Integrated PFAS Capture, Destruction and Resource Recovery

Abstract Per- and polyfluoroalkyl substances (PFAS) present a persistent water-treatment problem because technologies that remove PFAS from water do not necessarily destroy the compounds. Activated-carbon adsorption can concentrate PFAS from large volumes of contaminated water into a comparatively small mass of spent adsorbent, transferring rather than eliminating the contaminant burden. This paper proposes an integrated circular treatment concept in which PFAS-loaded activated carbon is regarded as an intermediate process material rather than a final waste. The proposed sequence comprises PFAS capture and concentration, solar-assisted thermal pretreatment, controlled defluorination and destruction, inorganic fluoride capture and potential recovery, activated-carbon regeneration, process-heat recovery and carbon reuse. Concentrated solar energy is proposed as a supplementary energy input and remains an experimental hypothesis rather than an assumed PFAS-destruction mechanism. Complete fluorine accounting is proposed as a central performance criterion. Destruction of identifiable parent PFAS alone would not establish complete mineralisation because shorter fluorinated transformation products may remain. Accordingly, fluorine should be quantified across inorganic fluoride, residual fluorinated compounds, regenerated carbon, gaseous treatment products and other residual streams. A preliminary mass balance using perfluorooctanoic acid (PFOA) illustrates the substantial proportion of molecular mass represented by fluorine and therefore the potential significance of fluoride recovery. The proposed system is evaluated principally through PFAS destruction efficiency, fluorine mass-balance closure, retention of activated-carbon adsorption performance, external-energy requirement and lifecycle treatment cost. The concept is deliberately structured to be experimentally falsifiable. If validated, the approach could provide a transition from capture-and-disposal towards capture, destruction, material recovery and adsorbent reuse. Wider applications include staged microplastic removal, wastewater and sludge-energy recovery, nutrient reclamation, rainwater harvesting and distributed community infrastructure. These remain extensions requiring separate validation rather than demonstrated outcomes of the PFAS proposal.