Adsorption of cobalt on xanthate functionalized amine resin in aqueous solutions: batch and fixed-bed studies

Removing ⁶⁰Co from the primary-circuit wastewater of nuclear power plant is essential for environmental protection and the health of workers. An efficient Co²⁺ adsorbent was prepared by modifying amine resin D380 with carbon disulfide (CS₂) under alkaline conditions to yield xanthate-functionalized amino resin (XD380). Key experimental variables governing Co²⁺ uptake in aqueous media were systematically examined. The maximum adsorption capacity reached 68.07 mg g⁻¹ at pH 7, with a XD380 dosage of 2.5 mg mL⁻¹.The Freundlich isothermal adsorption model and pseudo-second-order adsorption kinetics effectively describe the adsorption behavior. XD380 exhibits notable radiation resistance, reusability, and adsorption selectivity. In dynamic adsorption experiments, the dynamic equilibrium adsorption capacity reached 13.17 mg g⁻¹ under optimal conditions. Spectroscopic analyses before and after adsorption indicate that sulfur and nitrogen atomic groups serve as the primary binding sites, with Co²⁺ being adsorbed and fixed through chelation and complexation. These findings provide a solid experimental foundation for the potential application of XD380 in treating radioactive cobalt-bearing wastewater.