Efficiency of zinc stannate/multi-walled carbon nanotubes as the nanocomposite photocatalyst in the removal of methylene blue from aqueous solutions

Abstract

In the present study, the use of synthesized zinc stannate/multi-walled carbon nanotubes (ZSC) nanocomposite was investigated as the photocatalyst in the removal of methylene blue (MB) under visible light. The ZSC nanocomposite was synthesized by the hydrothermal method. The structural properties of the synthesized nanocomposite were investigated by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and UV-visible diffuse reflectance spectroscopy (DRS). The optimal values of parameters for the removal of the dye were as follows: 130 mg.L-1 photocatalyst dosage, 10 mg.L-1 dye concentration, pH = 9, and 10 cm distance of radiation source. In this condition, the removal degree was 94. The photocatalytic removal of dye was followed by pseudo-first-order kinetic and Langmuir-Hinshelwood kinetic models. Furthermore, the values of the equilibrium constant of adsorption (K-ads) and the rate constant of the surface reaction (k(c)) were obtained as 0.91 L.mg(-1) and 0.84 mg.L-1.min(-1), respectively.