Ethyl acrylate grafted chitosan for heavy metal removal from wastewater: Equilibrium, kinetic and thermodynamic studies

• Chitosan was successfully modified by ethyl acrylate (CEA).
• FTIR, C NMR and H NMR confirmed the modification of chitosan.
• Three heavy metal cations (Pb2+, Cd2+ and Zn2+) were removed from effluent by CEA.
• Isotherm, kinetic and thermodynamic of adsorption were studied.

In this study, the preparation, characterization and heavy metal removal ability of chitosan–ethyl acrylate (CEA) biopolymer were investigated. Ethyl acrylate was successfully grafted to chitosan, which was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). Three heavy metal cations (Pb2+, Cd2+ and Zn2+) were removed from the simulated wastewater in batch mode, and the effect of initial metal ions concentration, adsorbent dosage, solution temperature, contact time and initial pH on the adsorption efficiency was illustrated. The maximum Pb2+, Cd2+ and Zn2+ removal efficiency of 92%, 86% and 98% were achieved, respectively. The biosorption isotherm, kinetic, and thermodynamic parameters were also studied. The isotherm and kinetic data followed the Langmuir and pseudo-second-order models, respectively. The thermodynamic data showed that the biosorption process was a spontaneous, endothermic, and physisorption reaction. Efficient desorption of metal ions from the loaded CEA was found to be 98%, using HCl (0.6 M) at contact time of 80 min. The results indicated that CEA could be employed as a promising biopolymer for the removal of heavy metal from effluents.