Synthesis and characterization of crosslinked poly(vinyl alcohol)/poly(allylamine)/2-amino-2-hydroxymethyl-1,3-propanediol/polysulfone composite membrane for CO2/N2 separation

• We report a novel poly(vinyl alcohol)/amine blend membrane for CO2/N2 separation.
• Membranes were characterized using TGA, DSC, FTIR, XRD and SEM.
• Membrane showed very good thermal stability up to 170 °C.
• Maximum CO2/N2 selectivity of 260 and a CO2 permeance of 40 GPU were obtained.
• Membrane exhibited good stability during a 250 h test.

This study reports novel CO2-selective crosslinked thin film composite poly(vinyl alcohol) (PVA)/amine blend membranes, its structural characterizations and permeation studies. The characteristic properties of the active layer were examined with Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Effects of feed pressure, temperature, and sweep side water flow rate on transport properties (CO2 and N2 flux, CO2 permeability, and CO2/N2 selectivity) were investigated with a mixed gas stream containing 20% CO2 and 80% N2 by volume. The temperature, feed pressure and sweep side water flow rate were varied from 90 to 125 °C, 1.7 to 6.2 atm and 0.02 to 0.075 cm3/min, respectively. The good miscibility properties, obtained from the blended amines with crosslinked PVA, allowed a thin selective dense layer to be formed on self-made porous PSf support, which displays both high selectivity and permeability. The maximum CO2/N2 selectivity of 260 and a CO2 permeability of 555 Barrer were obtained for the membrane with 14 µm active layer thickness. Crosslinked PVA with blended amines membrane also exhibited a good stability during a 250 h test.