Advanced sulfonated polyester nanofiltration membranes for superior dye separation, desalination, and chlorine resistance

This study introduces an innovative thin-film composite (TFC) nanofiltration membrane made from sulfonated polyvinyl alcohol (SPVA)-based polyester, specifically engineered for effective wastewater treatment. This novel membrane is developed through interfacial polymerization on a polysulfone substrate, demonstrating exceptional water permeability and filtration efficiency. It is particularly effective in separating dyes and salts due to its superior hydrophilicity, optimized surface charge, and precisely tailored morphology. Critical fabrication parameters were finely tuned, utilizing a 2 wt% SPVA solution and a 0.35 wt% trimesoyl chloride (TMC) in the organic phase, with both immersion and polymerization times set at 2 min. The performance metrics are outstanding, featuring a water permeance of 97 L m−2 h−1·bar−1, high dye rejection rates (99.51 % for Congo Red and 99.55 % for Brilliant Blue), and significant salt permeability (30.35 % for Na2SO4 and 29.93 % for MgSO4). The membrane also exhibits excellent antifouling properties, robust chlorine resistance (up to 48,000 ppm h), and sustained operational stability, underscoring its industrial viability for dye and textile effluent treatment. The TFC-SPVA membrane addresses critical environmental challenges in wastewater management, marking a significant advancement in membrane technology.