Removal of basic dyes from aqueous solution by adsorption onto binary iron-manganese oxide coated kaolinite: Non-linear isotherm and kinetics modeling
Removal of basic dyes from aqueous solution by adsorption onto binary iron-manganese oxide coated kaolinite: Non-linear isotherm and kinetics modeling
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DOI：
10.1016/j.clay.2015.01.005
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发表时间：
2015-04-01
影响因子：
5.6
通讯作者：
Shahjahan
中科院分区：
文献类型：
--
作者：
Khan, Tabrez A.;Khan, Equbal A.;Shahjahan
研究了碱式品红（BF）和结晶紫（CV）染料在铁锰氧化物包覆高岭石（IMK）上的吸附性能。采用FT-IR、XRD、EDX和SEM对吸附剂进行了表征。考察了初始染料浓度、接触时间、吸附剂用量、初始溶液pH等参数对吸附效果的影响。数据拟合为非线性双参数Langmuir， Freundlich, Dubinin-Radushkevich （D-R）和三参数Toth等温线模型。这些数据最适合Langmuir和Toth模型。308 K时BF和CV的Langmuir饱和吸附量Q(0)分别为1036 mg/g和20.64 mg/g。非线性D-R模型的吸附表观能（1.10 ~ 238 kJ/mop）表明染料有物理吸附作用。吸附过程遵循准二级动力学。负的自由能变化值（2.27 ~ 6.125 kmol）和正的焓变值（6.70 ~ 6.68 kJ/mol）表明吸附过程的可行性、自发性和吸热性。熵变的正值（0.028 kJ/mol K）表明吸附剂-吸附质界面的随机性增加。结果表明，铁锰氧化物包覆高岭石是一种很有前途的低成本吸附剂，可用于去除废水中的BF和CV染料。(C) 2015 Elsevier B.V.版权所有
Adsorption of basic fuchsin (BF) and crystal violet (CV) dyes onto iron-manganese oxide coated kaolinite (IMK) was investigated. The adsorbent was characterized using FT-IR, XRD spectra, EDX and SEM images. The effect of various parameters such as initial dye concentration, contact time, adsorbent dose and initial solution pH was examined. The data were fitted into non-linear two-parameter Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and three-parameter Toth isotherm models. The data best fitted the Langmuir and Toth models. Langmuir saturation adsorption capacity (Q(0)) at 308 K for BF and CV was found to be 1036 mg/g and 20.64 mg/g, respectively. The value of apparent energy of adsorption obtained from non-linear D-R model (1.10-238 kJ/mop suggested physical adsorption of the dyes. The adsorption process followed pseudo-second order kinetics. The negative value of free energy change (2.27-6.125 kymol) and positive value of enthalpy change (6.70-6.68 kJ/mol) indicated the feasibility, spontaneity and endothermic nature of the adsorption process. The positive value of entropy change (0.028 kJ/mol K) revealed increased randomness at the adsorbent-adsorbate interface. The results showed that iron-manganese oxide coated kaolinite is a promising low cost adsorbent for the removal of BF and CV dyes from wastewater. (C) 2015 Elsevier B.V. All rights reserved.