▎ 摘　　要

Heavy metals are among the environmental pollutants that human exposure to water and food can cause acute and dangerous poisoning. There are various methods for the removal of heavy metals. Among them, adsorption is considered to be an effective method for the removal of heavy metals. In this study, magnetic graphene oxide (MGO) nanocomposites functionalized with different amine ligands were used to remove Pb2+ from aqueous solutions. X-ray diffraction, Fourier-transform infrared spectroscopy, Scanning electron microscopy, Energy-dispersive X-ray spectroscopy and Vibrating-sample magnetometer analyzes were applied to determine the structure and characterization of the synthesized nanocomposites. Then, the factors affecting the adsorption efficiency such as pH, adsorbent amount, contact time and lead concentration were investigated and the optimum conditions for Pb2+ removal was the initial Pb2+ concentration of 20 mg/L, pH = 4, the adsorbent weight of 40 mg and the reaction time of 10 min. Pb2+ adsorption efficiency for adsorbents functionalized with ethylenediamine (EDA), melamine and monoethanolamine was compared. It was observed Pb2+ adsorption efficiency for these three adsorbents were 98%, 96.34% and 97.65%, respectively. Kinetic, isotherm and thermodynamic studies were also performed for the synthesized adsorbent and its recovery in the sequential adsorption and desorption cycle was investigated. The EDA functionalized MGO (EDA-MGO) adsorbent demonstrated 8.8% decrease in Pb2+ adsorption efficiency after 5 successive cycles of adsorption and desorption. (C) 2021 Elsevier B.V. All rights reserved.