U.S.-France Cooperative Research: Speciation and Formation Mechanisms of Iron and Silicon Associations in Natural Media

9815274Teppen这个为期三年的奖项旨在支持美法在环境化学方面的合作研究，获奖者包括佐治亚大学萨凡纳河生态实验室的Brian Teppens、Paul M.Bertsch和马赛第三大学的Armand Masion。他们的研究目标是研究被认为导致土壤中铁石形成的铁-硅酸盐络合机理。他们将在原子尺度和半局部尺度上研究水中铁-硅酸盐络合物的形成，并将X射线吸收和散射实验结果与动态分子模拟相结合。美国调查人员将分子动力学方法方面的专业知识带到了这次合作中。此外，法国在铁水解方面的专门知识以及获得补充同步辐射仪器和设施的机会也与之相辅相成。实验将在纽约布鲁克海文的国家同步加速器光源和巴黎大学的LUE(L的电磁利用实验室)进行。随着时间的推移，热带土壤中会形成铁石，因为高温和水分会耗尽土壤中的有机质和无机植物养分。土壤变得富含铝和铁，铁被重新分配，由于侵蚀，铁石形成并暴露在土壤表面，从而限制了植物的生长。该项目将促进对这一过程以及如何以最佳方式管理热带土壤化学的了解。

9815274TeppenThis three-year award in support of U.S.-France collaborative research in environmental chemistry involves Brian Teppen, Paul M. Bertsch at the University of Georgia's Savannah River Ecology Laboratory and Armand Masion at the Universite d'Aix Marseille III. The objective of their research is the study of iron-silicate complexation mechanisms that are thought to result in ironstone formation in soils. They will study aqueous iron-silicate complex formation at the atomic scale and the semi-local scale and combine the results obtained from X-ray absorption and scattering experiments with dynamic molecular modeling. The US investigators bring to this collaboration expertise in molecular dynamics methods. This is complemented by French expertise in iron hydrolysis and by access to complementary synchrotron radiation instrumentation and facilities. The experiments will take place at the National Synchrotron Light Source at Brookhaven, New York and at LURE (Laboratoire pour l'Utilisation du Rayonnement Electromagnetique) at the University of Paris. Ironstone formation occurs in tropical soils over time as heat and moisture deplete soils of organic matter and inorganic plant nutrients. The soils become enriched in aluminum and iron, the iron is redistributed, and as a result of erosion, ironstones form and are exposed at the soil surface, thereby limiting plant growth. This project will advance understanding of this process and how to optimally manage the chemistry of tropical soils .