DB 86 Dye Removal by Catalytic Ozonation Using ZnO, CeO2, and ZnO/CeO2 Nanocatalysts

Abstract

Azo dyes, which are utilized within the textile sector, cause harm to the natural environment due to their hazardous, oncogenic, and genotoxic properties, even at low concentrations. Direct Blue (DB 86) is a widely utilized azo dye in the textile industry. In this research, the treatment of synthetic wastewater that contains 100 mg/L of DB 86 dye with the catalytic ozonation process was investigated. A comparative analysis of commercially purchased ZnO, CeO₂, and ZnO/CeO₂ (1:1, mol:mol) nanocatalysts has been conducted in the context of catalytic ozonation processes (COP). The investigation has identified optimal parameters of pH 11, 1200 mg/L ozone dose, 50 mg/L catalyst dose and 10 minutes reaction time for all three catalysts. The experimental findings revealed that the removal efficiencies of DB 86 at optimum conditions were 99.12%, 98.91%, and 98.98% for n.ZnO, n.CeO₂, and n.ZnO/n.CeO₂ catalysts, respectively. In contrast, the removal efficiency of DB 86 by the ozonation process was determined to be 83%. As a consequence of kinetic analyses for the removal of DB 86 by COP process in the presence of nanoparticles used, pseudo second order kinetics was followed with correlation coefficients (R²) of 0.9847 (n.ZnO), 0.9764 (n.CeO₂), and 0.9773 (n.ZnO/n.CeO₂).