Polyelectrolyte Functionalized Ti₂CT_x MXene Membranes for Pervaporation Dehydration of Isopropanol/Water Mixtures

Recently, owing to their excellent structural and transport properties, two-dimensional membranes have attracted tremendous interest for their potential application in molecular separation. In this work, a new type of functionalized Ti₂CT_x MXene membrane was proposed by introducing different kinds of polyelectrolytes to regulate the membrane physicochemical structure for pervaporation dehydration of isopropanol dehydration. The morphology, physical, and chemical properties of powders and MXene-based membranes were studied by SEM, AFM, FTIR, XPS, and contact angle test. Meanwhile, the effect of polyelectrolyte functionalization on the MXene membrane performance for isopropanol dehydration was also studied. The results showed that the poly­(diallyldimethylammonium chloride) (PDDA) functionalized MXene membrane possesses the highest separation performance owing to the optimized electrostatic effect and hydrophilicity. Besides, other influencing factors including PDDA concentration, MXene loading, and operating conditions on the MXene membrane performance were also systematically investigated. The developed PDDA functionalized MXene membrane showed excellent separation performance for dehydration of 90 wt % isopropanol/water at 50 °C with a total flux of 1237 g/m²·h and separation factor of 1932, showing great potential in application of solvent dehydration.