Evaluation of antibiotic oxytetracycline removal in water using a gas phase dielectric barrier discharge plasma. (15th November 2018)

• Record Type: Journal Article
• Authors: Tang, Shoufeng; Yuan, Deling; Rao, Yandi; Zhang, Jingyi; Qu, Ying; Gu, Jianmin
• Is Part Of: Journal of environmental management. Volume 226(2018)
• Page Start: 22
• Page End: 29
• Publication Date: 2018-11-15
• Subjects: Gas phase dielectric barrier discharge plasma -- Antibiotics -- Oxytetracycline -- Degradation mechanism; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2018.08.022
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Degradation of oxytetracycline (OTC), a primary member of antibiotics in water, was performed by a gas phase dielectric barrier discharge (GPDBD) plasma reactor. The influences of operation conditions including applied voltages, air bubbling rates, initial OTC concentrations and initial pH values on OTC abatement were investigated respectively. The results showed that the decontamination process can be fitted by first order kinetics, and the removal ratio and rate were affected obviously by those parameters. After 20 min of discharge treatment, approximately 93.4% of OTC was removed under the experimental conditions: applied voltage of 7.5 kV, air flow rate of 1.0 L/min, initial OTC concentration of 100 mg/L, and initial pH of 5.0. In addition, TOC and COD removal efficiency reached 43.0% and 73.7% at the original pH 9.3, respectively. Furthermore, the amounts of hydrogen peroxide and ozone in aqueous were quantitatively measured to evaluate their roles during antibiotic removal, and the main function of hydroxyl radicals was demonstrated by the radicals scavenger test. At last, the analyses of UV–Vis spectra and HPLC-MS were employed to study the OTC elimination mechanism, and the possible decomposition pathway was proposed based on the speculated intermediates. Graphical abstract: This Figure illustrates the main process of oxytetracycline (OTC) removal by a gas phase dielectric barrier discharge (GPDBD) plasma system. The production of OH, H2 O2, and O3 by discharge plasma is the critical step during OTC degradation process, and the OH radicals play a dominative role in organic compounds removal. HPLC-MS is employed to study the mechanism of OTC degradation. The results show that OTC would firstly be oxidized to some big molecule intermediates, and gradually be decomposed to a few of small molecule compounds and organic acids, even mineralized to CO2, H2 O, NH 4 + and NO 3 − ultimately. Image 1 Highlights: Oxytetracycline was degraded effectively by a gas phase DBD system. H2 O2 and O3 generated during discharge process were determined quantitatively. Radicals scavenger addition proved that OH played a vital role in removal process. Oxytetracycline degradation mechanism was proposed based on HPLC-MS analysis.