Synthesis of immobilized cerium doped ZnO nanoparticles through the mild hydrothermal approach and their application in the photodegradation of synthetic wastewater

Abstract

The difficulty associated with accessing water resources, wastewater treatment and recycling are crucial subjects of research. In this regard the present research focuses on the synthesis, characterization, and photodegradation of synthetic wastewater by immobilized cerium doped ZnO nanoparticles. This was an experimental study at laboratory scale. The nanoparticles were synthesized through the mild hydrothermal technique and characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive spectroscopy (EDS), and Photoluminance analyses (PL). In addition, a reactor was designed and constructed for the photodegradation of the synthetic beverage effluent at laboratory scale. The fabricated nanoparticles were fixed on sand-blast glasses. The experiments were conducted by examining the parameters of doping percentage, pH, nanoparticle density, initial density of the wastewater sample, as well as exposure time to ultraviolet light and sunlight illumination. The doping molar percentage of cerium oxide in the photodegradation of the synthetic wastewater was shown to be effective, and the optimal percentage was observed at 1%. The results showed higher efficiency under the acidic condition. Moreover, it was found that increasing the dosage of nanoparticles from 1 to 5% increase the efficiency from 35.33 to 51.56% under ultraviolet light and from 19.86 to 32.45% under the visible light illumination. Increasing the concentration of the effluent from 500 to 3000 mg/L resulted in the reduction of efficiency from 65.14 to 21.9% under ultraviolet light and from 42.13 to 10.12% under visible light illumination. It was also found that increasing the exposure time would increase the efficiency of the wastewater photodegradation. The immobilized cerium doped zinc oxide nanoparticles showed excellent crystallinity and were well-dispersed.