Development of UiO-67-polyaniline modified membrane for efficient dye–salt separation

Efficient dye-salt separation remains a critical challenge in wastewater treatment, particularly for textile effluents containing persistent organic dyes and high salinity. In this study, a novel multilayer membrane was developed by stabilizing UiO-67 metal–organic framework (MOF) particles on a polyacrylonitrile (PAN) support grafted with poly(methacrylate), followed by polyaniline (PANI) polymerization. All fabrication steps were conducted in aqueous solutions at room temperature. This tailored design, PAN-Gf-UiO-PANI, transformed the membrane from ultrafiltration to loose nanofiltration functionality, enabling simultaneous dye rejection and salt passage. The membrane achieved outstanding Congo red rejection (99.7 %) while maintaining high water permeance (18.4 L m⁻²h⁻¹ bar⁻¹) and over 99 % NaCl passage, demonstrating its effectiveness in dye–salt separation. It also exhibited excellent antifouling resistance, with a flux recovery ratio of 82 % after bovine serum albumin (BSA) fouling—significantly outperforming the pristine PAN membrane. Long-term filtration tests confirmed the membrane's stability and durability under both aqueous and saline conditions, underscoring its potential for real-world wastewater treatment. This study highlights MOF-based membrane surface modification as an effective strategy for fabricating high-performance membranes with enhanced selectivity, antifouling properties, and scalability, offering promising solutions for sustainable water treatment.