Chemical Engineering Journal, Vol.316, 813-822, 2017
Iron (II) as catalyst for thiocyanate wet oxidation: Mechanism and modelization
This study investigates, for the first time ever, the performance of iron(II) as homogeneous catalyst during the catalytic wet oxidation of thiocyanate. The results revealed the suitability of iron salts as cheap, nontoxic catalysts for the homogeneous wet oxidation of thiocyanate in acidic medium, greatly enhancing the oxidation rate and achieving efficiencies above 95% (75 min, 3.58 mM of catalyst). Ammonium, sulphate and bicarbonate were identified as the main reaction products. Other toxic intermediates such as cyanide, cyanate, nitrates or nitrites were not detected at any reaction time. According to the results obtained, a complete reaction pathway, based on the formation of two iron (III)-thiocyanate complexes, was proposed for the degradation of thiocyanate. Finally, a kinetic model, including the effect of the main operating conditions (temperature, pressure and initial concentrations of iron and thiocyanate), was successfully fitted to the experimental data. (C) 2017 Elsevier B.V. All rights reserved.