{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T04:57:05Z","timestamp":1774414625385,"version":"3.50.1"},"reference-count":44,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2024,2,3]],"date-time":"2024-02-03T00:00:00Z","timestamp":1706918400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["41601519"],"award-info":[{"award-number":["41601519"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["202210300099Y"],"award-info":[{"award-number":["202210300099Y"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["XJDC202210300157"],"award-info":[{"award-number":["XJDC202210300157"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Jiangsu Students\u2019 Platform for innovation and entrepreneurship training program","award":["41601519"],"award-info":[{"award-number":["41601519"]}]},{"name":"Jiangsu Students\u2019 Platform for innovation and entrepreneurship training program","award":["202210300099Y"],"award-info":[{"award-number":["202210300099Y"]}]},{"name":"Jiangsu Students\u2019 Platform for innovation and entrepreneurship training program","award":["XJDC202210300157"],"award-info":[{"award-number":["XJDC202210300157"]}]},{"name":"NUIST","award":["41601519"],"award-info":[{"award-number":["41601519"]}]},{"name":"NUIST","award":["202210300099Y"],"award-info":[{"award-number":["202210300099Y"]}]},{"name":"NUIST","award":["XJDC202210300157"],"award-info":[{"award-number":["XJDC202210300157"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Toxics"],"abstract":"<jats:p>Florfenicol (FLO) is a widely used antibacterial drug, which is often detected in the environment. In this paper, the photolysis mechanism of FLO in water was investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT). The focus of the study is to elucidate the direct photolysis mechanism of FLO in the water environment and the indirect photolysis of free radicals (\u00b7OH, \u00b7NO3, and \u00b7SO4\u2212) as active species. The effect of metal ions Ca2+\/Mg2+\/Zn2+ on the indirect photolysis was also investigated. The results show that the direct photolysis of FLO involves C\u2013C\/C\u2013N\/C\u2013S bond cleavage, the C5\u2013S7 bond cleavage is most likely to occur, and the C17\u2013C18 cleavage reaction is not easy to occur during the direct photodegradation of FLO. The indirect photolysis of FLO is more likely to occur in the environment than direct photolysis. The main indirect photolysis involves OH-addition, NO3-addition, and SO4-addition on benzene ring. The order of difficulty in the indirect photolysis with \u00b7OH is C2 &gt; C3 &gt; C4 &gt; C5 &gt; C6 &gt; C1, Ca2+ can promote the indirect photolysis with \u00b7OH, and Mg2+\/Zn2+ has a dual effect on the indirect photolysis with \u00b7OH. In other words, Mg2+ and Zn2+ can inhibit or promote the indirect photolysis with \u00b7OH. These studies provide important information for theoretical research on the environmental behavior and degradation mechanism of drug molecules.<\/jats:p>","DOI":"10.3390\/toxics12020127","type":"journal-article","created":{"date-parts":[[2024,2,5]],"date-time":"2024-02-05T03:28:29Z","timestamp":1707103709000},"page":"127","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Study on the Direct and Indirect Photolysis of Antibacterial Florfenicol in Water Using DFT\/TDDFT Method and Comparison of Its Reactivity with Hydroxyl Radical under the Effect of Metal Ions"],"prefix":"10.3390","volume":"12","author":[{"given":"Yue","family":"Kang","sequence":"first","affiliation":[{"name":"Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ying","family":"Lu","sequence":"additional","affiliation":[{"name":"Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2533-6793","authenticated-orcid":false,"given":"Se","family":"Wang","sequence":"additional","affiliation":[{"name":"Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,2,3]]},"reference":[{"key":"ref_1","first-page":"600","article-title":"An evaluation of the relative efficacy of tulathromycin for the treatment of undifferentiated fever in feedlot calves in Nebraska","volume":"48","author":"Schunicht","year":"2007","journal-title":"Can. 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