Broad-spectrum capture of hundreds of per- and polyfluoroalkyl substances from fluorochemical wastewater

Abstract

Abstract Hundreds of per- and polyfluoroalkyl substances (PFAS) are present in fluorochemical production effluents, and existing adsorption devices are inadequate to address this PFAS challenge given their extreme structural diversity. Here, we achieve the broad-spectrum capture of 107 PFAS from fluorochemical effluents using a treatment-train strategy that combines Zn-based electrocoagulation (EC) with anion-exchange resin (AER) beds. The “zero-carbon” adsorbent, zinc hydroxide flocs generated insitu by Zn-based EC, bulk removes PFAS with log K ow > 4 through a semi-micellar adsorption mechanism similar to mineral flotation and achieves adsorption capacities at the optimal level of all reported adsorbents. Technical-economic analysis and life-cycle environmental impact show that coupling Zn-based EC reduces the cost by an order-of-magnitude and the carbon-footprint by 70% compared to AER beds alone. It is also observed that iodinated PFAS, with some fluorine atoms are replaced by iodine atoms, exhibit significantly improved adsorption selectivity, which may shed light on designing environmentally-friendly fluorochemicals.