics as stable by‐products (such as tetrafluoromethane [CF 4 ], hexafluoroethane [C 2 F 6 ], and perfluoroisobutylene [C 4 F 8 ]) depending on the parent PFAS compound. Short‐chain PFAAs require higher temperatures to achieve thermal destruction than long‐chain PFAAs (Watanabe et al ), so their formation as by‐products during thermal treatment of long‐chain PFAAs can further complicate the objective of achieving complete mineralization during incineration.…”

“…As consideration of the life cycle of PFAS continues to evolve, more recent studies assessing thermal treatment includes a broad list of PFAAs and associated fluoro‐organic compounds as potential by‐products of thermal destruction (Watanabe et al ; Watanabe et al ; Aleksandrov et al ). As a result, the application of commercial incineration to mineralize PFAS in concentrated or dilute aqueous waste streams has become an area of focus for the research community, and was the subject of a recent solicitation for research and development (R&D) proposals from the Strategic Environmental Research and Development Program (SERDP ).…”