Cr(VI) adsorption by montmorillonite nanocomposites

被引:117
|
作者
Wang, Guifang [1 ,2 ,3 ]
Hua, Yuyan [1 ]
Su, Xin [4 ]
Komarneni, Sridhar [2 ,3 ]
Ma, Shaojian [1 ]
Wang, Yujue [5 ]
机构
[1] Guangxi Univ, Sch Resource & Met, Guangxi Expt Ctr Sci & Technol, Nanning 530004, Peoples R China
[2] Penn State Univ, Dept Ecosyst Sci & Management, 204 Mat Res Lab, University Pk, PA 16802 USA
[3] Penn State Univ, Mat Res Inst, 204 Mat Res Lab, University Pk, PA 16802 USA
[4] Guangxi Univ, Sch Environm, Nanning 530004, Peoples R China
[5] Tsinghua Univ, Sch Environm, Beijing 100084, Peoples R China
基金
中国国家自然科学基金;
关键词
Montmorillonite; Adsorption; Hexavalent chromium; Montmorillonite nanocomposites; AQUEOUS-SOLUTIONS; SIMULTANEOUS SORPTION; HEXAVALENT CHROMIUM; WASTE-WATER; REMOVAL; CLAY; EQUILIBRIUM; MECHANISM; BENTONITES; PHOSPHATE;
D O I
10.1016/j.clay.2016.02.008
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Various montmorillonite (Mt) nanocomposite adsorbents were, prepared with Al-13 cations, dodecyl trimethyl ammonium chloride (DTAC) or dodecyl amine (DA) and characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and BET surface area and pore size analyses. The adsorption of hexavalent chromium, Cr(VI) onto various Mt nanocomposites as a function of adsorbent dosage, initial Cr(VI) concentration, contact time and solution pH was investigated. The results showed that the obtained nanocomposites had large basal spacing and good porous structure, and the specific surface areas followed the order: OH-Al-Mt > DA-Al-Mt > DTAC-Al-Mt > Na+-Mt > DTAC-Mt > DA-Mt. The removal efficiency of Cr(VI) ions increased with increasing the adsorbent dosage and contact time, but decreased with increasing initial Cr(VI) concentration, as expected. The adsorption of Cr(VI) was highly pH-dependent and the maximum removal efficiency of Cr(VI) was found in the acid environment. The adsorption equilibrium time was 2 h and the adsorption kinetic data of Cr(VI) on various adsorbents were well described by the pseudo-second-order kinetics model, which indicated that the adsorption reaction of Cr(VI) ions with the adsorbents was mainly due to chemical adsorption. Both the Langmuir model and Freundlich model fitted the equilibrium data well, which suggested that the Cr(VI) adsorption onto various adsorbents was both as monolayer and on heterogeneous surface conditions. The adsorption results indicated that among all the adsorbents used in this experiment, the dodecyl amine and Al-13 cations composited with Mt (DA-Al-Mt) was the most effective for removing Cr(VI) from wastewater. (C) 2016 Elsevier B.V. All rights reserved.
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页码:111 / 118
页数:8
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