Photocatalytic degradation toward pharmaceutical pollutants using supported zinc oxide nanorods catalyzed visible light system

This study investigates the photocatalytic degradation of pharmaceutical wastes in an aqueous solution using supported zinc oxide nanorods (ZnO NRs) catalysts under visible light. Specific mass and surface area, optical and electronic properties, and surface defects of the catalyst determined the enhanced degradation of the pharmaceutical contaminants. The growth time of ZnO NRs is optimized and utilized to investigate the photocatalytic degradation of 10 mg/L of paracetamol, amoxicillin, and ciprofloxacin. Results show 65%, 62%, and 44% degradation of paracetamol, amoxicillin, and ciprofloxacin after 5 h of visible light irradiation. Interestingly, all pharmaceutical compounds have two different kinetics (Faster degradation is observed in the first two hours and slower at later hours). As the highest degraded pharmaceutical compound, the intermediate byproducts of paracetamol show the presence of aminophenol, nitrophenol, benzoquinone, and hydroquinone. This research will pave the way to an environmentally friendly wastewater treatment process suitable for pharmaceutical and hospital wastewater.