Mineralization of flumequine in acidic medium by electro-Fenton and photoelectro-Fenton processes

Sergi Garcia-Segura, José A. Garrido, Rosa M. Rodríguez, Pere L. Cabot, Francesc Centellas, Conchita Arias, Enric Brillas

Research output: Contribution to journalArticlepeer-review

120 Scopus citations

Abstract

The mineralization of flumequine, an antimicrobial agent belonging to the first generation of synthetic fluoroquinolones which is detected in natural waters, has been studied by electrochemical advanced oxidation processes (EAOPs) like electro-Fenton (EF) and photoelectro-Fenton (PEF) with UVA light. The experiments were performed in a cell containing a boron-doped diamond (BDD) anode and an air-diffusion cathode to generate H2O2 at constant current. The Fe2+ ion added to the medium increased the solubility of the drug by the formation of a complex of intense orange colour and also reacted with electrogenerated H2O2 to form hydroxyl radical from Fenton reaction. Oxidant hydroxyl radicals at the BDD surface were produced from water oxidation. A partial mineralization of flumequine in a solution near to saturation with optimum 2.0mM Fe2+ at pH 3.0 was achieved by EF. The PEF process was more powerful, giving an almost total mineralization with 94-96% total organic carbon removal. Increasing current accelerated both treatments, but with decreasing mineralization current efficiency. Comparative treatments using a real wastewater matrix led to similar degradation degrees. The kinetics for flumequine decay always followed a pseudo-first-order reaction and its rate constant, similar for both EAOPs, raised with increasing current. Generated carboxylic acids like malonic, formic, oxalic and oxamic acids were quantified by ion-exclusion HPLC. Fe(III)-oxalate and Fe(III)-oxamate complexes were the most persistent by-products under EF conditions and their quicker photolysis by UVA light explains the higher oxidation power of PEF. The release of inorganic ions such as F-, NO3- and in lesser extent NH4+ was followed by ionic chromatography.

Original languageEnglish (US)
Pages (from-to)2067-2076
Number of pages10
JournalWater Research
Volume46
Issue number7
DOIs
StatePublished - May 1 2012

Keywords

  • Electro-Fenton
  • Flumequine
  • Mineralization
  • Oxidation products
  • Photoelectro-Fenton
  • Water treatment

ASJC Scopus subject areas

  • Ecological Modeling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

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