title: Evaluation of three reagent dosing strategies in a photo-Fenton process for the decolorization of azo dye mixtures.
abstract: Three reagent dosing strategies used in the solar photo-assisted decolorization of a mixture of sulfonated dyes consisting of acid blue 113, acid orange 7 and acid red 151 were evaluated. Results demonstrated that the dosing strategy influenced both reagent consumption and the biodegradability and toxicity of the effluent. In one strategy (E(1)), the Fenton's reactants were dosed in a punctual mode, while in the other two strategies (E(2) an E(3)), the reactants were dosed continuously. In the E(2) strategy the reactants were dosed by varying the duration of the injection time. In the E(3) strategy, the reactants were dosed during 60 min at a constant rate, but with different concentrations. All cases showed that feeding the reactor between 40% and 60% of the maximal dose was sufficient to decolorize more than 90% of the mixture of azo dyes. The E(1) strategy was less effective for aromatic content reduction. Conversely, the continuous addition of the reagents (E(2) and E(3) strategies) improved the aromatic content removal. E(3) strategy was substantially more appropriate than E(1) strategy due to improved the effluent quality in two key areas: toxicity and biodegradability.
authors.affiliation: Laboratory for Research on Advanced Processes for Water Treatment, Instituto de Ingeniería, Unidad Académica Juriquilla, Universidad Nacional Autónoma de México, Querétaro, Mexico.
authors.forename: D
authors.initials: D
authors.lastname: Prato-Garcia
authors.forename: Germán
authors.initials: G
authors.lastname: Buitrón
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D003116:Color; D004396:Coloring Agents / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D055668:Photochemical Processes; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; C045076:Fenton's reagent; D006861:Hydrogen Peroxide; D007501:Iron