Journal
CHEMOSPHERE
Volume 274, Issue -, Pages -Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.chemosphere.2021.129713
Keywords
Electron beam irradiation (EBI); Sulfonamides; Degradation products; DFT calculation; Fukui function; Ecotoxicity
Categories
Funding
- National Natural Science Foundation of China [11675098, 11975147, 11875185, 11775138]
- Program for Changjiang Scholars and Innovative Research Team in University [IRT_17R71]
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This study investigated the degradation process and mechanism of sulfonamide antibiotics by electron-beam irradiation, showing that the removal efficiency was achieved with further mineralization. Environmental factors such as pH and O2 atmosphere were found to enhance the removal of sulfonamides, with hydroxyl radicals playing a dominant role in the degradation process. Toxicity experiments further indicated a significant decrease in toxicity of sulfonamide antibiotics after degradation.
Due to their widespread use and harmful effects on aquatic environment, sulfonamide antibiotics (SAs) have become an emerging pollutant of great concern around the world. In this study, we investigated the degradation process and mechanism of sulfamerazine (SMR), sulfadiazine (SDZ), and sulfapyridine (SPD) by electron-beam irradiation (EBI). The results showed that the three SAs were well suited to the pseudo-first-order reaction kinetics, and they could be almost completely removed with high efficiency (5 kGy). Among the environmental factors, pH (3.0) and O-2 atmosphere can further enhance the removal of the sulfonamides (SAs), while NO2- has the most pronounced degrading inhibitory effects among the many ions, these results illustrate that hydroxyl radicals play a dominant role. Compared with SMR and SDZ, the degree of mineralization of lower molecular weight SPD is obvious (45%). LC-MS and DFT calculations indicate that the concentrations of degradation products of the three SAs show a tendency to increase and then decrease, demonstrating that EBI can achieve efficient removal and further mineralization of SAs. Meanwhile, the results of the common product 4-Aminophenol produced during the degradation process further indicate that HO center dot is the predominant reactive oxygen species (ROS). In addition, acute toxicity experiments with luminescent bacteria and predictions of ECOSAR procedures proved the toxic effects greatly decreased after the degradation. This study provides new ideas for achieving efficient and profound removal of emerging pollutants from the aquatic environment. (C) 2021 Elsevier Ltd. All rights reserved.
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