Preparation of CeO₂/SiO₂ Adsorbent and Its Adsorption for Iodate

CeO₂/SiO₂ adsorbent was successfully prepared by vacuum impregnation using silica and cerium nitrate hexahydrate as support and raw material, respectively, and the prepared adsorbent was characterized by SEM, XRD and IR. The adsorption and desorption behavior of iodate with CeO₂/SiO₂ adsorbent were investigated by the static and dynamic adsorption experiments. The effects of pH, contact time, initial iodate concentration and coexisting anions on the adsorption were also studied. The results show that: CeO₂/SiO₂ has a high adsorption efficiency of iodate in a wide pH range, and the adsorption process can be described by a pseudo-second-order reaction and fitted by the Langmuir and Redlich-Peterson models. Coexisting anions affect the adsorption in the order of NO^-₃2-₄-₃2PO^-₄≈PO^3-₄. The column efficiency of the dynamic adsorption experiment reachs 90.96% and the breakthrough curve is fitted well by the Thomas model. The mechanism of adsorption is identified as the anion exchange by the analysis of IR spectra.