Vacuum-Assisted Interfacial Polymerization Technique for Enhanced Pervaporation Separation Performance of Thin-Film Composite Membranes

In this work, thin-film composite polyamide membranes were fabricated using triethylenetetramine (TETA) and trimesoyl chloride (TMC) following the vacuum-assisted interfacial polymerization (VAIP) method for the pervaporation (PV) dehydration of aqueous isopropanol (IPA) solution. The physical and chemical properties as well as separation performance of the TFC(VAIP) membranes were compared with the membrane prepared using the traditional interfacial polymerization (TIP) technique (TFC(TIP)). Characterization results showed that the TFC(VAIP) membrane had a higher crosslinking degree, higher surface roughness, and denser structure than the TFC(TIP) membrane. As a result, the TFC(VAIP) membrane exhibited a higher separation performance in 70 wt.% aqueous IPA solution at 25 °C with permeation flux of 1504 ± 169 g∙m(−2)∙h(−1), water concentration in permeate of 99.26 ± 0.53 wt%, and separation factor of 314 (five times higher than TFC(TIP)). Moreover, the optimization of IP parameters, such as variation of TETA and TMC concentrations as well as polymerization time for the TFC(VAIP) membrane, was carried out. The optimum condition in fabricating the TFC(VAIP) membrane was 0.05 wt.% TETA, 0.1 wt% TMC, and 60 s polymerization time.