Synergistic Antimicrobial and Photocatalytic Properties of PVP-Ag-PEG Nanocomposites for Sustainable Leachate Treatment

The aim of this study was to evaluate the effectiveness of bi-polymers (PVP + PEG)-capped silver (Ag) nanocomposites (PVP-Ag-PEG) in addressing the environmental challenges posed by landfill leachate. The synthesized nanocomposites were thoroughly characterized using X-ray diffraction (XRD), UV-visible spectroscopy (UV-vis), Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), and Selected area electron diffraction (SAED) techniques. The prepared nanocomposites exhibit mono-dispersed crystalline particles with face-centered cubic (FCC) structure and spherical shape with 8.18 nm size. The FTIR analysis confirms the effective reduction and stabilization of AgNPs by PEG and PVP. Density Functional Theory (DFT) calculations with the B3LYP method and the LANL2DZ basis set were employed to optimize the molecular structure of PVP-Ag-PEG and provide insights into its electronic structure and reactivity. The PVP-Ag-PEG nanocomposites exhibited concentration-dependent cytotoxicity, with enhanced cell death at higher concentrations against breast cancer cells. In addition, the prepared nanocomposites inhibited Pseudomonas aeruginosa, and Staphylococcus aureus, and bacterial strains isolated from landfill leachate, demonstrating their potential for environmental applications such as groundwater purification and leachate remediation. The photocatalytic activity of the prepared nanocomposites was assessed for both landfill leachate and congo red dye, and these were completely degraded within 70 and 100 min, respectively with high degradation efficiencies (84% and 97%, respectively) were attributed to the synergistic effects of PVP and PEG polymers in the reaction medium, likely due to the generation of ROS and the induction of oxidative stress, which resulted in the controlled, sustained release of Ag ions. Overall, bi-polymer-capped Ag nanocomposites present a cost-effective and eco-friendly alternative to traditional treatments, offering significant ecological benefits and providing a sustainable approach to mitigating the adverse effects of industrial waste and landfill leachate on groundwater.