Enhanced photocatalytic performance of UiO-66-NH2/TiO2 composite for dye degradation

In this study, the performance of TiO2, ZnO, UiO-66-NH2 and UiO-66-NH2/TiO2 nanoparticles was investigated. They apply as photocatalysts for the destruction of organic reactive red dye 120 (RR120) under UV light. In order to determine the optimal conditions, effects of different catalysts and initial dye concentration, H2O2 content and catalyst loading parameters were examined. Taguchi-designed experimental method was used to obtain optimal test conditions. The physical and chemical properties of synthetic photocatalysts were investigated by SEM, XRD, EDX, BET and DRS. SEM images show that the globular particles of titania are well placed on the surface of the metal-organic framework (MOF). XRD and EDX analyses also confirmed the presence of titania in the synthesised UiO-66-NH2/TiO2 photocatalyst. Optimal values of H2O2, pH, the amount of catalyst, the dye concentration and the type of available photocatalyst to remove the RR120 dye, were obtained by 80 μl/l, 3 mg/l, 5 mg/l and 20 mg/l, UiO-66-NH2/TiO2 catalyst, respectively. The required time for complete removal of RR120 dye under detection limit of 0.136 mg/l in optimal conditions was 10 min. The RR120 photocatalytic degradation followed the first-order kinetic equation according to the Langmuir–Hinshelwood model (kapp = 0.407 min−1). The result of optimisation showed the 20 wt% of the titania on MOF (UiO-66-NH2) photocatalyst can be used in advanced oxidation processes, and it can be used as a suitable option for cleaning coloured effluent.