Proficient Photocatalytic and Sonocatalytic Degradation of Organic Pollutants Using CuO Nanoparticles

In recent years, due to the advancement in nanotechnology, advanced oxidation processes (AOPs), especially sonocatalysis and photocatalysis, have become a topic of interest for the elimination of pollutants from contaminated water. In the research work reported here, an attempt has been made to study and establish a physicochemical mechanism for the catalytic activity of copper oxide nanoparticles (CuO NPs) in AOPs using the degradation of dyes as model contaminants. CuO NPs exhibited brilliant sonocatalytic and photocatalytic activities for the degradation of a cationic dye (Victoria Blue) as well as an anionic dye (Direct Red 81). The degradation efficiency of CuO NPs was calculated by analysing the variation in the absorbance of dye under a UV-Vis spectrophotometer. The influence of different operating parameters on the catalytic activity of CuO NPs, such as the amount of catalysts dose, pH of the solution, and the initial dye concentration, was thoroughly investigated. In addition, the kinetic process for the degradation was also examined. It was observed that both dyes exhibited and followed the pseudo-first-order kinetics relation. The rate constant for sonocatalysis was high as compared to photocatalysis. The rate constant for both sonocatalysis and photocatalysis was successfully established, and reusability tests were done to ensure the stability of the used catalysts. To get an insight into the degradation mechanism, experiments were performed by using OH radical scavengers. The efficacy of CuO NPs for dye decolorization was found to be superior for the sonocatalyst than the photocatalyst.