Photocatalytic degradation of methylene blue dye by magnetized TiO2-silica nanoparticles from rice husk

Abstract

In this current study, magnetized TiO₂-supported SiO₂ nanoparticles, synthesized from rice husk, was applied as a photocatalyst to degrade methylene blue dye (MBD) in aqueous solution using LED lamp as light source. The effects of MBD initial concentration, TiO₂ loading, pH and illumination time on the degradation efficiency of the photocatalyst on MBD was investigated using Box–Behnken design as the experimental design tool. Photocatalyst was characterized by Fourier transform infrared, scanning electron microscopy, energy-dispersive X-ray, thermogravimetric analysis and Brunauer–Emmett–Teller. At optimum predicted point where MBD initial concentration, TiO₂ loading, pH and illumination time were 10 ppm, 15%, 6 and 75 min, respectively, the predicted and experimental percentage of MBD removed were 97.66% and 96.89%, respectively. Correlation coefficient and ANOVA justified high significance of the developed model for prediction. Experimental data fitted excellently into pseudo-second-order kinetic model. The temperature effect revealed optimum MBD photocatalytic degradation at 50 °C by TiO₂/mRH-SNP. Characterization revealed the effects of magnetization and TiO₂ addition on the synthesized SiO₂ nanoparticles from rice husk. In conclusion, magnetized TiO₂-silica nanoparticles from rice husk could be effectively used to degrade MBD in solution.