CaMgAl-层状双氢氧化物的制备及其对刚果红的吸附性能  

Preparation of CaMgAl-Layered Double Hydroxide and Its Adsorption Properties for Congo Red

作　　者：倪涛 贾志刚[1] 李紫宇 NI Tao;JIA Zhigang;LI Ziyu(School of Chemistry and Chemical Engineering, Anhui University of Technology, Ma＇anshan 243002, Anhui, Chin)

机构地区：[1]安徽工业大学化学与化工学院

出　　处：《硅酸盐学报》2018年第4期572-579,共8页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(20907001);安徽工业大学研究生创新基金(2016002);安徽工业大学创新创业项目(201710360200)

摘　　要：以CaCl2·2H2O、Mg（NO3）2·6H2O、Al（NO3）3·9H2O为原料，采用共沉淀法制备了系列镁／钙摩尔比可调的CaMgAl-层状双氢氧化物（LDH）。对合成的CaMgAl-LDH样品的性能进行了表征，结果表明：在阴离子NO3^-和Cl^-共存的溶液中，NO3比Cl^-优先进入层间，且层间NO3^-导致层间距明显增大，形成的CaMgAl-LDH产物具有良好的热稳定性。以刚果红（CR）为模拟污染物，研究了CaMgAl-LDH对水溶液中阴离子染料的吸附性能。结果表明：CaMgAl-LDH对CR的吸附行为符合准二级动力学方程，其等温吸附曲线符合Langmnir方程，对吸附过程Gibbe自由能（△G^0）、熵（△S^0）以及焓（△H^0）的计算证明对CR的吸附是自发的吸热反应。CaMgAl-LDH对CR具有优良的吸附性能，其中Ca8Mg2Al5-LDH对CR的吸附效果最好，最大吸附容量为115．5mg／g，表明制备的CaMgAl-LDH是一种具有良好应用前景的阴离子染料吸附材料。A series of CaMgAl-layered double hydroxide （LDH） materials with different Mg/Ca molar ratios were prepared by a co-precipitation method using CaCl2·2H2O、Mg（NO3）2·6H2O and Al（NO3）3·9H2O as raw materials. The properties of as-prepared CaMgAl-LDH samples were characterized. The results indicate that the anion of NO3 can preferentially enter the layered structure in the solutions of coexisted NO3^- and Cl^-, and the intercalation of NO3^- leads to an increase in interlayer spacing. The as-formed CaMgAI-LDH has a superior thermal stability. The adsorption performance of CaMgAl-LDH onto Congo red （CR） was also investigated. The adsorption kinetic of CR onto CaMgAl-LDH follows the pseudo second order kinetic model and the Langmuir equation. Based on the calculated adsorption thermodynamic parameters such as the Gibbs free energy （△G^0）, entropy （△S^0） and enthalpy （△H^0）, the adsorptions are spontaneous and endothermic reactions. The CaMgAl-LDH has a good adsorption performance on CR, and Ca8Mg2Al5-LDH exhibits the optimum adsorption capacity of 115.5 mg/g for CR. These results indicate that CaMgAl-LDH obtained has a promising potential application as an efficient absorbent for water purification.

关 键 词：共沉淀法 钙镁铝层状氢氧化物 吸附 

分 类 号：TQ170.1[化学工程—硅酸盐工业]