Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China.
Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, PR China.
Water Res. 2019 Sep 15;161:288-296. doi: 10.1016/j.watres.2019.06.002. Epub 2019 Jun 5.
The carbonate radical (CO) is a strong oxidative radical that is generated via the reactions of HCO/CO with hydroxyl radical (HO) or triplet states of dissolved organic matter (DOM) in sunlit surface water. The bimolecular reaction rate constants of CO with various DOM isolates ( [Formula: see text] ) were calculated as 15-239 (mg of C/L) s and were correlate to the bulk DOM properties, such as the content of phenolic moieties, the specific UV absorbance (SUVA), the E2/E3 value, and the fluorescence index (FI). The spectroscopic E2/E3 values was found to strongly correlated (R = 0.93) with [Formula: see text] , and an empirical equation was established. Our results also demonstrate that CO is involved in the photobleaching of dissolved organic matter (DOM) and in particular reacts with electron-donor moieties, leading to faster decay rates at long wavelengths of UV-vis absorption. Furthermore, a model was developed to calculate the steady-state concentrations of CO during DOM photobleaching. These results allow us to estimate the reactivity of DOM with CO and to evaluate the role of CO in sunlit surface water. It will also allow a better assessment of the concentration and utilization of CO during the application of advanced oxidation processes.
碳酸根自由基（CO）是一种强氧化性自由基，通过 HCO/CO 与羟基自由基（HO）或溶解态有机物（DOM）三重态在阳光照射的地表水中共反应生成。CO 与各种 DOM 分离物（[公式：见正文]）的双分子反应速率常数（[Formula: see text]）计算为 15-239（mg 的 C/L）s，并与 DOM 的整体性质相关，如酚类部分的含量、特定紫外吸光度（SUVA）、E2/E3 值和荧光指数（FI）。发现分光 E2/E3 值与[公式：见正文]强烈相关（R = 0.93），并建立了一个经验公式。我们的结果还表明，CO 参与了溶解态有机物（DOM）的光漂白，特别是与电子供体部分反应，导致在较长的紫外可见吸收波长处更快的衰减速率。此外，还建立了一个模型来计算 DOM 光漂白过程中 CO 的稳态浓度。这些结果使我们能够估计 DOM 与 CO 的反应性，并评估 CO 在阳光照射的地表水环境中的作用。这也将有助于更好地评估高级氧化过程应用过程中 CO 的浓度和利用率。
