Strategic decolorization of rose bengal in an aqueous environment using a zinc oxide-loaded reduced graphene oxide photocatalyst

Abstract

The environmental and health hazards posed by synthetic organic dyes, such as Rose Bengal, have spurred significant concern in recent years. Herein, a novel zinc oxide/reduced graphene oxide (ZnO/rGO)-based photocatalyst is developed and used for the efficient decolorization of RB dye in aqueous solutions. The as-synthesized nanostructured material is characterized using advanced techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) mapping to elucidate its crystalline structure, morphology, and elemental composition. The XRD pattern confirmed the wurtzite crystalline phase structure with an average size of 67.8 nm, while SEM imaging verified the successful incorporation of ZnO nanoparticles into the rGO matrix. Further, the as-prepared material was used as a photocatalyst, which demonstrated remarkable performance in RB dye decolorization, achieving ≥96.1 % degradation within just 5 min at a minimal catalyst dosage of 8.0 mg. Moreover, kinetic studies revealed that the decolorization process followed a pseudo-second-order reaction mechanism, further enhancing the understanding of the catalytic behavior. It is more interesting that the catalyst exhibited exceptional reusability for up to seven cycles with only a decrease in catalyst efficiency from 96.1 % to 77.5 %, underscoring its practical viability and sustainability. The significance of this work lies in its contribution to addressing the environmental challenges associated with synthetic dyes, particularly rose bengal, by offering an efficient and reliable photocatalytic solution. The demonstrated efficacy of the ZnO/rGO photocatalyst not only showcases its potential for large-scale rose bengal dye degradation but also suggests broader applicability for the treatment of other synthetic dye pollutants.