Solar photocatalytic degradation of pharmaceutical compounds using ZnSnO3/CB composites

In this study, the activity of ZnSnO3 as a photocatalyst for the degradation of persistent micro–pollutants under simulated solar irradiation has been assessed. Zinc stannate (ZnSnO3), belongs to the class of ternary oxides and has a reported band gap of 2.4 eV. Due to its narrow band gap can be excited by visible light leading to the production of reactive oxidative species rendering it a promising photocatalyst. It was found that the ZnSnO3/CB (carbon black) composite exhibits enhanced photocatalytic activity in comparison with its pristine form, owing to the ability of CB to capture photoinduced electrons and prevent the recombination of electron – hole pairs. In the present study, complete removal of Losartan, a pharmaceutical compound used to treat high blood pressure, was achieved using ZnSnO3/CB under solar irradiation in 120 min. Photocatalytic experiments were conducted in a cylindrical pyrex glass reactor (V=120 mL). Solar irradiation was emitted by an Oriel LCS - 100 Watt solar simulator system. Changes in Losartan concentration were followed by high performance liquid chromatography (HPLC).