Fabrication of (Ni, S)-Codoped ZnO Nanophotocatalysts as Efficient Solar-Light Driven Photocatalysts for the Degradation of Organic Azo Dyes in Aqueous Media

In this study, a visible-light-active undoped ZnO and (Ni, S)-codoped ZnO photocatalyst was synthesized in nano form using the co-precipitation method with ZnSO₄•۷H₂O as a precursor. The structural and morphological properties of the synthesized photocatalyst were analyzed through spectroscopic methods, including XRD, FT-IR, SEM-EDAX, TEM, and UV-DRS analyses.  The photocatalytic activity of the synthesized materials was tested on an azo dye, Direct Red-۸۱ and its degradation efficiency was evaluated.    The results revealed that ۱۰۰% of Direct Red-۸۱ azo dye was degraded using (Ni, S)-codoped ZnO photocatalysts (۰.۱ g/۱۰۰ mL) under visible light irradiation within ۲۰ minutes. Moreover, ۹۹% mineralization was confirmed using COD and TOC analyses.   The reaction rate followed pseudo-first-order kinetics with a rate constant of ۰.۰۶۴ × ۱۰⁻³ min⁻¹. Furthermore, the photocatalysts demonstrated reusability and were effective for eight consecutive cycles without any loss in efficiency. These findings illustrate the enhanced photocatalytic activity of the (Ni, S)-codoped ZnO photocatalyst, which is attributed to the reduced rate of electron-hole recombination reactions. Additionally, the synthesized nanoparticles were eco-friendly, stable, and well-organized, making them suitable for the treatment of industrial and agricultural wastewater containing organic contaminants in relatively shorter periods under sunlight irradiation. Hence, the synthesized (Ni, S)-codoped ZnO photocatalyst serves as a significant tool for the treatment of effluents in various environmental applications.

کلیدواژه ها:

Photodegradation ، Visible light ، Direct Red ۸۱ ، pollutant ، Mineralisation