Chemical destruction of MTBE using Fenton's Reagent: effect of ferrous iron/hydrogen peroxide ratio

In-previous laboratory experiments Fenton's Reagent (FR) was successfully used as the source of hydroxyl radicals (OH.) for chemical treatment of low concentrations of methyl tert-butyl ether (MTBE) in water. Although under certain conditions MTBE degradation levels as high as 99.99% were achieved, none of these experiments resulted in complete MTBE mineralization-In all cases, these experiments applied FR as an equimolar concentration of ferrous iron (Fe2+) and hydrogen peroxide (H2O2). The present study investigates the effect of H2O2/Fe2+ molar ratio on the extent of degradation of, MTBE and intermediate products in water at pH = 3.0. The initial concentration. of MTBE. studied was 0.0227 mM (approximately 2 mg/L). Initially, the dose of Fe2+ was kept constant at a Fe2+/MTBE molar ratio of 10: 1 and the dose of H2O2 was varied to achieve different H2O2/Fe2+ molar ratios. The results revealed that higher degradation efficiency was achieved when FR was used as an equimolar mixture (H2O2/Fe2+ molar ratio = 1.0) The extent of MTBE degradation decreased when the H2O2/Fe2+ molar ratio was changed to values higher or lower than 1.0. These results suggest that a stoichiometric relationship (1:1) between the FR components gradation process for this reactant system. It is hypothesized that an excess of H optimizes the de O-2(2) enhances the effect of reactions that scavenge OH., while a decreased amount of H2O2 would be a limiting factor for the Fenton Reaction.