Electrospun Polyurethane-Based Nanofibrous Membranes Functionalized with UiO-66-NH₂ for Water Remediation

Water contamination resulting from anthropogenic activities poses a critical threat to ecosystems and human health. The development of efficient, sustainable, and selective materials for water purification has therefore become a pressing necessity. In this study, polyurethanes (PUs) with tailored soft and hard segments were synthesized and characterized to evaluate their suitability for the fabrication of electrospun membranes. ATR-FTIR confirmed successful polymerization, while thermal analyses revealed that molecular design strongly influences the polymers' thermal behavior. Among the synthesized materials, only two PUs exhibited solubility and spinnability, leading to homogeneous nanofibrous mats with average fiber diameters of approximately 500 nm. To enhance the adsorption capacity, specific surface area and interaction diversity of the membranes, metal-organic framework (MOF) particles were incorporated into the polymer solutions prior to electrospinning, allowing their immobilization within the fibrous polymer matrix. The resulting hybrid membranes showed remarkable improvements in methylene blue uptake, increasing from 29 to 34 mg·m^-2 in pristine membranes and 57 to 115 mg·m^-2 in the MOF-containing ones. This enhancement was attributed to the synergistic effect between the aromatic urethane structures and the MOF linkers, as well as to the increased effective surface area provided by the nanofibrous architecture. The results demonstrate the potential of electrospun PU-based membranes as pollutant removal, combining structural versatility, functional tunability, and compatibility.