In this study, ZnO-biochar (RHZ) composites were synthesized to overcome the ZnO-related problems (charge recombination, wider band gap, and poor visible light absorption) and improve the properties and photocatalytic performance of carbon-based ZnO photocatalysts. The antibacterial level of Sulfamethoxazole (SMZ) after treatment was checked by Bacillus subtilis activity. The research results show that the photocatalysis material has a great ability to degrade SMZ as well as other antibiotic residues in the water environment. RHZ composites can be used as stable, efficient, economical, and sustainable composite for the recovery of pharmaceutical wastewater.