阴离子型有机化合物在LDHs上的动力学和热力学研究  

Kinetics and Thermodynamics for Anionic Dye Adsorption on Calcined Layered Double Hydroxides

作　　者：薛继龙[1] 钱萍萍[1] 倪哲明[1] 

机构地区：[1]浙江工业大学化学工程与材料科学学院,杭州310014

出　　处：《无机化学学报》2014年第5期1009-1016,共8页Chinese Journal of Inorganic Chemistry

基　　金：浙江省自然科学基金(No.Y406069)资助项目

摘　　要：考察了水滑石焙烧产物MgAl-LDO吸附3种阴离子染料Acid Red88（AR88）、Acid Orange 3（AO3）、Acid Violet90（AV90）~程中的热力学和动力学机理．并在不同温度下探究该吸附过程的热力学参数。实验结果表明：MgAl-LDO对染料阴离子的吸附过程复合Langmuir吸附等温模型。且为自发、放热的过程。3种染料在MgAl-LDO上的吸附过程均符合准二级反应动力学模型，且该吸附过程是由MgAl-LDO与阴离子染料之间的反应速率控制而不是两者之间的扩散作用。计算所得的吉布斯自由能绝对值在7～15kJ·mol^-1．这主要是由染料阴离子与MgAl-LDHs层板的氢键作用产生，结合Materials Studio5．5软件模拟染料分子在MgAl-LDHs上的排列分布，推测MgAl-LDO对阴离子染料的吸附机理是表面吸附（占优势）与层间插层的协同作用。The adsorption thermodynamics and mechanism of acid red 88 （AR88）, acid orange 3 （AO3） and acid violet 90（AV90） on MgA1 Layered double hydroxides with 3：1 Mg/A1 molar ratio were investigated. The adsorption isotherms were measured at different temperatures, and the functions of thermodynamics were also calculated. The results indicated that the adsorption process on MgA1-LDO were well consistent with the Langmuir equation and were also spontaneous and exothermic. Three kinetics models were used to describe the kinetics experimental data, and it was found that the pseudo-second order kinetics model was best fitted. The Gibbs free energy was calculated to be 7 to 15 kJ. mo1-1 because of Hydrogen bonds between the layers and dye molecular. According to the calculation of Materials Studio5.5, the mechanism of adsorption process was that most dye anions were adsorbed on the surface of MgA1-LDO accompanied with intercalated into the layer.

关 键 词：镁铝水滑石 阴离子染料 吸附动力学 吸附热力学 

分 类 号：O614.241[理学—无机化学] O614.31[理学—化学]