Synthesis of nano zinc oxide on granular porous scoria: Application for photocatalytic removal of pharmaceutical and textile pollutants from synthetic and real wastewaters

• ZnO nanoparticles were synthesized by sol gel method on granular natural scoria.
• Nanocomposite characterization was studied by XRD, EDS, SEM, and BET analyses.
• Nanocomposite was used for textile and pharmaceutical wastewater treatment.
• Nanocomposite showed successive removal of pollutants from water and wastewater.

ZnO nanoparticles were synthesized by sol gel method on granular porous natural scoria. Structure and morphology of scoria, synthesized ZnO nanoparticles, and ZnO/scoria nanocomposite were studied by X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Approximately 49 mg of nano ZnO was immobilized per gram of scoria. Photocatalytic performance of ZnO/scoria nanocomposite was examined for phenazopyridine and Acid Blue 113 removal from synthetic aqueous solutions under UV irradiation in a continuous open channel reactor. Removal of Acid Blue 113 in pH of 5.5, flow rate of 15 ml/min and Acid Blue 113 concentration of 20 mg/L was obtained 70.78%. Removal of phenazopyridine in pH of 6.0, flow rate of 15 ml/min and concentration of 15 mg/L was obtained 72.55%. Also, prepared photocatalyst was used for treatment of pharmaceutical and textile pollutants from real wastewaters. COD reductions of these wastewaters were 40.55% and 58.25% respectively in their natural pH, 5 ml/min with initial COD of 800 and 510. Results reveal that ZnO/scoria nanocomposite is efficient for photocatalytic removal of pharmaceutical and textile pollutants with reusability.