Enhanced CO2 separation performance of polysulfone membranes via incorporation of pyrazole modified MCM-41 mesoporous silica as a nano-filler

Abstract

Polymeric membranes are one of the widely used materials of choice for CO2 capture from major industrial sources. However, the current generation of polymeric materials are unable to keep up with the increasing separation needs of CO2 from the air (CO2/N2) or natural gas (CO2/CH4) on an industrial scale due to their so-called permeability-selectivity tradeoff. In an effort to improve the overall gas separation performance of polymeric membranes, mixed matrix membranes (MMMs) have been suggested as a substitute strategy. In this study, Polysulfone (PSf) based MMMs were prepared by incorporating pyrazole modified MCM-41 mesoporous silica (MP) as a nano-filler in the polymer matrix to enhance the gas separation properties of membranes. MCM-41 nano-filler was synthesized and functionalized by post-grafting technique to prepare the MMMs of three different loadings (10, 20, and 30 wt%). All the membranes were characterized for physical, chemical, and thermal analysis. The CO2 gas separation performance of membranes was assessed, and the results concluded that the MCM-41-based MMMs showed the tradeoff between permeability and selectivity in the case of ideal and mixed gases. This permeability-selectivity trade-off is solved by the MP-based MMMs due to the presence of CO2-philic functional groups present on the surface of membranes. The PSf-MP membrane with the highest nanofiller loading (30 wt%) showed 79% more permeability than the pure PSf membrane. Additionally, it showed a significant enhancement of 33% and 51% in ideal selectivity for CO2/CH4 and CO2/N2, respectively, compared to pure PSf membrane. These findings support the lack of membrane faults, the enhanced filler/polymer interface, and the remarkable nano-filler dispersion in the polymer matrix. The excellent outcomes demonstrated the potential of these membranes for more industrial gas separation applications.