Fabrication of GCN (Graphitic Carbon Nitride) Nanosheets Based CA (Cellulose Acetate) Mixed Matrix Membranes for Carbon Capture

Abstract

In recent years, there has been an increasing demand for efficient separation technologies for CO2/CH4 gas mixtures, particularly in the natural gas processing industry. The separation of CO2 from CH4 is crucial to produce natural gas with a high heating value and reduced greenhouse gas emissions. Due to their low energy requirements, scalability, and affordability, membrane-based gas separation technologies have become a possible replacement for conventional separation techniques. In gas separation applications, mixed matrix membranes (MMMs), which incorporate the benefits of both polymers and inorganic materials, have gained a lot of interest. In this study, 2D graphitic carbon nitride nanosheets (g-C3N4) were added to the polymer matrix to enhance the performance of cellulose acetate MMMs for CO2/CH4 gas separation. The solution casting process was used to create CA based MMMs with different g-C3N4 loadings like 0.5,1.0 and 1.5 wt% using tetrahydrofuran (THF) as solvent. FTIR, XRD, SEM, UTM and permeation studies were used to characterize the produced MMMs. Incorporation of GCN into CA polymer matrix enhances its Thermal and Mechanical stability. It was found that GCN based CA MMMs give better CO2/CH4 selectivity of 2.73 at a GCN loading of 0.5 wt% with CO2 permeability of 78 Barrer at 2 bars. A more compact and dense structure could be seen in the SEM images, FTIR confirms the presence of functional groups, XRD confirms the presence of GCN nanosheets in the MMMs. Moreover, maximum tensile strength of 81.66 MPa was shown by 0.5 wt% g-C3N4/CA mixed matrix membrane. In this study, results suggest that addition of GCN into CA polymer matrix enhances CO2 gas permeability having less impact on CO2/CH4 selectivity, further research should be carried out to improve selectivity of these membranes.