Efficient photocatalytic methylene blue degradation by Fe3O4@TiO2 core/shell linked to graphene by aminopropyltrimethoxysilane.

Abstract

In the present article, Fe3O4@TiO2 core/shell (FT) linked to graphene was fabricated by sol-gel technique as a photocatalyst and was employed for the solar degradation of cationic methylene blue (MB) in aqueous solution. The prepared core/shells were linked to graphene oxide (FTGO) and reduced graphene oxide (FTRGO) via embedding into 3-aminopropyltrimethoxysilane (APS). The structure of this magnetic composition was characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and BET surface area measurements. The significance of the composite structure in photocatalytic degradation was spectrophotometrically tested by blending the obtained powders with wastewater containing methylene blue under solar irradiation. The appropriate dosage of APS to link the Fe3O4@TiO2 core/shell onto GO and RGO surfaces was determined to be 1ml per gram of FT. The kinetic studies were performed to investigate the effects of different parameters, such as composition structure, APS dosage, and repeatability. Kinetic data are well fitted by a first-order model with a high correlation coefficient. Regardless of the prominent advantage of composites in magnetic powder separation, the Fe3O4@TiO2 core/shell linked to graphene oxide is an efficient composite in comparison to FTRGO for the dye degradation without losing the original activity and stability.