OIL AND WATER SEPARATION MEMBRANE

Abstract

A separation membrane, such as for pressure-assisted oil and water separation. The membrane includes a porous substrate layer and an active layer arranged over at least a part of the substrate layer. The active layer is at least partially crosslinked and comprises 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 comprising a porous substrate layer and an active layer arranged over at least a part of the substrate layer, wherein the active layer is at least partially crosslinked and comprises a superhydrophilic agent.

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

3. (canceled).

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

5. (canceled).

6. The membrane according to claim Jany preceding claim, wherein the porous substrate layer has a surface roughness, Rz, of nm.

7. (canceled)

8. (canceled)

9. (canceled)

10. (canceled)

11. (canceled)

12. (canceled)

13. (canceled)

14. The membrane according to claim 13, wherein the superhydrophilic agent comprises a (co)polymer or precursor thereof selected from a polyelectrolyte, a polymer salt, and/or an ionised polymer, or precursor thereof.

15. The membrane according to claim 13, wherein the superhydrophilic agent comprises a (co)polymer in the form of a hydrogel, or is operable to form a hydrogel upon contact with water.

16. (canceled)

17. The membrane according to claim 1, wherein the superhydrophilic agent comprises a (co)polymer with a molecular weight (Mw) of ≥6,000 g/mol.

18. (canceled)

19. (canceled)

20. The membrane according to claim 1, wherein the crosslinker comprises a multi-functional acrylic or vinyl monomer, a divalent metal ion, multi-functional carbodiimide, multi-functional aziridine, silane; multi-functional epoxide and/or multi-functional isocyanate, or residue thereof.

21. (canceled)

22. The membrane according to claim 1, wherein the crosslinking density is at least 2 molar % of the crosslinkable functional groups.

23. The membrane according to claim 1, wherein the superhydrophilic agent comprises a polyelectrolyte (co)polymer selected from a (meth)acrylic acid (co)polymer; and/or a styrene sulfonate acid (co)polymer, wherein at least part of the acid is in the form of a suitable salt.

24. The membrane according to claim 1, wherein the superhydrophilic agent comprises a polyelectrolyte copolymer selected from polystyrene-alt-maleic acid) sodium, chitosan-g-poly(acrylic acid) copolymer sodium; 2-propenoic acid, 2-methyl, polymer with sodium; and/or 2-methyl-2((1-oxo-2-propen-1-yl)amino)-1-propanesulfonate.

25. (canceled)

26. The membrane according to claim 1, wherein the membrane comprises a first active layer that comprises a hydrophilic agent, and a second active layer that comprises the superhydrophilic agent.

27. (canceled)

28. (canceled)

29. (canceled)

30. The membrane according to claim 26, wherein the hydrophilic agent comprises a (co)polymer formed from monomers comprising vinylpyrrolidone, vinyl alcohol, allylamine, ethylenimine, allylammonium chloride, vinylamine, lysine, chitosan, silane-based and/or its derivatives; acrylics; acrylamide; and/or hydroxyalkylmethacrylate, and copolymers thereof.

31. The membraneaccording to claim 26, wherein the hydrophilic agent is selected from a graphene-based material.

32. (canceled)

33. (canceled)

34. (canceled)

35. The membrane according to claim 1, wherein the superhydrophilic agent comprises from a polystyrene sulphonate salt) and/or a polyacrylic acid salt.

36. (canceled)

37. The membrane according to claim 1, wherein the membrane comprises an intermediate layer between the substrate and the active layer.

38. (canceled)

39. The membrane according to claim 37, wherein the intermediate layer comprises a silane-based adhesion promoter.

40. (canceled)

41. (canceled)

42. (canceled)

43. (canceled)

44. A method of producing the separation membrane of 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. optionally, contacting the substrate with a coating composition comprising a hydrophilic 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. contacting the optionally coated substrate with a coating composition comprising a superhydrophilic agent or precursor thereof to form an active layer; g. optionally, drying the further active layer; wherein the active layer comprising the superhydrophilic agent is at least partially crosslinked.

45. (canceled)

46. A method of separating oil and water, comprising the steps of: a. selecting a membrane comprising a porous substrate layer and an active layer arranged over at least a part of the substrate layer, wherein the active layer is at least partially crosslinked and comprises a superhydrophilic agent, suitably a membrane according to claim 1; b. contacting the membrane with composition comprising oil and water; and c. effecting separation of the oil and water through the membrane, wherein the average pore size of the substrate is selected based on the operational pressure such that the substrate has a lower average pore size at higher operational pressure to give a membrane with a water flux of ≥100 Imh/bar during separation of the oil and water through the membrane.

47. (canceled)

48. (canceled)

49. (canceled)

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

51. A fuel tank comprising a drain valve, wherein the drain valve comprises a membrane according to claim 1. 52. 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

[0198] Formulation A: 100kg of a mixture containing 42.2 kg bis(trimethylsilyloxy)methylsilylpropyl glycerol methacrylate (SIMA) and 29.5 kg of 2-methacryloyloxyethyl phosphorylcholine (MPC) in isopropyl alcohol.

[0199] Formulation B: 100 kg of a mixture containing 1.7 kg triethyleneglycol dimethacrylate (TEGDMA) and 1.5 kg (3 mol % to total momomer in formulation A) 2,2-Dimethoxy phenylacetophenone (DMPA) in isopropyl alcohol.

[0200] Formulation C: 10% 3-Aminopropyltrimethoxysilane in 50 v/50 v water/ethanol

[0201] 50 kg of Formulation A was mixed with 50kg of Formulation B, and the mixture was then subjected to the elimination of oxygen by bubbling with argon gas to form Formulation D.

[0202] An asymmetric polyethersulfone membrane with a Sterlitech polyethylene terephthalate/polypropylene backing having pore size of 0.05 um was treated on the polyethersulfone side with oxygen plasma for 30 seconds. The treated substrate was then coated with Formulation C using doctor blade coating at a speed of 10 m/min with a gauge gap of 15 um. The treated membrane was then heated at 110° C. for 10 minutes.

[0203] The treated membrane was then coated with Formulation D using doctor blade coating, having a gauge gap of 20 um at a speed of 10 m/min. The coated membrane was then subjected to UV light irradiation using an ultra-high-pressure mercury lamp (UVL-400HA, Riko-kagaku Sangyo, Funabashi, Japan) for 1 minutes. The intensity of the UV light was at around 5 mW/cm.sup.2 with the wavelength in the range of 300-400 nm, achieved by a filter. The treated membrane was then immersed in a mixture of isopropyl alcohol and water (50 v/50 v) for 24 hours to ensure the complete removal of residual low molecular weight compounds.

[0204] The membrane was then dried at 40° C. for 4 hours.

[0205] The prepared dry membrane, with crosslinked MPC-SiMA superhydrophilic layer, was then cut into round samples of 5 cm in diameter and inserted into a drainage valve of a tank. The passage of kerosene through the valve from inside to outside of the tank was via the membrane, with the coated face of the membrane facing 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. The tank was pressurised to 3 bar which was maintained throughout the rest of the test. 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. All the kerosene remained within the tank with no leakage for at least 36 hours after which point the test was stopped.

Example 2

[0206] Formulation A: 2 wt % aqueous solution of sodium carboxymethyl cellulose with a degree of substitution 0.77, with average molar mass Mw=220k.

[0207] Formulation B: 2 wt % aqueous solution of poly(ethylene glycol), with Mw=1520

[0208] Formulation C: 4 wt % Citric acid as crosslinker in water

[0209] Formulation D was obtained by mixing 10 kg of Formulation B and 90 kg of Formulation A.

[0210] A 100 kg mixture containing 97.5 wt % formulation ID and 2.5 wt % formulation C was prepared and then coated on a 1 um (equivalent pore size) nonwoven polyester terephthalate (PET) substrate, using a RK doctor blade coating equipment, at a coating speed at 15 m/min, with a controlled gap of 10 um. The coated membrane was then heated at 80°C. for 4 hours to give a superhydrophilic active layer comprising citric acid crosslinked sodium carboxymethyl cellulose enhanced by polyethylene glycol).

[0211] 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, with the coated face of the membrane facing the inside of the tank. The valve had a close-open mechanism. Kerosene was then added to the tank. After that the valve was opened. No kerosene passed across the membrane. A pressure of 1 bar was applied through the rest of the test. 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 under 1 bar. All the kerosene remained in the tank for at least 36 hours after which point the test was stopped.

[0212] 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.

[0213] 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.

[0214] 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.

[0215] 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.