title: Photolytic and radiolytic oxidation of humic acid.
abstract: The reactions of Br(2)(˙-), Br˙, HO˙ and N(3)˙ with Aldrich humic acid (AHA) were investigated. The Br/Br(2)(˙-) radicals were obtained in flash-photolysis experiments (λ(exc) = 266 nm) performed with NaS(2)O(8) solutions in the presence of bromide ions. HO˙ and N(3)˙ radicals were generated by pulse radiolysis of N(2)O-saturated solutions. From the combination of a bilinear analysis and computer simulations of the absorbance traces, it was possible to obtain information on the rate constants for the reactions of Br(2)(˙-), Br˙, HO˙ and N(3)˙ with AHA and on the intermediate species involved in the mechanism. Evidence for the participation of phenoxyl radicals (λ(max) = 410 nm) is given.
authors.affiliation: Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA, CCT La Plata-CONICET/UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina.
authors.forename: Marcela V
authors.initials: MV
authors.lastname: Martin
authors.forename: Gustavo T
authors.initials: GT
authors.lastname: Ruiz
authors.forename: Mónica C
authors.initials: MC
authors.lastname: Gonzalez
authors.forename: Claudio D
authors.initials: CD
authors.lastname: Borsarelli
authors.forename: Daniel O
authors.initials: DO
authors.lastname: Mártire
mesh_terms: D001965:Bromides / Q000737:chemistry*; D006812:Humic Substances / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction / Q000528:radiation effects; D010782:Photolysis; D011675:Pulse Radiolysis; D017670:Sodium Compounds / Q000737:chemistry; D012996:Solutions; D013431:Sulfates / Q000737:chemistry
chemical_list: D001965:Bromides; D006812:Humic Substances; D017670:Sodium Compounds; D012996:Solutions; D013431:Sulfates; D017665:Hydroxyl Radical; C024625:sodium persulfate