Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, 430074, Wuhan, People's Republic of China.
School of Chemistry and Chemical Engineering, Shihezi University, Xinjiang, 832003, Shihezi, People's Republic of China.
Environ Sci Pollut Res Int. 2023 Apr;30(16):46657-46668. doi: 10.1007/s11356-023-25326-9. Epub 2023 Feb 1.
Substitution of aluminum under natural environmental conditions has been proven to inhibit the transformation of weakly crystalline iron (oxyhydr)-oxides towards well crystalline iron oxides, thereby enhancing their long-term stability. However, exploration on the role of aluminum substitution in bacteria-mediated iron oxides transformation is relatively lacking, especially in the anaerobic underground condition where iron (oxyhydr)-oxides are easy to reduced. In this study, we selected four different levels of substitution aluminum prevalent in iron oxides under natural conditions, which are 0 mol%, 10 mol%, 20 mol%, and 30 mol% (mol Al/mol (Al + Fe)) respectively. With the presence of Shewanella oneidensis MR-1, we conducted a 15-day anaerobic microcosm experiment in simulated groundwater conditions. The experiment data suggested that aluminum substitution result in a decrease in bio-reduction rate constants of ferrihydrite from 0.24 in 0 mol% Al to 0.17 in 30 mol% Al. Besides, when containing substituted aluminum, secondary minerals produced by biological reduction of ferrihydrite changed from magnetite to akaganeite. These results were attributed to the surface coverage of Al during the reduction process, which affects the contact between S. oneidensis MR-1 and the unexposed Fe(III), thus inhibiting the further reduction of ferrihydrite. Since iron (oxyhydr)-oxides exhibit a strong affinity on multiple kinds of pollutants, results in this study may contribute to predicting the migration and preservation of contaminants in groundwater systems.
在自然环境条件下，铝的替代已被证明能抑制弱结晶铁（氢）氧化物向结晶良好的铁氧化物的转化，从而增强其长期稳定性。然而，对于铝替代在细菌介导的氧化铁转化中的作用的探索相对较少，特别是在容易还原的地下厌氧条件下。在本研究中，我们选择了在天然条件下普遍存在于氧化铁中的四种不同程度的替代铝，分别为 0 mol%、10 mol%、20 mol%和 30 mol%（mol Al/mol（Al + Fe））。在希瓦氏菌（Shewanella oneidensis MR-1）的存在下，我们在模拟地下水条件下进行了为期 15 天的厌氧微宇宙实验。实验数据表明，铝的替代导致一水硬铝石的生物还原率常数从 0.24（0 mol% Al）降低至 0.17（30 mol% Al）。此外，当含有替代铝时，由一水硬铝石生物还原产生的次生矿物从磁铁矿变为纤铁矿。这些结果归因于还原过程中 Al 的表面覆盖，这影响了希瓦氏菌（Shewanella oneidensis MR-1）与未暴露的 Fe(III)之间的接触，从而抑制了一水硬铝石的进一步还原。由于铁（氢）氧化物对多种污染物具有很强的亲和力，因此本研究的结果可能有助于预测地下水中污染物的迁移和保存。
