Modification of CO2-selective mixed matrix membranes by a binary composition of poly(ethylene glycol)/NaY zeolite

Mixed matrix membranes (MMMs) were prepared by Pebax polymers incorporating with two dopants of poly(ethylene glycol) (PEG) and NaY zeolite. The surface morphology, chemical groups, microstructure, thermal properties and gas separation performance of as-obtained membranes were characterized by Scanning Electron Microscope, Infrared Spectroscopy, X-ray Diffraction, Thermogravimetry and Differential Scanning Calorimetry, and gas permeation technology, respectively. The effects of NaY amount, PEG function, permeation temperature and permeation pressure on the microstructure and properties of MMMs were investigated. The results showed that the addition of PEG as secondary composition obviously improved the compatibility of NaY and membrane matrix, and significantly elevated the CO2 permeability and CO2/N2 selectivity. The MMMs prepared by incorporating 20 wt% PEG and 30 wt% NaY zeolite in starting materials exhibited the maximum CO2/N2 selectivity of 107.9 together with the CO2 permeability of 172.6 Barrer. For CO2/N2 mixed gas, the designed membrane could directly enrich the concentration of CO2 from 15% to 96.7% by one step.