<p>Managing heavy metal ions in wastewater is imperative due to their profound impacts on human health and the ecosystem. Membranes endowed with adsorptive features present a highly promising solution for the efficient removal of contaminants such as cadmium (Cd²⁺), nickel (Ni²⁺), and lead (Pb²⁺). This study focuses on the preparation of adsorptive membranes by immobilizing HKUST-1 metal-organic framework on the surface of polyethersulfone (PES) for the removal of heavy metal ions from wastewater. HKUST-1 was integrated onto the membrane surface via gelatin-assisted growth and in-situ growth techniques, and further incorporated into a PES polymer matrix. Comprehensive characterization of these modified membranes was conducted using the FESEM, XRD, FTIR, EDAX, and contact angle analyses. The findings revealed that the PES/J (gelatin-assisted growth) membrane, in combination with the PES/I (in-situ growth) membrane, exhibited superior efficacy in heavy metal removal. Notably, the pure water flux of the gelatin-seed membrane increased approximately 2.5-fold compared to the pristine membrane. The PES/J membrane demonstrated high fluxes ranging between 80 and 140 lit/m².h.bar, whereas the pristine PES membrane had fluxes around 25–50 lit/m².h.bar. Furthermore, a uniform dispersion of HKUST-1 crystals on the membrane surface was observed for the adsorptive membrane prepared via the gelatin-assisted growth method, which led to a heavy metal removal efficiency of 100% after 80&#xa0;min for Cd²⁺ and Ni²⁺ and 60&#xa0;min for Pb²⁺ ions. The synthesis and characterization of these adsorptive nanocomposite membranes (ANMs) via in-situ growth, gelatin-assisted growth, and mixed matrix approaches demonstrate their potential for efficient heavy metal removal from wastewater.</p>