Highly efficient removal of toxic Pb2+ from wastewater by an alginate–chitosan hybrid adsorbent

BACKGROUND In this study, a low-cost and environment-friendly alginate–chitosan hybrid adsorbent (depicted as Alg-Chi) was developed for the removal of Pb 2+ from water. RESULTS Experimental results showed that the Alg-Chi exhibits high selectivity and affinity for Pb 2+ . The selectivity coefficients of the Alg-Chi for Pb 2+ /Cr 3+ , Pb 2+ /Co 2+ Pb 2+ /Cd 2+ , Pb 2+ /Zn 2+ , and Pb 2+ /Cu 2+ are all >5. It can uptake 96.8% of Pb 2+ from Pb 2+ -containing solutions (1.5 mmol L −1 ), and the maximum adsorption capacity for Pb 2+ reaches 468.5 mg g −1 , which is higher than that of most reported adsorbents for Pb 2+ . Moreover, the Alg-Chi can also be regenerated via simple acid elution and used repeatedly without loss in adsorption ability. CONCLUSIONS Analysis of the adsorption mechanism indicated that the Alg-Chi adsorbed Pb 2+ mainly through ion exchange and chemical coordination. Green and low-cost raw materials, simple preparation process, efficient removal efficiency and recyclable, these characteristics give the synthetic Alg-Chi broad application prospects in the field of Pb 2+ -containing wastewater treatment. © 2018 Society of Chemical Industry