热改性凹凸棒粘土的吸附热力学和动力学研究

进行了热改性凹凸棒粘土对亚甲基蓝的吸附热力学和动力学性能研究。实验表明：在初始染料质量浓度为50～600mg/L、温度为298～338K时，热改性凹凸棒粘土对亚甲基蓝的吸附符合Langmuir等温吸附方程，△H为1.92 KJ/mol，△G在-25.429～-29.097 KJ/mol之间，△S大于零，此过程为一自发的吸热过程；其吸附动力学数据符合准二级速率方程，吸附表观活化能分别为13.5676 KJ/mol。提出了热改性凹凸棒粘土对亚甲基蓝的吸附过程是由膜扩散和化学吸附共同控制的观点。

Study on adsorption thermodynamics and kinetics of thermal-modified attapulgite clay

In view of adsorption performance change of attapulgite clay after thermal modification,the adsorptive thermodynamics and kinetics of methylene blue on thermally modified attapulgite clay were investigated.The experimental results revealed that the methylene blue equilibrium adsorption data on the thermally modified attapulgite clay were fitted to Langmuir isotherm models when the initial concentration of the dye was in the range of 50-600 mg/L and the experimental temperature was in the range of 298-338 K.△H= 1.92 kJ /mol,△G was ranging from-25.429 to-29.097 kJ /mol,and △S was larger than 0.The process was endothermic and spontaneous.The adsorptive kinetics data were in good agreement with the pseudo-second rate equation.The apparent adsorption activation energy of the thermally modified attapulgite clay was 13.567 6 kJ/mol.It suggests this adsorption may involve the combined control of chemical adsorption and film diffusion.