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

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• 作者：Jianguo Zhou ; Yuefeng Wang ; Jitong Wang ; Wenming Qiao ; Donghui Long ; ^{longdh@mail.ecust.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Licheng Ling
• 关键词：Hexavalent chromium removal ; Adsorption ; Mesoporous carbon microspheres ; Magnetic separation
• 刊名：Journal of Colloid and Interface Science
• 出版年：2016
• 出版时间：15 January 2016
• 年：2016
• 卷：462
• 期：Complete
• 页码：200-207
• 全文大小：1783 K

文摘

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 Q_m value was as high as 165.3 mg/g. The thermodynamic parameters including standard Gibb’s free energy (ΔG⁰), standard enthalpy (ΔH⁰) and standard entropy (ΔS⁰) 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 156.3 mg/g, and a good regeneration ability with a capacity of 123.9 mg/g for the fifth adsorption–desorption cycle.