School of Water Resources and Environment and Research Center of Environmental Science and Engineering, Sino-Hungarian Joint Laboratory of Environmental Science and Health, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian District, 100083 Beijing, China.
Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, Leipzig 04318, Germany.
Environ Sci Technol. 2023 Feb 7;57(5):1930-1939. doi: 10.1021/acs.est.2c06783. Epub 2023 Jan 23.
The photosensitized transformation of organic chemicals is an important degradation mechanism in natural surface waters, aerosols, and water films on surfaces. Dissolved organic matter including humic-like substances (HS), acting as photosensitizers that participate in electron transfer reactions, can generate a variety of reactive species, such as OH radicals and excited triplet-state HS (HS*), which promote the degradation of organic compounds. We use phthalate esters, which are important contaminants found in wastewaters, landfills, soils, rivers, lakes, groundwaters, and mine tailings. We use phthalate esters as probes to study the reactivity of HS irradiated with artificial sunlight. Phthalate esters with different side-chain lengths were used as probes for elucidation of reaction mechanisms using H and C isotope fractionation. Reference experiments with the artificial photosensitizers 4,5,6,7-tetrachloro-2',4',5',7'-tetraiodofluorescein (Rose Bengal), 3-methoxy-acetophenone (3-MAP), and 4-methoxybenzaldehyde (4-MBA) yielded characteristic fractionation factors (-4 ± 1, -4 ± 2, and -4 ± 1‰ for H; 0.7 ± 0.2, 1.0 ± 0.4, and 0.8 ± 0.2‰ for C), allowing interpretation of reaction mechanisms of humic substances with phthalate esters. The correlation of H and C fractions can be used diagnostically to determine photosensitized reactions in the environment and to differentiate among biodegradation, hydrolysis, and photosensitized HS reaction.
有机化学品的光致转化是天然地表水、气溶胶和表面水膜中的重要降解机制。作为参与电子转移反应的光敏剂的溶解有机物，包括类腐殖质物质（HS），可以产生各种反应性物质，如 OH 自由基和激发的三重态 HS（HS*），从而促进有机化合物的降解。我们使用邻苯二甲酸酯，这是废水中、垃圾填埋场、土壤、河流、湖泊、地下水和矿山尾矿中发现的重要污染物。我们使用邻苯二甲酸酯作为探针，用人工阳光研究 HS 的反应性。我们使用具有不同侧链长度的邻苯二甲酸酯作为探针，通过 H 和 C 同位素分馏来阐明反应机制。使用人工光敏剂 4,5,6,7-四氯-2'，4'，5'，7'-四碘荧光素（孟加拉玫瑰红）、3-甲氧基-苯乙酮（3-MAP）和 4-甲氧基苯甲醛（4-MBA）的参考实验产生了特征分馏因子（-4 ± 1、-4 ± 2 和-4 ± 1‰用于 H；0.7 ± 0.2、1.0 ± 0.4 和 0.8 ± 0.2‰用于 C），允许解释 HS 与邻苯二甲酸酯的反应机制。H 和 C 分数的相关性可用于诊断环境中的光致反应，并区分生物降解、水解和光致 HS 反应。
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