title: Chemical destruction of MTBE using Fenton's reagent: effect of ferrous iron/hydrogen peroxide ratio.
abstract: 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 optimizes the degradation process for this reactant system. It is hypothesized that an excess of H2O2 enhances the effect of reactions that scavenge OH*, while a decreased amount of H2O2 would be a limiting factor for the Fenton Reaction.
authors.affiliation: Department of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, Ohio 45221, USA.
authors.forename: A
authors.initials: A
authors.lastname: Burbano
authors.forename: D
authors.initials: D
authors.lastname: Dionysiou
authors.forename: M
authors.initials: M
authors.lastname: Suidan
authors.forename: T
authors.initials: T
authors.lastname: Richardson
mesh_terms: D006861:Hydrogen Peroxide / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D008738:Methyl Ethers / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry; D010084:Oxidation-Reduction; D012997:Solvents / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: C045076:Fenton's reagent; D008738:Methyl Ethers; D016877:Oxidants; D012997:Solvents; C043243:methyl tert-butyl ether; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D007501:Iron