A novel magnetically separable CoFe2O4/SnO2 composite photocatalyst for the degradation of methylene blue dye from aqueous solution
Md. Tamez Uddin, Muhammad Zobayer Bin Mukhlish, Md. Rifat Hossain Patwary
Abstract
ABSTRACT In this paper, a magnetically separable CoFe 2 O 4 /SnO 2 nanocomposite was synthesized by a two-step procedure, first, the synthesis of CoFe 2 O 4 and SnO 2 nanoparticles by wet chemical precipitation method and second, the preparation of CoFe 2 O 4 /SnO 2 nanocomposites by solid-state reaction method. The resulting photocatalysts were characterized by X-ray diffraction (XRD), nitrogen adsorption– desorption analyses, scanning electron microscopy, energy dispersive X-ray spectroscopy (EDX) and UV-vis diffuse reflectance spectroscopy. The crystallization investigated by XRD confirmed the existence of both SnO 2 and CoFe 2 O 4 phases, which was further confirmed by EDX. The energy band gap of 5% CoFe 2 O 4 /SnO 2 nanocomposite observed by UV-Vis diffuse reflectance spectroscopy was estimated to be 3.7 eV, which was comparable with that of SnO 2 . The photocatalytic performance of the as-synthesized magnetic CoFe 2 O 4 /SnO 2 nanocomposites was investigated through methylene blue degradation reaction under UV irradiation. The CoFe 2 O 4 /SnO 2 nanocomposite containing 5 wt.% CoFe 2 O 4 exhibited improved photocatalytic performance compared with commercial P-25. Moreover, alkaline media was favorable for photocatalytic degradation of cationic dye methylene blue. Finally, CoFe 2 O 4 /SnO 2 nanoparticles can be separated and recovered quickly from suspension in the presence of an externally applied magnetic field without leaving residues in the solution. Therefore, it can be concluded that this work would replace the traditional semiconductor photocatalysts and the as-synthesized photocatalyst would be a promising candidate for environmental cleanup.