Browsing by Autor "Uli Nicol Hosse Pastor"

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ELECTROCHEMICAL OXIDATION OF SYNTHETIC ORGANIC DYES BY FERRATE (VI), USING COMMERCIAL STEEL WOOL ELECTRODES
(2018) Ramiro Escalera Vásquez; Uli Nicol Hosse Pastor; Pablo Marcelo Pérez García
This paper deals with the in-situ electrochemical oxidation of Reactive Black 5 (RB-5), Reactive Blue 19 (RB-19) and Allura Red AC (AR-AC), using commercial steel wool as electrodes. At the optimal conditions (18 V and NaOH 0.33M), the decolorization of RB-19 (anthraquinone-type dye) is much more rapid than those of azo dyes RB-5 and AR-AC. The reaction rates based on a first order reaction model were 0.134 min-1for RB-19, 0.043 min-1 for RB-5 and 0.028 min-1 for AR-AC. Color removal efficiencies were higher than 95% achieved in 120 min. The analyses of spectra of the three dyes in the visible region indicate a complete cleavage of both azo and quinoid chromophores. In the case of RB-19 no new absorption peaks occurred in the UV region, showing a partial oxidation of aromatic groups without the generation of intermediates. In case of both azo-type dyes RB-5 and AR-AC, formation/accumulation of intermediates followed by their partial oxidation may have occurred. All these observations indicate that the predominant mechanism for decolorization was the oxidation of the three dyes. We conclude that that the electrochemical oxidation by ferrate (VI), under low voltages and low NaOH concentrations, using commercial steel wool as electrodes is an efficient and cost-effective alternative for the decolorization of azo and anthraquinone type dyes. For future studies a COD analysis should be made in order to correlate the decolorization and the elimination of the organic load in the dye solutions.
ELECTROCHEMICAL OXIDATION OF SYNTHETIC ORGANIC DYES BY FERRATE (VI), USING COMMERCIAL STEEL WOOL ELECTRODES
(2018) Ramiro Escalera Vásquez; Uli Nicol Hosse Pastor; Pablo Marcelo Pérez García
This paper deals with the in-situ electrochemical oxidation of Reactive Black 5 (RB-5), Reactive Blue 19 (RB-19) and Allura Red AC (AR-AC), using commercial steel wool as electrodes. At the optimal conditions (18 V and NaOH 0.33M), the decolorization of RB-19 (anthraquinone-type dye) is much more rapid than those of azo dyes RB-5 and AR-AC. The reaction rates based on a first order reaction model were 0.134 min-1for RB-19, 0.043 min-1 for RB-5 and 0.028 min-1 for AR-AC. Color removal efficiencies were higher than 95% achieved in 120 min. The analyses of spectra of the three dyes in the visible region indicate a complete cleavage of both azo and quinoid chromophores. In the case of RB-19 no new absorption peaks occurred in the UV region, showing a partial oxidation of aromatic groups without the generation of intermediates. In case of both azo-type dyes RB-5 and AR-AC, formation/accumulation of intermediates followed by their partial oxidation may have occurred. All these observations indicate that the predominant mechanism for decolorization was the oxidation of the three dyes. We conclude that that the electrochemical oxidation by ferrate (VI), under low voltages and low NaOH concentrations, using commercial steel wool as electrodes is an efficient and cost-effective alternative for the decolorization of azo and anthraquinone type dyes. For future studies a COD analysis should be made in order to correlate the decolorization and the elimination of the organic load in the dye solutions.
REMOCIÓN DE LA MATERIA ORGÁNICA DE AGUAS RESIDUALES DE LA INDUSTRIA TEXTIL MEDIANTE LA APLICACIÓN DE FERRATO DE POTASIO SINTETIZADO
(2022) Ramiro Escalera; Uli Nicol Hosse Pastor; Sara Castillo
Se investigó el uso de ferrato de potasio sintetizado como opción de tratamiento para la remoción de la materia orgánica (DQO) y del color contenidos en aguas residuales de una planta teñidora y lavadora de telas. Los tintes orgánicos industriales usados en el proceso son: Reactive blue 19, Allura red y Reactive black 5. Como resultado de un diseño experimental a temperatura ambiente, se encontró una dosis óptima de ion ferrato de aproximadamente 90 mg-FeO42-/l a un pH = 7, condiciones que generaron una eficiencia de remoción de DQO disuelto de 82% La eficiencia de remoción de color fue mayor al 80% a pH = 7 y una dosis de ion ferrato de 120 mg/l. El proceso de coagulación-floculación tarda 21 min i.e. 1 min de agitación rápida y 20 min de agitación lenta y controlada a una velocidad de corte de 33 s-1. La velocidad de sedimentación crítica de los flóculos formados fue de 3,5 cm/min en las condiciones óptimas. Con esta velocidad se puede diseñar sedimentadores de una carga superficial de 50,4 m3/m2/d que es superior a los valores usados comúnmente en el diseño de sedimentadores en las plantas de clarificación de aguas destinadas al consumo humano. En conclusión, el estudio demuestra que el uso del ferrato de potasio como coagulante y oxidante, es efectivo para la remoción de la materia orgánica y la decoloración de aguas residuales provenientes de la industria textil.