纳米零价铁核壳形成演化对修复地下水的影响及作用机制

项目名称： 纳米零价铁核壳形成演化对修复地下水的影响及作用机制

项目编号： No.41472232

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 地质学

项目作者： 陈家玮

作者单位： 中国地质大学（北京）

项目金额： 98万元

中文摘要： 纳米零价铁(NZVI)原位修复污染地下水是近年国际开展的环境修复新技术。应用中NZVI存在易氧化、易团聚、迁移性差等问题，研究包覆型和负载型纳米铁成为热点，这类改性能提高NZVI分散稳定性、迁移性及修复效率，但是NZVI极易氧化形成表层为氧化铁内核为零价铁的核壳结构，反应中零价铁不断消耗导致核壳结构微区形态及成分改变，从而影响NZVI反应活性和使用寿命。因此项目拟在不同环境条件下定量研究NZVI(含包覆型和负载型)核壳结构的形成演化过程，及其对污染物修复效果的影响(以重金属六价铬和有机物三氯乙烯为例)，不仅阐明核壳结构还原降解作用机制，而且构筑似芬顿体系提出核壳氧化催化降解作用模型，同时揭示典型环境条件中天然有机质对不同核壳纳米零价铁的吸附/解吸作用及其对污染物修复效果的促进或抑制影响机制。成果对丰富地下水修复机理、根据环境选择适宜NZVI及注射方式原位修复等，具有重要科学意义和应用价值。

中文关键词： 纳米零价铁；核壳结构；形成演化；地下水修复；作用机制

英文摘要： Injection of nano zero-valent iron (NZVI) is an attractive new technique for in-situ groundwater remediation in recent years. However, oxidation and aggregation are easily happened on NZVI and lower its mobility and reactivity. It is a hot topic for scientists to modify NZVI using environmental-friendly coating or loading material to improve NZVI's dispersity, stabilization and remediation efficiency. But NZVI easily forms a core-shell structure with surface layer of oxide iron and inner core of zero-valent iron. Zero-valent iron consumption during reaction could change core-shell structure and composition, which impacts NZVI's reactivity and working life. Therefore, we would quantitatively study the formation and evolution process of NZVI core-shell structure under different environmental conditions, and the effect of core-shell iron on removal of pollutants like hexavalent chromium and trichloroethylene. We would elucidate iron-based core-shell reduction mechanism, propose the model of core-shell iron oxidation catalytic degradation in Fenton like system, reveal natural organic matter adsorption/desorption on different core-shell NZVI at typical conditions and the effect of such interaction on remediation enhancement or inhibition. So it is of important scientific significance and practical value that these results could enrich remediation theoretical research and guide us to choose appropriate NZVI and injection way for in-situ groundwater remediation.

英文关键词： nano zero-valent iron;core-shell structure;formation and evolution;groundwater remediation;interaction mechanism