Crosslinking modification of polyamide composite membranes toward high performance for DMAc/H2O dehydration

Abstract

Abstract Polar aprotic solvents such as dimethylacetamide (DMAc) play a crucial role in the chemical industry. Pervaporation is a membrane separation technology suitable for the dehydration of organic solvents. In this study, thin polyamide (PA) pervaporation membranes with different structures were prepared by interfacial polymerization using trimesoyl chloride (TMC) as the organic phase, and either m-phenylenediamine (MPDA), propylene diamine (DAPE), or tetraethylene pentamine (TEPA) as the aqueous phase. In addition, the PA pervaporation membranes' chemical composition, hydrophilicity, surface morphology, and cross-sectional morphology were examined by fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopic (AFM) and contact angle (CA) analysis, respectively. The results showed that the PA pervaporation membrane prepared with TEPA as the aqueous monomer exhibited a high degree of crosslinking, resulting in dense molecular chains. The permeation flux and water content of 10 wt % DMAc/H2O system were 17.8 L m− 2 h− 1 and 98.4 wt % at 500 Pa and 70 ° C, respectively. Therefore, the TEPA-PA membrane has a good separation performance even when dealing with a low-concentration DMAc/H2O system.