Electro-Fenton degradation of anti-inflammatory drug ibuprofen in hydroorganic medium

The oxidative degradation of ibuprofen in hydroorganic medium water/acetonitrile has been investigated by electro-Fenton processes. Experiments have been performed in a one-compartment cell with a Pt or BDD anode and a commercial 3D graphite felt cathode. The effect of operating conditions such as applied current, catalyst concentration, and supporting electrolyte nature has been studied. Ibuprofen decay kinetics and the evolution of its aromatic intermediates have been monitored during the electrolysis by HPLC and GC-MS analyses. The experimental results have shown that ibuprofen has been completely removed in all experimental conditions either by homogeneous OH formed in the bulk of the solution through electrochemically generated Fenton's reagent (H2O2 and Fe2+) and heterogeneous BDD(OH) at the anode surface from water oxidation. The removal rate has been more effective using a Pt anode than a BDD anode because of the greater regeneration of Fe2+ catalyst on the former. With both the anodes, the decay kinetics of ibuprofen always followed a pseudo-first-order reaction and the oxidation rate largely depends on applied current, Fe2+ concentration and electrolyte nature. Several aromatic by-products such as 1-(1-hydroxyethyl)-4-isobutylbenzene, 4-isobutylacetophenone, 4-isobutylphenol and benzoquinone has been identified, and a plausible reaction mechanism has been proposed.