One-step preparation of novel highly efficient thioanisole-modified resins and their performance for Pd recovery

Concentrating Pd from low concentrated solutions has been drawing great attention in recent years. In this paper, we successfully prepared two novel thioanisole-modified resins by grafting aminothioanisole directly onto Merrifield resins. These resins were characterized by elemental analysis , FT-IR, SEM-EDS and BET. The adsorption and desorption optimal conditions as well as the adsorption kinetics , isotherms, capacity, selectivity , reusability, and mechanisms of Pd by these resins were studied. The Pd adsorption onto Resin- para -1 and Resin- meta -1 both fit pseudo-second-order kinetic model and Hill isotherm model. They adsorb Pd through both anion exchange with the protonated amino groups and chelation with the thioether groups. The maximum amounts of Pd that adsorbed onto Resin- para -1 and Resin- meta -1 at 3 mol/L HCl are 67.6 mg/g and 59.6 mg/g, respectively. Resin- meta -1 exhibited significantly higher selectivity of Pd than Resin- para -1. The adsorbed Pd can be efficiently desorbed by 0.02–0.05 mol/L ammonium hydroxide solution. Resin- meta -1 exhibits excellent reusability. After 8 adsorption-desorption cycles, the Pd adsorption efficiency hardly changed. In short, Resin- meta -1 can be easily synthesized through only one step, and can efficiently recover Pd from its low concentrated acidic chloride solutions. • Two novel thioanisole-modified resins were successfully synthesized. • The Pd adsorption kinetics , isotherm, and mechanism were investigated. • Resin- para / met a-1 can efficiently concentrate Pd from highly acidic chloride solutions. • Resin- met a-1 can selectively adsorb Pd with high selectivity. • Resin- met a-1 exihibits excellent reusability performance.