Adsorption of platinum(IV), palladium(II) and gold(III) from aqueous solutions onto L-lysine modified crosslinked chitosan resin
Adsorption of platinum(IV), palladium(II) and gold(III) from aqueous solutions onto L-lysine modified crosslinked chitosan resin
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DOI：
10.1016/j.jhazmat.2006.11.049
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发表时间：
2007-07-19
影响因子：
13.6
通讯作者：
Ueda, Kazumasa
中科院分区：
文献类型：
--
作者：
Fujiwara, Kensuke;Ramesh, Attinti;Ueda, Kazumasa
采用L-赖氨酸化学修饰的交联壳聚糖树脂研究了水溶液中Pt（IV）、Pd（II）和Au（III）的吸附。批量吸附研究进行了各种参数，如初始金属离子浓度，接触时间，pH值和温度。Pt（IV）在pH 1.0时吸附量最大，Au（III）和Pd（II）在pH 2.0时吸附量最大。采用Langmuir和Freundlich等温模型对实验数据进行了分析。Langmuir吸附等温线对实验数据进行了最佳解释，其最大吸附量分别为Pt（IV）129.26 mg/g、Pd（II）109.47 mg/g和Au（III）70.34 mg/g。动力学数据进行了测试，使用伪一级和伪二级动力学模型。动力学数据与准二级动力学模型的相关性很好，表明化学吸附是限速步骤。热力学参数如吉布斯自由能（Δ G度）、焓（Δ H度）和熵（Δ S度）通过应用Van 't霍夫方程来评估。热力学研究表明，吸附过程是自发的放热过程。使用各种试剂进行解吸研究。当使用0.7M硫脲-2M HCl试剂时，获得最大的贵金属离子解吸百分比。(C)2006 Elsevier B. V.保留所有权利。
Crosslinked chitosan resin chemically modified with L-lysine has been used to investigate the adsorption of Pt(IV), Pd(II) and Au(III) from aqueous solutions. Batch adsorption studies were carried out with various parameters, such as initial metal ion concentration, contact time, pH and temperature. The maximum adsorption capacity was found at pH 1.0 for Pt(IV), at pH 2.0 for Au(III) and Pd(II). Langmuir and Freundlich isotherm models were applied to analyze the experimental data. The best interpretation for the experimental data was given by the Langmuir isotherm and the maximum adsorption capacity was found to be 129.26 mg/g for Pt(IV), 109.47 mg/g for Pd(II) and 70.34 mg/g for Au(III). The kinetic data was tested using pseudo-first-order and pseudo-second-order kinetic models. Kinetic data correlated well with the pseudo-second-order kinetic model, indicating that the chemical sorption was the rate-limiting step. Thermodynamic parameters like Gibbs free energy (Delta G degrees), enthalpy (Delta H degrees) and entropy (Delta S degrees) were evaluated by applying the Van't Hoff equation. The thermodynamic study indicated that the adsorption process is spontaneous and exothermic in nature. The desorption studies were carried out using various reagents. The maximum percent desorption of precious metal ions were obtained when the reagent 0.7 M thiourea-2 M HCl was used. (C) 2006 Elsevier B.V. All rights reserved.