Green synthesis of CuFe₂O₄ nanoparticles using plant waste for photocatalytic degradation of ciprofloxacin

This study reports the green synthesis of CuFe₂O₄ nanoparticles using plant waste materials as bio-reducing agents and their application as efficient heterogeneous photocatalysts for the degradation of ciprofloxacin (Cipro) antibiotic. Four bio-CuFe₂O₄ photocatalysts were synthesized via a sol–gel method using date pulps, date seeds, honeybee pollens, and lemon peels. The structural, morphological, and optical properties of the bio-CuFe₂O₄ nanoparticles were characterized using advanced techniques, including XRD, FTIR, SEM, TEM, UV–Vis DRS, PL, XPS, and XAFS. The CuFe₂O₄ derived from date pulp (bio-CuFe₂O₄/DP) exhibited the highest photocatalytic activity, achieving nearly 97 % Cipro degradation and 69.1 % TOC removal within 120 min in a photo-Fenton/peroxymonosulfate system under UV–Vis irradiation. The superior performance of bio-CuFe₂O₄/DP was attributed to its favorable physicochemical properties, including a higher bandgap, reduced electron-hole recombination, and faceted nanostructure. The bio-CuFe₂O₄/DP catalyst demonstrated high stability and reusability over five reaction cycles. Quenching experiments and EPR measurements revealed that SO₄^•–, HO^•, and O₂^•– were the active species responsible for the efficient Cipro degradation. LC-MS/MS analysis identified the transformation products, and possible degradation pathways were proposed. This study highlights the potential of biowaste-derived CuFe₂O₄ nanoparticles as stable and efficient photocatalysts for the remediation of pharmaceutical pollutants in wastewater.