Shanghai Institute of Pollution Control and Ecological Security , Shanghai 200092 , P.R. China.
Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, State Ministry of Education , Chongqing University , Chongqing 400045 , P.R. China.
Environ Sci Technol. 2019 Sep 3;53(17):10320-10328. doi: 10.1021/acs.est.9b01783. Epub 2019 Aug 15.
In this work, the kinetics and mechanisms of the reductive removal of BrO by sulfite in air atmosphere were determined. BrO could be effectively reduced by sulfite at pH 3.0-6.0, and the reduction rate of BrO increased with decreasing pH. The coexisting organic contaminants with electron-rich moieties could be degraded, accompanied with BrO reduction by sulfite. The reaction stoichiometries of -Δ[sulfite]/Δ[bromate] were determined to be 3.33 and 15.63 in the absence and presence of O, respectively. Many lines of evidence verified that the main reactions in the BrO/sulfite system in air atmosphere included the reduction of BrO to HOBr and its further reduction to Br, as well as the oxidation of HSO by BrO to form SO and its further transformation to SO. Moreover, SO rather than HOBr was determined to be the major active oxidant in the BrO/sulfite system. SO played a key role in the over-stoichiometric sulfite consumption because of its rapid reaction with dissolved oxygen. However, the formed SO was further oxidized by BrO in the N atmosphere. BrO reduction by sulfite is an alternative for controlling BrO in water treatment because it was effective in real water at pH ≤ 6.0.
在这项工作中，确定了亚硫酸盐在空气气氛中还原去除 BrO 的动力学和机制。在 pH 值为 3.0-6.0 时，BrO 可被亚硫酸盐有效还原，且 BrO 的还原速率随 pH 值降低而增加。具有富电子部分的共存有机污染物可被降解，同时亚硫酸盐还原 BrO。在不存在和存在 O 的情况下，-Δ[sulfite]/Δ[bromate]的反应化学计量比分别确定为 3.33 和 15.63。许多证据表明，空气气氛中 BrO/亚硫酸盐体系中的主要反应包括 BrO 还原为 HOBr 及其进一步还原为 Br，以及 BrO 将 HSO 氧化形成 SO 和其进一步转化为 SO。此外，确定 SO 而不是 HOBr 是 BrO/亚硫酸盐体系中的主要活性氧化剂。由于其与溶解氧的快速反应，SO 在过化学计量的亚硫酸盐消耗中起关键作用。然而，在 N 气氛中，形成的 SO 被 BrO 进一步氧化。亚硫酸盐还原 BrO 是水处理中控制 BrO 的一种替代方法，因为它在 pH 值≤6.0 的实际水中有效。
