Biogeochemical and mineralogical transformation of biogenic iron-rich minerals under environmental conditions

生物矿物是与微生物密切相关的矿物质。在自然环境中，富含铁的矿物通常与细菌有关，细菌利用铁的氧化作为能量来源，从而导致非常小的氧化铁颗粒的沉淀。由于其体积小，固有的大表面积，生物氧化铁可以隔离大量的可溶性污染物，这使得它们在以可溶性金属为主要污染物的自然修复策略中成为有效的吸附剂。然而，这些矿物的长期转化受到的限制很少。它们是无定形的吗？它们会转化成更多的结晶氧化物并释放它们吸收的污染物吗？它们在缺氧环境中会减少吗？本研究旨在通过研究各种生物成因铁矿物在环境相关条件下的长期生物地球化学和矿物转化来回答这些问题。四名研究生（2名硕士和2名博士）将通过进行短期和长期老化实验，并使用最先进的表征技术，如电子显微镜、微x射线衍射和基于同步加速器的分析，来解决上述问题。研究结果将为生物源铁矿物在修复策略中的潜在应用提供有价值的信息。

Biogenic minerals are minerals that form in close association with microorganisms. In natural environments, iron-rich minerals are often associated with bacteria using the oxidation of iron as a source of energy, which leads to the precipitation of very small iron oxide particles. Given their small size and their inherent large surface area, biogenic iron oxides can sequester large quantities of soluble contaminants, which makes them efficient sorbents in natural remediation strategies where soluble metals are the main contaminants. However, the long term transformation of these minerals is poorly constrained. Do they remain amorphous? Do they transform into more crystalline oxides and re-lease their sorbed contaminants? Do they undergo reduction in anoxic environments? The present proposal is designed to answer these questions by investigating the long term biogeochemical and mineral transformation of various biogenic iron minerals under environmentally relevant conditions. Four graduate students (2 M.Sc. and 2 Ph.D.) will tackle the above questions by performing short and long term ageing experiments and using state-of-the-art characterization techniques, such as electron microscopy, micro X-ray diffraction and synchrotron-based analyses. It is expected that the results will provide valuable information for the potential use of biogenic iron minerals in remediation strategies.