Equilibrium and kinetic studies of methyl orange adsorption on multiwalled carbon nanotubes
Equilibrium and kinetic studies of methyl orange adsorption on multiwalled carbon nanotubes
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DOI：
10.1016/j.cej.2011.03.031
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发表时间：
2011-05-15
影响因子：
15.1
通讯作者：
Chen, Xiaofeng
中科院分区：
文献类型：
--
作者：
Yao, Yunjin;He, Bing;Chen, Xiaofeng
研究了多壁碳纳米管（MWCNTs）对水溶液中甲基橙子的吸附，考察了吸附时间、用量、温度、pH值和溶液中甲基橙子浓度等因素对吸附的影响。平衡吸附数据进行了分析，使用三种常见的吸附模型：Langmuir。弗罗因德利希和坦金结果表明，Langmuir等温式与实验结果吻合较好。动力学分析进行了使用伪一阶和二阶模型和颗粒内扩散模型。回归结果表明，吸附动力学符合准二级动力学模型。使用从不同温度下的朗缪尔等温线获得的吸附平衡常数计算活化参数的值，例如标准自由能变化（Δ G（0））、标准焓变化（Δ H-0）和标准熵变化（Δ S-0）。结果表明，MWCNTs的Δ G（0）值均为负值，Δ H-0值和Δ S-0值分别为19.39 kJ/mol和0.1015 kJ/mol K，表明MWCNTs的吸附是一个自发的吸热过程。(C)2011 Elsevier B. V.保留所有权利。
The adsorption of methyl orange onto multiwalled carbon nanotubes (MWCNTs) from aqueous solutions was studied, in which the influence of contact time, dosage, temperature, pH, and methyl orange concentration in the solution were investigated. The equilibrium adsorption data were analyzed using three common adsorption models: Langmuir. Freundlich and Temkin. The results revealed that Langmuir isotherm fit the experimental results well. Kinetic analyses were conducted using pseudo-first and second-order models and the intra-particle diffusion model. The regression results showed that the adsorption kinetics was more accurately represented by pseudo-second-order model. Values of activation parameters such as Standard free energy changes (Delta G(0)), standard enthalpy change (Delta H-0), and standard entropy change (Delta S-0) were calculated using adsorption equilibrium constants obtained from the Langmuir isotherm at different temperatures. All Delta G(0) values were negative; the (Delta H-0) values and (Delta S-0) values of MWCNTs were 19.39 kJ/mol and 0.1015 kJ/mol K, respectively, indicating that the adsorption was feasible, spontaneous and endothermic process in nature. (C) 2011 Elsevier B.V. All rights reserved.