Photochemical formation of carbonate radical and its reaction with dissolved organic matters
Photochemical formation of carbonate radical and its reaction with dissolved organic matters
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碳酸酯自由基的光化学形成及其与溶解有机物的反应
DOI：
10.1016/j.watres.2019.06.002
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发表时间：
2019
期刊：
影响因子：
12.8
通讯作者：
Song Weihua
中科院分区：
文献类型：
--
作者：
Yan Shuwen;Liu Yingjie;Lian Lushi;Li Rui;Ma Jianzhong;Zhou Huaxi;Song Weihua
碳酸根（CO 3·−）是一种强氧化性自由基，通过HCO 3−/CO 3 2−与羟基自由基（HO·）或溶解有机物的三重态（3 DOM·）反应产生。CO 3·−与各种DOM分离物的双分子反应速率常数（kCO 3·−，D O M）为15-239（mg C/L）− 1 s− 1，并与DOM的整体性质（如酚类含量、比紫外吸收（苏瓦）、E2/E3值和荧光指数（FI））相关。光谱E2/E3值与kCO 3·−、DOM有很强的相关性（R2 = 0.93），并建立了经验方程。我们的研究结果还表明，CO 3·−参与溶解有机物（DOM）的光漂白，特别是与电子供体部分反应，导致在紫外-可见吸收的长波长下的衰减速率更快。此外，还建立了计算DOM光漂白过程中CO 3·−稳态浓度的模型.这些结果使我们能够估计DOM与CO 3·−的反应性，并评估CO 3·−在阳光照射的地表水中的作用。它还可以更好地评估高级氧化工艺应用过程中CO 3·−的浓度和利用率。
The carbonate radical (CO 3•−) is a strong oxidative radical that is generated via the reactions of HCO 3−/CO 3 2− with hydroxyl radical (HO•) or triplet states of dissolved organic matter (3 DOM∗) in sunlit surface water. The bimolecular reaction rate constants of CO 3•− with various DOM isolates (k CO 3•−, D O M) were calculated as 15–239 (mg of C/L)− 1 s− 1 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 2= 0.93) with k CO 3•−, D O M, and an empirical equation was established. Our results also demonstrate that CO 3•− 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 3•− during DOM photobleaching. These results allow us to estimate the reactivity of DOM with CO 3•− and to evaluate the role of CO 3•− in sunlit surface water. It will also allow a better assessment of the concentration and utilization of CO 3•− during the application of advanced oxidation processes.