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In the present study, peroxymonosulfate and hydrogen peroxide activation performances of various layered double hydroxide (LDH) catalysts were tested for the removal of the model food dye, tartrazine, from aqueous solutions. Catalytic activities of Cu-Fe-LDH, Co-Fe-LDH and Ni- Fe-LDH were compared in the presence of peroxymonosulfate and hydrogen peroxide. In the catalyst screening experiments performed by using different oxidants, Co-Fe-LDH and peroxymonosulfate were determined as the most suitable catalyst and the oxidant, respectively. The interactive effects of the catalyst loading, pH and the molar ratio of the oxidant to dye were investigated and the reaction conditions were optimized by using Box-Behnken Design and response surface methodology. Under the optimum reaction conditions determined as 2 g/L of catalyst loading, pH 3, and 11.36 oxidant/dye molar ratio, 87.35% organic matter removal and 97.47% decolorization efficiencies were achieved. [ABSTRACT FROM AUTHOR]

In this study, catalytic wet air oxidation using lanthanum cobalt oxide (LaCoO3) as catalyst was employed for the efficient treatment of synthetic sugar industry wastewater in a single process. A parametric study was performed to determine the optimum conditions. The results showed that reaction temperature and theoretical air percentage were the most effective parameters. Sugar derivatives were almost completely destroyed at the optimum conditions and total organic carbon (TOC) and chemical oxygen demand (COD) removals were determined as 91% and 87%, respectively, indicating a high mineralization degree, which was the main goal of advanced oxidation. The reaction kinetics were investigated by pseudo‐homogeneous and heterogeneous models based on two different parameters: sucrose and TOC concentration. The degree of fit showed that the reaction order was determined as two for the pseudo‐homogeneous approach. According to the surface concentration calculations for heterogeneous models, the presence of mass transfer limitations was only observed for oxygen as gas reactant. All heterogeneous models also fitted the reaction rate data accurately, but the Mars–van Krevelen was the selected model for sucrose and TOC oxidation with the best fit. [ABSTRACT FROM AUTHOR]