Characterization and assessment of the photocatalytic activity of ZnO-Fe3O4/TiO2 nanocomposite based on MIL-125(Ti) synthesized by mixed solvo-hydrothermal and sol-gel methods

Abstract

In the present study, the photocatalytic efficiency of a novel ZnO-Fe3O4/TiO2 nanocomposite derived from metal-organic framework MIL-125(Ti) was investigated for the removal of Reactive Blue 21 under ultraviolet (UV) light irradiation. X-ray diffraction analysis and energy-dispersive X-ray spectrometer combined with vibrating sample magnetometer revealed crystalline oxides characterized by the coexistence of the anatase TiO2 phase and ZnO-Fe3O4 particles. The BET results revealed that the as-synthesized oxide nanomaterials were mesoporous with the specific surface are about 12% smaller than that of metal-organic framework MIL-125(Ti), which developed of noble metal-anchored oxide for photocatalytic processes. The experimental findings revealed that the photocatalytic degradation capability of ZnO-Fe3O4/TiO2 is about five times higher than that of pure MIL-125(Ti). The optimum photocatalytic potential of 99% for discoloration of Reactive Blue 21 (RB21) dye was assigned at pH of 2, initial dye concentration of 50 mg/L, photocatalyst dose of 30 mg/100 mL, and temperature of 45 °C. The as-synthesized ZnO-Fe3O4/TiO2 composite was not thermodynamically favorable at all temperatures. Furthermore, the RB21 removal efficiency with ZnO-Fe3O4/TiO2 nanocomposite retained 97.10% from 99.89% of its initial photocatalytic activity after five successive catalytic cycles. Accordingly, ZnO-Fe3O4/TiO2 can be suggested as new promising alternatives for the reduction of colored dye wastewater from the textile industry.