Adsorption and reduction of hexavalent chromium on magnetic greigite (Fe3S4)-CTAB: leading role of Fe(ii) and S(-ii)

Yanxia Zhou; Yiting Zhao; Xiaoge Wu; Weiqin Yin; Jianhua Hou; Shengsen Wang; Ke Feng; Xiaozhi Wang

doi:10.1039/c8ra06534a

Adsorption and reduction of hexavalent chromium on magnetic greigite (Fe₃S₄)-CTAB: leading role of Fe(ii) and S(-ii)

RSC Adv. 2018 Sep 10;8(55):31568-31574. doi: 10.1039/c8ra06534a. eCollection 2018 Sep 5.

Authors

Yanxia Zhou¹, Yiting Zhao¹, Xiaoge Wu¹, Weiqin Yin¹, Jianhua Hou^{1

2}, Shengsen Wang^{1

2}, Ke Feng^{1

2}, Xiaozhi Wang^{1

2

3}

Affiliations

¹ College of Environmental Science and Engineering, Yangzhou University Jiangsu 225127 China xzwang@yzu.edu.cn.
² Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization Nanjing 210095 China.
³ Institutes of Agricultural Science and Technology Development, Yangzhou University Yangzhou 225127 Jiangsu China.

Abstract

In this study, a facile one-step route was used to synthesize a novel magnetic mesoporous greigite (Fe₃S₄)-CTAB composite, which was utilized to remove hexavalent chromium (Cr(vi)). The optimized Fe₃S₄-CTAB_0.75 composite with a CTAB dosage of 0.75 g possessed the maximum specific surface, showing the highest Cr(vi) adsorption capacity of 330.03 mg g^-1. The mechanism analysis revealed that Fe(ii) and S(-ii) were critical for the reduction of Cr(vi). CTAB can promote the removal of Cr(vi) by Fe₃S₄-CTAB composites, possibly due to increased S(-ii) concentration, better dispersion of nanoparticles, and greater zeta potential. Besides, there is mild effect of Fe⁰ on Cr(vi) removal, which is confirmed by the disappearance of the Fe⁰ peak from the XPS analysis. The pseudo-second-order kinetic model could explain the Cr(vi) removal processes well. The adsorption of Cr(vi) at different initial concentrations was more consistent with a Langmuir isotherm. The existence of H⁺ was beneficial for Cr(vi) removal by Fe₃S₄-CTAB_0.75. Our work confirmed that the obtained Fe₃S₄-CTAB_0.75 composites exhibit considerable potential for Cr(vi) removal from aqueous solution.