Catalytic oxidation of tartrazine in aqueous solution using a pillared clay with aluminum and iron

Abstract

In this work, pillared bentonite with Al?Fe (Al?Fe?PILC) was synthesized and used as a heterogeneous Fenton-like catalyst in the oxidation of tartrazine azo-dye in aqueous solution. The modification of bentonite with the Al-Fe mixed system in a concentrated medium, with ultrasound assisted intercalation was carried out, and the ob-Tained catalyst was characterized by XRF, XRD, and N2 adsorption at 77 K. The oxidation of tartrazine with Al?Fe?PILC, using different amounts of H2O2, expressed as a multiple (1, 3, 6, and 9) of a stoichiometry amount required to completely oxidize the dye was evaluated. The reaction of catalytic wet peroxide oxidation (CWPO) of the dye with 400 mg of Al?Fe?PILC and 6 times the stoichiometric amount of H2O2 at 25 °C, reached 98.2 1.8% of decolorization, 51.9 1.9% of TOC removal and 71.5 1.8% of TN removal. Results of this study show that the oxida-Tion of tartrazine increased with the amount of H2O2 up to a certain limit. This oxidation process can be considered as an alternative for treating wastewater containing azo-dye because the reaction takes place under mild experi-mental conditions (room temperature and atmospheric pressure).