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

Abstract

Abstract 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\u202f6.0 exceeded 96% within 30\u202fmin in the solution with 0.1\u202fmmol/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\u202fmL/min with the maximum dynamic capacity reaching 124\u202fmg/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.