Application of ZnO/Ag-incorporated PCL nanofiber membranes for antibacterial remediation of microbial contamination in urban water bodies

Electrospun nanofiber membranes incorporating ZnO and Ag nanoparticles were developed using a coaxial electrospinning technique to address microbial contamination in urban water bodies. Polycaprolactone (PCL) served as the polymer matrix, and five formulations (S0–S4) with increasing nanoparticle concentrations were synthesized. Morphological analyses revealed uniform fiber formation with optimal distribution of ZnO and Ag at moderate loadings. S3 (3 wt% ZnO, 0.3 wt% AgNO₃) exhibited a mean fiber diameter of 487 nm, pore size of 2.0 µm, and porosity of 82.8 %. ATR-FTIR and XRD analyses confirmed the presence and dispersion of the incorporated nanoparticles without altering PCL’s structural integrity. Wettability improved significantly, with water contact angle decreasing from 114.3° (S0) to 93.4° (S4). Mechanical testing showed that S3 retained tensile strength (4.3 MPa) and ductility (180 % elongation). Antibacterial assays demonstrated a peak inhibition zone of 11.2 mm against Staphylococcus aureus and 10.4 mm against Escherichia coli . Filtration trials using simulated urban wastewater revealed that S3 achieved a log reduction value of 4.4 (corresponding to 99.996 % bacterial removal), reduced turbidity by 91.8 %, and lowered conductivity by 12.3 %. Despite reduced flux with increasing nanoparticle content, S3 maintained a satisfactory water flux of 112.6 L/m 2 ·h. These multifunctional membranes offer a promising route for enhancing microbial safety and improving physical water quality without the drawbacks of traditional disinfection. This study provides insights into nanoparticle–polymer interactions and offers design guidelines for practical, high-performance water purification systems in urban environments.