Enhanced Removal of Methyl Violet Dye from Aqueous Solution by a Novel Co3O4@SiO2@TiO2-Ag Heterogeneous Semiconductor

Abstract

Background : This research introduces the application of a novel photocatalyst including Co3O4@SiO2@TiO2-Ag nanocomposite with highly photocatalytic stability and core-shell structure for the removal of toxic methyl violet from aqueous solution. Objective: The removal of toxic dyes and organic contaminants from water is outstanding research area between scientists. Methyl violet as a toxic cationic pollutant has disruptive influence for humans. In this research, with a aim to remove to methyl violet from the wastewater we developed a new photocatalyst including Co3O4@SiO2@TiO2-Ag nanocomposite as a eco-friendly and low-cost nanostructure with high photocatalytic activity in order to reduce the risks of this pollutant from aqueous media. Methods: The Co3O4@SiO2@TiO2-Ag nanostructure was prepared via hydrothermal and sol-gel methods and the structure elucidation of the prepared photocatalyst was analyzed by different spectroscopy techniques including XRD, FT-IR, FE-SEM, TEM, VSM and EDX. Results: Photodegradation of methyl violet in the presence of different structures showed that Co3O4@SiO2@TiO2-Ag is superior photocatalytic activity (about 98% was decomposed after 40 min) compared to the previous shells and pure Co3O4 NPs. Loadings of SiO2@TiO2-Ag nanocomposite over the Co3O4 surface led to the reduction in the band gap energy of visible light and improvement in the photocatalytic activity of Methyl Violet dye for the aqueous phase decomposition. Conclusion: The remarkable benefits of this nanocomposite are highly photocatalytic efficiency in the degradation of methyl violet (almost 100 % within 1 h), easy magnetic separation, low cost, and high chemical stability. The collected results demonstrated the rate of degradation is increased by increasing the irradiation time, while the rate of degradation is decreased by dye concentration.