Kinetics of Inorganic Sulfide Mineral Oxidation in Seawater

硫化物矿物的氧化在海底氧化还原生物的能量学中起着重要的作用，是过渡金属和硫从海洋地壳向海水循环的重要化学途径。此外，海底硫化物矿床的原位粉碎和开采会产生大量活性硫化物矿物颗粒表面，其快速氧化会产生局部酸度，可能影响敏感的海洋生物群。因此，确定海水中硫化物矿物的氧化速率有助于提高我们对这些过程的理解。在这个项目中，来自加州大学河滨分校的一位科学家将通过使用初始速率间歇反应器和长期混合流反应器，在一系列相关的化学和物理条件下，研究合成海水中黄铁矿和黄铜矿的非生物氧化速率。这项研究将深入了解(1)矿物表面积、pH值、盐度、温度和氧化剂浓度对氧化速率的定量影响；(2)氧化产物的性质和稳定性；(3)矿物表面氧化反应是否限制了自然界中所见的实际溶解速率。这项研究的结果也将提高科学家的能力。在其他地质和地球化学背景下模拟和解释硫化物氧化数据的能力。作为该项目的一部分，一名非裔美国研究生和一名美国原住民本科生将得到支持和培训。

The oxidation of sulfide minerals plays an important role along the seafloor in the energetics of redox-dependent organisms, and is a significant chemical pathway for the cycling of transition metals and sulfur from oceanic crust to seawater. In addition, in situ pulverization and mining of seafloor sulfide deposits create large amounts of reactive sulfide mineral grain surfaces whose rapid oxidation generates local acidity, potentially affecting sensitive oceanic biota. Thus, determining rates of sulfide mineral oxidation in seawater has merit to improve our understanding of these processes. In this project, a scientist from the University of California-Riverside would investigate the rates of abiotic oxidation of pyrite and chalcopyrite in synthetic seawater over a range of relevant chemical and physical conditions through the use of initial-rate batch reactors and longer-term mixed-flow reactors. This research would provide insight into (1) the quantitative effects of mineral surface area, pH, salinity, temperature and oxidant concentrations on rates of oxidation; (2) the nature and stability of the oxidation products; and (3) whether the mineral surface oxidation reactions limit the actual dissolution rates seen in nature. Results from this research would also enhance scientists? abilities to model and interpret data on sulfide oxidation in other geologic and geochemical settings than is currently possible. One African American graduate student and one Native American undergraduate student would be supported and trained as part of this project.