Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China; Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, 430070, China.
Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, China; Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan, 430070, China.
Chemosphere. 2024 Sep;363:142913. doi: 10.1016/j.chemosphere.2024.142913. Epub 2024 Jul 23.
The abiotic oxidation of As(III) is simultaneously mediated by the oxidation of Fe(II) in microaerobic environment, but the role of Fe minerals in the Fe(II)-mediated As(III) oxidation have been neglected. This work mimicked the microaerobic environment and examined the mechanisms of Fe(II) mediated the As(III) oxidation in the presence of Fe minerals using a variety of iron minerals (lepidocrocite, goethite, etc.). The results indicated the Fe(II) and As(III) oxidation rate were improved with Fe minerals, while As(III) oxidation efficiency increased by 1.3-1.8 times in comparison to that without minerals. Fe(II) mediated the As(III) oxidation happened on Fe minerals surface in the presence of Fe minerals. The As(III) oxidation efficiency increased with increasing Fe mineral concentrations (from 0.5 to 2 g L) but decreased with increasing pH values. Reactive oxygen species (ROS) that play a crucial role in As(III) oxidation were Fe(IV) and ·O, accounting for 42.7%-47.9% and 24.1%-29.8%, respectively. The Fe minerals facilitated the oxidation of As(III) by ROS and stimulated the release of ROS through the adsorbed-Fe(II) oxidation, both of which favored As(III) oxidation. This work highlighted the potential mechanisms of Fe minerals in promoting Fe(II) mediated the As(III) oxidation in microaerobic environment, especially in terms of As(III) oxidation efficiency, shedding a valuable insight on optimization of arsenic contaminated wastewater treatment processes.
在微氧环境中，砷（III）的非生物氧化同时由 Fe(II)的氧化介导，但在 Fe(II)介导的砷（III）氧化过程中，Fe 矿物的作用被忽视了。本研究模拟了微氧环境，使用各种铁矿物（针铁矿、水铁矿等）考察了 Fe 矿物存在时 Fe(II)介导的砷（III）氧化机制。结果表明，Fe 矿物的存在提高了 Fe(II)和砷（III）的氧化速率，而与无矿物相比，砷（III）的氧化效率提高了 1.3-1.8 倍。在 Fe 矿物存在的情况下，Fe(II)介导的砷（III）氧化发生在 Fe 矿物表面。砷（III）氧化效率随 Fe 矿物浓度（从 0.5 到 2 g/L）的增加而增加，但随 pH 值的增加而降低。在砷（III）氧化中起关键作用的活性氧物种（ROS）是 Fe(IV)和·O，分别占 42.7%-47.9%和 24.1%-29.8%。Fe 矿物通过 ROS 促进了砷（III）的氧化，并通过吸附-Fe(II)氧化刺激了 ROS 的释放，这两者都有利于砷（III）的氧化。这项研究强调了 Fe 矿物在促进微氧环境中 Fe(II)介导的砷（III）氧化方面的潜在机制，特别是在砷（III）氧化效率方面，为优化含砷废水处理工艺提供了有价值的见解。
