Effective removal of hexavalent chromium from aqueous solutions by adsorption on mesoporous carbon microspheres

Jianguo Zhou; Yuefeng Wang; Jitong Wang; Wenming Qiao; Donghui Long; Licheng Ling

doi:10.1016/j.jcis.2015.10.001

Effective removal of hexavalent chromium from aqueous solutions by adsorption on mesoporous carbon microspheres

J Colloid Interface Sci. 2016 Jan 15:462:200-7. doi: 10.1016/j.jcis.2015.10.001. Epub 2015 Oct 22.

Authors

Jianguo Zhou¹, Yuefeng Wang¹, Jitong Wang¹, Wenming Qiao¹, Donghui Long², Licheng Ling¹

Affiliations

¹ State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
² State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China. Electronic address: longdh@mail.ecust.edu.cn.

PMID: 26454379
DOI: 10.1016/j.jcis.2015.10.001

Abstract

High-surface-area mesoporous carbon microspheres were successfully synthesized by a spraying method with the purpose of removing Cr(VI) from waste water. Various factors influencing the adsorption of Cr(VI), including pH, adsorption temperature, and contact time were studied. As the adsorption process was pH dependent, it showed maximum removal efficiency of Cr(VI) at pH 3.0. Pseudo-second-order model was found to best represent the kinetics of Cr(VI) adsorption. The adsorption parameters were determined using both Langmuir and Freundlich isotherm models, and Qm value was as high as 165.3mg/g. The thermodynamic parameters including standard Gibb's free energy (ΔG(0)), standard enthalpy (ΔH(0)) and standard entropy (ΔS(0)) were investigated for predicting the nature of adsorption, which suggested the adsorption was an endothermic and a spontaneous thermodynamically process. Furthermore, Fe3O4-loaded MCMs were prepared to rapidly separate the adsorbent from the solution by a simple magnetic process. Fe3O4-loaded MCMs had a high adsorption capacity of 156.3mg/g, and a good regeneration ability with a capacity of 123.9mg/g for the fifth adsorption-desorption cycle.

Keywords: Adsorption; Hexavalent chromium removal; Magnetic separation; Mesoporous carbon microspheres.