High-performance photocatalytic degradation of binary mixture of RhB and DR23 dyes under UV irradiation using nanosized-ZnO

Abstract

Zinc oxide (ZnO) structures are used in the field of environmental issues, especially photocatalysts, due to their superior physical and chemical properties. In this study, ZnO structures were produced using the hydrothermal technique. The physical and photocatalytic properties of the synthesized ZnO structures were investigated. The crystal size of ZnO was calculated using XRD patterns and found to be 27–36 nm using the modified Scherrer equation, 33–40 nm using the Williamson Hall model depending on the precursor amount. Scanning electron microscope (SEM) images of the produced ZnO structures revealed that it had a structure in the form of cauliflower morphology. Changing of the ZnO structure with decreasing precursor amounts clearly narrowed the band gap energy. Experimental studies of photocatalytic activity of ZnO photocatalysts were examined in a UV-cabinet, under Ultraviolet–A (UVA) light irradiation and by degradation of Rhodamine B (RhB) and Direct Red 23 (DR23) binary mixture of dyestuff against time. As a result of the experimental studies, it was observed that the photocatalytic activity of ZnO structure showed 97.16% higher degradation efficiency in 180 min. In line with kinetic studies, the photocatalytic half-life of the RhB + DR23 dyestuff was calculated between 31.79 min and 52.91 min for all structures, reaction rate constant (k) was calculated as highest 0.0218 1/min for Z 36.6 RhB degradation, and the regression coefficient (R²) values were calculated between 0.54 and 0.98 for all structures.