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采用反相悬浮聚合溶胶-凝胶法制备了多孔纳米钛酸锶钡吸附剂,分别采用Fourier变换红外光谱、扫描电镜和X射线衍射进行表征。将该多孔纳米钛酸锶钡应用于水中镉离子的吸附,考察了吸附、洗脱条件对其吸附性能的影响,探讨了吸附热力学和动力学规律。结果表明:采用反相悬浮聚合溶胶-凝胶法合成的多孔材料,由纳米粒径的钛酸锶钡晶体组成,平均晶粒粒径为17nm。当pH值为4～7时,该吸附剂对水中的镉离子有很强的吸附能力。其吸附动力学符合Langmuir吸附等温模型和准二级动力学方程式,吸附过程的焓变为37.337kJ/mol,各温度下,Gibbs自由能变均为负值,熵变均为正,吸附活化能为32.965kJ/mol,该吸附为吸热的自发的物理过程。吸附后,该吸附剂可用1mol/L硝酸洗脱再生。
Porous nano-barium strontium titanate adsorbents were prepared by reverse phase suspension polymerization sol-gel method and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. The porous nanostructured barium strontium titanate was applied to the adsorption of cadmium ions in water. The effects of adsorption and elution conditions on its adsorption properties were investigated. The thermodynamic and kinetic laws of adsorption were discussed. The results show that the porous material synthesized by inverse suspension polymerization sol-gel method is composed of barium titanate nanoparticles with the average grain size of 17 nm. When the pH value of 4 to 7, the adsorbent on the water of cadmium ions have a strong adsorption capacity. The adsorption kinetics conformed to the Langmuir adsorption isotherm model and quasi-second-order kinetic equation. The enthalpy of the adsorption process was 37.337kJ / mol. The Gibbs free energy change was negative and the entropy change was positive at all temperatures. The adsorption activation energy Is 32.965 kJ / mol, the adsorption is an endothermic spontaneous physical process. After adsorption, the adsorbent can be regenerated with 1 mol / L nitric acid.