Bacterial Reduction of Iron in Clay Minerals

9523902 Stucki这是一项关于粘土矿物中结构铁（Fe）的细菌还原的跨学科研究。 细菌和铝硅酸盐粘土矿物是土壤和水生沉积物中含量最丰富、化学活性最高的两种成分。 两者都被独立地确定为决定退化速度的主要因素。在环境中，有毒金属和有机污染物的积累和运输;但对它们的相互作用机制，这如何影响它们的行为以及利用细菌-粘土反应在自然环境系统中实现最佳性能的潜力知之甚少。 铁在粘土晶体结构中的氧化还原（静电荷的变化）是一种潜在的具有非常重要意义的相互作用，但人们对它的关注很少，实验室中使用无机还原剂的研究表明，铁氧化态的变化深刻地改变了粘土的化学和物理行为。 当粘土和细菌相互作用时，环境中会发生同样的事情吗？ 如果是，程度如何、速度如何？ 在粘土的氧化还原过程中，细菌是否改变了其他化合物，如金属和有机酸？ 最佳条件是什么？ 因此，本研究的总体目标有两个方面：（1）确定土壤和沉积物中细菌减少的最佳条件;（2）确定细菌减少对粘土性质以及粘土-有机物和粘土-金属相互作用的影响。

9523902 Stucki This is an interdisciplinary study of the bacterial reduction of structural iron (Fe) in clay minerals. Bacteria and alumino-silicate clay minerals are two of the most abundant and most chemically active constituents of soils and aquatic sediments. Both have been independently identified as major players in determining the rates of degradation., accumulation, and transport of toxic metals and organic pollutants in the environment; but little is known about their interaction mechanism(s), how this affects their behavior, and the potential for exploiting bacterial-clay reactions to achieve optimal performance in natural environmental systems. Oxidation and reduction (change of electrostatic charge) of Fe in the clay crystal structure is one type of interaction that potentially is of very great significance, but little attention has been given to it. Studies using inorganic reducing agents in the laboratory revealed that changes in Fe oxidation state profoundly alter the chemical and physical behavior of the clay. Does the same thing happen in the environment when clays and bacteria interact? If so, to what extent and at what rate? Does the bacteria alter other compounds, such as metals and organic acids, during the oxidation-reduction process with clays? What are the optimum conditions? The overall goals of this study will, therefore, be two-fold: (1) to identify the optimum conditions under which bacteria reduction will occur in soils and sediments; and (2) to determine the effect of bacterial reduction on clay properties and on clay-organic and clay-metal interactions.