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

Abstract

• Eco-friendly method for MXene nanosheet synthesis using HCl, offering a safer alternative to HF. • Different loading of MXene nanosheets integrated into PIM-1 matrix for biogas upgrading. • MXene nanosheets enhanced the CO 2 permeability and selectivity in MXene/PIM-1 MMMs. • The introduction of MXene slightly mitigates the physical aging process in PIM-1. This study presents an approach by integrating MXene nanosheets (Ti 2 C 3 T x ) 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 1 H NMR, FTIR, XRD, TGA, nitrogen adsorption, SEM and EDS to assess their physicochemical properties. The research focused on evaluating the gas separation performance, particularly CO 2 /CH 4 separation, as well as the aging behavior of the MMMs. The incorporating of MXene nanosheets significantly enhanced the CO 2 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 CO 2 /CH 4 separation selectivity at 7652 Barrer of CO 2 permeability. In all membranes with aging time (60 days), there was a decrease in CO 2 permeability and a slight increase in CO 2 /CH 4 selectivity, observing that the introduction of MXene slightly mitigates the physical aging process in the PIM-1 polymer. Additionally, the permeability tests revealed higher CO 2 permeability and (CO 2 /CH 4 ) selectivity values for mixed gases compared to single gases. Overall, the study highlights the potential of MXene/PIM-1 MMMs as effective materials for CO 2 /CH 4 separation, outperforming pristine PIM-1.