摘要
以黏土为载体负载纳米零价铁(nZⅥ,nanoscale zero-valent iron)可改善零价铁颗粒的团聚行为,增强其反应性.在负载过程中铁和黏土用量比例不同,对nZⅥ颗粒团聚和反应性的影响也不同.以有机凹凸棒石(CTMAB/A)为载体,采用液相还原法在1:3和1:5两种铁土质量比条件下制备负载型纳米零价铁复合材料CTMAB/A-nZⅥ-3和CTMAB/A-nZⅥ-5.利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)表征了两种负载样品和不添加黏土载体时nZⅥ的分散差异,并通过X射线光电子能谱仪(XPS)分析样品与Cr(Ⅵ)反应后的产物分布.结果表明:降低负载反应时的铁土比能明显改善nZⅥ粒子的团聚现象、减小nZⅥ平均粒径、提高小粒径颗粒占比、增强其反应活性.小于10nm的nZⅥ颗粒在CTMAB/A-nZⅥ-3和CTMAB/A-nZⅥ-5负载nZⅥ总数中占比分别为3.60%和7.60%,在不负载的nZⅥ样品中占比为0.铁的投加量同为0.75g/L时,CTMAB/A-nZⅥ-5中铁对Cr(Ⅵ)去除率为86.20%,CTMAB/A-nZⅥ-3中为78.00%.
Loading on clay mineral can improve the agglomeration behavior of zero-valent iron particles and enhance their reactivity.Particle agglomeration and reactivity are related to the mass ratio of iron to clay.In this study,CTMAB/A-nZVI-3 and CTMAB/A-nZVI-5 were prepared using organic attapulgite(CTMAB/A) as carrier by liquid phase reduction method when the mass ratio of iron to clay were set to 1:3 and 1:5,respectively.The loaded sample and the unloaded nZVI sample were characterized by X-ray diffractometry(XRD) and scanning electron microscopy(SEM).The product of the sample after reaction with Cr(VI) was analyzed by X-ray photoelectron spectroscopy(XPS).The results showed that with the ratio of iron to clay decreasing,the agglomeration of nZVI particles were improved and the particle size distributions of nZVI were changed.The nZVI particles with particle size less than 10 nm accounted for 3.60% in CTMAB/A-nZVI-3,7.60% in CTMAB/A-nZVI-5,and zero in unloaded nZVI samples.When the amount of iron in supported samples was 0.75 g/L,the Cr(Ⅵ) removal rateresulting from iron was 86.20% in CTMAB/A-nZⅥ-5 samples and 78.00% in CTMAB/A-nZⅥ-3 samples.
作者
徐海玉
张明青
陈翌昱
XU Hai-yu;ZHANG Ming-qing;CHEN Yi-yu(School of Environmental Science and Spatial Informatics,China University of Mining and Technology,Xuzhou 221116,China)
出处
《中国环境科学》
EI
CAS
CSCD
北大核心
2019年第12期5079-5084,共6页
China Environmental Science
基金
国家自然科学基金资助项目(51874304)
徐州市科技计划项目(KC16SG262)
关键词
凹凸棒石
纳米零价铁
铁土比
六价铬
attapulgite
nanoscale zero-valent iron
mass ratio of ion to clay
Cr(Ⅵ)
