Relationship between Hg(Ii) Adsorption Property and Functional Group of Different Thioamide Chelating Resins

Three similar thioamide chelating resins (TMCR, ATMCR and CDMCR) were prepared by modifying chloromethylated (CPS) and ammoniated polystyrene (APS) beads with thiourea, ammonium thiocyanate and carbon disulfide for the comparative study of Hg(II) adsorption in aqueous. The resins were characterized with Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The factors affecting Hg(II) adsorption such as dosage, solution pH, initial concentration, temperature and contact time were investigated in detail. The resins have an ideal Hg(II) adsorption and regeneration performance as a whole, and they all obey the pseudo-second-order kinetic model. Isothermal adsorption thermodynamics showed that Hg(II) adsorption by TMCR belongs to a multilayer adsorption process, and that of ATMCR and CDMCR belong to chemical processes. ATMCR has the maximum adsorption capacity (636.94 mg/g at 318K) and the adsorption rate can still reach 94% after ten cycles. Selective adsorption and DFT calculation with Gaussian show that ATMCR exhibits a specific adsorption for Hg(II) with a stronger coordination than TMCR and CDMCR