Optimization of Polyacrylonitrile-2-aminothiazole Resin Synthesis, Characterization, and Its Adsorption Performance and Mechanism for Removal of Hg(II) from Aqueous Solutions

A novel chelating resin, polyacrylonitrile-2-aminothiazole (PAN-AT), was synthesized simply by the reaction of polyacrylonitrile with 2-aminothiazole. Optimization of the PAN-AT synthesis was carried out at different temperatures, different molar ratios of reagents, and different time intervals in N,N-dimethylformamide (DMF) using response surface methodology (RSM) for the first attempt. The functional group capacity (the content of the functional group) and the percentage conversion of the functional group of PAN-AT prepared under the optimum conditions were 3.94 mmol/g and 41.10%, respectively. The structure of PAN-AT was characterized by elemental analysis and FTIR. Meanwhile, the adsorption properties of the resin for Hg(II) were investigated by batch and column experiments. The results suggested that the resin possessed much better adsorption capability for Hg(II) than for other metal ions and the maximum saturated adsorption capacity estimated from the Langmuir model was 454.9 mg/g at 308 K. Furthermore, the resin could be regenerated through the desorption of the Hg(II) anions using 3.0 mol/L HNO3 solution and could be reused to adsorb again. Finally, the resin and its metal complexes were studied by SEM, TGA, and energy dispersive X-ray spectroscopy (EDS). Also, the PAN-AT chelating resin could provide a potential application for a treatment process of Hg(II) contaminated wastewater.