Investigation of photocatalytic degradation of clindamycin by TiO2

Abstract

Contaminants of emerging concern or simply emerging contaminants have been considered as a critical environmental issue in recent decades. These compounds have not routinely controlled and monitored; therefore they have posed risk to the health of human and environment. Drugs are considered as one of the most important emerging pollutants. They introduce to environment form different sources such as urine, human excretion, livestock, poultry, pharmaceutical, and hospitals. Although they are in trace levels, they are not biodegradable. They cannot be removed by conventional treatment processes. Advanced oxidation processes (AOPs) have been designed to address the deficiency of conventional methods in the removal of emerging pollutants. Production of highly reactive hydroxyl radicals is the base of AOPs. These very reactive radicals effectively oxidize emerging pollutants such as drugs. Among different approach of AOPs, photocatalytic degradation has been successfully applied to mitigate the side effects of emerging contaminants. The ability of the photocatalytic process in the removal of Clindamycin hydrochloride (CLM) from aqueous solutions in the presence of UV/TiO2 was studied. The effects of various parameters such as adsorption, photolysis, pH, catalyst dosage, initial concentration of antibiotic, and radiation time were investigated in a batch photoreactor. Results showed that photolysis and adsorption had a negligible contribution to the clindamycin removal. The maximum clindamycin removal rate was obtained under optimal conditions, such as pH of 5, 0.5 g/l of TiO2, initial clindamycin concentration of 2 /L. This optimum condition was achieved for 90 minutes. The CLM photocatalytic degradation kinetics showed that CLM degradation follows the pseudo-first-order kinetics.