Novel fabrication techniques for HKUST-1 adsorptive nanocomposite membrane for heavy metals removal from wastewater

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 min for Cd²⁺ and Ni²⁺ and 60 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.