The effect of iron(III)-sulfide interactions on electron transfer processes in anoxic aquifers

缺氧含水层中铁(III)-硫化物相互作用对电子传递过程的影响

• 批准号: 5454013
• 负责人: Professor Dr. Stefan Peiffer
• 金额: --
• 依托单位: Lehrstuhl für Hydrologie
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5454013?language=en
• 关键词: effect; iron; III; sulfide; interactions

Strong evidence exists that the oxidation of H2S by ferric (oxyhydr)oxides occurs also in ground water systems and may exert a major role for the sulphur and iron cycle and in particular for the electron and carbon flow in aquifers. To date, no systematic study has been performed that allows to quantitatively assess its significance in such systems. This project aims to fill this gap of knowledge. The extent of the reaction depends on mineral reactivity, which we hypothesize can be expressed in terms of a generalized kinetic model for the full pH range of environmental relvance. This model accounts for the adsorption of H2S at lower pH values and of HS- at circumneutral pH to the neutral ferric (oxyhydr)oxide surface to form the reactive species FeSH. Variations in reactivity may be caused by intrinsic factors such as surface acidity of the iron mineral and solution composition, such as ionic strength and competition with other ions. The overall goals of this project therefore are to demonstrate the validity of this approach in order to quantify the kinetics for abiotic anaerobic H2S oxidation by ferric (oxyhydr)oxides, and to elucidate the role of this process as a precursor reaction for further microbial transformation of sulphur species in the aquifer.

有强有力的证据表明，在地下水系统中也发生了铁(氧)氧化物对硫化氢的氧化作用，这可能对硫和铁的循环，特别是对含水层中的电子和碳流起主要作用。到目前为止，还没有进行系统的研究来定量评估其在这类系统中的意义。该项目旨在填补这一知识空白。反应的程度取决于矿物的反应性，我们假设这可以用环境相对酸碱度范围的广义动力学模型来表示。该模型解释了较低pH值下的H_2S和近中性pH下HS-在中性三氧化二铁表面的吸附，形成了活性物种FeSH。反应活性的变化可能是由内在因素引起的，如铁矿物的表面酸性和溶液组成，如离子强度和与其他离子的竞争。因此，该项目的总体目标是证明这一方法的有效性，以便量化铁(氧)氧化物氧化非生物厌氧硫化氢的动力学，并阐明这一过程作为进一步微生物转化含水层中硫物种的前体反应的作用。