Feasibility Study On The Electrochemical Reductive Decomposition Of Pfoa By A Rh/Ni Cathode

The discharge of widely used per- and poly-fluorinated compounds (PFCs) leads to their environmental prevalence, bioaccumulation and biotoxicity; and attracts researches focusing on their treatment in wastewater. Electrochemical reductive treatment is a promising alternative due to its milder reaction conditions and easy operation. The feasibility of electrochemical reductive decomposition of PFOA using a Rh/Ni cathode was explored. The Rh/Ni cathode was fabricated by coating Rh3+ on Ni foil through electrodeposition. The Rh coating was primarily elemental and in a Rh(111) crystalline form. PFOA decomposition and defluorination were observed when using the Rh/Ni cathode where DMF was the solvent and the cathode potential was -1.25 V. A hydrodefluorination reaction was considered having occurred. Because possessing d electrons and empty d orbitals, the Rh coating enhanced PFOA adsorption onto the cathode surface and facilitated C-F bond activation through Rh center dot center dot center dot F interactions. Moreover, the Rh(111) crystal helped chemisorb the generated H* and supply it participating in PFOA decomposition. With the continuous interaction of cathode-supplied electrons, C-F bond would ultimately dissociate and transform to C-H bond by H* substitution. Adding FeCp2* as a supporting electrolyte enhanced PFOA decomposition by working as the shuttle facilitating PFOA migration to the cathode surface.