坡缕石对水中亚甲基蓝的吸附动力学

ADSORPTION KINETICS OF METHYLENE BLUE ONTO PURIFIED PALYGORSKITE FROM AQUEOUS SOLUTIONS

研究了坡缕石对水中亚甲基蓝的吸附动力学,在初始浓度为120～210mg／L,转速为100-200 r／min,温度为298-328 K时,坡缕石对亚甲基蓝的吸附动力学数据均符合准二级速率方程。结果表明:坡缕石对亚甲基蓝的吸附仅在外表面吸附,吸附表观活化能为13．92 kJ/mol,说明此吸附并不是由单一的化学吸附为速率控制步骤,是由化学吸附和液膜扩散共同控制的吸附过程。

The adsorption kinetics of purified palygorskite for methylene blue from aqueous solutions was investigated. Kinetics data for the adsorption of methylene blue from aqueous solutions were in good agreement with the pseudo-second rate equation within an initial concentration range of 120-210 mg/L, an agitation speed range of 100-200 r/min and an experimental temperature range of 298-328 K. The results show that methylene blue is only adsorbed on the external surface of the purified palygorskite. The apparent adsorption activation energy is 13.92 kJ/mol. A relatively low apparent adsorption activation energy suggests that the adsorption of methylene blue may involve not only chemisorption but also a physical adsorption process, which is likely due to its combined control of chemical adsorption and film diffusion.