活性炭纤维对亚甲基蓝的吸附动力学和热力学研究

Kinetics and thermodynamics of adsorption of methylene blue on the activated carbon Fiber

研究了活性炭纤维(ACF)对亚甲基蓝的吸附性质,并与颗粒活性炭(GAC)进行了比较。结果表明,活性炭纤维吸附量大,吸附优势明显。同时研究了活性炭纤维对亚甲基蓝的吸附热力学和动力学性质,利用Langmuir和Freundlich吸附等温模型来描述活性炭纤维对亚甲基蓝的吸附行为,相关性都较好,但Langmuir等温模型的拟合性更好。利用准一级动力学模型和准二级动力学模型考察了吸附动力学,活性炭纤维吸附亚甲基蓝的动力学曲线更符合准二级动力学模型。热力学参数△Gθ、△Hθ和△Sθ的计算结果表明,活性炭纤维吸附亚甲基蓝是自发的吸热熵增过程。

This paper studied the adsorption of methylene blue on activated carbon fiber （ACF） whose adsorption ability was compared with granular activated carbon （GAC）. The results show that ACF has better performance. The adsorption of methylene blue on ACF was explored from the aspects of thermodynamics and kinetics.Langmuir and Freundlich isotherm equations were linearized to evaluate the adsorption behavior. They were both suitable to analyze the equilibrium data for the adsorption of methylene blue on ACF. But the Langmuir model fitted better. Pseudo-first-order and pseudo-second-order action models for the adsorption of methylene blue on ACF were also determined. The pseudo-second-order kinetic model provided the better correlation. The thermodynamic parameters ΔG^θ,ΔH^θ and ΔS^θ were calculated. The result shows that the adsorption of methylene blue onto ACF is a spontaneous endothermic entropy increase process.