Amine-functionalized (Al) MIL-53/VTEC™ mixed-matrix membranes for H2/CO2 mixture separations at high pressure and high temperature

VTEC™ PI-1388 and 20wt% (Al) NH₂-MIL-53/VTEC™ PI-1388 mixed-matrix membranes (MMMs) with different thicknesses were tested for gas permeation of H₂ and CO₂ from 5 to 30bar and from 35 to 300°C. 50/50 H₂/CO₂ mixtures were also tested at 30bar and 250°C with stage cuts that ranged from 0.05 to 1. Gas permeation data show that the affinity of (Al) NH₂-MIL-53 for VTEC™ PI-1388 is strong enough to perform gas separations under these conditions. At 30bar and at temperatures above 200°C, the performance of the MMMs for H₂/CO₂ separation improved significantly with increasing temperature. Specifically, the H₂ permeability of the MMM at 300°C increased by 70% with respect to that of VTEC™ PI-1388 (VTEC™ PI-1388: H₂ = 85 Barrer, H₂/CO₂ = 4.0; MMM: H₂ = 144 Barrer, H₂/CO₂ = 5.8). Gas mixture separations using VTEC™ PI-1388 and the MMM depended on the stage cut and reached a maximum H₂/CO₂ separation of 7.2 for VTEC™ PI-1388 and 7.5 for the MMM at a stage cut of 0.05.