CeO_2/SiO_2吸附剂的制备及其对碘酸根的吸附

以多孔二氧化硅为载体、六水合硝酸铈为原料,采用真空灌注法制备了CeO_2/SiO_2吸附剂,并利用扫描电镜(SEM)、X射线衍射(XRD)、红外光谱(IR)等方法对其进行表征。同时,通过静态和动态吸附实验探究了CeO_2/SiO_2对碘酸根的吸附和脱附行为,考察了pH、反应时间、碘酸根浓度以及共存阴离子等因素对CeO_2/SiO_2吸附性能的影响。研究结果表明:CeO_2/SiO_2在较广的pH值范围内对碘酸根有较高的吸附率,吸附过程符合准二级动力学模型以及Langmuir和Redlich-Peterson模型;共存阴离子对吸附的影响大小为NO_3~-SO_4~(2-)HCO_3~-H_2PO_4~-≈PO_4~(3-);动态吸附实验的柱利用率高达90.96%,且穿透曲线符合Thomas模型;通过IR谱图分析推测CeO_2/SiO_2的吸附机理为阴离子交换。

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.