Bisphenol A removal from water by biomass-based carbon:isotherms, kinetics and thermodynamics studies

Abstract Biomass-based carbon was modified and used as an efficient bisphenol A (BPA) sorbent. The simple and environmentally friendly modification method produced sorbent with a capacity of 41.5 mg/g. The raw material was modified with FeCl₃ (Fe-CR), treated with hydrochloric acid (H-CR) or modified with CaCl₂ (Ca-CR). Batch sorption experiments were performed to evaluate the effects of the initial pH, sorbent dosage, temperature, and contact time on BPA removal. BPA removal with modified carbons was notably higher than that with unmodified carbon. All sorbent materials exhibited very high sorption capacities and compared favourably to materials reported in the literature. Several isotherms were applied to describe the experimental results of Fe-CR, H-CR, and Ca-CR modified carbon residues and the Sips model showed the best fit for all sorbents. Kinetic studies for the best sorbent material (Fe-CR) showed that the sorption process follows Elovich kinetics. Desorption cycles were implemented, and sorption capacity remained with three cycles