有机凹凸棒石负载纳米零价铁去除水中六价铬

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%.

Removal of Cr(VI) from aqueous solution using organically modified attapulgite-supported nanoscale zero-valent iron

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 10nm 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 0.75g/L, the Cr(VI) removal rateresulting from iron was 86.20% in CTMAB/A-nZVI-5samples and 78.00% in CTMAB/A-nZVI-3samples.