Facile synthesis of NiAl2O4/g-C3N4 composite for efficient photocatalytic degradation of tetracycline

Designing high-efficiency photocatalysts responsive to visible light is important for the degradation of antibiotics in water. Heterojunction engineering is undoubtedly an effective strategy to improve the photocatalytic performance. In this work, spinel-type metal oxides (NiAl2O4, NAO) are synthesized by a simple sol-gel and calcination process. After compounding graphitic carbon nitride (g-C3N4), NAO/g-C3N4 heterojunction is obtained, which then is used as the photocatalyst for tetracycline hydrochloride (TC). The effects of photocatalyst dosage, the initial concentration of TC, and solution pH on photodegradation performance are systematically studied. The removal rate of TC on NAO/g-C3N4 reach up to similar to 90% after visible light irradiation for 2 hr and the degradation rate constant is similar to 7 times, and similar to 32 times higher than that of pure NAO and g-C3N4. The significantly improved photocatalytic activity can be attributed to the synergistic effect between well matched energy levels in NAO/g-C3N4 heterojunctions, improvement of interfacial charge transfer, and enhancement of visible light absorption. This study provides a way for the synthesis of efficient photocatalysts and an economic strategy for removing antibiotics contamination in water. (C) 2022 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.