Molecular simulations of hybrid cross-linked membranes for H2S gas separation at very high temperatures and pressure: Binary 90%/10% N2/H2S and CH4/H2S, ternary 90%/9%/1% N2/CO2/H2S and CH4/CO2/H2S mixtures

Molecular dynamics (MD) simulations have previously identified four hybrid inorganic-organic membranes based on POSS or OAPS silsesquioxanes hyper-cross-linked with small PMDA or 6FDA imides, which are able to maintain reasonable CO2/N2 and CO2/CH4 permselectivities at very high temperatures (300 °C and 400 °C) and pressure (60 bar). Experimentally, the polyPOSS-imides are known to degrade above 300 °C while the polyOAPS-imides can resist up to above 400 °C. In the present work, the same four model polyOAPS/POSS-imide networks are further tested for their gas separation abilities of H2S-containing mixtures. Indeed, hydrogen sulfide is a hazardous gas present in many gas feeds, and, within the context of a toxic penetrant under harsh conditions, simulations are a useful task to perform before embarking on difficult experiments.