摘要
以天然芝麻叶为吸附剂,亚甲基蓝(MB)为吸附质,考察芝麻叶吸附亚甲基蓝的动力学、热力学以及溶液pH值、吸附剂投入量、温度等对吸附的影响。采用准一级、准二级、颗粒内扩散吸附动力模型及Langmuir,Freundlich及Dubinin-Radushkevich(D-R)等温模型分别对吸附动力学和吸附等温线进行分析。结果表明,芝麻叶对亚甲基蓝的吸附是一个物理吸附控制的准二级动力学过程。Langmuir,D-R方程都能较好地描述吸附等温线。溶液pH值、吸附剂投入量和温度对吸附有一定影响。吸附热力学函数的计算结果表明吸附是一个自发的吸热过程,高温利于吸附。由D-R方程计算的吸附自由能E为6.804 4—7.087 7 kJ/mol,表明吸附过程为物理吸附。天然芝麻叶吸附剂对去除水溶液中的亚甲基蓝染料效果佳,是一种具有发展潜力的吸附剂。
With natural sesame leaves as low-cost adsorbent,the adsorption of methylene blue（MB） from aqueous solution was studied by batch adsorption technique.The adsorption experiments were carried out under different conditions of solution pH,sesame leaves dose,and temperature.The pseudo-first order,pseudo-second order,and the intraparticle diffusion models and Langmuir,Freundlich and Dubinin-Radushkevich（D-R） isotherms models were used to describe the kinetic data.The experimental results show that the pseudo-second order equation is the best model that describes the adsorption behavior.The equilibrium data were fitted to Langmuir,D-R isotherms,and the equilibrium adsorption was well described by the Langmuir isotherm model.The adsorption free energy value（E=6.804 4-7.087 7 kJ/mol） derived from the D-R model indicates that the adsorption is governed by physical process.The calculation values of thermodynamic parameters present that the adsorption is spontaneous and endothermic in nature.The practical implication is the development of an effective and economic technology for MB removal with sesame leaves from contaminated water.
出处
《化学工程》
CAS
CSCD
北大核心
2011年第6期40-43,49,共5页
Chemical Engineering(China)
关键词
芝麻叶
亚甲基蓝
吸附
等温线
吸附动力学
sesame leaves
methylene blue
adsorption
isotherms
adsorption kinetics
