Reduction of iron(III) minerals by natural organic matter in groundwater
Reduction of iron(III) minerals by natural organic matter in groundwater
复制标题
DOI：
10.1016/s0016-7037(99)00267-7
复制
发表时间：
1999-10-01
影响因子：
5
通讯作者：
Banwart, SA
中科院分区：
文献类型：
--
作者：
Banwart, SA
阿斯波硬岩实验室是瑞典研究乏核燃料地质处置的原型储存库，建造该实验室的入口隧道增加了有机碳从地表向地下水的迁移。这种增加的有机物质的输入已诱导与铁（III）矿物作为微生物呼吸中的终端电子受体的还原相关的有机碳的加速氧化。在现场的主要溶质离子的水化学建模表明，有机碳的表观一阶衰减常数为3.7 +/- 2.6/年。这种快速的周转并不伴随着亚铁的等量动员。铁矿物溶解度的热力学计算表明，含铁粘土矿物可能形成于水力渗透性裂缝中。这些相的氧化还原的条件电位与现场测得的氧化还原电位一致。计算出的潜力是足够低的，这样的阶段将提供减少能力，防止未来的O-2入侵到地下水，从而缓冲存储库对工程屏障的氧化腐蚀。版权所有（C）1999 Elsevier Science Ltd.
Construction of the entrance tunnel to the Aspo Hard Rock Laboratory, a prototype repository in Sweden for research into the geological disposal of spent nuclear fuel, has resulted in increased transport of organic carbon from the surface into the groundwater. This increased input of organic matter has induced accelerated oxidation of organic carbon associated with reduction of iron(III) minerals as the terminal electron acceptor in microbial respiration. Hydrochemical modeling of major solute ions at the site indicates an apparent first-order decay constant for organic carbon of 3.7 +/- 2.6/yr. This rapid turnover is not accompanied by an equivalent mobilization of ferrous iron. Thermodynamic calculation of iron mineral solubility suggests that ferrous clay minerals may form in hydraulically transmissive fractures. The conditional potentials for the oxidation-reduction of such phases coincide with measured redox potentials at the site. The calculated potential is sufficiently low so that such phases would provide reducing capacity against future intrusion of O-2 into the groundwater, thus buffering a repository against oxic corrosion of the engineered barriers. Copyright (C) 1999 Elsevier Science Ltd.