title: Preliminary investigation of the supply of chemical species to an aqueous solution using a hydrogen-oxygen flame.
abstract: A new method of supplying radical species to aqueous solutions using a hydrogen-oxygen flame is investigated. When a hydrogen-oxygen flame is directed on the surface of an aqueous solution, hydroxyl radicals (*OH) produced in the flame are extracted into the aqueous phase. The presence of *OH in the aqueous solution was confirmed by electron paramagnetic resonance with spin trapping using 5,5-dimethyl-1-pyrroline-N-oxide. The extraction of *OH into the aqueous solution was monitored using a quantitative analysis of hydrogen peroxide (H2O2). The effects of the hydrogen and oxygen gas flow rates, hydrogen/oxygen ratio, and atmosphere on H2O2 formation were studied. When the hydrogen-oxygen flame blew on a phosphate buffer solution (pH 6.7) under an Ar atmosphere, the concentration of H2O2 increased with the blowing time of the flame and the flow rate of hydrogen gas. Under air, nitrate and nitrite ions were formed in the aqueous phase in addition to H2O2, and the H2O2 concentration was lower than that under argon. The application of this new method to an aqueous solution of Cu(II)-ethylenediaminetetraacetic acid (EDTA) caused a remarkable decrease in the concentration of Cu(II)-EDTA and total organic carbon.
authors.affiliation: Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan. miho@tohtech.ac.jp
authors.forename: Miho
authors.initials: M
authors.lastname: Uchida
authors.forename: Takahiro
authors.initials: T
authors.lastname: Sogabe
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Ikoma
authors.forename: Akitsugu
authors.initials: A
authors.lastname: Okuwakit
mesh_terms: D004492:Edetic Acid / Q000032:analysis; D005390:Fires; D006859:Hydrogen / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D012996:Solutions; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D016877:Oxidants; D012996:Solutions; D014874:Water Pollutants, Chemical; D017665:Hydroxyl Radical; D006859:Hydrogen; D004492:Edetic Acid; D010100:Oxygen