光谱学与光谱分析, 2009, 29 (3): 824, 网络出版: 2009-12-15  

负载型纳米钛酸锶钡对水中Cd2+吸附行为研究

Adsorption Behavior of Immobilized Nanometer Barium-Strontium Titanate for Cadmium Ion in Water
作者单位
1 沈阳理工大学 环境与化学工程学院,辽宁 沈阳 110168
2 中国科学院 沈阳应用生态研究所,辽宁 沈阳 110016
摘要
采用络合溶胶-凝胶法制备了钛酸锶钡溶胶,将其浸渍在硅胶G上,经高温煅烧后,制得固载于硅胶G上的纳米钛酸锶钡,以X射线衍射(XRD)、扫描电镜(SEM)和傅里叶变换红外光谱(FTIR)进行了表征。以火焰原子吸收为检测手段,系统地研究了负载型纳米钛酸锶钡对水中Cd2+的吸附行为。结果表明,纳米钛酸锶钡能够牢固地负载于硅胶G表面。当介质的pH值为4-7时,该吸附剂对水中的Cd2+具有很强的吸附能力,其吸附行为符合Freundlich吸附等温模型和HO准二级动力学方程式,并分别计算了吸附过程的焓变(ΔΗ),自由能变(ΔG)和熵变(ΔS)等热力学参数,表明该吸附过程是自发的吸热物理过程。被吸附的Cd2+可用1mol·L-1的硝酸完全洗脱回收。将其应用于水中痕量Cd2+的吸附,建立了负载型纳米钛酸锶钡吸附富集,火焰原子吸收法测定水中痕量Cd2+的新方法。用于自来水和地表水中镉的测定,结果满意。
Abstract
Nanometer barium-strontium titanate immobilized on silica gel G was successfully prepared by the citrate acid sol-gel method and characterized using X-ray diffraction (XRD),scanning electron microscope (SEM) and Fourier transform infrared spectrophotometer (FTIR).By means of the determination of flame atomic absorption spectrometry(FAAS),the adsorption behavior of immobilized nanometer-barium strontium titanate for cadmium ion was investigated.The results showed that the nanometer barium-strontium titanate was immobilized on the silica gel G firmly,gaining a new sort of adsorbent.And the cadmium ion studied could be quantitatively retained in the pH value range of 4-7.The adsorption behavior followed a Freundlich adsorption isotherm and a pseudo-second-order kinetic model.The thermodynamic constants of the adsorption process,such as enthalpy changes(ΔH),Gibbs free energy changes(ΔG) and entropy changes(ΔS),were evaluated.These showed that the adsorption of cadmium ion by immobilized nanometer barium-strontium titanate was endothermic and spontaneous physical process.The cadmium ion adsorbed could be completely eluted using 1 mol·L-1 HNO3.A new method for the determination of trace cadmium ion in water based on this immobilized nanometer barium-strontium titanate preconcentration and FAAS determination was proposed.The method has been applied to the determination of trace cadmium ion in tap water and river water with satisfactory results.

张东, 张文杰, 关欣, 高虹, 何红波. 负载型纳米钛酸锶钡对水中Cd2+吸附行为研究[J]. 光谱学与光谱分析, 2009, 29(3): 824. ZHANG Dong, ZHANG Wen-jie, GUAN Xin, GAO Hong, HE Hong-bo. Adsorption Behavior of Immobilized Nanometer Barium-Strontium Titanate for Cadmium Ion in Water[J]. Spectroscopy and Spectral Analysis, 2009, 29(3): 824.

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