Electrochemical-driven filtering system for sodium diclofenac removal from water

In the present study, a three-dimensional (3D) electrode system, consisted of graphite porous anode and stainless-steel cathode with a granular activated carbon (GAC) filtering material that acted as particulate electrode under electric voltage applying, named electrochemical filtering system (EF), was assessed comparatively with simple GAC filtering system (SF), to the advanced removal and degradation of sodium diclofenac (DCF) from water. Better performance expressed as DCF and TOC removal degree was found for EF (> 94% and > 83%) versus SF (<73% and respective, <66%). A complex process consisted of sorption and degradation via •OH radicals generated by electrooxidation occurred for when filtering material from SF was converted into particulate electrode for EF, through different pathways characterized by a wide variety of reactions, which were proved by FTIR results and GC–MS identified by-products. The DCF removal capacity was much improved by EF in comparison with SF, and operational parameter of breakthrough time was found to be about three times higher for EF versus SF. All results highlighted that electrochemical filtering could be regarded as a promising method in application of advanced treatment of water envisaging the removal and degradation of emerging pollutants.