Amine-containing polymer/zeolite Y composite membranes for CO2/N2 separation

• New amine-containing polymer/zeolite Y composite membranes were synthesized.
• Zeolite Y layer improved performance when the amine layer was more than 200 nm.
• Effects of mobile carrier, composition and thickness on performance were studied.
• The membrane showed ~1100 GPU and >200 CO2/N2 selectivity at 57 °C.

New amine-containing polymer/zeolite Y composite membranes were successfully synthesized for CO2/N2 separation from flue gas. The polyvinylamine (PVAm) with a high molecular weight (MW¯=719,000) was synthesized and used as the fixed-site carrier for CO2 facilitated transport. The PVAm was incorporated with different aminoacid salts (mobile carriers), including potassium glycinate (KG), lithium glycinate (LiG) and piperazine glycinate (PG). The amine-containing polymer blend solution was coated onto a zeolite Y seed layer on top of a polyethersulfone (PES) substrate. The composite membrane with a selective amine layer thickness of more than 200 nm showed a better CO2/N2 separation performance compared to the membrane without the zeolite Y seed layer, which was due to the fact that the zeolite Y layer had a smaller interparticle pore size than the PES substrate, resulting in minimizing the penetration of amine-containing polymer solution into the pores underneath and thus reducing the mass transfer resistance of CO2 molecules through the membrane. The effects of different kinds of mobile carriers and various compositions and thicknesses of the amine-containing polymer layer were investigated. The resultant amine-containing polymer/zeolite Y composite membrane exhibited a CO2 permeance up to ~1100 GPU and a CO2/N2 mixed gas selectivity of at least 200 at the typical flue gas temperature of 57 °C. This high separation performance showed a great potential for the application of carbon capture from flue gas.