活性炭负载纳米零价铁去除溴酸盐的研究

实验采用液相还原法制备活性炭负载纳米零价铁材料(nZVI/AC),并利用X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)等对其结构进行表征.考察了不同反应条件下nZVI/AC对BrO3-的去除效率,并研究其去除机理.结果表明nZVI/AC具有很高的表面反应活性,且nZVI和活性炭(AC)之间存在协同作用. BrO3-的去除效率随 pH 值的减小而增大, 共存离子NO3-和SO42-对其去除率影响不大但降低了去除速率.机理分析表明BrO3-被nZVI/AC吸附而使局部BrO3-浓度升高,并被nZVI迅速还原为无毒的Br-.

Removal of Bromate Using Nanoscale Zero-valent Iron Supported on Activated Carbon

Nanoscale zero-valent iron supported on activated carbon (nZVI/AC) was synthesized in liquid phase reduction method. The nZVI/AC was characterized through X-ray diffraction (XRD), scanning electron microscope(SEM) and transmission electron microscope (TEM). The removal of BrO-3 with nZVI/AC under different conditions and the removal mechanisms were assessed. The results showed that nZVI/AC displayed high reactivity to BrO-3, which should be attributed to the synergetic adsorption and reduction ability of AC and nZVI. The removal efficiency of bromate increased as initial pH decreased. NO-3 and SO2-4 had little effect on BrO-3 removal, but could decrease the removal rate. The BrO-3 removal mechanism indicated that bromate in aqueous solution was adsorbed onto nZVI/MAC, which led to the increase of local bromate concentration in the vicinity of iron nanoparticles, and subsequently reduced to innocuous bromide rapidly with nZVI.