Preparation of a PVA/Chitosan/Glass Fiber Composite Membrane and the Performance in CO2 Separation

In this study, a novel composite membrane was developed by casting the mixed aqueous solution of chitosan (CS) and polyvinyl alcohol (PVA) on a glass fiber microporous membrane. The polymeric coating of a composite membrane containing amino groups and hydroxyl groups has a favorable CO2 affinity and provides an enhanced CO2 transport mechanism, thereby improving the permeance and selectivity of CO2. A series of tests for the composite membranes were taken to characterize the chemical structure, morphology, strength, and gas separation properties. ATR-FTIR spectra showed that the chemical structure and functional group of the polymer coating had no obvious change after the heat treatment under 180 °C, while SEM results showed that the composite membranes had a dense surface. The gas permeance and selectivity of the composite membrane were tested using single gases. The results showed that the addition of chitosan can increase the CO2 permeance which could reach 233 GPU. After a wetting treatment, the CO2 permeance (454 GPU) and gas selectivity (17.71) were higher than that of dry membranes because moisture promotes the composite membrane transmission. After a heat treatment, the permeance of N2 decreased more significantly than that of CO2, which led to an increase in CO2/N2 selectivity (10.0).