GeFSIX-1-Cu based semi-interpenetrating network mixed matrix membranes for efficient CO2 separation

In order to increase CO2 separation efficiency, semi-interpenetrating network mixed matrix membranes (SIPN-MMMs) were loaded with GeFSIX-1-Cu (Cu(4,4 '-bipyridine)(2)(GeF6)) and poly ethylene glycol dimethyl ether (PEGDME). Two long-chain polymers poly ethylene glycol diacrylate (PEGDA) and poly ethylene glycol methyl ether acrylate (PEGMEA) jointly constituted a crosslinked PEO backbone, and CO2-philic short-chain polymer PEGDME and anion-pillared hybrid porous materials GeFSIX-1-Cu were embedded into the backbone to introduce strong CO2 adsorption sites and provide extra pore channels. Increasing GeFSIX-1-Cu loading in SIPN-MMMs initially improved CO2 permeability and CO2/N-2, CO2/CH4, and CO2/H-2 selectivity, because the porous structure of GeFSIX-1-Cu provides additional pore channels for gas transport. In addition, the strong binding affinity between GeF62- and CO2 leads to improved membrane selectivity. When GeFSIX-1-Cu loading increased above 3 wt%, both CO2 permeability and CO2/N-2, CO2/CH4, and CO2/H-2 selectivity decreased, due to agglomeration of excess GeFSIX-1-Cu loading in SIPN-MMMs. The highest CO2 permeability of 786 Barrer and CO2/N-2 ideal selectivity of 43 (at GeFSIX-1-Cu loading of 3 wt%) were 36% and 38% higher than those of pure SIPN membrane, respectively, resolving the trade-off between permeability and selectivity, and surpassing the Robeson upper bound (2008).

Automated summary

By loading GeFSIX-1-Cu and PEGDME, the CO2 separation efficiency of SIPN-MMMs was improved. Increasing the loading of GeFSIX-1-Cu initially enhanced CO2 permeability and selectivity, but excessive loading resulted in decreased performance.