Preparation and application of Ag–Ce–O composite metal oxide catalyst in catalytic ozonation for elimination of Reactive Black 5 dye from aqueous media

Abstract

It is necessary to treat textile effluents before discharging them into natural water bodies as they harm the environment. Compared to conventional treatment methods, catalytic ozonation has gained attention due to its effectiveness in removing refractory organic pollutants. In this study, the coprecipitation method was used to synthesize a composite metal oxide of silver and cerium oxide, and the synthesized catalyst was used to eliminate the Reactive Black 5 (RB5) dye. X-ray diffraction, scanning electron microscopic, and Brunauer–Emmett–Teller surface area analyses were performed to characterize the synthesized catalyst. Afterwards, relevant experimental parameters, such as pH, ozone and catalyst dosages, and initial dye concentration, were investigated. The experiments revealed that the optimal experimental conditions were a pH value of 10, a catalyst dosage of 0.7 g/L, and an ozone dosage of 60 L/h. In these optimized conditions, the RB5 dye was entirely removed, and a chemical oxygen demand removal efficiency of 88% was achieved within a reaction time of 80 min. Furthermore, the recycling potential of the catalyst was tested for three cycles, and no deterioration in its activity was observed. Additionally, studies were conducted using a hydroxyl radical scavenger in order to understand the reaction pathway of the system. As a result, the indirect pathway was more dominant than the direct pathway in the system.