Green synthesis, characterization, and multifunctional applications of Ag@CeO₂ and Ag@CeO₂-pullulan nanocomposites for dye degradation, antioxidant, and antifungal activities

The synthesis and characterization of novel nanocomposites with unique properties have garnered significant interest. Ag@CeO₂ nanocomposite and its pullulan counterparts were prepared using a green approach involving rosemary extract. Characterization techniques, including Fourier Transform Infrared Spectroscopy, UV–visible spectroscopy, zeta potential, Dynamic Light Scattering, High-Resolution Transmission Electron Microscopy, Energy-Dispersive X-ray Spectroscopy, Scanning Electron Microscopy, and X-ray Diffraction, confirmed the formation of Ag@CeO₂ nanoparticles (NPs). Pullulan led to increased particle size and improved homogeneity. Employing the Artificial Neural Networks (ANN) model to optimize methylene blue removal by Ag@CeO₂ NPs and Ag@CeO₂-pullulan NPs demonstrated predictive capabilities up to 97.53 % of MB removal (R² = 0.9991). The antioxidant test demonstrated that rosemary extract exhibited the highest activity (IC₅₀ = 0.011 mg/mL), then Ag@CeO₂ NPs (IC₅₀ = 0.039 mg/mL), and Ag@CeO₂-pullulan NPs (IC₅₀ = 0.041 mg/mL). Both Ag@CeO₂ NPs and Ag@CeO₂-pullulan NPs inhibited Candida albicans growth, with the latter exhibiting enhanced efficacy (MIC = 468.27, MFC = 936.53, and IC₅₀ = 129.60 μg/mL). The study successfully synthesized novel Ag@CeO₂-based nanocomposites coupled with pullulan with promising applications in dye removal, and antimicrobial therapy. The incorporation of pullulan improved the properties of the nanocomposites, enhancing their potential for practical use in environmental and biomedical applications.