Synthesis of Nano Ag-La-Co Composite Metal Oxide for Degradation of RB 5 Dye Using Catalytic Ozonation Process

Abstract

Nanoscale composite metal oxide of Ag-La-Co was prepared by co-precipitation method for the treatment of Reactive Black 5 using catalytic ozonation process. Further, the catalyst was characterized by transmission electron microscope, X-ray powder diffraction (XRD), scanning electron microscope - energy dispersive X-ray (SEM-EDX) and Brunauer–Emmett–Teller (BET) surface area analyzer for clarity of the phenomenon. The factors such as amount of catalyst (0.2–1.2 g/L), solution pH (2, 7, and 12), initial dye concentration (100–1,000 mg/L), and ozone flow rate (30–60 LPH) were found to influence the process. The characterization results confirm the formation of the composite metal oxide of Ag-La-Co. The degradation efficiency of catalytic ozonation was 63% compared to 32% and 4% in ozonation without catalyst and adsorption on the catalyst, respectively. Furthermore, it was observed that a pseudo-first-order kinetics model fits well with the experimental data. In addition, the effect of tert-butyl alcohol, a hydroxyl radical scavenger, has been studied. Lastly, the repetitive use of the synthesized catalyst showed that even after three consecutive runs, the catalytic activity is not much degraded, and therefore, the degradation efficiency of the synthesized catalyst was comparatively high; about 95% of Total Organic Carbon (TOC) removal was achieved at solution pH 7, amount of catalyst 1 g/L, reaction time 80 min, and ozone flow rate 30 LPH, indicating an economically viable option for industrial wastewater treatment.