GB2201355A - A porous membrane - Google Patents
A porous membrane Download PDFInfo
- Publication number
- GB2201355A GB2201355A GB08804412A GB8804412A GB2201355A GB 2201355 A GB2201355 A GB 2201355A GB 08804412 A GB08804412 A GB 08804412A GB 8804412 A GB8804412 A GB 8804412A GB 2201355 A GB2201355 A GB 2201355A
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- GB
- United Kingdom
- Prior art keywords
- dynamic membrane
- membrane according
- layer
- micron
- particles
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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- 239000012528 membrane Substances 0.000 title claims abstract description 58
- 239000002245 particle Substances 0.000 claims abstract description 45
- 239000011159 matrix material Substances 0.000 claims abstract description 32
- 238000000926 separation method Methods 0.000 claims abstract description 24
- 239000000470 constituent Substances 0.000 claims abstract description 11
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 claims abstract description 10
- 239000007788 liquid Substances 0.000 claims description 25
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 20
- 239000011236 particulate material Substances 0.000 claims description 20
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 18
- 239000000377 silicon dioxide Substances 0.000 claims description 10
- 229910021502 aluminium hydroxide Inorganic materials 0.000 claims description 9
- 239000011148 porous material Substances 0.000 claims description 9
- 235000012239 silicon dioxide Nutrition 0.000 claims description 9
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 6
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 claims description 5
- 239000000126 substance Substances 0.000 claims description 5
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Inorganic materials O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 4
- 239000004408 titanium dioxide Substances 0.000 claims description 3
- 230000001419 dependent effect Effects 0.000 claims 3
- 239000002002 slurry Substances 0.000 abstract description 5
- 229910052719 titanium Inorganic materials 0.000 abstract description 2
- 229910052726 zirconium Inorganic materials 0.000 abstract description 2
- 239000012736 aqueous medium Substances 0.000 abstract 2
- MXRIRQGCELJRSN-UHFFFAOYSA-N O.O.O.[Al] Chemical compound O.O.O.[Al] MXRIRQGCELJRSN-UHFFFAOYSA-N 0.000 abstract 1
- 229910052814 silicon oxide Inorganic materials 0.000 abstract 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 21
- 239000007900 aqueous suspension Substances 0.000 description 8
- 239000003921 oil Substances 0.000 description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 238000000576 coating method Methods 0.000 description 6
- 239000012466 permeate Substances 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000002861 polymer material Substances 0.000 description 4
- 230000008929 regeneration Effects 0.000 description 4
- 238000011069 regeneration method Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 3
- 239000004744 fabric Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000000725 suspension Substances 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 2
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 230000005661 hydrophobic surface Effects 0.000 description 2
- 229920002647 polyamide Polymers 0.000 description 2
- -1 polypropylene Polymers 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 235000011121 sodium hydroxide Nutrition 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical class [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- AYJRCSIUFZENHW-DEQYMQKBSA-L barium(2+);oxomethanediolate Chemical compound [Ba+2].[O-][14C]([O-])=O AYJRCSIUFZENHW-DEQYMQKBSA-L 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 239000001175 calcium sulphate Substances 0.000 description 1
- 235000011132 calcium sulphate Nutrition 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 238000009295 crossflow filtration Methods 0.000 description 1
- WCOATMADISNSBV-UHFFFAOYSA-K diacetyloxyalumanyl acetate Chemical compound [Al+3].CC([O-])=O.CC([O-])=O.CC([O-])=O WCOATMADISNSBV-UHFFFAOYSA-K 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 229910001679 gibbsite Inorganic materials 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 229910052809 inorganic oxide Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- UQXWTFXBTIZNGU-UHFFFAOYSA-M oxygen(2-) zirconium(3+) chloride Chemical compound [O-2].[Zr+3].[Cl-] UQXWTFXBTIZNGU-UHFFFAOYSA-M 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 229920002492 poly(sulfone) Polymers 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- KKEYFWRCBNTPAC-UHFFFAOYSA-L terephthalate(2-) Chemical compound [O-]C(=O)C1=CC=C(C([O-])=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-L 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229910001928 zirconium oxide Inorganic materials 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
- B01D65/02—Membrane cleaning or sterilisation ; Membrane regeneration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
- B01D17/08—Thickening liquid suspensions by filtration
- B01D17/085—Thickening liquid suspensions by filtration with membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D37/00—Processes of filtration
- B01D37/02—Precoating the filter medium; Addition of filter aids to the liquid being filtered
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/14—Dynamic membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
- B01D2321/281—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling by applying a special coating to the membrane or to any module element
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
A porous membrane for separation of undissolved constituents from an aqueous medium comprises a support matrix (11a) with through-passages (22), an inner layer (11ba) of particles of aluminum hydroxide and/or at least partially hydrated aluminum oxide with a mean particle size exceeding 0.1 micron and an outer layer (11bb), of colloidal particles, substantially insoluble in the aqueous medium and with a mean size of less than 0.1 micron preferably, there is arranged between the inner and outer layer at least one intermediate layer (11bc) of particles of intermediate size. The layers are deposited on matrix 11a from successive slurries. The outer and intermediate layers may be oxides of Si, Ti or Zr. In Fig. 1, two such membranes are arranged in a cross-flow filter with a rubber-bladed rotor between them. <IMAGE>
Description
A Dynamic Membrane for Separation of a Liquid
Medium at Least Substantially Consisting of Water
The present invention relates to a dynamic membrane for separation of a liquid medium, at least substantially consisting of water, from undissolved constituents therein, comprising a liquid-penetrable support matrix having through-passages therein, in which passages and on the surface of which matrix a layer of a particulate material is arranged.
A dynamic membrane according to this invention may be arranged in a separation device which, in addition to the dynamic membrane, comprises a chamber to which the liquid medium can be supplied on one side of the membrane. The layer of particulate material, which is small-sized, is porous with finer pores than the through-passages in the support matrix. In such a separation device, a supplied liquid medium, while maintaining a pressure in the chamber, may be led past the dynamic membrane and be divided into one flow - the permeate flow - which passes through the dynamic membrane, and another flow - the reject flowwhich flows past the dynamic membrane.Separation devices based on dynamic membranes may be used for clarifying water with respect to undissolved liquid constituents, for example dispersed or emulsified oil, or undissolved solid particles, for example for separation of different types of slurries, such as a coal-water slurry, a peat-water slurry, and waste water from the production of cellulose.
When using a dynamic membrane, for clarifying a liquid, an increasingly thicker coating consisting of constituents undissolved in the liquid medium, is deposited, which successively reduces liquid flow through the dynamic membrane. Therefore, after some time in operation, the collected coating must be removed and either the layer of the small-sized particulate material be replaced by a new one, or the original properties of the membrane must be restored in some other way. This regeneration of the membrane should preferably be carried out without dismantling the separation device.Up to the present time, regeneration has been effected by back flushing with a liquid or compressed air, or by. dissolution or washing away of the coating and the particulate material in a liquid with a subsequent supply of a slurry of new particulate material to the matrix under such conditions that a fresh layer of the particulate material is deposited on the support matrix, and in the through-passages thereof. It is, of course, of vital importance to maintain as high a flow rate as possible through the membrane for as long a period of time as possible, so that any interruption in the filtration process for necessary regeneration of the membrane needs to be done quickly and/or at the greatest possible time intervals.
Silicon dioxide or zirconium dioxide is usually used as the small-sized particulate material in a dynamic membrane.
According to one aspect of the invention a dynamic membrane for separation of a liquid medium, at least substantially consisting of water, from undissolved constituents therein, comprises a liquid-penetrable support matrix with through-passages, in the passages of which and on the surface of which matrix there is arranged an inner porous water-holding layer of particles of aluminium hydroxide and/or particles of at least partially hydrated aluminium oxide with a mean particle size exceeding 0.1 micron and an outer layer, arranged outside the inner layer, of colloidal particles of a substance which is at least substantially insoluble in the liquid medium and has a mean particle size of less than 0.1 micron. The mean particle size in the inner layer preferably lies in the range 0.5 to 5 microns.
By mean particle size" of a particulate material is meant, in this specification, that particle size for which 50 per cent by weight of the particulate material has a smaller particle size and 50 per cent by weight of the particulate material has a larger particle size.
According to a specially preferred embodiment of the invention there is arranged, between the inner layer and the outer layer of particulate materials, at least one intermediate layer of particles of a substance which is at least substantially insoluble in the liquid medium and has a mean-particle size which lies between the mean particle size of the particulate material in the inner layer and the mean particle size of the particulate material in the outer layer. The particulate material in an intermediate layer preferably has a mean particle size lying in the range of 0.1 to 0.5 micron.
The support matrix with through-passages may advantageously consist of a woven or felted product built up of fibres of a polymer material such as polyamide, polypropylene, cellulose acetate, polysulphone, polyethyleneglycol terephthalate, or polyurethane, or of fibres of a metallic material such as stainless steel, or of a natural fibre such as cotton. The support matrix may also consist of a sintered porous material with through pores. A porous plate of metal (such as stainless steel), or of a ceramic material (such as aluminium oxide) or a porous film of a polymer material, for example any of the above-mentioned polymer materials. The through-passages preferably have sizes in the range of 0.1 to 10 microns.
The thickness of the support matrix may advantageously lie in the range 0.1 to 10 mm.
As will be clear from what has been said above, the particulate material in the inner porous layer may consist of aluminium hydroxide or hydrated aluminium oxide. The hydration may take place by the oxide itself taking up water on its surface. The pore size in the inner porous layer preferably lies in the range 0.1 to 1 micron and the thickness of #the layer advantageously lies in the range 5 to 100 microns. This inner layer is water-rich, has good penetrability to water and is hydrophilic.
The particulate material in the outer porous layer and in one or more possibly occurring porous intermediate layers may, inter alia, consist of an inorganic oxide such as an oxide of silicon, titanium, or zirconium, or of water insoluble inorganic salts, such as sulphates or carbonates, for example barium sulphate, calcium sulphate, barium carbonate, or calcium carbonate. The pore size in the outer porous layer preferably lies in the range of 0.005 to 0.1 micron and the thickness of the layer advantageously lies in the range of 1 to 20 microns. The pore size in any intermediate layer preferably amounts to 0.02 to 0.5 micron, and the thickness advantageously lies in the range of 1 to 20 microns. Outer layers and intermediate layers have a mechanically stabilizing effect on the inner, waterholding layer.
The outer layer is able to provide a very even surface, which reduces the risk of clogging of any solid particles. This applied particularly to cross-flow filtration. In separating oil from water, a very thin oil film is formed on the surface, which reduces the wear on the surface of the membrane, whereas oil never penetrates deeper down into the inner porous layer and blocks~the passages or channels in the deeper parts which are available for liquid flow.
The outer layer is in itself hydrophilic but may be treated to give it a more or less hydrophobic surface if this is desirable from the point of view of the separation process to be conducted. A hydrophobic surface can be obtained by treating the particles or the finished layer formed from the particles with a wax or a silane.
A dynamic membrane according to the present invention is particularly suited for use when filtering in accordance with the cross-flow principle.
A particularly valuable property of a membrane according to the present invention is that, where necessary, it can be regenerated by scraping.
By use of the present invention, it has proved to be possible to provide a dynamic membrane through which a high flow rate can be maintained for a considerably longer period of time than has proved to be possible with pri-or art dynamic membranes. By first arranging on the support matrix an inner layer of a particulate material with the ability to retain water and then arranging outside this layer at least an outer layer of a particulate substance which is at least substantially insoluble in the liquid medium the particles in said outer layer having a smaller particle size than those forming the inner layer, the outer layer can protect the inner layer against clogging by undissolved constituents in the liquid medium.
A separation device incorporating a membrane in accordance with this invention represents a further aspect of the invention.
The invention will now be explained in greater detail, by way of example, with reference to the accompanling drawing, wherein
Figure 1 shows a separation device with a dynamic membrane according to the present invention in a section, perpendicular to the dynamic membrane, through the axis of a rotor in the separation device.
Figure 2 shows the dynamic membrane and the rotor of
Figure 1 viewed in the direction of the rotor axis from the interior of the separation device, and
Figures 3 and 4 each show a cross-section of a small part of a dynamic membrane according to the present invention, on a considerably enlarged scale in two different embodiments.
The separation device shown in Figure 1 comprises a chamber 10 of cylindrical shape and two round dynamic membranes 11 and 12 are arranged at each of the two opposite end surfaces of the chamber. At their edges each membrane is sealingly attached to the walls of the chamber by seals (not shown). Each dynamic membrane consists of a porous matrix 11a and 12a, respectively, which can be a fine-meshed woven cloth with a central circular aperture llai and 12at, respectively, and of layers lib and 12b, respectively, of a small-sized particulate material of the kind illustrated in Figures 3 and 4.At one point on the envelope surface, the chamber is provided with an inlet 13 for liquid medium which is to be treated in the separation device, and at a diametrically opposite point on the envelope surface the chamber is provided with an outlet 14 for the part of the supplied medium - the reject - which passes past the dynamic filters. The inlet 13 and the outlet 14 are arranged in the side walls 15 and 16 of the chamber. That part of the liquid in ~ the supplied mediumthe permeate - which passes through the dynamic membranes, flows into channels 17 in the walls 18 and 19 of the chamber, eventually passing to a permeate outlet 20.
A rotor 21 is arranged in the chamber 10, in the exemplified case comprising a rotor shaft 21a, the centre line of which coincides with the symmetry axis of the cylindrical chamber. Two wings or blades 21b of the rotor 21 are arranged in the chamber 10. The rotor shaft is journal led in the walls of the chamber by means of sealing bearings (not shown).
When the separation device is in operation, the liquid medium with undissolved constituents to 0be subjected to clarifying is continuously led via the inlet 13 into the chamber 10 of the separation device. The liquid may, for example, consist of water containing oil drops and solid particles, such as oil-containing water from oil refineries or oil platforms, or waste water from workshops with cutting or grinding machines. The main part of the water passes through the dynamic membranes 11 and 12 as a permeate flow and can normally be led to a recipient via the outlet 20. The remaining liquid - the reject flow - is discharged via the outlet 14 and is returned to the polluted starting material or is subjected to an after treatment which in most cases is simple.During the course of the process described, a pressure difference of preferably between 0.03 and 0.3 MPa is maintained between the media on either side of a dynamic membrane. The undissolved constituents which are successively accumulated on the dynamic membranes are removed by means of the rotor 21 when the coatings of the undissolved constituents constitute too great a resistance to the permeate flow for the separation to be carried out at a commercially satisfactory rate.
In the cases shown in Figures 3 and 4, the support matrix lla consists of a fabric of polyamide, crosssections of the fibres of which are shown in the Figures.
The fabric has a thickness of 0.2 mm and the through passages 22 a size of 5 microns. The inner porous layer ilba consists of particles of aluminium hydroxide with a mean particle size of about 1 micron. The thickness of the layer Ilba is on average 40 microns. The layer is applied on the support matrix by an aqueous suspension of
Al(OH)3 being sucked through the support matrix until the amount of- Al (OH)3 taken up by the support matrix amounts to 25 g/m2. The aqueous suspension of Al (OH)3 can be produced by suspending 6 parts by weight aluminium acetate in 106 parts by weight water containing hydrochloric acid to a pH of 1.5 and precipitation of the aluminium hydroxide under vigorous stirring at a temperature below 500 with ammonia while adjusting the pH to 7.5.After that, in the case shown in Figure 4, an intermediate layer llbc, consisting of particles of silicon dioxide with a mean particle size of 9.2 micron, is applied in an analogous manner by an aqueous suspension of such particles being sucked through the support matrix with an applied inner layerllba until the absorbed quantity of SiO2 amounts to 6 g/m2 and the thickness of the porous layer llbc thus formed amounts to about 10 microns. The aqueous suspension can be produced by mixing and shaking for 2 hours 250 parts by volume of water, 35 parts by volume of 25 per cent ammonia, 500 parts by volume of ethanol, and 120 parts by volume of tetraethyl orthosilicate and thereafter neutralizing the mixture to a pH of 7 with hydrochloric acid.Finally, the outer layer 11bob is applied on the support matrix Ila with the layer 11ba in the case according to Figure 3 and the layers liba and llbc in the case according to Figure 4 by an aqueous suspension of silicon dioxide with a mean particle size of the particles of 0.08 micron being sucked through the support matrix until the quantity of Sic2 absorbed by the support matrix amounts to 3 g/m2 and the thickness of the layer amounts to 5 microns. This aqueous suspension of silicon dioxide can be produced by mixing 2 parts by volume of saturated ammonia hydroxide, 50 parts by volume of ethanol, and 4 parts by volume of tetrapenthyl orthosilicate. The application of the layers elba, 11bob, and llbc can be carried out either before or after the support matrix has been placed in the separation device. It is possible to apply some of the layers, for example layers flba and llbb, on the support matrix outside the separation device and one of the layers, for example layer llbc, while the support matrix is located in the separation device.
As mentioned previously, the rotor 21 is used for removing coatings accumulated on the dynamic membranes.
The wings 21b of the rotor are then used as scrapers. They are therefore made of a material which does not damage the dynamic membranes, such as rubber, polytetrafluorethylene, or some other polymer material, and are arranged movable relative to the membranes in a direction perpendicular to the membranes. This movability can be achieved either by making the rotor shaft 21a with the rotor displaceable in a stationary chamber 10, or by making the chamber displaceable along a rotor arranged stationarily in the longitudinal direction of the rotor shaft.
The rotor can -be utilized for regeneration of the dynamic membranes by bringing the rotor wings into contact with the layer lib on the support matrix and displacing the wings along the support matrix. The layers 11bob and llbc and possibly part of the layer liba are then suitably removed in connection with the removal of the coatings of the undissolved constituents of the liquid medium from the membranes. If required, particles of aluminium hydroxide are then applied on the support matrix using the previously described suspension in the manner previously described for restoring the layer Ilba. Thereafter, the layers llbc and 11bob are applied in the above-described manner while using the above-described suspensions of silicon dioxide.
Instead of aluminium hydroxide the layer llba may be a layer of hydrated aluminium oxide (e.g. a quality with the designation CTG-SG from Aluminum Corp. of America) or a mixture of the mentioned hydrated aluminium oxide and aluminium hydroxide. ~ Such a mixture can be produced by suspending 25 parts by weight of the hydrated oxide in 5000 parts by weight of hot water and by mixing the bottom phase thus formed with 100 parts by weight of the above described suspension of Al (OH)3. After this mixture has been sucked through the support matrix, it is suitable also to suck -up through the support matrix that solution, formed and decanted above the bottom phase, which is obtained when suspending the oxide in the hot water.
Instead of the silicon dioxide used in the above-noted example, the layer 11bob may be a layer of titanium dioxide applied from a water suspension produced by hydrolysis of titanium chloride in water and neutralized with caustic soda to a pH of 1.5, or a layer of zirconium dioxide applied from an aqueous suspension produced by dissolution of zirconium oxide chloride in water, precipitation of the zirconium oxide occurring with caustic soda to a pH of 5.5 and acidification with hydrochloric acid to pH of 1.5. It is also possible to use commercially available colloidal solutions (e.g. a colloidal solution of silica M-12475 from the company E Merck, Fed. Rep. of Germany).
Claims (15)
1. A dynamic membrane for separation of a liquid medium, at least substantially consisting of water-, fr#om undissolved constituents therein, comprising a liquidpenetrable support matrix with through-passages, in the passages of which and on the surface of which matrix there is arranged an inner porous water-holding layer of particles of aluminium hydroxide and/or particles of at least partially hydrated aluminium oxide with a mean particle size exceeding 0.1 micron and an outer layer arranged outside the inner layer, of colloidal particles of a substance which is at least substantially insoluble in the liquid medium and has a mean particle size of less than 0.1 micron.
2. A dynamic membrane according to claim 1, in which the particulate material in the inner layer has a mean particle size in the range of 0.5 to 5 micron.
3. A dynamic membrane according to claim 1 or claim 2, in which between the inner layer and the outer layer there is arranged at least one intermediate layer of particles of a substance w#hich is at least substantially insoluble in the liquid medium and has a mean particle size which lies between the mean particle sizes of the particulate materials in the inner and outer layers.
4. A dynamic membrane according to claim 3, in which the particles in the intermediate layer have a mean particle size in the range of 0.1 to 0.5 micron.
5. A dynamic membrane according to any one of claims 1 to 4, in which the pore sizes in the inner layer lie in the range of 0.1 to 1 micron.
6. A dynamic membrane according to any one of claims 1 to 5, in which the pore sizes in the outer layer lie in the range of 0.005 to 0.1 micron.
7. A dynamic membrane according to either of claim 3 or claim 4, in which the pore sizes in the intermediate layer lie in the range of 0.02 to 0.5 micron.
8. A dynamic membrane according to any one of claims 1 to 7, in which the outer layer comprises silicon dioxide.
9. A dynamic membrane according to any one of claims 1 to 7, in which the outer layer comprises titanium dioxide.
10. A dynamic membrane according to any one of claims 1 to 7, in which the outer layer comprises zirconium dioxide.
11. A dynamic membrane according to claim 3 or claim 4 or any claim dependent thereon, in which the intermediate layer comprises silicon dioxide.
12. A dynamic membrane according to claim 3 or claim 4 or any claim dependent thereon, in which the intermediate layer comprises titanium dioxide.
13. A dynamic membrane according to claim 3 or claim 4 or any claim dependent thereon, in which the intermediate later comprises zirconium dioxide.
14. A dynamic membrane substantially as hereinbefore described with reference to, and as illustrated in, Figure 3 or Figure 4 of the accompanying drawing.
15. A separation device incorporating a membrane as claimed in any one preceding claim.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE8700811A SE457607B (en) | 1987-02-26 | 1987-02-26 | DYNAMIC MEMBRANE FOR SEPARATION OF A LIQUID, AATMINSTONE MAINLY IN THE WATER EXISTING MEDIUM |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8804412D0 GB8804412D0 (en) | 1988-03-23 |
| GB2201355A true GB2201355A (en) | 1988-09-01 |
Family
ID=20367679
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08804412A Pending GB2201355A (en) | 1987-02-26 | 1988-02-25 | A porous membrane |
Country Status (3)
| Country | Link |
|---|---|
| GB (1) | GB2201355A (en) |
| NO (1) | NO165947C (en) |
| SE (1) | SE457607B (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993000146A1 (en) * | 1991-06-25 | 1993-01-07 | Thomas Handtmann | Process and device for filtering liquids |
| US5196380A (en) * | 1991-06-06 | 1993-03-23 | Arizona Board Of Reagents | Reactive membrane for filtration and purification of gases of impurities |
| EP0623380A1 (en) * | 1992-03-30 | 1994-11-09 | Nicolaos Iniotakis | Membrane for the separation of polydispersions and/or emulsions and process for the manufacture of said membrane |
| US5635148A (en) * | 1991-06-06 | 1997-06-03 | Arizona Board Of Regents On Behalf Of The University Of Arizona | Reactive membrane for filtration and purification of gases of impurities and method utilizing the same |
| US5679249A (en) | 1991-12-24 | 1997-10-21 | Pall Corporation | Dynamic filter system |
| EP0870787A1 (en) * | 1997-04-08 | 1998-10-14 | Toyo Engineering Corporation | Method of continuously dissolving rubber |
| US5829139A (en) * | 1995-05-03 | 1998-11-03 | Pall Corporation | Method for forming a reactive medium |
| US6117322A (en) | 1993-06-23 | 2000-09-12 | Pall Corporation | Dynamic filter system |
| WO2004002605A1 (en) * | 2002-06-26 | 2004-01-08 | Den Kongelige Veterinær-Og Landbohøjskole | Dual porosity filter |
| US7465692B1 (en) | 2000-03-16 | 2008-12-16 | Pall Corporation | Reactive media, methods of use and assemblies for purifying |
| US20120118813A1 (en) * | 2008-11-07 | 2012-05-17 | Technologies Avancees Et Membranes Industrielles | Filtration membrane having improved resistance to abrasions |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111392818A (en) * | 2020-02-12 | 2020-07-10 | 中国海洋石油集团有限公司 | Dynamic membrane for treating oily sewage and preparation method and application thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB501334A (en) * | ||||
| GB1384919A (en) * | 1972-06-06 | 1975-02-26 | Inst Gonogo Dela Sib Otdel Aka | Process for purifying water |
| GB1468928A (en) * | 1973-05-10 | 1977-03-30 | Union Carbide Corp | Ultrafiltration apparatus and process for the treatment of liquids |
-
1987
- 1987-02-26 SE SE8700811A patent/SE457607B/en not_active IP Right Cessation
-
1988
- 1988-02-24 NO NO880817A patent/NO165947C/en not_active IP Right Cessation
- 1988-02-25 GB GB08804412A patent/GB2201355A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB501334A (en) * | ||||
| GB1384919A (en) * | 1972-06-06 | 1975-02-26 | Inst Gonogo Dela Sib Otdel Aka | Process for purifying water |
| GB1468928A (en) * | 1973-05-10 | 1977-03-30 | Union Carbide Corp | Ultrafiltration apparatus and process for the treatment of liquids |
Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5196380A (en) * | 1991-06-06 | 1993-03-23 | Arizona Board Of Reagents | Reactive membrane for filtration and purification of gases of impurities |
| US5635148A (en) * | 1991-06-06 | 1997-06-03 | Arizona Board Of Regents On Behalf Of The University Of Arizona | Reactive membrane for filtration and purification of gases of impurities and method utilizing the same |
| US5637544A (en) * | 1991-06-06 | 1997-06-10 | Arizona Board Of Regents On Behalf Of The University Of Arizona | Reactive membrane for filtration and purification of gases of impurities and method utilizing the same |
| US5445745A (en) * | 1991-06-25 | 1995-08-29 | Handtmann; Thomas | Filtering method for filtering liquids |
| WO1993000146A1 (en) * | 1991-06-25 | 1993-01-07 | Thomas Handtmann | Process and device for filtering liquids |
| US6106713A (en) | 1991-12-24 | 2000-08-22 | Pall Corporation | Dynamic filter system |
| US5679249A (en) | 1991-12-24 | 1997-10-21 | Pall Corporation | Dynamic filter system |
| EP0623380A1 (en) * | 1992-03-30 | 1994-11-09 | Nicolaos Iniotakis | Membrane for the separation of polydispersions and/or emulsions and process for the manufacture of said membrane |
| US6117322A (en) | 1993-06-23 | 2000-09-12 | Pall Corporation | Dynamic filter system |
| US6066591A (en) * | 1995-05-03 | 2000-05-23 | Pall Corporation | Reactive medium for purifying fluids |
| US5829139A (en) * | 1995-05-03 | 1998-11-03 | Pall Corporation | Method for forming a reactive medium |
| US5929205A (en) * | 1997-04-08 | 1999-07-27 | Toyo Engineering Corporation | Method of continuously dissolving rubber |
| EP0870787A1 (en) * | 1997-04-08 | 1998-10-14 | Toyo Engineering Corporation | Method of continuously dissolving rubber |
| US7465692B1 (en) | 2000-03-16 | 2008-12-16 | Pall Corporation | Reactive media, methods of use and assemblies for purifying |
| WO2004002605A1 (en) * | 2002-06-26 | 2004-01-08 | Den Kongelige Veterinær-Og Landbohøjskole | Dual porosity filter |
| US7588686B2 (en) | 2002-06-26 | 2009-09-15 | University Of Copenhagen | Dual porosity filter |
| US20120118813A1 (en) * | 2008-11-07 | 2012-05-17 | Technologies Avancees Et Membranes Industrielles | Filtration membrane having improved resistance to abrasions |
| US9669362B2 (en) * | 2008-11-07 | 2017-06-06 | Technologies Avancees Et Membranes Industrielles | Filtration membrane having improved resistance to abrasions |
Also Published As
| Publication number | Publication date |
|---|---|
| NO165947B (en) | 1991-01-28 |
| SE457607B (en) | 1989-01-16 |
| NO880817L (en) | 1988-08-29 |
| NO165947C (en) | 1991-05-08 |
| NO880817D0 (en) | 1988-02-24 |
| SE8700811L (en) | 1988-08-27 |
| SE8700811D0 (en) | 1987-02-26 |
| GB8804412D0 (en) | 1988-03-23 |
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