Developing visible light responsive Z-scheme BN-PDI photocatalysts with good degradation performance for antibiotics

A series of boron nitride/3, 4, 9, 10-Perylenetetracarboxylic dianhydride (BN/PDI) materials have been synthesized as well as their adsorption and photodegradation efficiency for tetracycline (TC) under visible light irradiation are investigated. When the ratio between BN and PDI is 400:2 as well as the temperature is 350 °C, the synthesized BNPDI-2-350 has the highest adsorption (28.78 mg/g) and photodegradation (70.52%) efficiency for TC. The XRD, FTIR, XPS, TEM characterization results and theoretical calculation results show that BNPDI-2-350 is a BN-based composite, which is formed by the interaction of BN and PDI through π-π stacking. In addition, the charge transfer from PDI to BN also makes very important contribution for the formation of BNPDI-2-350. The photodegradation of TC by BNPDI-2-350 follows the Z-scheme heterojunction mechanism. The difference in degradation efficiency between the first and the fifth time is kept within 10% revealing a good cyclic degradation efficiency. The photodegradation efficiency of BNPDI-2-350 to TC under visible light is 1.10 times and 2.49 times that of TiO2 (P25) and g-C3N4, respectively. Therefore, BN-PDI-2-350 has a good application prospect in sewage treatment.