Scavenger-free solar photocatalytic degradation of Textile Dyes and Antibiotics using magnetically separable bi-junctional photocatalyst

Abstract

The field of solar photocatalysis has been plagued by photocatalysts with low photon-to-electron conversion efficiency, resulting in poor photocatalytic degradation rates of water pollutants. With a keen idea to improve the existing photocatalysts, we developed a scavenger-free, magnetically separable, bi-junctional solar photocatalyst. The photocatalyst comprises Fe²⁺ doped zinc ferrite as core, ZnO as shell, and irregular CuO nanoparticles in conjunction with the surface of core-shell nanoparticles prepared using a combination of microwave-assisted solvothermal technique and microwave-assisted reflux method. The photocatalytic degradation properties of the solar photocatalyst were modelled and optimized with the help of Methyl Orange under direct sunlight. This novel composite degrades Methyl Orange roughly four times faster than core-shell nanoparticles. The photocatalyst meets most of the criteria for working of a promising solar photocatalyst, such as 1) excellent absorption of sunlight, 2) two physically distinct heterojunction and absorbing regions for efficient charge carrier generation and separation, 3) scavenger-free degradation of textile dyes and antibiotics, 4) High surface area (39 m²g ⁻¹), 5) good stability, 6) excellent reusability, 7) and easy separation of nanoparticles for reuse with the help of a magnet. The prepared photocatalyst efficiently degrades fluoroquinolone antibiotics such as Ciprofloxacin Hydrochloride, Norfloxacin, and Ofloxacin. The photocatalyst demonstrates the capability to efficiently degrade textile dyes such as Methyl Orange, Methylene Blue, Orange G, Fluorescein sodium salt, Rhodamine B, and Crystal Violet. Additionally, the bi-junctional photocatalyst can be coated with a thin layer of silver to achieve twice the degradation rate. This enhancement is attributed to the Localized Surface Plasmon Resonance (LSPR) effect. The current work presents an effective and economical option for removing dyes and antibiotics in wastewater, marking a significant stride towards sustainable industrial practices.