玻璃纤维滤膜基纳米钛酸锶钡的制备及其对Cd2+吸附行为

Preparation of Strontium-Barium Titanate Based on Glass Fiber Filter and Its Adsorption Behavior for Cadmium Ion

摘要:

采用柠檬酸络合溶胶-凝胶法制备玻璃纤维滤膜基纳米钛酸锶钡（BBST），用X射线衍射（XRD）、扫描电镜（SEM）和傅里叶变换红外光谱（FTIR）进行表征。并系统地研究玻璃纤维滤膜基钛酸锶钡对水中Cd2+吸附行为。结果表明，纳米钛酸锶钡通过Si-O-Ti和B-O-Ti键与玻璃纤维滤膜结合，成为新型多孔块体吸附剂。当介质的pH值为4~8时，该吸附剂对水中的Cd2+具有很强的吸附能力，吸附容量为9.8 mg·g-1；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，吸附过程焓变（△H）为17.241 kJ·mol-1，各温度下的自由能变（△G）均小于零，熵变（△S）均为正值，该吸附过程是自发的吸热物理过程。

关键词:钛酸锶钡;玻璃纤维滤膜;吸附行为;Cd2+

Abstract:

Strontium-barium titanate based on glass fiber filter (BBST) was prepared by the citrate acid complex sol-gel method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and fourier transform infrared spectrophotometer (FT-IR). The adsorption behavior of BBST for cadmium ion in distilled water was investigated. The results show that the strontium-barium titanate could bond with glass fiber filter through Si-O-Ti and B-O-Ti bonding to produce a new sort of porous block adsorbent. The cadmium ion could be quantitatively retained in the medium with pH value range of 4-8, and the capacity of adsorption was 9.8 mg·g-1. The adsorption behavior followed Freundlich adsorption isotherm model and HO pseudo-second-order kinetic equation. The enthalpy changes (△H) of the adsorption process was 17.241 kJ·mol-1. At various temperatures, Gibbs free energy changes (△G) were negative, and entropy changes (△S) were positive. These showed that the adsorption of cadmium ion by BBST was endothermic and spontaneous physical process.

Key words:strontium-barium titanate; glass fiber filter; adsorption behavior; cadmium ion