Jia Yulu, Zhang Chengyang, Zheng Hongcen, Zhang Guoyang, Zhang Shujuan
State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing, 210023, China.
State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing, 210023, China.
Chemosphere. 2024 Mar;351:141195. doi: 10.1016/j.chemosphere.2024.141195. Epub 2024 Jan 17.
Indirect photodegradation is an important pathway for the reduction of steroid estrogens in sunlit surface waters. Nevertheless, the kinetics and mechanisms governing the interaction between coexisting carbonyl compounds and estrogens under visible light (Vis) remain unexplored. This study systematically investigates the Vis-induced photodegradation of 17β-estradiol (E2) in the presence of five specific carbonyl compounds-biacetyl (BD), acetone, glyoxal, pyruvic acid, and benzoquinone. The results demonstrate that, among these compounds, only BD significantly enhanced the photodegradation of E2 under Vis irradiation (λ > 400 nm). The pseudo-first order photodegradation rate constants (k) of E2 in the Vis/BD system were 0.025 min and 0.076 min in ultrapure water and river water, respectively. The enhancing effect of BD was found to be pH-dependent, increasing the pH from 3.0 to 11.0 resulted in a 76% reduction in the k value of E2 in the Vis/BD system. Furthermore, the presence of humic acid, NO, or HCO led to an increase of more than 35% in the k value of E2, while NO exerted a pronounced inhibitory effect, resulting in a 92% decrease. Peroxyacetyl and peroxymethyl radicals, derived from BD in a yield ratio of 9, played a crucial role in the degradation of E2. These peroxyl radicals primarily targeted electron-rich hydroxyl sites of E2, initiating hydroxylation and ring-opening reactions that culminated in the formation of acidic byproducts. Notably, toxicity evaluation indicates that these hydroxylated and acidic products exhibited lower toxicity than the parent compound E2. This study highlights the important role of peroxyl radicals in estrogen degradation within aquatic environment, and also helps to design efficient visible light-responsive photo-activators for the treatment of estrogen-contaminated waters.
间接光降解是阳光照射的地表水中甾体雌激素减少的重要途径。然而，可见光（Vis）下共存羰基化合物与雌激素之间相互作用的动力学和机制仍未得到探索。本研究系统地研究了在五种特定羰基化合物（双乙酰（BD）、丙酮、乙二醛、丙酮酸和苯醌）存在下，可见光诱导的17β-雌二醇（E2）的光降解。结果表明，在这些化合物中，只有BD在可见光照射（λ>400nm）下显著增强了E2的光降解。在超纯水和河水中，E2在Vis/BD体系中的准一级光降解速率常数（k）分别为0.025min⁻¹和0.076min⁻¹。发现BD的增强作用与pH有关，将pH从3.0提高到11.0导致Vis/BD体系中E2的k值降低76%。此外，腐殖酸、NO₃⁻或HCO₃⁻的存在导致E2的k值增加超过35%，而NO₂⁻则产生显著的抑制作用，导致降低92%。由BD以9:1的产率比产生的过氧乙酰基和过氧甲基自由基在E2的降解中起关键作用。这些过氧自由基主要靶向E2的富电子羟基位点，引发羟基化和开环反应，最终形成酸性副产物。值得注意的是，毒性评估表明，这些羟基化和酸性产物的毒性低于母体化合物E2。本研究突出了过氧自由基在水生环境中雌激素降解中的重要作用，也有助于设计用于处理受雌激素污染水体的高效可见光响应光活化剂。
