Two-step synthesis of a ternary composite based on TiO2 for effective removal of organic pollutants by photocatalytic degradation

Abstract

To address environmental problems, it is difficult to design effective heterogeneous photocatalysts for the removal of dye pollutants. In this context, a straightforward reflux approach was used to fabricate a new, high-purity, and inexpensive TiO₂/Mn_0.5Cd_0.5S/NiCoB nanocomposite. With a degradation percentage of over 92% of rhodamine B (RhB), after 30 minutes of exposure to visible light, the prepared nanocomposite demonstrated its efficacy in degradation of both cationic and anionic dyes. In contrast, pure samples of TiO₂ and TiO₂/Mn_0.5Cd_0.5S only demonstrated 25.2% and 46.8% degradation, respectively, under the same conditions. The degradation of other contaminants, including Eosin Yellow (EY), malachite green (MG), and methylene blue (MB), was conducted to further assess the photocatalytic activity of the synthesized sample. The results indicated a degradation of 79.5%, 71.7%, and 68.9%, respectively. Additionally, the anatase structure of the synthesized nano-titanium dioxide was demonstrated by the HR-TEM results. Moreover, the mechanism of the photocatalytic process was investigated. The results showed that the produced ˙O₂⁻ ion was a significant predominant species in the photodegradation of dye pollutants. The results indicated that the reaction kinetics adhered to the Hinshelwood model. Furthermore, the recyclability of the synthesized photocatalyst was investigated, which was confirmed after six process cycles.