Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon, Turkey.
J Environ Manage. 2011 Dec;92(12):3082-90. doi: 10.1016/j.jenvman.2011.07.022.
The ability of Turkish illitic clay (TIC) in removal of Cd(II) and Pb(II) ions from aqueous solutions has been examined in a batch adsorption process with respect to several experimental conditions including initial solution pH, contact time, initial metal ions concentration, temperature, ionic strength, and TIC concentration, etc. The characterization of TIC was performed by using FTIR, XRD and XRF techniques. The maximum uptake of Cd(II) (11.25 mg g(-1)) and Pb(II) (238.98 mg g(-1)) was observed when used 1.0 g L(-1) of TIC suspension, 50 mg L(-1) of initial Cd(II) and 250 mg L(-1) of initial Pb(II) concentration at initial pH 4.0 and contact time of 240 min at room temperature. The experimental data were analyzed by the Langmuir, Freundlich, Temkin and Dubinin Radushkevich (D-R) isotherm models. The monolayer adsorption capacity of TIC was found to be 13.09 mg g(-1) and 53.76 mg g(-1) for Cd(II) and Pb(II) ions, respectively. The kinetics of the adsorption was tested using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models. The results showed that the adsorption of Cd(II) and Pb(II) ions onto TIC proceeds according to the pseudo-second-order model. Thermodynamic parameters including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes indicated that the present adsorption process was feasible, spontaneous and endothermic in the temperature range of 5-40 °C.
土耳其伊利石粘土（TIC）在去除水溶液中的 Cd(II)和 Pb(II)离子方面的能力已在批量吸附过程中进行了研究，考察了包括初始溶液 pH、接触时间、初始金属离子浓度、温度、离子强度和 TIC 浓度等在内的几个实验条件。TIC 的特征通过 FTIR、XRD 和 XRF 技术进行了表征。当使用 1.0 g L(-1)的 TIC 悬浮液、50 mg L(-1)的初始 Cd(II)和 250 mg L(-1)的初始 Pb(II)浓度，在初始 pH 4.0 和室温下接触 240 分钟时，观察到 Cd(II)（11.25 mg g(-1)）和 Pb(II)（238.98 mg g(-1)）的最大吸附量。实验数据通过 Langmuir、Freundlich、Temkin 和 Dubinin Radushkevich（D-R）等温模型进行了分析。TIC 对 Cd(II)和 Pb(II)离子的单层吸附容量分别为 13.09 mg g(-1)和 53.76 mg g(-1)。吸附动力学通过准一级、准二级、Elovich 和内扩散模型进行了测试。结果表明，Cd(II)和 Pb(II)离子在 TIC 上的吸附遵循准二级模型。热力学参数包括吉布斯自由能（ΔG）、焓（ΔH）和熵（ΔS）变化表明，该吸附过程在 5-40°C 的温度范围内是可行的、自发的和吸热的。
