Fast decolorization of rhodamine-B dye using novel V2O5-rGO photocatalyst under solar irradiation

Abstract

Degradation of dyes through Metal-oxide semiconductors using Advanced Oxidation Process (AOP) presents a unique opportunity for the development of advanced treatment techniques for effective removal of dyes from industrial wastewater. In this paper, an experimental study is being carried out by synthesizing the vanadium pentoxide–reduced graphene oxide (V2O5-rGO) nanocomposite for effective dye-degradation through photocatalysis under solar irradiation. V2O5-rGO nanocomposite is obtained by using an easy and efficient procedure of V2O5 nanowire in an rGO solution. V2O5 nanowires when bonded to rGO sheets (2D), serves as an excellent catalyst for the degradation of Rhodamine-B (RhB) dye. V2O5-rGO nanocomposites has been characterized using FESEM (Field Emission Scanning Electron Microscope), XRD (X-Ray Diffraction), and FTIR (Fourier Transform Infrared spectroscopy) techniques. V2O5-rGO is primarily used as a photocatalyst which utilizes sunlight for degradation of aqueous Rhodamine-B (RhB) dye through the principle of photoreaction. The nanocomposite shows ̴ 97% dye removal efficiency of RhB (20 mg/L) solution for a short processing time of 50 min. The study shows an increased generation of hydroxyl radicals (∙OH) in the presence of rGO sheets in the catalyst, which supports the photocatalytic process through suppression of electron (e-) and hole (h+) recombination causing the degradation of RhB dyes. Adding rGO shows ~84% faster decolorization in comparison to pure V2O5. The catalyst efficacy is further evaluated through varying pH of the RhB solution medium. A pH dependency of the reaction rate is observed with the fastest degradation time in the presence of V2O5-rGO nanocomposite being achieved at a pH of 9. Reusable catalytic properties for the suspended V2O5-rGO nanocomposite are studied for 6 cycles and the degradation efficiency of more than 90% is observed in 50 min. A brief study is performed to determine the decreased photocatalytic performance, which is fully reverted using simple chemical treatment by H2O2 and UV irradiation for further usage of the photocatalyst.