Preparation of ligand-functionalized UiO-66-X(X=H,NH2,Br)/PDINH composites for the photocatalytic degradation of tetracycline

• Novel UiO-66-Br/PDINH was made by acid-catalyzed amination and hydrothermal methods. • The degradation percentage of tetracycline reached 97.8 % after 120 min irradiation. • UiO-66-Br/PDINH has better catalytic effect than UiO-66/PDINH and UiO-66-NH 2 /PDINH. • The material has large specific surface area, pore volume and abundant active sites. • The Z-scheme heterojunction accelerated the charge transfer and photodegradation. • The degradation pathway and mechanism were proposed on calculations and experiments. In this study, the heterojunction nanocomposites UiO-66-X(X=H,NH 2 ,Br)/PDINH were prepared by acid-catalyzed amination and hydrothermal methods. In order to investigate the effect of ligand modification on the performance of the catalyst. Tetracycline (0.01 g/L) was chosen as the target pollutant, and the degradation effect of tetracycline by different materials at 0.3 g/L under simulated sun light was compared by the controlled variable method. All composites showed better performances compared to the monomers. Among them, UiO-66-Br/PDINH showed the highest photodegradation efficiency (97.8 %), which was superior to the UiO-66/PDINH and UiO-66-NH 2 /PDINH. This good photocatalytic activity is mainly attributed to two aspects: (1) The construction of Z-scheme heterojunction was conducive to promoting the separation of photogenerated carriers; (2) The target contaminant TC molecules and UiO-66-Br had strong intermolecular forces and were more tightly bound. Based on the energy band theory, the formation mechanism of Z-scheme heterojunction and photocatalytic degradation mechanism of TC were elucidated.