Fabrication of direct Z-scheme Co3O4/BiOI for ibuprofen and trimethoprim degradation under visible light irradiation

Abstract

The escalation of pharmaceutical products development and sales in the last few decades have raised concerns about their effect on the environment, particularly water and consequently their removal from wastewater. Composites of cobalt oxide (Co3O4) and bismuth oxyiodide (BiOI) were synthesised and evaluated for degradation of ibuprofen (IBU) and effect of trimethoprim (TMP) under visible light irradiation. The properties of the as synthesised composites were evaluated using different techniques such as FTIR, SEM, TEM, XRD, BET, TGA, UV–Vis and PL. The self-assembled direct Z-scheme heterojunction showed high photocatalytic activity for degradation of ibuprofen (97.02%) after adding 2 mg of TMP. TOC reduction of 85.68 ± 2.22% at pH 11.3 was also calculated. The enhanced photocatalytic activity of the Z-scheme heterojunction was attributed to strong visible light absorption properties of the catalyst and improved separation of photoexcited charge carriers resulting from the built-in electric field formed between the BiOI microspheres and the Co3O4 wormy epitaxy established after equilibrium Fermi level was reached. The Z-scheme heterojunction is a promising material for the removal of pharmaceuticals in aquatic effluents.