Chemical and Bacterial Reactions at the Surfaces of Environmentally-Important Metal Sulfide Minerals: Linking Atomic and Field Scales

环境地球化学和生物地球化学项目的这个奖项 是由地球科学，化学， 化学和运输系统工程。 Jillian F.班菲尔德，地质学 和罗伯特J.哈默斯，化学系，该大学 威斯康星-麦迪逊大学将在原子水平上研究 在水溶液和表面之间的界面处发生的反应 金属硫化物矿物。 他们将采用多学科方法， 结合生物、地质和化学因素， 结果来自广泛的实验方法，包括STM，XPS， 和共聚焦显微镜。 将进行平行的实地和实验室研究， 进行。 地表是由自然的无机- 和有机介导的风化将被比较， 综合风化矿物，探讨适用性 自然系统的实验室研究。 的目标 研究是为了确定溶解的机制和速率， 沉淀和金属硫化物表面的离子吸附; 电化学氧化和还原对表面形貌的影响; 杂质在改变电化学过程速率中的作用. 细菌在控制表面微观结构中的作用 特性和溶解速率。 矿物的化学风化作用是岩石 转化为土壤和沉积物的成分。 硫化矿物 例如方铅矿、闪锌矿和黄铜矿被开采为 重要的元素，如铅，锌和铜，释放金属 和酸化水。 酸度的增加加速了 其他矿物。 了解溶解和结晶 金属硫化物的行为，通过化学和细菌途径， 对开发金属形态的预测模型很重要， 生物利用度 本研究的目的是提高对 自然系统，并开发准确的实验室测试和预测 模型

This award in the Environmental Geochemistry and Biogeochemistry Program is jointly supported by the Divisions of Earth Sciences, Chemistry, and Chemical and Transport Systems Engineering. Jillian F. Banfield, Geology Department, and Robert J. Hamers, Chemistry Department, of the University of Wisconsin-Madison will investigate at an atomic level the nature of reactions occurring at interfaces between aqueous solutions and surfaces of metal sulfide minerals. They will use a multidisciplinary approach, incorporating biological, geological and chemical factors, and integrate results from a wide array of experimental methods, including STM, XPS, and confocal microscopy. Parallel field and laboratory studies will be conducted. Surfaces formed as a consequence of natural inorganically- and organically-mediated weathering will be compared to synthetically-weathered minerals to explore the applicability of laboratory-based studies to natural systems. The goals of the investigation are to determine the mechanisms and rates of dissolution, precipitation, and ion adsorption at metal sulfide surfaces; the effect of electrochemical oxidation and reduction on surface morphology; the role of impurities in modifying rates of electrochemical processes at surfaces; and the role of bacteria in controlling surface microstructural characteristics and dissolution rates. Chemical weathering of minerals is the process by which rocks are converted into the constituents of soils and sediments. Sulfide minerals such as galena, sphalerite, and chalcopyrite are mined as sources of important elements, such as lead, zinc, and copper, releasing the metals and acidifying water. The increase in acidity accelerates weathering of other minerals. Understanding the dissolution and crystallization behavior of metal sulfides, by chemical and bacterial routes, is important to developing predictive models of metal speciation and bioavailability. The goal of this study is to improve understanding of natural systems and to develop accurate laboratory tests and predictive models.