腐殖酸可提高羧甲基纤维素钠改性的零价纳米铁在氧化铁包覆石英砂中的迁移  

Humic acid could enhance the transport of CMC modified nano zerovalent iron in iron oxide-coated quartz sand

作　　者：王妍 刘宇轩 谷成阳 杨新瑶[1] WANG Yan;LIU Yuxuan;GU Chengyang;YANG Xinyao(Key Lab of Eco-restoration of Reginal Contaminated Environmental,Shenyang University,Shenyang,110044,China;Geological Institute of China Metallurgical Geology Bureau,Sanhe,065201,China)

机构地区：[1]沈阳大学区域污染环境生态修复教育部重点实验室,沈阳110044 [2]中国冶金地质总局第一地质勘查院,三河065201

出　　处：《环境化学》2025年第3期1038-1045,共8页Environmental Chemistry

基　　金：国家自然科学基金(42177406)资助.

摘　　要：零价纳米铁(NZVI)作为在污染场地修复中广泛使用的纳米修复剂,其迁移能力低是制约修复效率的瓶颈.本文利用羧甲基纤维素钠(CMC-Na)对NZVI进行改性得到CNZVI.基于柱实验,研究了在纯石英砂(PS)和氧化铁包覆石英砂(IOPS)介质中,腐殖酸(HA)与CNZVI共注射对于提高CNZVI迁移能力的效果.研究结果表明,氧化铁涂层通过改变砂粒表面电性增加CNZVI在砂粒表面的沉积位点,抑制其迁移.HA与CNZVI共注射之后,与其竞争在氧化铁砂表面的沉积位点,并且通过静电斥力和空间位阻抑制CNZVI在砂粒表面沉积,从而能有效提高CNZVI的迁移能力.HA浓度在0 mg·L^(-1)到60 mg·L^(-1)范围内,CNZVI迁移能力随着HA浓度的提高而显著提高.反之,在纯石英砂介质中,HA对于CNZVI的迁移未产生显著影响,可能是因为纯石英砂与HA之间的负电排斥阻止了HA的竞争性沉降和对石英砂表面沉积点位的占据.本研究结果表明,HA对于CNZVI迁移的提升效果受多孔介质表面物理化学性质的影响,在富含氧化铁的含水层中能更好地促进CNZVI的迁移.Low mobility of nano zero-valent iron(NZVI)is a bottleneck restricting the application of NZVI,one of the most used nano-materials for environmental remediation.In this paper,NZVI was modified with sodium carboxymethyl cellulose(CMC-Na),and co-delivered with humic acid(HA)to explore the HA effect on promoting NZVI mobility in pure quartz sand(PS)and iron oxidecoated quartz sand(IOPS).The results showed that the iron oxide coating increased the deposition sites of CNZVI on the sand surface and lowered its mobility.The co-injected HA could promote CNZVI mobility via site competition and site blocking mechanisms in IOPS.The promoting effect increased with HA levels over the range of 0 to 60 mg·L^(-1) HA.Conversely,HA had insignificant effect on the CNZVI in PS,probably because the negative electric repulsion operating at the PS-HA interface prevented HA adsorption on the sand and the subsequent site blocking effect.These findings imply that the mobility promoting effect of HA relies on the physicochemical properties of the porous media surface,and HA could be a useful additive to promote CNZVI mobility in iron oxide-coated aquifer.

关 键 词：零价纳米铁(NZVI) 氧化铁砂 腐殖酸 迁移. 

分 类 号：X-1[环境科学与工程] O6[理学—化学]