Bereket G, Aro AZ, ozel MZ
Chemistry Department, University of Osmangazi, Eskisehir, Turkey
J Colloid Interface Sci. 1997 Mar 15;187(2):338-43. doi: 10.1006/jcis.1996.4537.
Removal of Pb(II), Cd(II), Zn(II), and Cu(II) from aqueous solutions using the adsorption process on bentonite has been investigated. In order to find out the effect of temperature on adsorption, the experiments were conducted at 20, 35, and 50degreesC. For all the metals, maximum adsorption was observed at 20degreesC. The rate of attaining equilibrium of adsorption of metal ions follows the order Zn(II) > Cu(II) > Cd(II) > Pb(II). Equilibrium modeling of the adsorption showed that adsorption of Pb(II), Cd(II), and Cu(II) were fitted to a Langmuir isotherm, while the adsorption of Zn(II) was fitted to a Freundlich isotherm. Dynamic modeling of the adsorption showed that the first order reversible kinetic model was held for the adsorption process. The overall rate constant k', the adsorption rate constant k1, the desorption rate constant k2, and the equilibrium constant Ke for the adsorption process were calculated. From the results of the thermodynamic analysis, standard free energy DeltaG0, standard enthalpy DeltaH0, and standard entropy DeltaS0 of the adsorption process were calculated.
研究了利用膨润土吸附法从水溶液中去除Pb(II)、Cd(II)、Zn(II)和Cu(II)。为了探究温度对吸附的影响，实验在20℃、35℃和50℃下进行。对于所有金属，在20℃时观察到最大吸附量。金属离子达到吸附平衡的速率顺序为Zn(II) > Cu(II) > Cd(II) > Pb(II)。吸附的平衡模型表明，Pb(II)、Cd(II)和Cu(II)的吸附符合朗缪尔等温线，而Zn(II)的吸附符合弗伦德利希等温线。吸附的动力学模型表明，吸附过程符合一级可逆动力学模型。计算了吸附过程的总速率常数k'、吸附速率常数k1、解吸速率常数k2和平衡常数Ke。根据热力学分析结果，计算了吸附过程的标准自由能ΔG0、标准焓ΔH0和标准熵ΔS0。
