Carbothermal synthesis of ordered mesoporous carbon-supported nano zero-valent iron with enhanced stability and activity for hexavalent chromium reduction

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• 作者：Ying Dai^a ; ^b ; ¹ ; Yuchen Hu^a ; ¹ ; Baojiang Jiang^a ; Jinlong Zou^a ; ^c ; ^{zoujinlong@aliyun.com" class="auth_mail" title="E-mail the corresponding author} ; Guohui Tian^a ; Honggang Fu^a ; ^{fuhg@vip.sina.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Nano zero-valent iron ; Ordered mesoporous carbon ; Carbothermal reduction ; Hexavalent chromium ; Reduction
• 刊名：Journal of Hazardous Materials
• 出版年：2016
• 出版时间：15 May 2016
• 年：2016
• 卷：309
• 期：Complete
• 页码：249-258
• 全文大小：3294 K

文摘

Composites of nano zero-valent iron (nZVI) and ordered mesoporous carbon (OMC) are prepared by using simultaneous carbothermal reduction methods. The reactivity and stability of nZVI are expected to be enhanced by embedding it in the ordered pore channels. The structure characteristics of nZVI/OMC and the removal pathway for hexavalent chromium (Cr(VI)) by nZVI/OMC are investigated. Results show that nZVI/OMC with a surface area of 715.16 m² g⁻¹ is obtained at 900 °C. nZVI with particle sizes of 20–30 nm is uniformly embedded in the OMC skeleton. The stability of nZVI is enhanced by surrounding it with a broad carbon layer and a little γ-Fe is derived from the passivation of α-Fe. Detection of ferric state (Fe 2p_3/2, around 711.2 eV) species confirms that part of the nZVI on the outer surface is inevitably oxidized by O₂, even when unused. The removal efficiency of Cr(VI) (50 mg L⁻¹) by nZVI/OMC is near 99% within 10 min through reduction (dominant mechanism) and adsorption. nZVI/OMC has the advantage in removal efficiency and reusability in comparison to nZVI/C, OMC and nZVI. This study suggests that nZVI/OMC has the potential for remediation of heavy metal pollution in water.