V2O5 based nanocomposites with MOF and rGO for the adsorption and photocatalytic degradation of methylene blue dye

In the present work, vanadium pentoxide-metal organic framework (V2O5-MIL 125 MOF) and vanadium pentoxide-reduced graphene oxide (V2O5-rGO) nanocomposites were successfully synthesized using a facile low-temperature hydrothermal treatment. These synthesized catalysts were used to study the adsorption capacity and photocatalytic degradation of methylene blue (MB) dye in aqueous solutions, under dark and UV light conditions. The influence of adsorption on dye removal and its isotherm revealed that both nanocomposites follow the Freundlich isotherm. The kinetics of adsorption indicated pseudo-second-order behavior. V2O5-MIL 125 MOF and V2O5-rGO exhibited maximum dye adsorption capacities of 62 and 24 mg/g, respectively. The optimal values for maximum photocatalytic degradation were determined, and the mechanism of degradation was verified using radical scavengers. A 125 W high-pressure mercury vapor light was employed as the light source for all dye degradation studies. Maximum degradation was obtained at neutral conditions (pH 7.4) of the solution, ambient temperature (30±2˚C), and 10 ppm initial dye concentration. The synthesized photocatalysts V2O5-MIL 125 MOF and V2O5-rGO exhibited maximum degradation of 87% within 270 min and 82% within 300 min of UV light exposure, respectively. The adsorption and photocatalytic effects of V2O5-MIL 125 MOF and V2O5-rGO were also compared with pure vanadium pentoxide (V2O5), where both showed better activity.