Transport and reactivity of engineered iron nanoparticles in natural porous media

这项拨款申请将支持研究调查潜在的改进，以就地修复技术的污染地下水。零价铁（还原铁）的纳米颗粒具有反应性，能够快速消除地下水中常见的一些有毒和潜在致癌污染物，如三氯乙烯，铬和砷。这使得零价铁的纳米颗粒成为污染场地地下水修复的优良反应物。此外，零价铁被转化为氧化铁，其在土壤中普遍存在并天然存在。 通过受控的实验室研究，拟议的研究将调查模型含水层砂中纳米铁颗粒的运输和反应性。地下水和土壤矿物化学对零价铁纳米颗粒的迁移和反应性有很大影响，从而影响修复操作的效率。特别是，该研究将调查地下水环境中常见的天然有机分子（如腐殖酸和微生物聚合物）的影响，因为它们有可能显著改变纳米铁颗粒的运输和反应性。了解这些影响将有助于确定补救所需的操作参数。该研究还将研究零价铁的废纳米颗粒或氧化纳米颗粒的再活化，以便在可以产生氢，硫化物或还原铁的常见土壤微生物的帮助下继续降解污染物。在修复操作中应用微生物再生氧化的纳米颗粒是新颖的，并且可以导致修复所需的铁纳米颗粒的量的减少。

This grant application will support research investigating potential improvements to in situ remediation technologies for contaminated groundwater. Nanoparticles of zero valent iron (reduced iron) are reactive and are able to rapidly eliminate a number of toxic and potentially carcinogenic pollutants commonly encountered in groundwater, such as trichloroethylene, chromium and arsenic. This makes the nanoparticles of zero valent iron an excellent reactant for remediation of groundwater at contaminated sites. Furthermore, the zero valent iron is converted to iron oxides, which are ubiquitous in soil and naturally present. Through controlled laboratory studies, the proposed research will investigate the transport and reactivity of nanoiron particles in model aquifer sands. Groundwater and soil mineral chemistry can have a strong influence on the transport and reactivity of zero valent iron nanoparticles, and thus impact the efficiency of remediation operations. In particular, the research will investigate the effects of natural organic molecules such as humic acids and microbial polymers that are commonly encountered in groundwater environments, as they have the potential to significantly alter transport and reactivity of naniron particles. The knowledge of these effects will help identify required operating parameters for remediation. The research will also investigate the reactivation of spent or oxidized nanoparticles of zero valent iron for continued pollutant degradation with the help of common soil microorganisms that can produce hydrogen, sulfides or reduce iron. The application of microorganisms for regeneration of oxidized nanoparticles in remediation operation is novel, and can lead to reductions in the amount of iron nanoparticles required for remediation.