Enhancing CO2/CH4 separation performance in PIM-1 based MXene nanosheets mixed matrix membranes

Abstract

This study presents an approach by integrating MXene nanosheets (Ti2C3Tx) into polymer of intrinsic microporosity (PIM-1) matrix to develop mixed matrix membranes (MMMs) for biogas upgrading. Different concentrations (1–5 wt%) of MXene were incorporated into PIM-1, and the resulting materials were characterized to 1H NMR, FTIR, XRD, TGA, nitrogen adsorption, SEM and EDS to assess their physicochemical properties. The research focused on evaluating the gas separation performance, particularly CO2/CH4 separation, as well as the aging behavior of the MMMs. The incorporating of MXene nanosheets significantly enhanced the CO2 permeability and selectivity of PIM-1 by enhancing gas solubility and diffusivity. The most promising results were observed at 5 wt% filler loading, achieving a 13.5 CO2/CH4 separation selectivity at 7652 Barrer of CO2 permeability. In all membranes with aging time (60 days), there was a decrease in CO2 permeability and a slight increase in CO2/CH4 selectivity, observing that the introduction of MXene slightly mitigates the physical aging process in the PIM-1 polymer. Additionally, the permeability tests revealed higher CO2 permeability and (CO2/CH4) selectivity values for mixed gases compared to single gases. Overall, the study highlights the potential of MXene/PIM-1 MMMs as effective materials for CO2/CH4 separation, outperforming pristine PIM-1.