Zn / Al 双金属氧化物对水中硫酸根离子的吸附性能简

研究了用Zn/Al水滑石制得的Zn/Al双金属氧化物（Zn/Al-300）吸附剂对水中硫酸根离子的吸附，考查了吸附剂投加量、初始pH等因素对硫酸根离子吸附的影响。结果表明，Zn/Al-300对水中硫酸根离子的吸附符合Langmuir吸附等温方程，理论最大吸附量为62.5 mg/g。运用动力学方程进行拟合，吸附过程符合准二级动力学方程；溶液的pH影响吸附剂对硫酸根的吸附，在pH=5.5时硫酸根的去除率最大；X射线衍射结果显示，水滑石经过焙烧后丧失了原有的构形，并在吸附硫酸根离子后重新恢复水滑石的部分层状结构。吸附机制主要为Zn/Al-300从溶液中获取阴离子以重建水滑石的晶体结构，即“记忆效应”。对吸附后的双金属氧化循环应用4此后，吸附容量几乎不变，说明双金属氧化物具有可循环型。通过将Zn/Al-300与其他几种吸附剂的经济性分析，表明此吸附剂在使用过程中具有一定优势。

Adsorptive removal of sulfate from water by Zn/Al layered double oxide

The adsorption characteristics of sulfate from aqueous solution by the Zn/Al layered double oxide (Zn/Al-300) and its influencing factors,such as the pH of aqueous solution,dosage of Zn/Al-300,equilibrium isotherm and adsorption kinetic were studied.The results showed that the adsorption of sulfate on Zn/Al-300 was conformed to the Langmuir isotherm equation and the maximum adsorption capacity of Zn /Al-300 for sulfate was 62.5mg/g which was close to the stoichiometric adsorption.Three kinetic models were used to fit the experimental data,indicating that the pseudo-second-order kinetics model could better describe the adsorption process.The adsorption of sulfate with the maximum removal rate was found at pH=5.5.The results by X-ray diffraction ( XRD) showed that the reconstruction of its original layered structure in the presence of appropriate anions is mainly attributed to the removal sulfate mechanism of Zn/Al-300.Zn/Al-300 has a good desorption and it can be regenerated by calcination.Through the economical analysis and comparison, it was found that the Zn/Al-300 could be used to remove sulfate at the lowest costs.