Sonocatalytic degradation of RB-5 dye using ZnO nanoparticles doped with transition metals

In this study, ZnO was doped and co-doped with rhodium and tungsten to assess the impact of these transition metals on the sonocatalytic degradation of reactive black 5 azo dye (RB-5). Structural analysis revealed that doping ZnO with 1% Rh and W does not alter its wurtzite hexagonal structure, although minor changes in cell parameters were observed due to differences in electronic density. Interestingly, co-doping resulted in lower degradation efficiency than single doping, with W-ZnO emerging as the most effective catalyst, achieving 100% RB-5 degradation within 60 min, likely due to a higher density of oxygen vacancies and hydroxyl groups. Moreover, a 2^k factorial design identified optimal sonocatalytic conditions for W-ZnO, including a catalyst concentration of 0.75 g/L, a power tip of 225 W, and a hydrogen peroxide volume of 27 μL. The findings highlight the potential for doped ZnO nanoparticles in advanced oxidation processes and green chemistry applications, making this method an environmentally friendly alternative for wastewater treatment.