Weak magnetic field accelerates chromate removal by zero-valent iron
Weak magnetic field accelerates chromate removal by zero-valent iron
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弱磁场加速零价铁去除铬酸盐
DOI：
10.1016/j.jes.2014.10.017
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发表时间：
2015-05-01
影响因子：
6.9
通讯作者：
Li, Lina
中科院分区：
文献类型：
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作者：
Feng, Pian;Guan, Xiaohong;Li, Lina
首次将弱磁场用于零价铁去除Cr（VI）的研究。Cr（VI）的去除率提高了1.12-5.89倍，且在Cr（VI）浓度较高和pH值较高时效果更为显著。在无Cr（Ⅵ）存在的情况下，WMF诱导的Cr（Ⅵ）去除率促进因子与Fe 2+释放率促进因子之间呈正相关，VI）pH 4.0-5.5。这些现象表明，ZVI腐蚀与Fe 2+释放的Cr（VI）去除过程中的限制步骤。叠加的WMF对ZVI去除Cr（VI）的表观活化能的影响可以忽略不计，表明WMF加速了ZVI去除Cr（VI），但没有改变其机理。用WMF形成的钝化层比没有WMF的多孔得多，从而促进质量传递。因此，WMF可以加速ZVI腐蚀并减轻钝化层的不利影响，从而导致ZVI更快速地去除Cr（VI）。利用ZVI的磁记忆效应，提出了一种由小反应器和大反应器组成的两阶段ZVI磁化和磁化ZVI去除污染物的方法。(C)2015中国科学院生态环境科学研究中心由爱思唯尔公司出版
Weak magnetic field (WMF) was employed to improve the removal of Cr(VI) by zero-valent iron (ZVI) for the first time. The removal rate of Cr(VI) was elevated by a factor of 1.12-5.89 due to the application of a WMF, and the WMF-induced improvement was more remarkable at higher Cr(VI) concentration and higher pH. Fe2+ was not detected until Cr(VI) was exhausted, and there was a positive correlation between the WMF-induced promotion factor of Cr(VI) removal rate and that of Fe2+ release rate in the absence of Cr(VI) at pH 4.0-5.5. These phenomena imply that ZVI corrosion with Fe2+ release was the limiting step in the process of Cr(VI) removal. The superimposed WMF had negligible influence on the apparent activation energy of Cr(VI) removal by ZVI, indicating that WMF accelerated Cr(VI) removal by ZVI but did not change the mechanism. The passive layer formed with WMF was much more porous than without WMF, thereby facilitating mass transport. Therefore, WMF could accelerate ZVI corrosion and alleviate the detrimental effects of the passive layer, resulting in more rapid removal of Cr(VI) by ZVI. Exploiting the magnetic memory of ZVI, a two-stage process consisting of a small reactor with WMF for ZVI magnetization and a large reactor for removing contaminants by magnetized ZVI can be employed as a new method of ZVI-mediated remediation. (C) 2015 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.