Removal of methyl orange from aqueous solution by uncalcined and calcined MgNiAl layered double hydroxides (LDHs)
Removal of methyl orange from aqueous solution by uncalcined and calcined MgNiAl layered double hydroxides (LDHs)
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DOI：
10.1016/j.cej.2012.01.112
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发表时间：
2012-04
影响因子：
15.1
通讯作者：
H. Zaghouane-Boudiaf;M. Boutahala;L. Arab
中科院分区：
文献类型：
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作者：
H. Zaghouane-Boudiaf;M. Boutahala;L. Arab
研究了未经焙烧的MgNiAl-CO_3和焙烧后的MgNiAl-C水滑石对阴离子染料甲基橙子（MO）的吸附性能。各种条件，如初始染料浓度，吸附剂的用量，接触时间，溶液的pH值，和温度进行了研究。吸附动力学进行了研究，使用经典的伪一级，二级和颗粒内扩散模型方程。动力学数据符合准二级动力学模型。吸附焓变（ΔH°）为正值，吉布斯自由能（ΔG°）为负值，表明吸附过程是自发的吸热过程。采用Langmuir、Freundlich和Redlich-Peterson三种非线性吸附模型对平衡吸附数据进行了分析。结果表明，Langmuir和Redlich-Peterson等温线与实验结果拟合良好，相关系数较高。吸附等温线符合Langmuir吸附等温式，最大吸附量qmax为375 mg/g。这一结果对于选择吸附剂，优化水环境修复技术具有实际意义。
In this study, both uncalcined (MgNiAl–CO3) and calcined (MgNiAl–C) hydrotalcites were used in the adsorption of methyl orange (MO) from aqueous solution as an anionic dye in a batch system. Various conditions such as initial dye concentration, adsorbent dosage, contact time, solution pH, and temperature were investigated. The adsorption kinetics was studied using classic equations of pseudo-first-order, -second-order and intraparticle diffusion models. The dynamical data fit well with the pseudo-second-order kinetic model. The positive value of the changes in enthalpy (ΔH°), the negative value of Gibbs free energy (ΔG°), showed that the adsorption is endothermic and spontaneous for all the studied temperatures. The equilibrium adsorption data were analyzed using three non linear adsorption models: Langmuir, Freundlich and Redlich–Peterson. The results showed that Langmuir and Redlich–Peterson isotherms fit the experimental results very well with high correlation coefficients. The Langmuir isotherm model exhibited a maximum adsorption capacity qmaxof 375mg/g for the calcined MgNiAl–C. This result is of practical interest, with respect to the selection of sorbents, to optimize aquatic environment remediation technologies.