The Degradation of Aqueous Oxytetracycline by an O3/CaO2 System in the Presence of : Performance, Mechanism, Degradation Pathways, and Toxicity Evaluation

• Published in: Molecules (Basel, Switzerland) Switzerland), 2024-01, Vol.29 (3), p.659
• Main Authors: Zedian Li, Liangrui Xiang, Shijia Pan, Dahai Zhu, Shen Li, He Guo
• Format: Article
• Language: English
• Subjects: <named-content content-type="inline-formula"> <mml:math id="mm140006"> HCO 3 − </mml:math> </named-content>; CaO2; degradation; oxytetracycline
• ISSN: 1420-3049
• DOI: 10.3390/molecules29030659

This research constructed a novel O3/CaO2/ HCO3− system to degrade antibiotic oxytetracycline (OTC) in water. The results indicated that CaO2 and HCO3− addition could promote OTC degradation in an O3 system. There is an optimal dosage of CaO2 (0.05 g/L) and HCO3− (2.25 mmol/L) that promotes OTC degradation. After 30 min of treatment, approximately 91.5% of the OTC molecules were eliminated in the O3/CaO2/ HCO3− system. A higher O3 concentration, alkaline condition, and lower OTC concentration were conducive to OTC decomposition. Active substances including ·OH, 1O2, · O 2− , and · HCO3− play certain roles in OTC degradation. The production of ·OH followed the order: O3/CaO2/ HCO3− > O3/CaO2 > O3. Compared to the sole O3 system, TOC and COD were easier to remove in the O3/CaO2/ HCO3− system. Based on DFT and LC-MS, active species dominant in the degradation pathways of OTC were proposed. Then, an evaluation of the toxic changes in intermediates during OTC degradation was carried out. The feasibility of O3/CaO2/ HCO3− for the treatment of other substances, such as bisphenol A, tetracycline, and actual wastewater, was investigated. Finally, the energy efficiency of the O3/CaO2/ HCO3− system was calculated and compared with other mainstream processes of OTC degradation. The O3/CaO2/ HCO3− system may be considered as an efficient and economical approach for antibiotic destruction.