Thin‐film hydrogel polymer layered polyvinyltrimethylsilane dual‐layer flat‐bed composite membrane for CO 2 gas separation

The gas transport property of the hydrogel chitosan (CS) and the CS‐polyethylene glycol (CS+PEG) polymer blend surface‐modified polyvinyltrimethylsilane (PVTMS) composite membranes have been evaluated for pure CO 2 , N 2 , and CH 4 gases. The physic‐chemical characteristics and the surface morphological features of the prepared pure and the composite PVTMS membranes were interrogated with the Fourier transform infrared spectroscope, high‐resolution scanning electron microscope, thermogravimetric analysis, and differential scanning calorimeter. Effect of water wetting of the membrane, number of sequential coating, and the transmembrane pressure on the gas transport properties of the pure and composite PVTMS membranes was concurrently studied. The acceptable CO 2 permeability of 153 barrer and the gas‐pair CO 2 /N 2 selectivity of 33 and the CO 2 /CH 4 selectivity of 23 were obtained for the CS+PEG‐modified PVTMS membrane under the optimum conditions, that is, transmembrane pressure of 76 cmHg and the reaction temperature of 30°C. The CO 2 separation performance of the modified PVTMS composite membrane against the N 2 and the CH 4 gases moved close to Robeson's upper bound 2008. Enhancement in the CO 2 separation efficacy of the modified PVTMS membrane than the pure PVTMS membrane has proved good efficiency of the modified membrane towards CO 2 capture application.