Development of highly permselective Mixed Matrix Membranes comprising of polyimide and Ln-MOF for CO2 capture

Mixed Matrix Membranes (MMMs) with hybrid organic-inorganic characteristics offer a strong alternative to traditional polymer-based membranes to reduce the trade-off between gas permeability and selectivity. This work incorporated lanthanum-Metal Organic Frameworks in the Matrimid to fabricate MMMs. To understand the effects of nano-filler on membranes' morphology, porosity, thermal stability, and chemical composition, MMMs were fabricated with three different loadings of nano-filler, i.e., 10, 20 and 30 wt%. The selectivity and permeability of CH4, CO2, and N-2 gases through MMMs were investigated at 10 bar pressure and temperatures ranging from 25 to 55 C. All MMMs exhibited enhanced CO2 permeation with increased nano-filler loading because the porous nano-filler provided additional channels and fractional free volume in the polymer matrix. The 30 wt% loaded membrane showed a 183% increase in permeability of CO2 than neat membrane. With increasing nano-filler loading, the selectivity of MMMs increased from 34.1 to 48.45 for CO2/N-2 and from 36.2 to 54.67 for CO2/CH4, confirming the absence of membrane defects, improved filler/polymer interface, and excellent dispersion of nano-filler in the polymer matrix. The results proved that these membranes could be further used for gas separation industrial applications.

Automated summary

This study developed mixed matrix membranes (MMMs) with hybrid organic-inorganic characteristics by incorporating lanthanum-Metal Organic Frameworks (La-MOFs) into Matrimid. The MMMs exhibited enhanced CO2 permeation and selectivity with increasing loading of the nano-filler. The results suggest that these membranes have potential for important applications in gas separation industries.