Chemical Disequilibria in Diffuse Flow Hydrothermal Vents: An Experimental Study on H2-O2 Redox Equilibria in the presence of Fe-Oxides

摘要0752221（Foustoukos）智力优势：该研究开发了一种新的流通式反应器，使稳态系统中许多氧化还原敏感反应的受控研究成为可能，例如涉及金属或微生物的反应。 该设计将允许富含H2（aq）的水溶液在温度和压力（50- 200 oC/250 bar）下与含O2（aq）的水溶液混合之前进行水热预处理。该装置将允许反应流体的氧化还原容量的稳态控制和实时测量，同时保持用于Knallgas反应进行的恒定驱动力。 H2（aq）-O2（aq）氧化还原平衡将在铁氧化物的存在下进行检查，以评估磁铁矿在促进H2（aq）氧化的相对能力，同时与O2（aq）-富集流体平衡。 将对反应堆进行试验，以研究在海底条件下海水和热液喷口流体混合区形成的氧化还原梯度中亚稳氧化/还原性含水物质的相对稳定性，这一系统对大洋中脊系统的热量和质量转移至关重要。 这些热液在挥发物和金属在深海环境中的重新分布以及为海底和海底以下的微生物提供代谢活跃条件方面发挥着关键作用。更广泛的影响：该项目包括通过卡内基NSF-REU和当地高中实习生计划培训本科生和高中生。它还支持早期职业科学家的专业发展。 该研究的主要影响是开发了一种新型的、新型的、带有原位传感器的流通式反应器，可以实时测量关键的地球化学溶液性质。 除了为科学建设基础设施外，这项工作还具有与石油和化学工程领域交叉的潜力，并有可能应用于有毒废物的生物修复。

ABSTRACT 0752221 (Foustoukos)Intellectual Merit: The research develops a new flow-through reactor that makes possible the controlled study of many redox sensitive reactions in steady-state systems, such as those that involve metals or microbes. The design will allow aqueous solutions enriched in H2(aq) to be hydrothermally pretreated before being mixed with O2(aq)-bearing aqueous solutions at temperatures and pressures (50-200oC/250 bars). The apparatus will allow steady state control and real-time measurements of the redox capacity of the reacting fluids, while maintaining a constant driving force for Knallgas reaction to proceed. The H2(aq)-O2(aq) redox equilibria will be examined in the presence of Fe-oxides, to evaluate the relative capacity of magnetite in promoting H2(aq) oxidation while in equilibria with O2(aq)-enriched fluids. The reactor will be tested by experiments designed to study the relative stability of metastable oxidizing/reducing aqueous species in redox gradients developed within the mixing zone of seawater and hydrothermal vent fluids at seafloor conditions, a system that is important in the transfer of heat and mass in mid-ocean ridge systems. These hydrothermal fluids play a key role in the re-distribution of volatiles and metals in abyssal environments and in providing metabolically active conditions for microbes both on and below the seafloor. Broader Impacts: The project includes training of undergraduate and high-school students through the Carnegie NSF-REU and through local high-school intern programs. It also supports professional development of an early career scientist. A primary impact of the research is the development of a novel, new, flow-through reactor with in-situ sensors that allow real-time measurements of key geochemical solution properties. In addition to building infrastructure for science, the work has crossover potential to the fields of petroleum and chemical engineering and has potential applications to bioremediation of toxic waste.