▎ 摘　　要

A novel adsorbent for divalent metal cations 600 was prepared as nanocomposite of Fe-Mg (hydr)oxide with graphene oxide by one-step coprecipitation. This material showed adsorption selectivity of Pb2+ > Cu2+ > Ag+ > Zn2+ >> CO2+, Ni2+, Cd2+ with high adsorption capacity of 100-600 mg/g for Pb2+, Cu2+, Ag+, and Zn2+. Distribution coefficient (K-d) was as high as similar to 10(7) mL/g for Pb2+ and Cu2+. The adsorption isotherms for Pb2+, Cu2+, Ag+, and Zn2+ followed the Langmuir model, indicating monolayer adsorption. The adsorption kinetics for Pb2+, Cu2+, Ag+, and Zn2+ followed pseudo-second-order model, suggesting chemisorption. Removal of 50 ppm Pb2+ or Cu2+ from 100 mL solution by 0.1 g of the nanocomposite was over 99.7%. The thermodynamics studies implied that the adsorption process toward heavy metals was spontaneous and endothermic. Together with recyclability through magnetic separation, this adsorbent would be useful in polluted water processing.