title: Photocatalytic degradation of tetracycline in aqueous solution by nanosized TiO2.
abstract: Tetracyclines are widely-used antibiotics in the world. Due to their poor absorption by human beings, or poultry and livestocks, most of them are excreted into the environment, causing growing concern about their potential impact, while photodegradation has been found to dominate their sequestration and bioavailability. Coupling with high-performance liquid chromatography-mass spectroscopy (HPLC-MS), gas chromatography-mass spectroscopy (GC-MS) and electron spin resonance (ESR), the mechanism of photocatalytic degradation of TC in aqueous solution by nanosized TiO2 (P25) under UV irradiation was investigated. The photocatalysis eliminated 95% of TC and 60% of total organic carbon (TOC) after 60 min irradiation, and NH4(+) ion was found to be one of the end-products. Bioluminescence assay showed that the toxicity of TC solution reached the maximum after 20 min irradiation and then gradually decreased. The degradation of TC included electron transfer, hydroxylation, open-ring reactions and cleavage of the central carbon. A possible photocatalytic degradation pathway of TC was proposed on the basis of the identified intermediates. Overall, the TiO2 photocatalysis was found to be a promising process for removing TC and its intermediates.
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Xiang-Dong
authors.initials: XD
authors.lastname: Zhu
authors.forename: Yu-Jun
authors.initials: YJ
authors.lastname: Wang
authors.forename: Rui-Juan
authors.initials: RJ
authors.lastname: Sun
authors.forename: Dong-Mei
authors.initials: DM
authors.lastname: Zhou
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004578:Electron Spin Resonance Spectroscopy; D004784:Environmental Monitoring; D008401:Gas Chromatography-Mass Spectrometry; D013058:Mass Spectrometry; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D010782:Photolysis; D013752:Tetracycline / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D064751:Ammonium Compounds; D000900:Anti-Bacterial Agents; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D014025:Titanium; D013752:Tetracycline
keywords: Mechanism; Photocatalysis; Tetracycline; TiO(2)