Chemical Characteristics of Ciprofloxacin and Its Degradation Products: On the Road to Understanding Its Potential Hazards.

Antibiotics such as ciprofloxacin (CIP) are considered emerging contaminants because of their widespread use in human and veterinary medicine, their persistence in the environment, and their incomplete removal during wastewater treatment. To mitigate pollution, the photocatalytic degradation of antibiotics is an available option. However, some of the degradation products could be more harmful than the original compound. The main idea of this investigation is to determine the chemical properties of the main photodegradation products of CIP to understand the positive or negative consequences of degrading CIP. Density functional theory calculations were performed to investigate the electron transfer capacity of CIP and 20 selected degradation products. Fukui functions were also calculated to determine the reactive atoms. To identify the degradation products, this investigation presents theoretical and experimental ultraviolet (UV)/visible spectra of the photocatalytic degradation of CIP using zinc oxide nanowires (ZnO NW). The 3 h photocatalytic reaction showed an 89% of CIP degradation, indicating the effectiveness of ZnO NW photocatalyst. The agreement between the experiment and theory indicates that two degradation products (B5 and B8) are formed during the photocatalytic experiment. Concerning the electron transfer capacity, B8 is a better electron donor and could help to prevent oxidative stress by donating electrons to free radicals. B5 is a better electron acceptor, but it is not as good as