Zirconium-loaded magnetic interpenetrating network chitosan/poly(vinyl alcohol) hydrogels for phosphorus recovery from the aquatic environment

Phosphorus (P) recovery from the aquatic environment by sorption depends mainly on effective sorbents. In this study, a novel zirconium-loaded magnetic chitosan/poly(vinyl alcohol) interpenetrating network (IPN) hydrogel was synthesized, characterized with different methods and then tested for P sorption. The effects of sorbent dosage, pH, co-existing anions and natural organic matter (NOM) were investigated. Isotherm results showed monolayer sorption was dominant. The max sorption capacity reached at pH = 5. Thermodynamically, the sorption process was spontaneous and exothermic. The pseudo-first-order kinetic model and intra-particle diffusion model fitted experimental data well. Besides, the hydrogels exhibited selectivity towards P sorption, and its maximum sorption capacity was favorable compared with other sorbents. Results of desorption and regeneration illustrate that the sorption capacity of hydrogels stayed relatively high and stable. The sorption mechanism was inner-sphere complex and ligand exchange. This study provides a promising sorbent for P recovery from the aqueous environment.