Photocatalytic Degradation of Tetracycline by g-C3N4/BiOBr Composite

The widespread use of tetracycline (TC) has posed a serious threat to human health and water pollution. A new photocatalyst of g-C3N4/BiOBr composite was synthesized by the hydrothermal method and g-C3N4 was prepared by secondary calcination method using melamine as raw material in this study. Investigations were made into the photocatalytic activity of TC degradation when exposed to visible light (λ ≥ 420 nm). The effects of g-C3N4/BiOBr mass ratio, TC initial concentration, catalyst dosage and pH on photocatalytic properties were investigated. The results showed that pH = 6, 50 mg catalyst and 10 mg/L initial TC concentration achieved optimal catalytic effect when the mass ratio of g-C3N4 to BiOBr was 1:2. The TC photocatalytic degradation efficiency was as high as 90.84% after 120 min of photoreaction. The composite had better photocatalytic performance because g-C3N4 and BiOBr form z heterojunctions to effectively enhance visible light absorption, improve photogenerated electron transfer, as well as promote the separation of photogenerated electrons and holes. It can increase the photocatalytic activity effectively by making more active sites of the catalyst participate in the photocatalytic oxidation reaction. Therefore, the z-type photocatalytic material g-C3N4/BiOBr prepared in this study degrades TC wastewater and laid the foundation for photocatalytic technology in the treatment of TC wastewater.