Kinetics and mechanisms of pH-dependent selenite removal by zero valent iron
Kinetics and mechanisms of pH-dependent selenite removal by zero valent iron
复制标题
零价铁去除 pH 值依赖性亚硒酸盐的动力学和机制
DOI：
10.1016/j.watres.2013.07.011
复制
发表时间：
2013-10-01
期刊：
影响因子：
12.8
通讯作者：
Zhang, Xiangzi
中科院分区：
文献类型：
--
作者：
Liang, Liping;Yang, Wenjun;Zhang, Xiangzi
研究了零价铁（ZVI）去除Se（IV）的动力学及其作用机理。当pH从4.0增加到7.0时，ZVI去除Se（IV）的比速率常数从92.87 L h（-1）m（-2）降低到6.87 L h（-1）m（-2）。Se（IV）的去除率与Fe（II）的生成率之间的正相关性以及1，10-菲咯啉对Se（IV）去除率的抑制表明，ZVI和吸附在ZVI表面的Fe（II）都对Se（IV）的还原去除有贡献.软X射线STXM测量证实了Fe（II）在ZVI和新鲜形成的氧化铁（氢）的表面上的吸附。XANES谱表明，在pH 4.0-7.0范围内，Se（IV）在ZVI表面吸附后被还原为Se（0）。当ZVI与含Se（IV）的溶液在pH 6.0下反应3 h时，观察到核-壳结构。Se（IV）被还原成Se（0）并与新形成的Fe（III）共沉淀，形成围绕铁芯的壳。反应24小时后，生成的Se（0）被多层Fe（III）氧化物/氢氧化物包围。SEM和XRD分析表明，在pH 6.0时，ZVI的腐蚀产物由无定形的氢氧化铁转变为纤铁矿（γ-FeOOH）。ZVI的最终腐蚀产物在pH 5.0时含有纤铁矿和针铁矿，而在pH 4.0和7.0时它们是X射线无定形的。(C)2013爱思唯尔有限公司保留所有权利。
The kinetics of Se(IV) removal by zero valent iron (ZVI) open to the air as a function of pH and the involved mechanisms were investigated in this study. The specific rate constants of Se(IV) removal by ZVI decreased from 92.87 to 6.87 L h(-1)m(-2) as pH increased from 4.0 to 7.0. The positive correlation between the removal rate of Se(IV) and the generation rate of Fe(II) and the depression of Se(IV) removal in the presence of 1,10-phenanthroline indicated that both ZVI and adsorbed Fe(II) on ZVI surface contributed to the reductive removal of Se(IV). The soft X-ray STXM measurement confirmed the adsorption of Fe(II) on the surface of ZVI and freshly formed ferric (hydr)oxides. Se(IV) was removed by adsorption followed by reduction to Se(0) on ZVI surface at pH 4.0-7.0, as revealed by XANES spectra. A core-shell structure was observed when ZVI reacted with Se(IV)-containing solution for 3 h at pH 6.0. Se(IV) was reduced to Se(0) and co-precipitated with the freshly formed Fe(III), forming the shell surrounding the iron core. After reaction for 24 h, the generated Se(0) was surrounded by multiple layers of Fe(III) oxides/hydroxides. SEM images and XRD patterns revealed that the corrosion products of ZVI at pH 6.0 transformed from amorphous iron hydroxides to lepidocrocite (gamma-FeOOH) as reaction proceeded. The final corrosion products of ZVI contained both lepidocrocite and goethite at pH 5.0 while they were X-ray amorphous at pH 4.0 and 7.0. (C) 2013 Elsevier Ltd. All rights reserved.