title: Photocatalytic degradation of ofloxacin and evaluation of the residual antimicrobial activity.
abstract: Ofloxacin is an antimicrobial agent frequently found in significant concentrations in wastewater and surface water. Its continuous introduction into the environment is a potential risk to non-target organisms or to human health. In this study, ofloxacin degradation by UV/TiO2 and UV/TiO2/H2O2, antimicrobial activity (E. coli) of samples subjected to these processes, and by-products formed were evaluated. For UV/TiO2, the degradation efficiency was 89.3% in 60 min of reaction when 128 mg L(-1) TiO2 were used. The addition of 1.68 mmol L(-1) hydrogen peroxide increased degradation to 97.8%. For UV/TiO2, increasing the catalyst concentration from 4 to 128 mg L(-1) led to an increase in degradation efficiency. For both processes, the antimicrobial activity was considerably reduced throughout the reaction time. The structures of two by-products are presented: m/z 291 (9-fluoro-3-methyl-10-(methyleneamino)-7-oxo-2,3-dihydro-7H-[1,4]oxazino[2,3,4-ij]quinoline-6-carboxylic acid) and m/z 157 ((Z)-2-formyl-3-((2-oxoethyl)imino)propanoic acid).
authors.affiliation: UNICAMP, FEC/DSA, Campinas, São Paulo, Brazil. jorober@fec.unicamp.br.
authors.forename: M S
authors.initials: MS
authors.lastname: Peres
authors.forename: M G
authors.initials: MG
authors.lastname: Maniero
authors.forename: J R
authors.initials: JR
authors.lastname: Guimarães
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D002384:Catalysis; D048168:Escherichia coli K12 / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D015242:Ofloxacin / Q000737:chemistry* / Q000494:pharmacology*; D010782:Photolysis; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D014867:Water; C009495:titanium dioxide; D015242:Ofloxacin; D006861:Hydrogen Peroxide; D014025:Titanium