CO 2 separation using surface-functionalized SiO 2 nanoparticles incorporated ultra-thin film composite mixed matrix membranes for post-combustion carbon capture

Abstract CO 2 separation across polyethylene glycol (PEG)-based ultra-thin film composite mixed matrix membranes (UTFC-MMMs) containing surface-functionalized SiO 2 nanoparticles (SFSNPs) were investigated. The SFSNPs were prepared by physicochemical adsorption of polyethyleneimine (PEI), polydopamine (PDA) and codeposition of PEI and PDA onto the porous SiO 2 nanoparticles (diameter of ~10 nm). A cross-linked PEG-based polymer incorporating the SFSNPs was formed into an ultra-thin, CO 2 selective layer of ~ 55 nm via a novel nano-coating technology, namely continuous assembly of polymers (CAP). The resulting PEG-based UTFC-MMMs demonstrate the potential of ultra thin films prepared by the CAP nanotechnology to enhance CO 2 separation. The mixed matrix membranes achieved a CO 2 permeance of ~1300 GPU (1 GPU=10 −6  cm 3 (STP) cm −2  s −1  cmHg −1 ) and a favorable CO 2 /N 2 selectivity of 27, which is a 30% and 25% rise in CO 2 permeance and CO 2 /N 2 selectivity respectively above the values obtained from simple PEG-based UTFC membranes.