Abstract: The dispersion mechanism of carboxymethyl cellulose (CMC) modified zero-valent iron (ZVI) particles in quartz sand was studied. Influences of porous medium，flow rate on transport were also investigated. The results showed that dispersion mechanism of CMC modified ZVI particles followed the DLVO model. Potential barrier increment brought by electrostatic repulsion and steric hindrance had positive correlation with CMC concentration，promoting the dispersion of ZVI. Zero valent iron particles modified with 500% CMC (mass ratio of CMC to ZVI) were fully dispersed as observed from SEM and light absorbance decreased by 31% in 90 minutes. Influenced by interaction energy between ZVI and quartz sand，filling medium adsorption sites and shear force，transport ability had positive correlation with CMC dosage，and increased with bigger medium size and higher fluid velocity.

Key words: zero-valent iron, sodium carboxymethyl cellulose, DLVO, transport

摘要： 利用羧甲基纤维素钠（CMC）对零价铁进行改性，通过Zeta电位、粒型粒度和沉降曲线的变化探讨改性剂添加量影响零价铁分散的机理，同时考察改性剂添加量、流速和多孔介质类型对零价铁迁移的影响。结果表明，CMC对零价铁的分散机理符合DLVO模型，静电空间位阻带来的势垒增加量与CMC添加量成正相关，能促进零价铁的分散；经500%CMC（CMC与零价铁的质量比）改性的零价铁分散性能最好，成颗粒状、吸光度在90 min下降31%。受零价铁与石英砂作用能、填充介质的吸附位点和剪切力的影响，零价铁的迁移能力随着CMC添加量的增多，填充介质粒径的增大和流速的增加而增强。

关键词: 零价铁, 羧甲基纤维素钠, 沉降, 迁移