零价纳米铁吸附去除水中六价铬的研究

利用液相还原法制备的零价纳米铁(nZVI)进行了去除水中Cr(Ⅵ)的实验研究.结果表明,nZVI对Cr的去除效果明显优于还原铁粉和粉末活性碳;pH值越小、初始Cr浓度越低、nZVI放置时间越短及投加量越大均有利于水中Cr(Ⅵ)的去除,最佳去除率近100%;反应动力学拟合结果表明,nZVI去除六价铬符合准二级动力学模型;反应后nZVI颗粒的扫描电镜及电子能谱结果显示Cr占12.02%(wt),结合对反应溶液中Cr(Ⅵ)和Cr(Ⅲ)分析,说明吸附、还原与共沉淀可能是nZVI去除水中六价铬的主要机理.

Removal Cr6+ from water using nanoscale zero-valent iron

The removal of Cr6+ from water using nanoscale zero-valent iron (nZVI) prepared with the liquid phase reduction method was investigated. Results showed that removal rate of Cr6+ observed from nZVI was much higher than those from iron powder and activated carbon. Lower pH and initial Cr6+ concentration, more fresh nZVI and dosage were favorable of removal of Cr6+ in water, and the best removal rate was nearly 100%. The fitting results of reaction dynamics indicated that Cr6+ removal by nZVI was well consonant with pseudo second-order model. Cr element with 12.02% (wt) concentration was detected on the post-reaction nZVI particle surface by SEM and EDS. The analysis of Cr6+ and Cr3+ concentration in reaction solution of adsorption, suggested that reduction and co-precipitation should be the mainl mechanism of the Cr6+ removal from water using nZVI.