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Ozonation and advanced oxidation processes based on photocatalysis (P.C.) and non-thermal plasma generated in a dielectric barrier discharge (DBD) in different gas atmospheres were compared for the degradation and mineralization of 2,4-dichlorophenoxy acetic acid (2,4-D) and 2,4-dichlorophenol (2,4-DCP) in aqueous solutions, using a planar falling film reactor with comparable design. The energetic yields (G 50 ) as measure of the efficiencies of the different methods are for 2,4-D in the order DBD/Ar-Fenton > ozonation > DBD/Ar > P.C.ozonation > DBD/Ar:O 2 ≫ DBD/Air > P.C.oxidation. For 2,4-DCP the order is ozonation ≫ DBD/Ar-Fenton > P.C.ozonation > DBD/Ar > DBD/Ar:O 2 ≫ P.C.oxidation > DBD/Air. The degradation by using ozone is very effective, but it should be noted that the mineralization measured by the total organic carbon (TOC) removal is low. The reason is the formation of stable towards ozone intermediates, especially low chain carboxylic acids. The fate of these intermediates during the degradation with the different methods has been followed and discussed. [ABSTRACT FROM AUTHOR]

The efficiencies of ozonation and different advanced oxidation processes (AOPs) including photocatalytic ozonation, Fenton, photo-Fenton, photocatalytic oxidation, UVA/Ti02/H202, and non-thermal plasma generated by a dielectric barrier discharge (DBD) were compared in terms of the energy yield (G50) for decolorization of MB and total organic carbon (TOC) removal using a planar falling film reactor. Fenton oxidation and ozonation were found to be the most efficient methods for the decolorization of MB, although these techniques attained rather low mineralization. A combination treatment of the ozonation with the photocatalysis demonstrates a synergistic effect on the mineralization efficiency. The photocatalytic oxidation and UVA/Ti02/H202 provide only a moderate MB decolorization. The degradation efficiency of the DBD plasma is significantly dependent on the composition of gas atmosphere. The addition of Fe2+ to the solution in the DBD plasma under argon atmosphere improves the degradation efficiency due to the occurrence of Fenton reaction. The energy yield for 50% conversion of MB is calculated between 0.13 and 20.5 g/kWh, and the maximum and minimum values were obtained by the ozonation and photocatalytic oxidation, respectively. Ozonation with the highest energy yield provided a moderate mineralization by only 19%, while the DBD plasma obtained the highest TOC removal by 88%. [ABSTRACT FROM AUTHOR]

The efficiencies of ozonation and different advanced oxidation processes (AOPs) including photocatalytic ozonation, Fenton, photo-Fenton, photocatalytic oxidation, UVA/TiCVPčb, and non-thermal plasma generated by a dielectric barrier discharge (DBD) were compared in terms of the energy yield (G50) for decolorization of MB and total organic carbon (TOC) removal using a planar falling film reactor. Fenton oxidation and ozonation were found to be the most efficient methods for the decolorization of MB, although these techniques attained rather low mineralization. A combination treatment of the ozonation with the photocatalysis demonstrates a synergistic effect on the mineralization efficiency. The photocatalytic oxidation and UVA/TIO2/H2O2 provide only a moderate MB decolorization. The degradation efficiency of the DBD plasma is significantly dependent on the composition of gas atmosphere. The addition of Fe2+ to the solution in the DBD plasma under argon atmosphere improves the degradation efficiency due to the occurrence of Fenton reaction. The energy yield for 50% conversion of MB is calculated between 0.13 and 20.5 g/kWh, and the maximum and minimum values were obtained by the ozonation and photocatalytic oxidation, respectively. Ozonation with the highest energy yield provided a moderate mineralization by only 19%, while the DBD plasma obtained the highest TOC removal by 88%. [ABSTRACT FROM AUTHOR]