In this study, a novel photoelectro-Fenton (PEF) process using microwave discharge electrodeless lamp (MDEL) as a UV irradiation source was developed for the removal of antibiotic ciprofloxacin (CIP) in water. Comparative degradation of 200mgL-1 CIP was studied by direct MDEL photolysis, anodic oxidation (AO), AO in presence of electrogenerated H2O2 (AO-H2O2), AO-H2O2 under MDEL irradiation (MDEL-AO-H2O2), electro-Fenton (EF) and MDEL-PEF processes. Higher oxidation power was found in the sequence: MDEL photolysis < AO < AO-H2O2< MDEL-AO-H2O2< EF < MDEL-PEF. Effects of current density, pH, initial Fe2+ concentration and initial CIP concentration on TOC removal in MDEL-PEF process were examined, and the optimal conditions were ascertained. The releases of three inorganic ions (F-, NH4+ and NO3-) and two carboxylic acids (oxalic and formic acids) were qualified. Seven aromatic intermediates mainly generated from hydroxylation, dealkylation and defluorination of CIP were detected by UPLC-QTOF-MS/MS technology. Therefore, plausible degradation sequences for CIP degradation in MDEL-PEF process including all detected products were proposed.
Keywords: Activated carbon fiber; Ciprofloxacin; Degradation mechanism; Microwave discharge electrodeless lamp; Photoelectro-Fenton.
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