负载型纳米二氧化钛对重金属离子吸附性能的研究

采用溶胶-凝胶法制备二氧化钛溶胶, 将其浸渍在硅胶上, 合成了负载型纳米二氧化钛材料, 以X射线衍射(XRD)、扫描电镜(SEM)等手段对其进行了表征. 以ICP-AES为检测手段, 系统地研究了负载型纳米TiO₂材料对重金属离子Cd^2＋, Cr^3＋, Cu^2＋和Mn^2＋的吸附性能. 结果表明, 在pH 8～9范围内, 所研究的重金属离子均可被定量富集, 吸附的金属离子可用0.5 mol/L的HNO₃完全解脱. 负载型纳米二氧化钛对Cd^2＋, Cr^3＋, Cu^2＋和Mn^2＋的静态吸附容量分别为8.3, 13.1, 12.6和5.1 mg/g, 与未负载的纳米二氧化钛相近. 将其应用于环境标准样品中Cd^2＋, Cr^3＋, Cu^2＋和Mn^2＋的分离富集与测定, 结果满意.

Study on the Adsorption Behavior of Heavy Metal Ions on Nanometer TiO2 Supported on Silica Gel

Nanometer TiO₂ supported on silica gel (supported nanometer TiO₂) was prepared by Sol-Gel method. The product was characterized using XRD and SEM. The adsorption behavior of supported nanometer TiO₂ towards Cd^2＋, Cr^3＋, Cu^2＋and Mn^2＋ was investigated by ICP-AES. It was found that the adsorption percentages of the metal ions studied were more than 90% in pH 8.0～9.0, and 0.5 mol/L HNO₃ was sufficient for complete elution. The adsorption capacity of supported nanometer TiO₂ for Cd^2＋, Cr^3＋, Cu^2＋and Mn^2＋ was found to be 8.3, 13.1, 12.6 and 5.1 mg/g, respectively. A method using supported nanometer TiO₂ as adsorbent coupled with ICP-AES has been developed for the separation/preconcentration and determination of Cd^2＋, Cr^3＋, Cu^2＋and Mn^2＋in environmental sample.