Efficient mineralization of antibiotic ciprofloxacin in acid aqueous medium by a novel photoelectro-Fenton process using a microwave discharge electrodeless lamp irradiation.

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 200 mg L −1 CIP was studied by direct MDEL photolysis, anodic oxidation (AO), AO in presence of electrogenerated H 2 O 2 (AO-H 2 O 2 ), AO-H 2 O 2 under MDEL irradiation (MDEL-AO-H 2 O 2 ), electro-Fenton (EF) and MDEL-PEF processes. Higher oxidation power was found in the sequence: MDEL photolysis < AO < AO-H 2 O 2 < MDEL-AO-H 2 O 2 < EF < MDEL-PEF. Effects of current density, pH, initial Fe 2+ 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 − , NH 4 + and NO 3 − ) 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. [ABSTRACT FROM AUTHOR]