CO2 separation using thermally stable crosslinked poly(vinyl alcohol) membrane blended with polyvinylpyrrolidone/polyethyleneimine/tetraethylenepentamine

This article reports structural characterizations and permeation of novel CO2-selective crosslinked thin film composite poly (vinyl alcohol) (PVA)/polyvinylpyrrolidone (PVP) blend membranes doped with suitable amine carriers. The characteristic properties of the active layer were examined by Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The effects of active layer thickness, feed pressure, temperature, and sweep side water flow rate on transport properties (CO2 and N2 flux, CO2 permeance, 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 selective dense layer containing amine carrier displays both high selectivity and permeance. The maximum CO2/N2 selectivity of 270 and a CO2 permeance of 29 GPU were obtained for the composite membrane with 45 µm active layer thickness at 2.8 atm feed side absolute pressure and 100 °C temperature. Crosslinked-PVA–PVP with blended amines membrane also exhibited a good stability during a 300 h test.