Quantifying Bacteria-Metal-Mineral Adsorption: Wet Chemistry and Advanced Photon Source Approaches

量化细菌-金属-矿物质吸附：湿化学和先进光子源方法

• 批准号: 9905704
• 负责人: Jeremy Fein
• 金额: $ 22.56万
• 依托单位: University of Notre Dame
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2004-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9905704&HistoricalAwards=false
• 关键词: Quantifying; Bacteria; Metal; Mineral; Adsorption

Fein9905704The proposed research will use bulk adsorption and EXAFS experiments to calibrate a surface complexation approach to quantifying bacterial adsorption of aqueous metals in groundwater systems. In order to remediate dissolved heavy metal contamination in groundwater, we must understand the chemical controls on contaminant mobilities. Bacteria are ubiquitous in low-temperature water-rock, and depending on conditions, they can either enhance or retard contaminant transport through adsorption reactions. With our current knowledge, it is impossible to predict if bacterial adsorption effects occur given a set of conditions, or to predict the magnitude of such effects. The primary questions we will answer with the proposed research are as follows: (1) Does a reversible equilibrium state exist for metal-bacteria adsorption reactions, or do kinetics, inorganic metal precipitation, or cell metabolic processes prevent equilibrium from being attained?; (2) Do the reaction stoichiometries that we obtain from bulk adsorption experiments agree with direct observations of the metal-bacteria surface complexes that we will make using XAFS studies on the Advanced Photon Source at Argonne National Laboratory?; and, (3) Can we expand the surface complexation equilibrium thermodynamic approach to describe bacteria-mineral adsorption reactions? We will conduct bulk adsorption and desorption experiments, examining both isolated metal-bacteria and bacteria-mineral systems, to rigorously test the reversibility of the metal-bacteria-mineral adsorption reactions. Furthermore, we will quantify the importance of adsorption/desorption kinetics, surface precipitation, and metabolism on metal uptake by the cell. Coupling the direct observations of the surface complex that are possible with the Advanced Photon Source with the laboratory adsorption/desorption experiments is a powerful technique to unequivocally determine both the reaction stoichiometry and the equilibrium constants for the important adsorption/desorption reactions.This proposal was submitted in response to the Environmental Geochemistry and Biogeochemistry solicitation NSF 99-9, and is being funded jointly by the Divisions of Chemistry, Earth Sciences, Ocean Sciences, and MPS Office of Multidisciplinary Activities.

Fein 9905704拟议的研究将使用大量的吸附和EXAFS实验来校准表面络合的方法来量化细菌吸附的含水金属在地下水系统。为了修复地下水中的溶解态重金属污染，我们必须了解污染物迁移的化学控制。细菌在低温水岩中普遍存在，根据不同的条件，它们可以通过吸附反应促进或阻碍污染物的迁移。 根据我们目前的知识，不可能预测在给定的一组条件下是否会发生细菌吸附效应，或者预测这种效应的大小。本研究的主要问题是：（1）金属-细菌吸附反应是否存在可逆的平衡态，或者是动力学、无机金属沉淀或细胞代谢过程阻止了平衡的实现？(2)我们从本体吸附实验中获得的反应化学计量学与我们将在阿贡国家实验室的先进光子源上利用XAFS研究对金属-细菌表面复合物进行的直接观察是否一致？（3）能否将表面络合平衡热力学方法扩展到描述细菌-矿物吸附反应？ 我们将进行大量的吸附和解吸实验，检查两个孤立的金属细菌和细菌矿物系统，严格测试金属细菌矿物吸附反应的可逆性。此外，我们将量化的吸附/解吸动力学，表面沉淀和代谢的细胞对金属吸收的重要性。 将先进光子源可能的表面复合物的直接观测与实验室吸附/解吸实验相结合是一种强有力的技术，可以明确地确定重要吸附/解吸反应的反应化学计量和平衡常数。由化学、地球科学、海洋科学和MPS多学科活动办公室共同资助。