ZnO/ZrO2 nanocomposite: Sonosynthesis, characterization and its application for wastewater treatment.

ZnO/ZrO2 nanocomposites with different ZnO: ZrO2 molar ratios (2:1, 1:1, and 1:2)were prepared by sol gel approach under ultrasonic irradiation. For preparation of the nano-composites, the ZnO gel was directly incorporated into the ZrO2 gel at different molar ratios. The reaction mixture was stirred continuously for two days and then it was ultrasonoicated for 30min. The filtrated composite gel was washed, and then calcinated at 300°C in furnace for 3h. X-ray powder diffraction patterns exhibited well-formed crystal structures and pure crystalline phases in the synthesized nanoparticles (NPs). The FT-IR analyses indicated that the positions of peaks related to Zn-O and Zr-O absorption bands did not change in nano-composites. In addition, FESEM images indicated uniform spherical morphology of the NPs. The highest photo-degradation performance of Congo red (as a model water pollutant) was obtained by 1:2molar ratio of ZrO2: ZnO in the nano-composite. The particle size and band gap were considered as important factors on nano-catalysts performance. Furthermore, the effects of ultrasonic irradiation, pH, and the concentration of pollutant in solution were investigated on photocatalytic performance of optimum nanocomposite.