Highly efficient CH4 purification by LaBTB PCP-based mixed matrix membranes†
Membrane-based technology for CO2/CH4 separation has received significant interests due to its potentially lower energy consumption relative to that of conventional approaches such as cryogenic distillation and chemisorption. Engineering a new membrane material with excellent performance is a crucial step in achieving this goal. In this study, we report the facile fabrication of novel mixed-matrix membranes (MMMs) that contain a porous coordination polymer (PCP) filler (LaBTB). CO2/CH4 mixed-gas permeation measurements showed that LaBTB/6FDA–DAM polyimide exhibited reduced trade-off and plasticization effects and thus surpassed the 2008 Robeson upper-bound even under RH 70% moisture (stable CO2 permeability of 700 barrer and CO2/CH4 selectivity of 30 within 120 h). Importantly, the positive effect of LaBTB within LaBTB/6FDA–DAM for selective CO2 capture has been established by in situ IR spectroscopy. Excellent separation performance combined with their outstanding water/moisture stability suggests that LaBTB-based MMMs are promising candidates for feasible CO2/CH4 separation.