Chromate removal by surface-modified nanoscale zero-valent iron: Effect of different surface coatings and water chemistry
Chromate removal by surface-modified nanoscale zero-valent iron: Effect of different surface coatings and water chemistry
复制标题
表面改性纳米零价铁去除铬酸盐：不同表面涂层和水化学的影响
DOI：
10.1016/j.jcis.2016.03.011
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发表时间：
2016-06-01
影响因子：
9.9
通讯作者：
Wu, Yanan
中科院分区：
文献类型：
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作者：
Dong, Haoran;He, Qi;Wu, Yanan
本研究研究了表面改性的纳米零价铁（SM-nZVI）的胶体稳定性和反应性之间的相关性，其受表面涂层（即，聚丙烯酸[PAA]和淀粉）在各种地球化学条件下的作用。一般而言，nZVI的胶体稳定性随着表面涂层负载量的增加而增强，而SM-nZVI最有效地去除Cr（VI）存在最佳负载量。在低于最佳负载量的负载量下，表面涂层可以增强颗粒稳定性，通过提供更多可用的表面位点来促进Cr（VI）的还原。然而，在nZVI颗粒表面上的过负载的表面涂层降低了Cr（VI）的还原，由于反应位点的占用和抑制的Cr（VI）离子从水到颗粒表面的传质，通过提供静电或空间排斥。研究了Ca ~（2+）和腐殖酸（HA）对PAA改性nZVI（P-nZVI）和淀粉改性nZVI（S-nZVI）胶体稳定性和反应活性的影响。对于不同的SM-nZVI，观察到不同的稳定性行为和反应性。结果表明，Ca ~（2+）或HA的存在改变了SM-nZVI的表面化学性质、粒子间的相互作用以及粒子与杂质间的相互作用，从而影响了粒子的稳定性和反应活性。(C)2016 Elsevier Inc. All rights reserved.
This study investigated the correlation between the colloidal stability and reactivity of surface-modified nano zero-valent iron (SM-nZVI) as affected by the surface coating (i.e., polyacrylic acid [PAA] and starch) under various geochemical conditions. Generally, the colloidal stability of nZVI was enhanced with increasing loading of surface coating, while there is an optimum loading for the most efficient Cr(VI) removal by SM-nZVI. At lower loadings than the optimum loading, the surface coating could enhance the particle stabilization, facilitating the Cr(VI) reduction by providing more available surface sites. However, the over-loaded surface coating on the surface of nZVI particles decreased the Cr(VI) reduction due to the occupation of the reactive sites and the inhibition of the mass transfer of Cr(VI) ions from water to the particle surface by providing the electrostatic or steric repulsion. The effects of Ca2+ ions or humic acid (HA) on the colloidal stability and reactivity of PAA-modified nZVI (P-nZVI) and starch modified nZVI (S-nZVI) were examined. Differing stability behavior and reactivity were observed for different SM-nZVI. It was found that the presence of Ca2+ or HA altered surface chemistry of SM-nZVI, the particle-particle interaction and the particle-contaminant interaction, and hence influencing the stability behavior and reactivity of the particles. (C) 2016 Elsevier Inc. All rights reserved.