Anti-bacterial nanocomposites (NC1–NC4) based on cellulose acetate were prepared by dispersing ZnO nanofillers in the cellulose acetate matrix. Anti-bacterial nanocomposites were structurally and morphological examined by XRD (X-ray powder diffraction), FESEM (field emission scanning electron microscopy), and FT-IR (Fourier transform infrared) spectroscopy. All the spectroscopic techniques suggested that nanocomposites are successfully synthesized. All the nanocomposites showed anti-bacterial activity which increased as a function of zinc oxide. Further the selectivity of anti-bacterial nanocomposites was investigated toward different metal ions, including Zn 2+ , Cd 2+ , Pb 2+ , Mn 2+ , Ni 2+ , Fe 2+ , Al 3+ , Sb 3+ , and Sr 3+ . The selectivity data suggests that nanocomposites are more selective toward Fe 2+ . NC1 displayed highest uptake aptitude for Fe 2+ with highest distribution coefficient of 7549.123mLg −1 . Therefore, NC1 was subjected to water permeability to explore the role of anti-bacterial nanocomposite as membrane for water purification. The results suggest that these materials are possibly appropriate for water treatments.