Persistent and mobile trace organic contaminants (TrOCs) in urban stormwater are difficult to remove through sedimentation- or sorption-based treatment and pose a risk to aquatic ecosystems and drinking water supplies. We demonstrate that the chemical oxidant peroxydisulfate (PDS) can be activated by shrimp shell biochar at pH 7 to form reactive species that selectively react with widespread stormwater contaminants. Of 11 TrOCs tested, oxidative transformation was observed for 1,3-diphenylguanidine, 2-hydroxybenzothiazole, 1H-benzotriazole, 5-methyl-benzotriazole, and diuron during water treatment with biochar and PDS. Laboratory batch experiments conducted with street runoff and a synthetic water showed that the water matrix, containing up to 7.5 mg/L dissolved organic carbon and 100 mM chloride, had a minor effect on the formation of reactive species and contaminant transformation. Using a set of scavengers and probe compounds, we provide evidence for singlet oxygen (¹O₂) as the predominant reactive species in the biochar/PDS system, which is in agreement with the selectivity of the process to oxidize electron-rich organic contaminants. The results of our study inform new strategies for stormwater treatment using heterogeneous oxidation processes for the abatement of persistent and mobile organic contaminants.

中文翻译：

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通过生物炭活化过硫酸盐，去除城市雨水中的痕量有机污染物

城市雨水中的持久性和移动性痕量有机污染物 （TrOC） 难以通过沉淀或吸附处理去除，并对水生生态系统和饮用水供应构成风险。我们证明化学氧化剂过氧化物二硫酸盐 （PDS） 可以在 pH 值为 7 时被虾壳生物炭激活，形成反应性物质，选择性地与广泛的雨水污染物反应。在测试的 11 种 TrOC 中，在用生物炭和 PDS 处理水过程中观察到 1,3-二苯基胍、2-羟基苯并噻唑、1H-苯并三唑、5-甲基苯并三唑和敌草隆的氧化转化。用街道径流和合成水进行的实验室批量实验表明，含有高达 7.5 mg/L 溶解有机碳和 100 mM 氯化物的水基质对活性物质的形成和污染物转化的影响很小。使用一组清除剂和探针化合物，我们提供了单线态氧 （¹O₂） 作为生物炭/PDS 系统中主要反应性物质的证据，这与氧化富含电子的有机污染物的过程的选择性一致。我们的研究结果为使用非均相氧化过程的雨水处理新策略提供了信息，以减少持久性和移动性有机污染物。