Enhanced photocatalytic degradation of reactive blue 19 using zeolitic imidazolate framework-8 composited with Fe3O4/MnO2 heterojunction

Abstract

The present study offers a novel recyclable Fe3O4/MnO2/ZIF-8 heterojunction photocatalyst for the degradation of reactive blue 19 (RB19) under visible light irradiation. The catalyst was facilely synthesized by depositing Fe3O4/MnO2 nanocomposite onto the surface of ZIF-8 and characterized by field-emission scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spec-troscopy, X-ray diffraction, nitrogen adsorption-desorption isotherms and UV-vis spectroscopy. Morphology and structure characterization of the prepared photocatalyst indicated that polyhedral ZIF-8 (ca. 500 nm) was coated by MnO2/Fe3O4 nanorods. The synergy effect of Fe3O4/MnO2/ZIF-8 compos-ite exhibited an excellent photocatalytic activity toward RB19 degradation of 99.5 % after 60 min of irra-diation due to high surface area and heterojunction formation. According to scavenger tests, the photodegradation of RB19 dye over Fe3O4/MnO2/ZIF-8 was mainly contributed by OH and U2? reactive radicals. The kinetic study showed that the catalytic degradation of RB19 on Fe3O4/MnO2/ZIF-8 was better described by the first-order kinetic model. The new catalyst was easily recovered using an external mag-netic field because of its magnetic properties. Besides, Fe3O4/MnO2/ZIF-8 showed high recyclability and stability, maintaining a high removal efficiency of 91.3 % even after ten repeated cycles. The overall results indicated that the fabricated composite can be used as an efficient photocatalyst for treating organic dyes in wastewater. (c) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.