Theoretical investigation on the degradation of sulfadiazine in water environments: Oxidation of •OH, SO4•−and CO3•−and reactivity of (TiO2)nclusters (n = 1–6)

Autor: Xu, Mengmeng, Yan, Suding, Liu, Xiufan, Sun, Simei, Khan, Zia UI Haq, Wu, Wenzhong, Sun, Jingyu
Zdroj: Journal of Environmental Chemical Engineering; June 2023, Vol. 11 Issue: 3
Abstrakt: This study reported the degradation of micro pollutants through reactive radicals like •OH, SO4•−and CO3•−. Sulfadiazine (SDZ) is widely used antibiotic and emerging water pollutant. The synergistic degradation of sulfadiazine by •OH, SO4•−and CO3•−was investigated through quantum chemistry methods. The degradation of SDZ by •OH radicals was dependent on radical adduct formation (RAF) reactions while degradation of SDZ by SO4•−radical was caused by RAF, hydrogen atom transfer (HAT) and also single electron transfer (SET). The degradation of SDZ by CO3•−radical mainly caused by RAF and HAT. The degradation rate constants of SDZ initiated through •OH, SO4•−and CO3•−radicals were calculated separately: kSDZ-SO4•−(5.29 × 1010M−1s−1) > kSDZ-•OH(1.38 × 1010M−1s−1) > kSDZ-CO3•−(1.28 × 108M−1s−1).The degradation mechanism of SDZ by (TiO2)n(n = 1–6) cluster was investigated. The conformation between benzene ring and heterocyclic ring of SDZ has a lower adsorption energy and the (TiO2)ncluster (n = 5) is the most stable adsorption conformation with SDZ. The toxicity assessment showed that most of the degradation products were less toxic and eco-friendly. However, O-P1, P4 and P9 exhibited more severe aquatic toxicity.
Databáze: Supplemental Index
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