Synergistic photocatalysis of magnetic Fe3O4/CdS/ZnO nanocomposite for efficient and recyclable removal of tetracycline and Eosin Y

Abstract

The increasing global threat posed by persistent organic pollutants, including pharmaceutical residues and hazardous dyes, requires efficient, recyclable, and durable photocatalysts. To address this challenge, we successfully developed a novel magnetic ternary Fe3O4/CdS/ZnO nanocomposite via a simple chemical co-precipitation method. The structure and photocatalytic activity were rigorously characterized using XRD, TEM, FTIR, Raman, FE-SEM, PL, BET, VSM, and DRS. XRD confirmed a multi-phase structure including cubic spinel Fe3O4, hexagonal CdS and ZnO, with particle size of approximately 35 nm as measured by TEM .Importantly, photoluminescence studies revealed substantial quenching of electron-hole recombination in Fe3O4/CdS/ZnO compared to Fe3O4/CdS. Furthermore, the ternary nanocomposite exhibited superparamagnetic behavior (Ms ≈ 22 emu/g) and a significantly large specific surface area (approximately 69.55 m2/g), essential for facile magnetic recovery and high photocatalytic efficiency. Zeta potential analysis gave a value of approximately − 40 mV, confirming a negatively charged surface. This negative charge is expected to facilitate strong interaction between the nanocomposite and the dye molecules. The photocatalytic performance of Fe3O4/CdS/ZnO was evaluated through degradation of tetracycline (TC) under UV light and Eosin Y dye under visible light, achieving 88% degradation (90 min) and 92% degradation (150 min), respectively. These findings confirm that the optimized nanostructure enhances charge carrier separation and transfer. Compared with previously reported binary or ternary systems, this novel composite offers competitive or superior multifunctional performance under both UV and visible light. Overall, the magnetic Fe3O4/CdS/ZnO nanocomposite represents a highly effective, recyclable, and sustainable material for the neutralization of organic pollutants.