REACTIVE ELECTROCHEMICAL MEMBRANES FOR THE DEGRADATION OF PER- AND POLYFLUOROALKYL SUBSTANCES

Abstract

Per- and polyfluoroalkyl substances (PFAS) are extremely stable and widely used in consumer goods, industrial processes, and aqueous film-forming foams (AFFFs), and have been shown to pose a serious and ongoing danger to global water security. Due to the general inefficiency of conventional water treatment techniques, sophisticated destructive technologies must be developed. Reactive electrochemical membranes (REMs), which combine filtration with in-situ electrochemicaloxidation and reduction for targeted pollutant degradation, have become a potential solution. Using titanium oxide nanotubes (TiOxNTs) as the anode and cathode material, this thesis explores the creation of an affordable, dual-function REM system. TiOxNTs provide an electrochemically adjustable, mechanically durable, and scalable platform in contrast to costly noble-metal electrodes. The anodic and cathodic performance of TiOxNTs REMs for the degradation of complicated AFFF-contaminated groundwater and model PFAS chemicals (PFOA, PFOS, andPFBA) is comprehensively assessed in this study. Near-complete elimination of UV-absorbing intermediates indicates that TiOxNTs anodes mineralize PFAS by hydroxyl radical-mediated oxidation, exhibiting great stability with low surface fouling, according to electrochemical studies. At the same time, TiOxNTs cathodes demonstrate remarkable reductive activity, which promotes defluorination via surface-activated pathways and direct electron transfer. This is demonstrated by the gradual increase in fluoride ion release and solution conductivity. This work establishes TiOxNTs as a low-cost, highly effective bifunctional material for REMs, offering a scalable and sustainable electrochemical approach for the full breakdown of persistent PFAS in contaminated water sources.