Effect of solution flow rate on the fabrication of outer surface selective layer hollow fiber membranes for dye rejection

Various industries, such as food, petrochemicals, and pharmaceuticals, have recognized the importance of separation technologies for large molecules such as dye. A thin polyamide layer is commonly used in thin film composite membranes for separation applications, but fabricating a polyamide selective layer on hollow fiber (HF) membranes remains challenging. This research focuses on producing polyamide-based HF membranes by circulating aqueous and organic solutions during interfacial polymerization. By varying the solution flow rate, the dye rejection performance was investigated concerning morphology, polyamide thickness, mechanical properties, and hydrophilicity. All generated membranes consistently rejected over 98 % of congo red dye, with the highest rejection rate for methyl orange reaching approximately 92 %. The most efficient membranes were produced with an aqueous solution flow rate of 180 ml/min and an organic solution flow rate of 220 ml/min. These membranes exhibited notable ethanol permeance, with rejection rates of 99.75 % for congo red and 91.68 % for methyl orange. Additionally, they show promise for application in reverse osmosis processes for salt removal.