Preparation and adsorption properties of chelating resins from thiosemicarbazide and formaldehyde

A novel chelating resin was synthesized in just one step under mild synthetic conditions. The synthesis was carried out through the copolymerization of thiosemicarbazide and formaldehyde in an aqueous solution. The adsorption properties for some noble metal ions were investigated. The results showed that the resin had high adsorption selectivity for Au(III) and Ag(I). The adsorption capacities for the two metal ions reached up to 7.3 and 11.8 mmol/g, respectively. The adsorption rate for the two metal ions in a dilute solution was 99.9%. The adsorption fit first-order kinetics, and an isothermal adsorption study indicated that it corresponded to Langmuir monomolecular layer adsorption. The change in the bonding energy during the chelating process was investigated with X-ray photoelectron spectroscopy. The study revealed that nitrogen and sulfur atoms of the resins were electron donors and metal ions were electron acceptors in the process.