Gas Separation Membranes
A gas separation membrane comprising: (i) a porous substrate: (ii) a gutter layer comprising a cross-linked polysiloxane polymer; (iii) a discriminating layer comprising at least 60 w/w % of ethylene oxide (EO) groups and at least 0.15 mmol/g of thioether groups; and (iv) optionally a protective layer comprising a cross-linked polysiloxane polymer; wherein: (a) the gutter layer has an average thickness of less than 2.5 μm; and (b) the discriminating layer has an average thickness of greater than 0.2 μm and less than 5 μm.
1 - 9 . (canceled)
10 . A gas separation membrane comprising:
(i) a porous substrate;
(ii) a gutter layer comprising a cross-linked polysiloxane polymer;
(iii) a discriminating layer comprising at least 60 w/w % of ethylene oxide (EO) groups and at least 0.15 mmol/g of thioether groups; and
(iv) optionally a protective layer comprising a cross-linked polysiloxane polymer;
wherein:
(a) the gutter layer has an average thickness of less than 2.5 μm; and
(b) the discriminating layer has an average thickness of greater than 0.2 μm and less than 5 μm;
(c) the gas membrane has a H 2 S permeance >400 GPU.
11 . The gas separation membrane according to claim 10 wherein the discriminating layer has an average thickness between 0.3 μm and 3 μm.
12 . The gas separation membrane according to claim 10 wherein said discriminating layer comprising thioether groups between 0.15 and 0.60 mmol/g.
13 . The gas separation membrane according to claim 10 wherein the thioether groups are of the formula —CH 2 —S—CH 2 —.
14 . The gas separation membrane according to claim 10 wherein the porous substrate comprises polyacrylonitrile, polysulphone, polyvinylidenefluoride, polyether ether ketone or polytetrafluoroethylene.
15 . A process for preparing a gas separation membrane having a H 2 S permeance >400 GPU comprising the steps of:
(i) forming a gutter layer of average thickness of less than 2.5 μm on a porous substrate;
(ii) forming on the gutter layer a discriminating layer comprising at least 60 w/w % of EO groups and at least 0.15 mmol/g of thioether groups, and having an average thickness greater than 0.2 μm and less than 5; and
(iii) optionally forming on the discriminating layer a protective layer comprising a cross-linked polysiloxane polymer.
16 . A gas separation module comprising a gas separation membrane according to claim 10 .
17 . The gas separation module according to claim 16 wherein the gas separation membrane is in the form of a flat sheet, a spiral-wound sheet or a hollow-fibre.