In this study, polyacrylic acid (PAA) was grafted onto a polyamide (PA) surface through ultraviolet-initiated graft polymerization to improve the pervaporative dehydration of aqueous alcohol solutions. The PA layer was formed on the surface of a polyacrylonitrile support by the interfacial polymerization of 1,4-bis(3-aminopropyl)piperazine and trimesoyl chloride. Afterward, the PAA was deposited under varying grafting conditions—different acrylic acid concentrations, periods of irradiation time, and irradiation distances. Attenuated total reflectance-Fourier transform infrared and X-ray photoelectron spectra indicated the presence of more carboxyl groups on the membrane surface after grafting PAA. Images from field emission scanning electron microscopy and atomic force microscopy illustrated that the membrane became rougher. PAA also improved the membrane hydrophilicity. The dehydration of 90 wt% aqueous ethanol solutions by pervaporation demonstrated that the flux and water concentration in permeate were enhanced from 803 ± 55 to 830 ± 59 g m−2 h−1 and 84.9 ± 2.5 to 99.5 ± 0.3 wt%, respectively. Furthermore, the PAA-PA membranes showed stable performance at wide operating conditions.
- Acrylic acid
- Ultraviolet-initiated graft polymerization