Department of Environmental Engineering, Zhejiang University, Hangzhou, PR China.
J Contam Hydrol. 2010 May 20;114(1-4):35-42. doi: 10.1016/j.jconhyd.2010.02.006. Epub 2010 Mar 2.
The reduction of hexavalent chromium or Cr(VI) by zero-valent iron (Fe(0)) nanoparticles has received increasing attention in recent years. However, Fe(0) nanoparticles prepared using conventional methods suffered several drawbacks due to their high reactivity towards surrounding media, which led to the formation of much larger flocs and significant loss in reactivity. To overcome these problems, we synthesized Fe(0) nanoparticles by applying water-soluble carboxymethyl cellulose (CMC) as a stabilizer. CMC-stabilized Fe(0) nanoparticles displayed much less agglomeration but greater Cr(VI) reduced power than those prepared without a stabilizer. At a dose of 0.15 g L(-)(1), CMC-stabilized Fe(0) nanoparticles were able to reduce 100% of 10 mg L(-)(1) Cr(VI) in minutes. Several factors that may affect the efficiency of Cr(VI) removal were investigated. These included the concentration of CMC, the concentration of Fe(0) nanoparticles, the initial Cr(VI) concentration, the pH value, the reaction temperature and the concentration of the calcium cation in the reaction mixture. Our study suggested that the introduction of an innocuous stabilizer such as CMC could significantly improve the performance of Fe(0) nanoparticles for environmental remediation applications.
近年来，零价铁（Fe(0)）纳米颗粒将六价铬（Cr(VI)）还原受到了越来越多的关注。然而，由于传统方法制备的 Fe(0)纳米颗粒对周围介质具有很高的反应性，导致形成更大的絮体并显著降低反应性，因此存在一些缺点。为了克服这些问题，我们通过应用水溶性羧甲基纤维素（CMC）作为稳定剂来合成 Fe(0)纳米颗粒。CMC 稳定的 Fe(0)纳米颗粒的团聚程度较小，但还原 Cr(VI)的能力比没有稳定剂制备的纳米颗粒更强。在剂量为 0.15 g L(-)(1)时，CMC 稳定的 Fe(0)纳米颗粒能够在几分钟内将 10 mg L(-)(1)的 Cr(VI)完全还原。研究了可能影响 Cr(VI)去除效率的几个因素。这些因素包括 CMC 的浓度、Fe(0)纳米颗粒的浓度、初始 Cr(VI)浓度、pH 值、反应温度以及反应混合物中钙离子的浓度。我们的研究表明，引入无害稳定剂（如 CMC）可以显著提高 Fe(0)纳米颗粒在环境修复应用中的性能。
