Iodide Adsorption from Water and Wastewater Using a Selective Hydrated Zr (IV) Oxide Particle-Impregnated Anion Exchange Resin; Batch and Column Studies

Water pollution by iodo-compounds such as iodide ions is known as a vital issue due to its detrimental effect on human health. In the present study, hydrated zirconium oxide particle (HZO)-impregnated anion exchange resin, was synthesized for selective iodide adsorption from aqueous solutions. The hybrid anion exchanger impregnated with zirconium oxide particles (HAIX–Zr) resin indicated a promising static adsorption capacity of ۵۸۴.۷۲ mg/g (from Isotherm studies and the D-R model). It was ۲۵% more than the static adsorption capacity of the counter-parent resin (from Isotherm studies and the Langmuir model). The best result of adsorption performance was related to pH of ۳. It was ۷% higher than the capacity of resin in neutral pH and it was close to maximal, over a wide range of pHs (۲-۷). Breakthrough curves of both kinds of resins, with and without the presence of encountered anions were fitted with common breakthrough curve modes. The maximum dynamic capacity of resin for iodide adsorption using counter parent and HAIX–Zr resins were ۴۳۴.۲ and ۴۶۳.۷ mg/g. The iodide removal selectivity in the presence of three commonly encountered anions SO۴۲-, NO۳-, and Cl- was enhanced in the batch and continuous column phase, and it was more evident in continuous column phase adsorption. The Pseudo-second-order kinetics model was very compatible with the kinetics data of both resins.  An iodide adsorption mechanism was proposed using the results of batch experiments and resin characterizations (X-ray Photoelectron Spectroscopy (XPS) and Raman spectra). With the hard soft acid base theory HSAB, Donnan membrane effect, and the slight potential of modified resin for iodide oxidation to iodine, the iodide capacity and selectivity adsorption on the resin were improved.

کلیدواژه ها:

pollution ، Iodide ، Adsorption ، Anion exchange resin ، Hybrid anion exchange ، Hydrated zirconium oxide