In this research, tetracycline photodegradation under UV light was investigated over bare TiO2 and a series of MCM-41 supported CuO-TiO2 heterojunctions varying in CuO content with the intent of exploring the effect of MCM-41 presence and especially, CuO addition. Several techniques including XRD, FESEM, EDX, DRS, BET, and PL were applied to characterize the physicochemical and photophysical properties of synthesized nanocomposites. It was found that the co-existence of MCM-41 and CuO enhances the surface dispersion of Ti species, leading to less number of agglomerates and smaller particle size of TiO2, which it promoted photophysical properties and reinforced the interaction of surface species with the support and thereby, the photosite leachings were lessened. However, the excessive loadings alleviate the synergetic effect of CuO due to the significant decrease of surface area, the appearance of more number of agglomerations, and surface coverage of MCM-41. The results revealed that CuO addition not only enhances the photocatalytic activity of TiO2/MCM-41 but also makes it reusable in further experiments. It was also observed that the highest photodegradation of tetracycline was obtained over TiO2-CuO/MCM-41 nanocomposite containing 5 wt% CuO. It is attributed to less electron-hole recombination, appropriate band gap, smaller number of agglomerations, and more uniform dispersion of photosites. Following the obtained results, a possible reaction mechanism was also proposed.
Keywords: CuO nanoparticles; Photocatalysis; Tetracycline; TiO2/MCM-41 nanocomposite; Water treatment.