碱熔融法合成NaA和NaX型粉煤灰沸石对亚甲蓝的吸附动力学研究

Adsorption Kinetics of Methylene Blue on NaA and NaX Zeolite Synthesized from Fly Ash Using Alkaline Fusion Method

以粉煤灰为原料采用碱熔融法合成了两种单一沸石矿物种的NaA和NaX型沸石,通过静态吸附实验,研究了这两种沸石对水溶液中亚甲蓝(MB)的吸附特性,从动力学角度探讨了吸附机理.结果表明:在所研究的浓度和pH值条件下,合成NaA和NaX型沸石对亚甲蓝的吸附平衡数据符合Langmuir等温吸附方程,静态饱和吸附量(Qm)分别为37.81和43.02 mg.g-1;氢键作用是影响亚甲蓝吸附行为的主要因素;通过动边界模型研究表明,两种沸石对亚甲蓝吸附过程的速度控制步骤为液膜扩散,且亚甲蓝的吸附过程符合伪二级方程.

Single-phase zeolites NaA and NaX were synthesized from fly ash using alkaline fusion method during hydrothermal reaction. With the static method, the adsorption properties of NaA and NaX zeolite to MB in aqueous solution were studied and adsorption mechanism was discussed from kinetic point of view. The results show that, in the present studied concentration and pH value, the equilibrium adsorption data fitted to Langmuir isotherms and the greatest adsorption capacity of MB on NaA and NaX zeolite is 37.81 and 43.02 mg·g-1,respectively. Hydrogen bond is important influential factors on adsorption behavior. Moving boundary model analysis shows that the adsorption rate of MB on NaA and NaX zeolite was mainly governed by liquid film diffusion. And, the adsorption processes of MB follow a pseudo-second-order kinetic model.