Microwave assisted synthesis of poly (N-vinylimidazole) grafted chitosan as an effective adsorbent for mercury (II) removal from aqueous solution: Equilibrium, kinetic, thermodynamics and regeneration studies

摘要

In the present study, chitosan-N-vinyl imidazole was first synthesized and characterized and then its capacity for removal of mercury (II) ions from water was assessed. The graft copolymerization of N-vinyl imidazole onto chitosan chains has been developed in aqueous medium using microwave irradiation. The obtained copolymer was characterized by Fourier Transform Infrared (ATR-FTIR), solid-state C-13 Nuclear Magnetic Resonance (NMR), Differential Scanning Calorimetric (DSC) and Thermogravimetric Analysis (TGA). Mercury (II) ions removal capacity by the chitosan-N-vinyl imidazole were investigated in aqueous solutions using different amounts of these ions at pH = 6.0. The effect of the contact time, kinetics and thermodynamic studies on the adsorption of mercury ions was also reported. The maximum adsorption capacity was found to be 112.35 mg g(-1) from the Langmuir isotherm model at 25 degrees C. The obtained negative value of (kJ mol(-1)) and (kJ mol(-1)) indicated the spontaneous and endothermic nature of the reactions. The regeneration of CS-N-vinyl imidazole was investigated using PEG-400 in water as desorbing agent. This data make chitosan-N-vinyl imidazole a potential material adsorbent for mercury (II) removal.