Adsorption behaviors and mechanisms of gold recovery from thiosulfate solution by ion exchange resin

The adsorption behaviors and mechanisms of gold from thiosulfate solution on strong-base anion exchange resin were systematically investigated. The comparison experiment of adsorption ability and selectivity for gold showed that gel Amberlite IRA-400 resin with Type I quaternary ammonium functional group had better adsorption performance. The increases of resin dosage, ammonia concentration and solution pH were favorable to gold adsorption, whereas the rises of cupric and thiosulfate concentrations were disadvantageous to gold loading. Microscopic characterization results indicated that gold was adsorbed in the form of [Au(S2O3)2]3- complex anion by exchanging with the counter ion Cl-in the functional group of the resin. Density functional theory calculation result manifested that gold adsorption was mainly depended on the hydrogen bond and van der Waals force generated between O atom in [Au(S2O3)2]3- and H atom in the quaternary ammonium functional group of the resin.