OIL AND WATER SEPARATION MEMBRANE

Abstract

A separation membrane, suitably for oil and water separation. The membrane including a porous substrate layer and an active layer arranged over at least a part of the substrate layer. The active layer includes a hydrophilic agent and a superhydrophilic agent. Also described is a method of producing the separation membrane and a drain valve comprising the membrane.

Claims

1. A separation membrane, suitably for oil and water separation, comprising a porous substrate layer and an active layer arranged over at least a part of the substrate layer, wherein the active layer comprises a hydrophilic agent and a superhydrophilic agent,

2. The membrane according to claim 1, wherein the membrane comprises a first active layer comprising the hydrophilic agent, and a second active layer comprising a super hydrophilic agent.

3. (canceled)

4. The membrane according to claim 1, wherein the active layer is formed from a coating composition comprising the hydrophilic agent and/or the superhydrophilic agent or precursor thereof.

5. The membrane according to claim 1, wherein the porous substrate layer comprises a polymeric substrate, a polymeric substrate comprising inorganic filler, a ceramic substrate, a composite substrate, a metal substrate, an inorganic substrate, inorganic-organic substrate, and/or a casted substrate.

6. (canceled)

7. The membrane according to claim 1, claim, wherein the porous substrate layer comprises a polymeric porous substrate formed from polyethylene terephthalate-based (PET) membrane.

8. (canceled)

9. The membrane according to claim 1, wherein the porous substrate layer comprises a surface roughness, Rz, of ≥500 nm.

10. The membrane according to claim 1, wherein a contact angle of water on the substrate surface is ≤65°.

11. The membrane according to claim 1, wherein the hydrophilic agent, and/or active layer comprising the hydrophilic agent, has a contact angle of ≤55°.

12. (canceled)

13. The membrane according to claim 1, wherein the hydrophilic agent comprises a (co)polymer formed from vinylpyrrolidone, vinyl alcohol, allylamine, ethylenimine, allylammonium chloride, vinylamine, lysine, chitosan, silane-based and/or its derivatives; and/or acrylic or a copolymer thereof.

14. The membrane according to claim 1, wherein the hydrophilic agent comprises a copolymer formed from. acrylamide and acrylic acid monomers with polyallylammonium chloride.

15. (canceled)

16. The membrane according to claim 1, wherein the hydrophilic agent is selected from a graphene-based material, metal organic framework material, silicene, germanene, stanene, boron-nitride, carbon nitride, metal-organic nanosheets, molybdenum disulfide, tungsten disulfide, polymer/graphene aerogel, and/or positively charged polymers.

17. (canceled)

18. The membrane according to claim 1, wherein the hydrophilic agent comprises a platelet size distribution D50 of from 100 nm to 14,000 nm.

19. (canceled)

20. The membrane according to claim 1, wherein the oxygen content of the hydrophilic agent is from 25 to 45%.

21. The membrane according to claim 1, wherein a water contact angle of the superhydrophilic agent, or the active layer is ≤20°.

22. (canceled)

23. The membrane according to claim 1, wherein the superhydrophilic (co)polymer and/or hydrophilic (co)polymer is the form of a hydrogel, or he operable to form a hydrogel upon contact with water.

24. The membrane according to claim 1, wherein the superhydrophilic agent comprises a (co)polymer formed from monomers including a vinyl monomer, a silane-based monomer and/or its derivatives; an acrylic monomer, thiol functionalised acrylate monomers, acryloylmorpholine; carbohydrate monomer; a polyacid and/or polyol, optionally with crosslinkers.

25. (canceled)

26. (canceled)

27. (canceled)

28. (canceled)

29. (canceled)

30. (canceled)

31. (canceled)

32 (canceled)

33. The membrane according to claim 2, wherein the thickness of the second active layer is from 100 nm to 100 um.

34. The membrane according to claim 1, wherein the membrane comprises an intermediate layer between the substrate and a first active layer, and/or between a first active layer and a second active layer.

35. (canceled)

36. The membrane according to claim 34, wherein the intermediate layer comprises a silane-based adhesion promoter.

37. (canceled)

38. (canceled)

39. (canceled)

40. (canceled)

41. A method of producing a separation membrane according to claim 1, the method comprising the steps of: a. optionally, preparing a substrate by treating the substrate with physical rinsing, chemical treatment, radiation treatment, plasma treatment, and/or thermal treatment; b. optionally, contacting the substrate with an intermediate layer coating composition to form an intermediate layer; c. contacting the substrate with a coating composition comprising a hydrophilic agent or precursor thereof, and optionally further comprising a superhydrophilic agent or precursor thereof, to form an active layer; d. optionally, drying the active layer; e. optionally, contacting the active layer with an intermediate layer coating composition to form an intermediate layer; f. if a superhydrophilic agent was not contacted with the substrate in step (c), contacting the coated substrate with a coating composition comprising a superhydrophilic agent or precursor thereof to form a further active layer; and g. optionally, drying the further active layer.

42. (canceled)

43. A drainage device comprising a membrane according to claim 1.

44. A fuel tank comprising a drain valve, wherein the drain valve comprises a membrane according to claim 1.

45. (canceled)

46. An automotive product or any part thereof comprising a fuel tank that comprises a drain valve, wherein the drain valve comprises a membrane according to claim 1.

Description

EXAMPLES

Example 1

[0185] Formulations:

[0186] Formulation A: 200 l of 2 mg/ml silane in water. The aerie was 3-aminopropyltrimethoxysilane (CAS no. 919-30-2).

[0187] Formulation B: 100 l of 1 mg/ml graphene oxide (GO) in water. The GO was purchased from Sigma-Aldrich, 2 mg/ml in water, with a refractive index of n20/D 1.333.

[0188] Formulation C: 200 l of 20 wt % polyacrylate sodium. The polyacrylate sodium was purchased from Sigma-Aldrich, with a Mw ˜8000 g/mol, 45 wt % in water.

[0189] The above formulations were prepared by Silverson high shear mixer at 5000 rpm.

[0190] Application of primer layer:

[0191] A pre-cut PET mono-filament woven substrate having area of 1×5 m2 was dip-coated in Formulation A for 5 min using an industrial dip coating equipment from DipTech System. The coated layer was then dried in an oven at 80° C. for 5 minutes.

[0192] Application of first active layer:

[0193] The treated substrate was then dipped in Formulation B for 5 minutes, followed by drying in oven at 80° C. for 5 minutes. This process was repeated for another 2 cycles, before the resultant substrate was dried in an oven at 80° C. for 5 minutes.

[0194] Application of the second active layer:

[0195] The resultant substrate was then coated with Formulation C using knife-over-roll coating with an industrial knife-over-roll coating machine from HAS Group, at a speed of 1 m/min, and dried in air.

[0196] The prepared dry membrane was then cut into round samples of 5 cm in diameter, and inserted into a drainage valve of a tank. The passage for kerosene through the valve from inside to outside of the tank was via the membrane, and the coated faced of the membrane faces the inside of the tank. The valve had a close-open mechanism. Kerosene was then added to the tank, after which the valve was opened. No kerosene passed across the membrane. After 36 hours water was added to the kerosene in the tank. The water almost immediately drained through the membrane exiting out of the tank via the membrane. The kerosene remained inside the tank after all the water had fully drained by gravity. All the kerosene remained in the tank for at least 36 hours after which point the test was stopped.

Example 2

[0197] Formulations:

[0198] Formulation A: 200 l of 2 mg/ml tannic acid in water.

[0199] Formulation B: 200 l of 2 mg/ml sodium periodate (oxidant) in water.

[0200] Formulation C: 100 l of 1 mg/ml GO in water. The GO was purchased from Sigma-Aldrich, 2 mg/ml in water, with a refractive index of n20/D 1.333.

[0201] Formulation D: 200 l of 2 mg/ml silane in water. The silane was 3-aminopropyltrimethoxysilane (CAS no. 919-30-2).

[0202] Formulation E: 200 l of 20 wt % polyacrylate sodium. The polyacrylate sodium was purchased from Sigma-Aldrich, with a Mw ˜8000 g/mol, 45 wt % in water.

[0203] The formulations were prepared by Silverson high shear mixer at 5000 rpm.

[0204] Application of primer layer:

[0205] A pre-cut metal mesh substrate having area of 1×5 m2 was dip-coated in Formulation A for 5 min using an industrial dip coating equipment from DipTech System. The coated layer was then dried in oven at 80° C. for 5 minutes, and then dipped in Formulation B (oxidant) for 5 min, followed by drying in oven at 80° C. for 5 minutes.

[0206] Application of the first active layer:

[0207] The treated substrate was then dipped in Formulation C for 5 minutes, followed by drying in an oven at 80° C. for 5 minutes. The treated substrate was then dipped in Formulation D for 5 minutes and then dried in an oven at 80° C. for 5 minutes. The process was repeated for another 2 cycles, after which the resultant substrate was dried in an oven at 80° C. for 5 minutes;

[0208] Application of the second active layer:

[0209] The resultant substrate was then coated with Formulation E using knife-over-roll coating, using an industrial knife-over-roll coating machine from HAS Group, at a speed of 1 m/min, and dried in air.

[0210] The prepared dry membrane was then cut into round samples of 5 cm in diameter, and inserted into a drainage valve of a tank. The passage for kerosene through the valve from inside to outside of the tank was via the membrane. The coated face of the membrane faced the inside of the tank. The valve had a close-open mechanism. Kerosene was added to the tank and the valve was then opened. No kerosene passed across the membrane. After 36 hours water was mixed into the kerosene. The water almost immediately drained through the membrane exiting out of the tank via the membrane. The kerosene remained inside the tank after all the water had fully drained by gravity. All the kerosene remained in the tank for at least 36 hours at which point the test was stopped.

Example 3

[0211] Formulation A: 60 mol of acrylamide monomers was mixed with 40 mol acrylic acid (AA) monomers to form a precursor mixture containing 40 mol % AA. The total monomer concentration was then diluted to 5 wt %, and template copolymerization was carried out in the presence of 40 mol poly(allylammonium chloride) having Mw 10,000 Da. 0.3 wt % 2,2-azobis(2-methylpropionamidine) dihydrochloride (AIBA) of total monomer weight ratio was added as initiator. N,N′-methylene bisacrylamide (MBAM) was added as crosslinking agent at 1.5 wt % of total monomer.

[0212] Formulation B: 200 l of 20 wt % polyacrylate sodium. The polyacrylate sodium was purchased from Sigma-Aldrich, with a Mw ˜8000 g/mol, 45 wt % in water.

[0213] A PET woven membrane substrate having pore size of 5 um or open mesh equivalent to 5 um was then coated with Formulation A using mayor bar coating, at a coating speed of 20 m/s, with bar size having 12 um wires. The coated PET substrate was then subjected to copolymerization, carried out in a constant temperature water bath at 55° C. for 12 h, then cooled to room temperature. The polymers obtained were then washed in water to remove the residual monomer, and then dried at 60° C. for 5 h.

[0214] The prepared dry membrane was then cut into round samples of 5 cm in diameter and inserted into a drainage valve of a tank. The passage for kerosene through the valve from inside to outside of the tank was via the membrane, and the coated faced of the membrane faces the inside of the tank. The valve had a close-open mechanism. Kerosene was then added to the tank, after which the valve was opened. No kerosene passed across the membrane. After 36 hours water was added to the kerosene in the tank. The water almost immediately drained through the membrane exiting out of the tank via the membrane. The kerosene remained inside the tank after all the water had fully drained by gravity. All the kerosene remained in the tank for at least 36 hours after which point the test was stopped.

[0215] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0216] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[0217] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0218] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.