Oxygen/nitrogen transport in ionomer composite membranes containing a cobalt Schiff base complex

Abstract

Different amounts of (N,NЈ-disalicylideneethylenediamin)cobalt (CoS) were blended to a cobalt (II)-neutralized sulfonated EPDM (Co (II) -S-EPDM) ionomer membrane to enhance its oxygen-enriching ability. Various influence factors on permeabilities and selectivities of the composite membranes, such as the gas pressure difference, the CoS content, and the testing temperature have been investigated. Oxygen permeability coefficients (P O 2 ) and oxygen/nitrogen separation factors (␣ O 2 /N 2 ) increased simultaneously by decreasing the gas pressure difference or by increasing the CoS content. In comparison with the EPDM matrix, P O 2 and ␣ O 2 /N 2 of Co (II) -S-EPDM-CoS (85/15) composite membrane increased from 11.0 Barrer and 4.38 to 37.0 Barrer and 9.60. Obvious enhancement in the oxygen-enriching property shows that the dual actions of cobaltous ion crosslinking and addition of an abundant cobalt complex may be an effective way to improve a rubbery polymer membrane. As high as 15 wt % of the CoS could be blended.

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

“…The EPDM can be sulfonated at widespread degrees by controlling the amount of sulfonation agent, reaction time and temperature. This has been extensively used to produce the fixed carrier membranes for facilitating oxygen transport through the research polymeric membranes such as octyl methacrylate and vinyl imidazole copolymers [52][53][54], polystyreneblock-polyisoprene-block-polystyrene)-graft-poly(1-vinylimidazole) (SIS-g-VIm) [55], and the commercial membranes such as polycarbonate [56], ethyl cellulose [57,58] and EPDM [59]. This technique prevents the need for pre-dissolution of the raw polymer.…”

“…Composite membranes were synthesized from incorporating the Co(II)-N,N'disalicylideneethylenediamine (Cosalen) into Co(II)-neutralized sulfonated EPDM (Co(II)-S-EPDM) by Zhang and Lin [59]. In comparison with the neat EPDM, the Co(II)-S-EPDM/Cosalen membrane with 15 wt.% Co-Salen loading led to an increase in O 2 permeability from 11 to 37 barrer and the O 2 /N 2 selectivity from 4.38 to 9.6.…”

Facilitated oxygen transport in a novel silicone polymer membrane containing carboxylic cobalt groups

“…We previously reported on the preparation and oxygen‐enriching properties of a rubbery cobalt‐neutralized sulfonated EPDM membrane, with an interesting finding that the ionomer membrane exhibited a facilitated transport property for oxygen 22–23. Based on this consideration, PDMS with a high vinyl content, such as 5 mol %, was selected as a polymer membrane material to prepare a novel PDMS‐crosslinked membrane containing carboxylic groups and cobaltous ions.…”