Facilitated transport of CO2 through Co(II)-S-EPDM ionomer membrane

A new facilitated transport ionomer membrane was prepared by incorporating Co(II) ions, as fixed carrier, into the sulfonated ethylene-propylene-diene terpolymer, Co(II)-S-EPDM, and was applied for preferential transport of carbon dioxide rather than nitrogen from CO2/N2 gas streams. The membranes were also characterized by using the FTIR, SEM and TG/DSC analyses. Furthermore, single gas permeation experiments at different membrane thicknesses (30 and 200 μm), sulfonic group contents (0.1 and 0.2 mmol of sulfonic acid (SO3H)/g EPDM), feed gas pressures (2-10 bar) and temperatures (30-50 °C) were carried out. The permeation results of the dense Co(II)-S-EPDM ionomer membranes show that the incorporation of Co(II) ions into the sulfonated EPDM ionomers increases the permeance of both CO2 and N2 gases. Moreover, due to facilitated CO2 transport by the carriers, the CO2/N2 selectivity is also increased. These are mainly attributed to the formation of polymer coordinate complexes in the ionomer.