Department of Environmental Science, Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, 430079, PR China.
J Hazard Mater. 2013 Sep 15;260:255-62. doi: 10.1016/j.jhazmat.2013.05.028. Epub 2013 May 22.
Photooxidation of arsenite(As(III)) in a suspension of natural montmorillonite under the irradiation of metal halide lamp (λ ≥ 313 nm)has been investigated. The results showed that the natural montmorillonite induced the photooxidation of As(III) by generating hydroxyl radicals (HO·) and hydroperoxyl/superoxide radicals (HO₂·/O₂⁻·). HO· which was responsible for the As(III) photooxidation. Approximately 38% of HO· was generated by the photolysis of ferric ions, and the formation of the remaining 62% was strongly dependent on the HO₂·/O₂⁻·. The presence of free ironions (Fe(2+) and Fe(3+)), made significant contributions to the photogeneration of these reactive oxygen species (ROS). The photooxidation of As(III) in natural montmorillonite suspensions was greatly influenced by the pH values. The photooxidation of As(III) by natural montmorillonite followed the Langmuir-Hinshelwood equation. In addition, the photooxidation of As(III) could be enhanced by the addition of humic acid. This work demonstrates that photooxidation may be an important environmental process for the oxidation of As(III) and may be a way to remove As(III) from acidic surface water containing iron-bearing clay minerals.
在金属卤灯光（λ≥313nm）照射下，研究了天然蒙脱石悬浮液中砷酸根（As(III)）的光氧化作用。结果表明，天然蒙脱石通过产生羟基自由基（HO·）和过氢氧自由基/超氧自由基（HO₂·/O₂⁻·），诱导了 As(III)的光氧化。HO·是 As(III)光氧化的主要原因。约 38%的 HO·是由铁离子的光解产生的，其余 62%的 HO·的形成强烈依赖于 HO₂·/O₂⁻·。游离铁离子（Fe(2+)和 Fe(3+)）的存在对这些活性氧物质（ROS）的光生成有重要贡献。天然蒙脱石悬浮液中 As(III)的光氧化受 pH 值的影响很大。天然蒙脱石对 As(III)的光氧化符合 Langmuir-Hinshelwood 方程。此外，腐殖酸的加入可以增强 As(III)的光氧化。本研究表明，光氧化可能是 As(III)氧化的一个重要环境过程，也可能是一种从含有含铁粘土矿物的酸性地表水去除 As(III)的方法。
