Uptake of chloride ion from aqueous solution by calcined layered double hydroxides: Equilibrium and kinetic studies
Uptake of chloride ion from aqueous solution by calcined layered double hydroxides: Equilibrium and kinetic studies
复制标题
煅烧层状双氢氧化物从水溶液中吸收氯离子：平衡和动力学研究
DOI：
10.1016/j.watres.2005.11.043
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发表时间：
2006-02-01
期刊：
影响因子：
12.8
通讯作者：
Duan, X
中科院分区：
文献类型：
--
作者：
Lv, LA;He, J;Duan, X
层状双氢氧化物（LDH）在一定温度范围内煅烧（表示为CLDH）已被证明在适当的阴离子存在下恢复其原始层状结构。根据这种所谓的“记忆效应”，在间歇模式下研究了煅烧MgAl-CO_3 LDH从水溶液中吸收氯离子。平衡等温线表明，CLDH对氯离子的吸收符合Langmuir和Freundlich方程，且Langmuir模型比Freundlich模型更适合实验数据。CLDH对氯离子的最大吸收容量为149.5 mg/g，接近化学计量吸收（168 mg/g）。还探讨了溶液pH值、初始氯化物浓度、吸附剂用量和温度对氯化物去除动力学的影响。用四种动力学模型对实验数据进行拟合，发现准二级动力学模型能较好地描述吸收过程。E.结果表明，CLDH对氯离子的吸收受氯离子与CLDH反应速率的控制，而不是受扩散的控制。通过X射线衍射、红外光谱和热重-质谱分析证实了氯离子的去除机理。(c)2005爱思唯尔有限公司保留所有权利。
Layered double hydroxides (LDH) calcined within a certain temperature range (denoted as CLDH) have been shown to recover their original layered structure in the presence of appropriate anions. in the light of this so-called "memory effect", uptake of chloride ion from aqueous solution by calcined MgAl-CO3 LDH was investigated in batch mode. The equilibrium isotherm showed that the uptake of chloride ion by CLDH was consistent with the Langmuir and Freundlich equations and that the Langmuir model gave a better fit to the experimental data than the Freundlich model. The maximum uptake capacity of CLDH for chloride ion was 149.5 mg/g, close to the stoichiometric uptake (168 mg/g). The influence of varying pH of solution, initial chloride concentration, adsorbent quantity, and temperature on the kinetics of chloride removal has also been explored. Four kinetic models were used to fit the experimental data, and it was found that the pseudo - second-order kinetics model could be used to describe the uptake process satisfactorily. The calculated value of E. was found to be 56.8kJ/mol, which suggests that the process of uptake of chloride ion is controlled by the rate of reaction of chloride ion with the CLDH rather than diffusion. A mechanism for removal of chloride ion has been confirmed by X-ray diffraction, FT-IR spectroscopy and TG-MS measurements. (c) 2005 Elsevier Ltd. All rights reserved.