Hydrothermal low-temperature preparation and characterization of ZnO nanoparticles supported on natural zeolite as a highly efficient photocatalyst

Nanoparticles of zinc oxide were supported on natural zeolite using a hydrothermal method. The catalyst was characterized by X-ray diffraction, UV-vis diffuse reflectance spectra, scanning electron microscopy, and energy-dispersive X-ray techniques. The maximum rate constant for photodegradation of methylene blue (MB) was observed at 80 wt.% ZnO. The influence of various parameters such as catalyst composition, initial concentration of MB, calcination temperature, pH, and catalyst weight on the photodegradation reaction was studied. It was found that photodegradation of MB followed pseudo-first-order kinetics. The rate constant of the reaction for 80 wt.% ZnO at optimized conditions was approximately 3.8 times higher than that for bare ZnO. The photocatalyst had good reusability after four runs. The higher activity of the supported catalyst is due to greater adsorption of MB on the catalyst and its capability to delocalize the conduction-band electrons of excited ZnO.