CERAMIC MEMBRANE PRODUCED BY BINDER JETTING

Abstract

A ceramic membrane including a feed flow inlet, a retentate flow outlet, a permeate flow outlet, a membrane interface portion. The membrane interface portion include a feed flow channel fluidly coupled to the feed flow inlet and to the retentate flow outlet and permeate flow channel fluidly coupled to the retentate flow outlet, wherein the membrane interface portion is operable to allow for fluid communication between the feed flow channels and the permeate flow channels through a membrane portion, and wherein the ceramic membrane has an open porosity of at least 10%. Also provided is a process for preparing the ceramic membrane by additive manufacture.

Claims

1. A ceramic membrane comprising: a feed flow inlet, a retentate flow outlet, a permeate flow outlet, a membrane interface portion comprising a feed flow channel fluidly coupled to the feed flow inlet and to the retentate flow outlet and permeate flow channel fluidly coupled to the retentate flow outlet, wherein the membrane interface portion is operable to allow for fluid communication between the feed flow channels and the permeate flow channels through a membrane portion, and wherein the ceramic membrane has an open porosity of at least 10%.

2. A process to produce a ceramic membrane, such as a nanofiltration ceramic membrane, comprising using a binder jetting ceramic printer with a ceramic powder and a binder.

3. The process according to claim 2, wherein the binder comprises a retained binder.

4. The process according to claim 2, wherein the process comprises: a. providing a layer of a ceramic powder on a powder bed, b. selectively depositing a binder, typically a retained binder, onto the layer of ceramic powder, c. repeating steps (a)-(b) to form a 3D printed green body.

5. A ceramic membrane obtainable by the process according to claim 2.

6. The ceramic membrane according to claim 1, wherein the ceramic membrane comprises a microfiltration ceramic membrane, ultrafiltration ceramic membrane and/or nanofiltration ceramic membrane.

7. (canceled)

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11. (canceled)

12. The ceramic membrane according to claim 1, wherein the ceramic membrane comprises a closed porosity of from 0 to 90%.

13. The ceramic membrane according to claim 1, wherein the ceramic powder comprises alumina, aluminum nitride, aluminum oxide, barium titanate, beta-tricalcium phosphate, biological ceramics, bismuth, boron carbide, carbides, hydroxyapatite, iron oxide, magnesium silicates, nitrides, oxides, silicon aluminum, silica, silicon carbide, silicon dioxide, silicon nitride, titanate, titanium dioxide, yttrium carbonate, YSZ (yttria stabilised zirconia), zinc oxide, zirconate, zirconia and zirconium, or a mixture thereof.

14. The ceramic membrane according to claim 1, wherein the ceramic powder comprises a volume mean average size of from 1 nm to 100 m.

15. The ceramic membrane according to claim 1, wherein the ceramic powder comprises a coarse ceramic powder fraction and a fine ceramic powder fraction.

16. The ceramic membrane according to claim 1, wherein the coarse ceramic powder fraction comprises a volume mean average particle size of at least 0.1 m.

17. (canceled)

18. The ceramic membrane according to claim 1, wherein the ceramic powder comprises a ceramic powder fraction having a generally spherical particle shape and ceramic powder fraction having generally non-spherical particle shape.

19. (canceled)

20. The ceramic membrane according to claim 1, wherein the binder reacts with the ceramic powder of the powder bed to bind the ceramic powder together.

21. The ceramic membrane according to claim 1, wherein the binder comprises a metallic binder, a ceramic binder and/or a polymeric binder.

22. (canceled)

23. The ceramic membrane according to claim 1, wherein the binder comprises a retained binder such that the retained binder is at least partially retained in the final ceramic membrane; and/or wherein the retained binder is fully retained in the final ceramic membrane.

24. (canceled)

25. The ceramic membrane according to claim 1, wherein the retained binder comprises a partially sacrificial binder.

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27. (canceled)

28. The ceramic membrane according to claim 1, wherein the binder is in the form of a binder composition.

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30. (canceled)

31. The ceramic membrane according to claim 1, wherein the binder composition has a viscosity of at least 1 cP.

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49. (canceled)

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53. (canceled)

54.-73. (canceled)

74. A process of separating a component from a feed flow composition, comprising: a. introducing a feed flow composition into a ceramic membrane according to claim 1 so that the feed flow contacts the ceramic membrane; b. effecting separation of at least a portion of the component from the feed flow through the membrane of the ceramic membrane into a permeate flow composition.

75. (canceled)

76. (canceled)

77. Apparatus for reducing the ratio of divalent ions to a monovalent ion in an aqueous solution from a source aqueous solution that contains a higher ratio of divalent ions to the monovalent ion, wherein the apparatus comprises: a first separation portion operable to receive prefiltered aqueous solution and form an intermediate aqueous solution having a lower ratio of divalent ions to the monovalent ion than the prefiltered aqueous solution; and/or a second separation portion operable to receive the intermediate aqueous solution and form a product aqueous solution having a lower ratio of the divalent ions to the monovalent ion than the intermediate solution, wherein the first and/or the second separation portion comprises a separation portion comprising a membrane according to claim 1.

78. (canceled)

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Description

BRIEF DESCRIPTION OF DRAWINGS

[0480] FIG. 1 shows a perspective view of a first embodiment of a membrane according to the present invention with unit cells based on a TPMS gyroid lattice.

[0481] FIG. 1A shows a perspective lateral cut-away view of the membrane of FIG. 1

[0482] FIG. 2 shows a perspective vertical cut-away view of the membrane of FIG. 1.

[0483] FIG. 3 shows a perspective partial cut-away view of an upper portion of the membrane of FIG. 1.

[0484] FIG. 4 shows a top view of the membrane of FIG. 1.

[0485] FIG. 5 shows a perspective view of the feed channels of the membrane of FIG. 1.

[0486] FIG. 5A shows a perspective vertical cut-away view of the feed channels of the membrane of FIG. 1.

[0487] FIG. 6 shows a perspective view of the permeate channels of the membrane of FIG. 1.

[0488] FIG. 7 shows a perspective view of a second embodiment of a membrane according to the present invention.

[0489] FIG. 7A shows a perspective vertical cut-away view of the membrane of FIG. 7.

[0490] FIG. 8 shows a perspective view of the permeate channels of the membrane of FIG. 7.

EXAMPLES

Example 1

[0491] Materials: Purified propan-2-ol (PrOH), titanium(IV) isopropoxide [TTIP](97.0%), 1,2-dimethoxyethane (anhydrous, 99.5%, inhibitor-free), titanium(IV) oxide (20-30 nm particle size), were purchased from Sigma-Aldrich.

[0492] Formulation of binder ink: 40 g of TiO2 nanopowder (15-30 nm) was added to a Schlenk flask, which was then added with 41 propan-2-ol, 780 ml of 1,2-dimethoxyethane and 200 ml of titanium(IV) isopropoxide using standard Schlenk techniques. Prior to printing, the resulting solution was mixed for 60 minutes, using Silverson high shear mixer at rpm of 6000.

[0493] Powder bed preparation: Alumina (Al.sub.2O.sub.3) powder (99.9% purity) with mean particle diameter of 10 m was used as the filler particles. The powder was sieved through 150 mesh, before added to the powder bed.

[0494] Printing: Binder droplet volume was set to 30 picoliter. Print head to powder bed distance was set to 2 mm. Separation between consecutive droplets was set to 10-50 m. Horizontal printing speed (translational velocity) was set to 120 mm/s. Velocity of droplet was set to 5-8 m/s.

[0495] Once a layer has been printed, the powder-bed is lowered by a layer thickness of 100 m and fresh powder is spread on top of the previous layer followed by levelling through a rotating roller (roller diameter of 20 mm, roller traverse speed of 5 mm/s, roller counter-rotation of 300 rpm).

[0496] The print-head consecutively deposits binder to form the subsequent layer and to bond it to the previous layer. This layer-by-layer process is repeated until the part is completed.

[0497] De-binding and sintering: The printed part was then annealed at temperature of 500 C. for 30 min.

[0498] A first embodiment of a membrane (100) according to the present invention is shown in FIGS. 1-6. The first embodiment of a membrane (100) according to the present invention has a membrane interface portion (102) containing feed flow channels (104), permeate flow channels (106) and membrane portions (108) separating the two. The membrane interface portion (102) is created by a three-dimensional array of unit cells based on TPMS gyroid lattice formed of repeating unit cells and includes a network of interconnected feed flow channels (104) and permeate flow channels (106). Feed flow enters the membrane interface portion (102) in the Z direction at the proximal end A and passes through the feed flow channels (104) in the overall Z direction with the retentate existing the membrane interface portion (102) at the distal end B.

[0499] Membrane (100) has a first unit cell layer (110) arranged toward the proximal end A of the membrane interface portion (102) and a second unit cell layer (112) arranged toward the distal end B. The unit cell layers extend substantially transversely to the overall flow direction Z along the lateral directions X and Y.

[0500] Each unit cell (114) of the unit cell layers has a feed flow channel (104), a permeate flow channel (106) and a membrane portion (108) having pores allowing for fluid communication between the feed flow channels (104) and permeate flow channels (106). The feed flow channels (104) and the permeate flow channels (106) of adjacent unit cells are fluidly connected. Membrane interface portion (102) has a plurality of permeate flow outlets (116) arranged around and longitudinally along the peripheral side face. The permeate flow channels (106) are connected to the openings of the permeate flow outlets (116) on the peripheral surface of the membrane through which the permeate can exit the membrane interface portion (102).

[0501] The lateral cell sizes C and D for the unit cells of the first unit cell layer (110) were 30 mm and the lateral aspect ratio reduced from 1 to 0.7 from the first unit cell layer (110) in the proximal end to the second unit cell layer (112) in the distal end. The feed flow direction cell size E for the unit cells in the first unit cell layer (110) was 50 mm and the feed flow direction aspect ratio gradually reduced from 1.7 to 0.7 from the first unit cell layer (110) at the proximal end to the second unit cell layer (112) at the distal end. As shown in FIG. 2, the thickness of the unit cell walls also reduced from 2 mm the first unit cell layer (110) at the proximal end to 1 mm in the second unit cell layer (112) at the distal end.

[0502] FIGS. 5 and 5A show the network of interconnected feed flow channels (104) in the membrane. FIG. 6 shows the network of permeate flow channels (106).

[0503] A second embodiment of a membrane (200) according to the present invention as shown in FIGS. 7-8. The membrane of the second embodiment (200) is the same as the membrane of the first embodiment (100) except that the membrane interface portion (202) is formed of a three-dimensional array of unit cells (214) based on TPMS diamond lattice (216) of repeating unit cells (214).

[0504] 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.

[0505] 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.

[0506] 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.

[0507] 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.