Title : Novel engineered biochar-driven water purification for decontamination of per- and polyfluoroalkyl substances in water
Among various adsorbent materials, biochar has attracted comprehensive attention because of its superior performance, low cost, and production from a variety of biomass and solid wastes. Due to its high performance as an adsorbent for water purification, various types of biochar have been studied for removal of emerging contaminants including per- and polyfluoroalkyl substances (PFASs). However, effective applications of biochar for adsorption of PFAS needs to be investigated for its practical application along with understanding of the underlying mechanisms. In this study, FeCl3 was applied for activating the dairy manure biochar ([email protected]) to promote the adsorption of perfluorooctanoic acid (PFOA) in DI water, wastewater effluent and lake water. The detailed analysis of biochar properties indicated that the enhancement would be mainly due to the surface complexation of PFOA-Fe-CO groups on [email protected] surface. The adsorption was further enhanced by lower pH to accelerate electrostatic attraction via iron-dominant catalysts in [email protected] Furthermore, adsorption isotherm, kinetics and model-fittings indicated the adsorption was mainly driven by chemical adsorption on a heterogeneous surface, which matches our previous deduction for the mechanisms. Efficient adsorptive removal of PFOA was achieved at low concentration in both lake water and wastewater effluent. Thermal and alkaline desorption could regenerate [email protected] effectively indicating its promising reusability. Overall, this study sheds light on the elimination of PFAS pollution by iron-engineered biochar and the underlying mechanisms associated with adsorption of PFAS.