Electrochemical incineration of the antibiotic ciprofloxacin in sulfate medium and synthetic urine matrix

Vanessa S. Antonin, Mauro C. Santos, Sergio GARCIA SEGURA, Enric Brillas

Research output: Contribution to journalArticle

96 Scopus citations

Abstract

The degradation of 100mL of 0.245mM of the antibiotic ciprofloxacin in 0.05M Na2SO4 at pH 3.0 has been studied by electrochemical oxidation with electrogenerated H2O2 (EO-H2O2), electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar PEF (SPEF). Electrolyses were performed with a stirred tank reactor using either a boron-doped diamond (BDD) or Pt anode and an air-diffusion cathode. In EF, PEF and SPEF, ciprofloxacin was rapidly removed due to its oxidation with OH formed from Fenton's reaction between added Fe2+ and H2O2 generated at the cathode. The larger electrochemical incineration of the antibiotic was achieved by SPEF with BDD with 95% mineralization thanks to the additional attack by hydroxyl radicals formed from water oxidation at the BDD anode surface and the photolysis of final Fe(III)-oxalate and Fe(III)-oxamate species from sunlight. Up to 10 primary intermediates and 11 hydroxylated derivatives were identified by LC-MS, allowing the proposal of a reaction sequence for ciprofloxacin mineralization. A different behavior was found when the same antibiotic concentration was oxidized in a synthetic urine matrix with high urea content and a mixture of PO43-, SO42- and Cl- ions. Since Fenton's reaction was inhibited in this medium, only EO and EO-H2O2 processes were useful for mineralization, being the organics mainly degraded by HClO formed from Cl- oxidation. The EO process with a BDD/stainless steel cell was found to be the most powerful treatment for the urine solution, yielding 96% ciprofloxacin removal and 98% mineralization after 360min of electrolysis at optimum values of pH 3.0 and current density of 66.6mAcm-2. The evolution of released inorganic ions was followed by ion chromatography.

Original languageEnglish (US)
Pages (from-to)31-41
Number of pages11
JournalWater Research
Volume83
DOIs
StatePublished - Oct 5 2015
Externally publishedYes

Keywords

  • Ciprofloxacin
  • Electro-Fenton
  • Electrochemical oxidation
  • Photoelectro-Fenton
  • Sunlight
  • Wastewater treatment

ASJC Scopus subject areas

  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Ecological Modeling
  • Medicine(all)

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