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

扩散流热液喷口中的化学不平衡：铁氧化物存在下 H2-O2 氧化还原平衡的实验研究

• 批准号: 0752221
• 负责人: Dionysios Foustoukos
• 金额: $ 18.87万
• 依托单位: Carnegie Institution of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-02-15 至 2011-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0752221&HistoricalAwards=false
• 关键词: Chemical; Disequilibria; Diffuse; Flow; Hydrothermal

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.

摘要0752221(福斯托科斯)智力价值：这项研究开发了一种新的流动反应器，使在稳态系统中对许多氧化还原敏感反应进行受控研究成为可能，例如那些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(50-200oC/250巴)下与含O2(AQ)的水溶液混合之前进行水热预处理。该装置将允许对反应流体的氧化还原能力进行稳态控制和实时测量，同时保持Knallgas反应进行的恒定驱动力。在Fe-氧化物存在的情况下，将研究H2(AQ)-O2(AQ)氧化还原平衡，以评估磁铁矿在与富含O2(AQ)的流体达到平衡时促进H2(AQ)氧化的相对能力。将通过实验对反应堆进行测试，这些实验旨在研究在海底条件下海水和热液喷口流体混合区内形成的氧化还原梯度中亚稳态氧化/还原水物种的相对稳定性，这一系统在大洋中脊系统的热量和质量传输中非常重要。这些热液在深海环境中挥发物和金属的重新分布以及为海底和海底以下的微生物提供新陈代谢活跃的条件方面发挥了关键作用。更广泛的影响：该项目包括通过卡内基NSF-REU和当地的高中实习生计划对本科生和高中生进行培训。它还支持早期职业科学家的专业发展。这项研究的主要影响是开发了一种带有现场传感器的新型流动反应器，可以实时测量关键的地化溶液性质。除了为科学建设基础设施外，这项工作还具有跨越石油和化学工程领域的潜力，并有可能应用于有毒废物的生物修复。