Fabrication and Permeation Analysis of Polysulfone (PSf) Modified Cellulose Triacetate (CTA) Blend Membranes for CO2 Separation from Methane (CH4)

Increasing demands for clean energy and more efficient separation techniques have spurred the fabrication and development of advanced membrane materials for gas separation applications. Methane (CH4), carbon dioxide (CO2), hydrogen sulfide (H2S), and higher hydrocarbons are the most important constituents of natural gas, which induces global warming and lowers the calorific value of fossil fuels. Membrane technology has been proven to be one of the most promising and advanced technologies for CO2 capture and separation. In this study, blended membranes composed of different weight percents of polysulfone and cellulose triacetate were fabricated and evaluated for their CO2/CH4 separation performance. Polysulfone and cellulose triacetate were both selected because they are chemically compatible, have good mechanical strength, are economical, have better separation performance, and are green in nature as well. The fabrication process involves the preparation of cellulose triacetate/polysulfone well-homogenized blended membrane solutions in N-methyl pyrrolidone, followed by the solution casting technique. The fabricated membranes were then characterized using various techniques. Dense, defect-free membranes exhibit promising performance in terms of CO2/CH4 selectivity, showing a significant improvement over the pristine membranes without compromising on the permeabilities. On Robeson's upper bound graph, a notable CO2/CH4 selectivity of 30.70 with a CO2 permeability of 11.12 Barrer was observed for a 6 weight percent cellulose triacetate/polysulfone sample at 4 bars, as compared to the selectivity of pristine cellulose triacetate and polysulfone, which had a value of 9.82 and 10.35, respectively. Moreover, the ultimate tensile strength test results show an improvement in tensile strength of up to 62% for the 6 weight percent sample as compared to the pure cellulose triacetate membrane. [GRAPHICS] .