The rapid removal of iodide from aqueous solutions using a silica-based ion-exchange resin

Rapid and efficient removal of radioactive iodine from nuclear accidents and effluent waste is significantly essential to protect the living environment and maintain human health. Here, we describe a novel silica-based quaternized poly(4-vinyl pyridine) ion-exchange resin (SiPyR-N4) used for the removal of iodide from aqueous solution. Adsorption experiments including the effect of pH, contact time, concentration of iodide, and influence of coexisting anions were investigated in detail. A series of experimental results showed that the composite possessed excellent adsorption performance towards I-. The removal efficiency at pH 6.0 exceeded 96% within 30 min in the solution with 0.1 mmol/L iodide. The adsorption kinetics and isotherms can be nicely described by the pseudo-second kinetic model and Redlich-Peterson model. The thermodynamic process was also evaluated, which indicated that the adsorption reaction was a spontaneous and exothermic process. Furthermore, XPS spectrum demonstrated that the adsorption of SiPyR-N4 was dominated by ion-exchange. Versus commercial resins, SiPyR-N4 in column experiment showed considerable application potential. SiPyR-N4 exhibited an excellent immobilization capability towards iodide at a flow rate of 8 mL/min with the maximum dynamic capacity reaching 124 mg/g, while the commercial products D201 and IRA-900 were immediately leaked under the same condition. Regeneration experiments suggested that SiPyR-N4 could be used repeatedly. In conclusion, this work presents a promising sorbent for capture and enrichment of iodide from waste water on a large scale.