The effect of polymer composition on CO2/CH4 separation of supported carbon membrane

Abstract

Recently, membrane technology has attracted vast attention from many scientists and engineers, particularly from the industrial area. The membrane for gas separation is favoured due to its economically feasibility and high separation performance with respect to gas permeability and selectivity. In this study, the effect of different polymer concentrations (5, 10, 13, 15 and 18 wt%) on the gas permeation properties of CO2/CH4 separation was investigated. Matrimid 5218 was chosen as the based polymer for tubular carbon membrane preparation owing to its excellent membrane properties (i.e. high mechanical and thermal stability) in order to fulfil the membrane requirement for high gas separation performance. The commercialised tubular membrane was dip-coated into Matrimid/NMP solution and then proceed with carbonisation process at the optimum condition with a heating rate of 2 K/min and under Argon gas flow rate at 200 mL/min at temperature of 1,123.15 K by using argon gas. The pure gas permeation tested for both CO2 and CH4 was carried out under room temperature at pressure controlled at 800 kPa. From the experimental results, the tubular membrane made of 15 wt % Matrimid performed the highest CO2/CH4 selectivity (87.34 %) as compared to the other membranes. The excellent performance obtained from the membrane could be attributed by the micropores formation, where the chain of the polymer had increased its packing density. Thus, membrane porosity can be increased by increasing the polymer concentration in the solution.