Immobilization of Bi2MoO6/ZnO heterojunctions on glass substrate: Design of drug and dye mixture degradation by solar-driven photocatalysis

Abstract

In this study, the Bi2MoO6/ZnO heterostructures were quickly and easily obtained using the sonochemical method and impregnated on a glass plate using epoxy resin. The influence of increasing the percentage of ZnO (1:1, 2:1, 4:1 and 8:1% by weight) in relation to Bi2MoO6 on the formation of the heterostructure was investigated. The XRD results of the heterostructures indicated the presence of ZnO phases with a hexagonal structure and Bi2MoO6 with an orthorhombic structure. According to FESEM and HRTEM analyses, the morphology of ZnO is controlled with the addition of Bi2MoO6. The photocatalytic activity of the heterostructures was evaluated using a mixture (MIX) of methylene blue dye and diclofenac potassium, obtaining photocatalytic efficiency of 99.7 % and 90 % in 100 min under solar irradiation, with the ZN8B1 heterostructure, respectively. Aiming to increase the reuse of the material, the ZN8B1 heterostructure was impregnated into a glass plate, obtaining an efficiency of on average 65.2 % for 10 reuse cycles, showing that the impregnate can be applied to effluent treatment. The evaluation of the effect of photocatalyst dosage, contaminant concentration and pH effect was carried out with the MIX solution in order to simulate real conditions. Furthermore, a possible photocatalytic mechanism was proposed based on inhibition tests, verifying that the •O2– and •OH radicals were the dominant active species, which followed the Z-scheme mechanism.