green synthesis of magnesium oxide nanoparticles in MFI type zeolite and its application as a photocatalyst

Rice husk silica (RHS), an agriculture waste, was used as a silica source for MFI zeolite synthesis. Magnesium oxide (MgO) nanoparticles (NPs) were grown in zeolite substrates using a solid state reaction. The synthesized nanocomposite (NC) was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS) and transmission electron microscopy (TEM) techniques. The BET results demonstrated specific surface area of MgO/RHS-MFI NC was smaller than RHS-MFI zeolite. It was founded that magnesium oxide NPs can be encapsulated into pores of RHS-MFI zeolite. The most principal objective of this research was evaluation of the capability of photocatalytic process of MgO/RHS-MFI zeolite heterogeneous nanocomposite over methylene blue (MB) dye. The results showed the MB degradation reached 80 % under UV light at pH=9. RHS-MFI affected the photocatalytic activity of magnesium oxide due to decrease of recombination rate of the electro-hole in magnesium oxide semiconductor. A plausible oxidation mechanism was also proposed.