Novel magnetic beads based on sodium alginate gel crosslinked by zirconium(IV) and their effective removal for Pb2+ in aqueous solutions by using a batch and continuous systems

Novel magnetic sodium alginate gel beads (Fe3O4@SA–Zr) were successfully prepared by using zirconium(IV) as crosslinking ions, and used as adsorbent for removal of Pb2+ ions from aqueous solutions in batch and fixed-bed column systems. Fe3O4@SA–Zr was characterized by SEM, FT-IR, XRD and VSM. Fe3O4@SA–Zr had the macroporous structure, exhibited greater stability and possessed a sensitive magnetic response. More importantly, Fe3O4@SA–Zr exhibited high adsorption capacity, fast kinetics and high selectivity towards Pb2+ ions. Experimental data was well described by Langmuir isotherm with a maximum adsorption capacity of 333.33 mg/g. FTIR and XPS indicated that the carboxyl and hydroxyl groups of SA and hydroxyl groups binding to Fe and Zr species were involved in Pb2+ adsorption. Fixed-bed column packed with Fe3O4@SA–Zr exhibited higher removal efficiency for Pb2+ions. Consequently, Fe3O4@SA–Zr with excellent absorbability, stability and reusability could be used as a promising adsorbent for Pb2+ removal in wastewaters.