DE10139559A1 - Hybrid membranes including a polymer separation layer and a ceramic support material useful nanofiltration, reverse osmosis, ultrafiltration, and microfiltration and in pressure membrane processes - Google Patents

Abstract

It has been found that a hybrid membrane with a polymer separation layer and a ceramic support material combines the separation properties of polymer membranes and largely the chemical and pressure resistance of a ceramic membrane, and that, the polymer membranes are easily prepared from flexible inorganic chemically resistant and pressure resistant support materials. Hybrid membranes with a selective separation layer, in which the support material is permeable to inorganic material, and the selective separation layer is based on a polymer. An Independent claim is also included for preparation of the hybrid membrane as indicated above involving application of a solution of an organic polymer to the inorganic support material with formation of a polymer layer on the support material.

Description

The invention relates to a hybrid membrane made of an inorganic permeable material Carrier material with an organic selective separating layer.

Ceramic membranes have been known for more than 10 years and are nevertheless due to their quite high price wherever there is either good temperature resistance (> 80 ° C) or good chemical resistance must be guaranteed. Commercially these membranes are available for microfiltration and for ultrafiltration applications. Recently, various applications in pervaporation and in the Nanofiltration reports (K.-V. Peinemann and S. P. Nunes, Membrane Technology; 2001, VCH-Verlag).

The ceramic materials of the separating layers used in the latter applications are used, are nanoparticulate and have a very large surface area. This and that Limiting materials such as γ-alumina or silicon dioxide causes them Membranes do not have the required acid or alkali resistance. RO Membranes and membranes that separate according to the solution diffusion mechanism, are not accessible from ceramic materials.

Polymeric membranes made from a wide variety of polymers are suitable for wide pH ranges and many applications available relatively inexpensively. However, most of the materials not solvent-resistant or not resistant at temperatures above 80 ° C.

There are currently many studies to improve these properties Polymer membranes and there are always new polymer materials with another Application area developed. However, there are two points that require significant expansion stand in the way of the application area of the polymer membranes. For one, there are none sufficiently resistant polymeric carrier materials such as carrier fleece are available and secondly, all polymers are plastically deformable at higher temperatures. this causes a compacting of the entire membrane if this is under pressure operated at higher temperatures. This compacting leads so far that the Pore structure of a membrane is completely compressed and then no filtrate more can pass through the membrane. When using such a membrane in one medium temperature range, there is a user-acceptable level River waste.

Another disadvantage of polymer materials is that they are affected by solvents or oils. or can be dissolved or that the oils have a softening effect. This three effects all lead to the fact that either the separation capacity of the membrane is impaired or that the membrane is compacted even at very low temperatures. Ultimately, compacting always means that the membrane is smaller Has flow rates or becomes unusable due to insufficient flows.

It can therefore be said that polymeric membrane materials can do much more than the polymeric membranes are currently performing. The weak point of the polymeric membranes are not the materials, or the selective layers. These can be done by skillful Tailor material selection and chemical modification for the separation task. The The weak point of the polymeric membranes is the polymer support structure of the membranes. The polymeric carrier fleeces and the polymeric asymmetrical carrier membranes (Mit Pore sizes of up to 5 µm) do not meet the requirements.

DE 199 12 582 attempts to increase the stability of the membranes in that the polymer matrix is mixed with inorganic metal oxide powder, which has the stability elevated. The admixture of the inorganic filler ensures that the Pore structure of the membrane is retained even if, for example, in the Airflow is dried. A compacting of the membrane at higher temperatures is also not avoided by this method.

From WO 99/62620 an ion-conducting composite material is used as a membrane can be known, the ionic conduction, inter alia, by adding ion-conducting polymers to the composite material was achieved. These are polymers However, this does not exist as a separating layer, but rather pulls out so that one Ion conduction can take place through the entire pores from one side to the other Composite.

WO 99/62624 describes composite materials with hydrophobic properties which are considered Membrane can be used, described on the inner and outer Surfaces can have polymers. These polymers are not the separation active Layer, but serve to produce the hydrophobicity of the composite. The In the production of these composite materials, polymers become the sol, from which a Suspension, which is applied to a carrier and solidified, added. In this way the polymer is distributed over the entire cross-section of the composite material. The The pore size of this composite material is determined by the inorganic particles.

The task was therefore to create a membrane with the positive separation properties To develop polymer membrane, which at higher temperatures and when exposed to Oils or solvents are sufficiently stable and inexpensive can be manufactured.

Surprisingly, it was found that a hybrid membrane is a polymer Separating layer and a ceramic carrier material, the separation properties of a Polymer membranes and largely the chemical resistance and Has pressure resistance of a ceramic membrane. Also, surprisingly found that the methods of making polymeric membranes are very easy on one flexible inorganic chemically resistant and pressure stable carrier material applicable are.

The present invention therefore relates to a hybrid membrane according to claim 1, with a selective separation layer, the membrane being an inorganic permeable carrier material and polymeric material, which is characterized in that the selective separation layer by the polymer Material is formed.

The present invention also relates to a method for producing a Hybrid membrane with a selective separation layer, the membrane being an inorganic permeable carrier material and polymeric material, and the selective Separating layer is formed by the polymeric material, which is characterized in that that a solution of an organic polymer is applied to a ceramic support and a polymer layer is formed on the carrier.

The present invention also relates to the use of a hybrid membrane according to one of claims 1 to 12 as a membrane in pressure-driven membrane processes, in nanofiltration, reverse osmosis, ultrafiltration or microfiltration, in pervaporation or in vapor permeation, in a membrane reactor or as a membrane in the Gas separation.

The hybrid membranes according to the invention have the advantage that they and are more dimensionally stable than pure organic polymer membranes, polymer membranes Polymer carriers or as polymer membranes to which inorganic substances have been added. In particular, the desired selectivity and remains in the membranes according to the invention the flow of the separation layer is maintained even at higher temperatures and at higher pressure, d. H. the undesirable phenomenon of compacting the membrane is avoided. In addition, the hybrid membranes according to the invention are tolerant to chemicals and especially stable against common solvents.

The hybrid membrane according to the invention can also have a ceramic support structure have that is thin and flexible, so that the hybrid membrane is also flexible. The Hybrid membranes therefore almost imply when choosing the modules and housings no limits compared to pure polymer membranes.

The hybrid membrane according to the invention is described below by way of example without that the invention should be limited to these embodiments.

The hybrid membrane according to the invention with a selective separation layer, the Membrane an inorganic permeable carrier material and polymeric material has, is characterized in that the selective separation layer by the polymer Material is formed.

As inorganic permeable carrier materials are z. B. microfiber nonwovens, Metal fleeces, dense fiberglass or metal mesh but also ceramic or Carbon fiber fleece or fabric. It is clear to the expert that here everyone else known, preferably flexible with open pores or openings in the corresponding Size-provided materials can be present as carrier materials. Be exemplary Expanded metals or laser-dotted sheets or foils made of metals.

The hybrid membranes according to the invention preferably have inorganic ones Support materials that have pore sizes of less than 20 µm. Point particularly preferably the carrier materials, a pore size of less than 1 micron and very particularly preferred of less than 0.25 µm.

The inorganic permeable carrier material can be a ceramic composite material. The inorganic carrier material preferably has an oxide selected from Al ₂ O ₃ , TiO ₂ , ZrO ₂ or SiO ₂ . The inorganic carrier material likewise preferably has a material selected from ceramic, SiC, Si ₃ N ₄ , C, glass, metal or semimetal.

The hybrid membrane according to the invention very particularly preferably has a flexible membrane inorganic permeable composite material, which is based on an inorganic carrier is based on and / or in which a suspension of an inorganic component and a sol was solidified. The one present in the membrane according to the invention Carrier material can include metal, glass, ceramic, or a combination of these materials. The permeable carrier material preferably has woven fabric, non-woven fabric, sinter powder or Sintered fibers made of metal, glass, ceramic or a combination of these materials. As well The permeable carrier material can have woven or non-woven fabrics made of carbon fibers. The permeable carrier material can also be a material which itself as Microfiltration membrane, ultrafiltration membrane, nanofiltration membrane or Gas separation membrane can be used. So there are also such Combination of materials can be used as carrier materials in which a micro, nano and / or ultrafiltration membrane as a layer on and / or in a support or in and / or was applied to a micro, nano and / or ultrafiltration membrane.

The production of such composite materials is described in detail in WO 99/15262. Typical examples of such composite materials are e.g. B. ceramic membranes, the under the name CREAFILTER can be obtained from Creavis GmbH, Marl. Under the type designations CREAFILTER Z240S; Z100S and Z25S are composite materials based on steel mesh, on which a suspension of aluminum oxide particles in solidified in a zircon sol. Point according to their type designation these composite pores with an average pore diameter of 240 nm, 100 nm and 25 nm.

All the composite materials described in WO 99/15262 are based on composite materials, which an inorganic or ceramic material applied to and in a porous support exhibit. The hybrid membrane according to the invention can be used as a carrier material Composites described below as well as the supports on which they are based exhibit.

The composite materials have at least one openwork and permeable carrier. On at least one side of the carrier and inside the Carrier, the carrier has at least one inorganic component that is essentially at least one compound made of a metal, a semimetal or a mixed metal has at least one element of the 3rd to 7th main group. Under the inside of a The carrier is understood to be the cavities or pores of the carrier.

The composite materials can be applied by applying a suspension, the at least one Connection of at least one metal, a semi-metal or a mixed metal with At least one element of the 3rd to 7th main group, inorganic component and having a sol, on an openwork and permeable support, and through heating at least once, in which the at least one inorganic component having suspension on or in or on and solidified in the carrier can be obtained.

The carrier can have at least one material selected from carbon, metals, alloys, Glass, ceramics, minerals, amorphous substances, natural products, composite materials or from at least a combination of these materials. The bearers who the can have the aforementioned materials, can by a chemical, thermal or a mechanical treatment method or a combination of the treatment methods have been modified. The composite materials preferably have a carrier which has at least one metal, which according to at least one mechanical Deformation technique or treatment method, such as. B. pulling, upsetting, milling, rolling, stretching or forging was modified. The composite materials very particularly preferably have at least one support that is at least woven, glued, matted or ceramic bonded fibers, or at least sintered or bonded shaped bodies, spheres or particles has on. In a further preferred embodiment, a perforated carrier be used. Permeable supports can also be those that are Laser treatment or ion beam treatment become permeable or have been made.

It may be advantageous if the carrier selected fibers from at least one material made of carbon, metals, alloys, ceramics, glass, minerals, amorphous substances, Composites and natural products or fibers from at least a combination of these Materials such as B. asbestos, glass fibers, rock wool fibers, carbon fibers, metal wires, Steel wires or coated fibers. Carriers are preferably used which have at least interwoven fibers made of glass, metal or alloys. Made of fibers Metal can also serve as wires. The composite materials very particularly preferably have a carrier on the at least a fabric made of steel or stainless steel, such as. B. from Steel wires, steel fibers, stainless steel wires or stainless steel fibers produced by weaving Fabric, which preferably has a mesh size of 5 to 500 microns, particularly preferably mesh sizes of 50 to 500 microns and very particularly preferably mesh sizes from 70 to 120 µm.

The carrier of the composite materials can also have at least one expanded metal with a Have pore sizes of 5 to 500 microns. According to the invention, however, the carrier can also at least one granular, sintered metal, a sintered glass or a metal fleece with a Pore size from 0.1 microns to 500 microns, preferably from 3 to 60 microns.

The composite materials preferably have a carrier which contains at least aluminum, Silicon, cobalt, manganese, zinc, vanadium, molybdenum, indium, lead, bismuth, silver, gold, Nickel, copper, iron, titanium, platinum, stainless steel, steel, brass, an alloy of these Materials or one coated with Au, Ag, Pb, Ti, Ni, Cr, Pt, Pd, Rh, Ru and / or Ti Has material.

The inorganic component present in the composite materials can have at least one compound of at least one metal, semimetal or mixed metal with at least one element from the 3rd to 7th main group of the periodic table or at least a mixture of these compounds. The compounds of the metals, semimetals or mixed metals can have at least elements of the subgroup elements and the 3rd to 5th main group or at least elements of the subgroup elements or the 3rd to 5th main group, these compounds having a grain size of 0.001 to 25 µm. The inorganic component preferably has at least one compound of an element of the 3rd to 8th subgroup or at least one element of the 3rd to 5th main group with at least one of the elements Te, Se, S, O, Sb, As, P, N, Ge , Si, C, Ga, Al or B or at least one connection of an element of the 3rd to 8th subgroup and at least one element of the 3rd to 5th main group with at least one of the elements Te, Se, S, O, Sb, As , P, N, Ge, Si, C, Ga, Al or B or a mixture of these compounds. The inorganic component particularly preferably has at least one compound of at least one of the elements Sc, Y, Ti, Zr, V, Nb, Cr, Mo, W, Mn, Fe, Co, B, Al, Ga, In, Tl, Si, Ge , Sn, Pb, Sb or Bi with at least one of the elements Te, Se, S, O, Sb, As, P, N, C, Si, Ge or Ga, such as. B. TiO ₂ , Al ₂ O ₃ , SiO ₂ , ZrO ₂ , Y ₂ O ₃ , BC, SiC, Fe ₃ O ₄ , SiN, SiP, nitrides, sulfates, phosphites, silicides, spinels or yttrium aluminum garnet, or one of these Elements themselves. The inorganic component can also be aluminosilicates, aluminum phosphates, zeolites or partially exchanged zeolites, such as, for. B. ZSM-5, Na-ZSM-5 or Fe-ZSM-5 or amorphous microporous mixed oxides, which can contain up to 20% non-hydrolyzable organic compounds, such as. B. vanadium oxide-silica glass or alumina-silica-methyl-silicon sesquioxide glasses.

At least one inorganic component is preferably in a grain size fraction with a grain size of 1 to 250 nm or with a grain size of 260 to 10000 nm, particularly preferably from 10 to 150 nm or from 300 to 1000 nm.

It can be advantageous if the composite materials used have at least two Have grain size fractions of at least one inorganic component. The Grain size ratio of the grain size fractions in the composite material is from 1: 1 to 1: 10000, preferably from 1: 1 to 1: 100. The ratio of the Grain size fractions in the composite can preferably range from 0.01 to 1 to 1 Be 0.01.

The permeability of the composite materials can be determined by the grain size of the used inorganic component limited to particles with a certain maximum size become.

The composite material can have at least one catalytically active component. The The catalytically active component can be identical to the inorganic component. This applies in particular when the inorganic component is catalytic on the surface has active centers.

The one preferably used as carrier material in the hybrid membrane according to the invention Composite material is preferably bendable without destroying the composite material or executed flexibly. The composite material is preferably down to a radius 5 m, particularly preferably down to 500 mm and very particularly preferably down to 25 mm bendable.

The hybrid membrane according to the invention can be a gas-tight polymer layer as a separating layer exhibit. In the context of the present invention, gas-tight is understood to mean the one Gas cannot pass through the separating layer in a laminar flow. Rather, it takes place the separation z. B. of gas mixtures at the interface instead that the gases of the separating gas mixture at different speeds through the membrane diffuse or be transported through.

The gas-tight polymer layer can e.g. B. from polydimethylsiloxane (PDMS), polyvinyl alcohol, Methyl cellulose or cellulose acetate or a polymer mixture which contains at least one of the compounds mentioned, exist or these compounds or Have modifications of these compounds. In addition, the polymers Starting materials to form the gas-tight layers are crosslinkable, in particular Contain UV-crosslinkable groups.

It is also possible that the hybrid membrane instead of the gas-tight separating layer porous separating layer with defined pores. The hybrid membrane preferably has a porous separation layer with pores with a size of 0.5 to 100 nm, especially preferably from 1 to 50 nm and very particularly preferably from 1 to 10 nm.

The porous separating layer is preferably a polymer layer which contains at least one polymer, selected from a polyimide, a polyamide, polyvinylidene fluoride (PVDF), Polytetrafluoroethylene (PTFE), polyolefin, polyamideimide, polyetherimide, polysulfone and / or Polyether sulfone or at least one other membrane-forming polymer or its Modifications.

The hybrid membranes according to the invention preferably have a polymer layer a thickness of 0.5 to 10 microns, preferably 1 to 8 microns, the porous Separating layers have thicker layers than the gas-tight separating layers. preferred gastight polymer layers have layer thicknesses of 0.5 to 5 μm, preferably of 1.25 to 3.75 µm and most preferably from 1.5 to 2.75 µm. Preferred porous Polymer layers have layer thicknesses of 5 to 50 μm, preferably 5.5 to 20 μm and very particularly preferably from 5.5 to 10 μm.

The hybrid membrane according to the invention is preferably flexible, very particularly preferred the membrane of the invention can be down to a radius of 5 m, preferably down to 500 mm, particularly preferably down to 25 mm and very particularly preferred Bend down to a radius of 5 mm.

The hybrid membrane according to the invention is preferably by means of the inventive A method for producing a hybrid membrane with a selective separation layer, wherein the membrane is an inorganic permeable carrier material and polymeric material and the selective separation layer is formed by the polymeric material which is characterized in that a solution of an organic polymer on the inorganic carrier material applied and a polymer layer is formed on the carrier becomes.

The method can be carried out in various ways. Preferably done the implementation of the method in the plants known from the prior art and Devices for the production of polymer membranes with the difference that instead the polymeric carrier membrane or instead of the polymeric carrier fleece the inorganic Carrier material is used. This inorganic carrier material is preferably so procure that the pores, meshes or openings are less than 20 µm in diameter be. The carrier material is particularly preferably flexible and has Machine direction a correspondingly good tensile strength, preferably a tensile strength of at least 5 N / cm, particularly preferably at least 20 N / cm. Most notably the carrier material preferably has a tensile strength of at least in the machine direction 50 N / cm, preferably 100 N / cm, especially when using glass or Steel tissues.

By using carrier materials with high tensile strength, that the hybrid membrane has a similar high tensile strength as the carrier material having.

Microglass fiber nonwovens, metal nonwovens are preferably used as carrier materials Glass fiber or metal mesh, but also ceramic or carbon fiber fleeces and fabrics used. It is clear to the person skilled in the art that all other known flexible with open Pores or openings in the appropriate size materials are used can.

Very particularly suitable as a carrier material for the process for the production of hybrid membranes are flexible, permeable composite materials which consist of ceramic or oxide particles, preferably SiC, Si ₃ N ₄ , Al ₂ O ₃ , TiO ₂ , ZrO ₂ or SiO ₂ and a carrier which preferably comprises a ceramic, carbon, a glass, a metal or a semimetal, particularly preferably in the form of fibers. These preferably have pore sizes of less than 20 μm, particularly less than 1 μm and very particularly preferably less than 0.25 μm. Such carrier materials can be obtained under the name CREAFILTER from Creavis, Marl. We mainly used the Z240S for our tests; Z100S and Z25S.

The limitation to the smallest possible pore size in the used Carrier materials are advantageous because the polymer solution is too large in the pores Membrane would suck, resulting in an unnecessarily large flow resistance in the finished Membrane leads. Pores that are too small can also have an adverse effect, since in In some cases, the adhesion of the polymer layer is too low and it is during the Use for delamination and thus for the complete destruction of the membrane comes. For this reason, the carrier materials used preferably have a Minimum pore size of 5 nm, preferably of 10 nm and very particularly preferably of 25 nm.

The production of such composite materials that can be used as carrier materials is used, for. B. in WO 99/15262 described in detail and is based on the application of a suspension which at least one, a compound of at least one metal, a semi-metal or one Mixed metal with at least one element from the 3rd to 7th main group, having an inorganic component and a sol, on an openwork and permeable carrier, and solidifying the suspension by at least once Heating, in which the at least one inorganic component Suspension on or in or on and solidified in the carrier. The carrier can at least a material selected from carbon, metals, alloys, glass, ceramics, Minerals, amorphous substances, natural products, composites or from at least one Combination of these materials. It may be advantageous if the carrier has fibers from at least one material selected from carbon, metals, alloys, Ceramics, glass, minerals, amorphous substances, composites and natural products or fibers from at least a combination of these materials, such as. B. asbestos, Glass fibers, rock wool fibers, carbon fibers, metal wires, steel wires or coated fibers, having. Carriers are preferably used which have at least woven fibers made of glass, Have metal or alloys. Wires can also serve as fibers made of metal. All the composite materials particularly preferably have a carrier which has at least one Fabrics made of glass, steel or stainless steel, such as. B. from steel wires, steel fibers, Stainless steel wires or fibers made of woven fabrics, which preferably a mesh size of 5 to 500 microns, particularly preferably mesh sizes of 50 to 500 microns and very particularly preferably have mesh sizes of 70 to 120 microns. The suspension is preferably solidified at a temperature of 50 to 1000 ° C. particularly preferably at a temperature of 50 to 100 ° C for 10 min to 5 hours or at a temperature of 101 to 800 ° C for 1 second to 10 min, very particularly preferred at a temperature of 350 to 550 ° C.

The coating of the carrier material with the solution, which has at least one polymer, for the production of the hybrid membranes can according to the prior art Doctor coating, spraying, rolling, printing or by dip coating techniques respectively. The application thickness of the polymer solution is preferably less than 250 μm, particularly preferably less than 100 μm and very particularly preferably less than 50 μm. The Application thickness can e.g. B. can be influenced by so-called recoating systems.

The polymer layer can be formed in two different ways. In the first The embodiment of the method according to the invention is the polymer layer by removal of the solvent at a temperature of 50 to 350 ° C, preferably at a Temperature from 50 to 125 ° C, from 126 to 250 ° C or from 251 to 350 ° C and especially preferably formed at a temperature of 260 to 340 ° C. As a polymer solution preferably a solution of polydimethylsiloxane (PDMS), polyvinyl alcohol, Methyl cellulose or cellulose acetate or a polymer mixture which is at least one of the has mentioned compounds used. The known solvents are suitable Solvents that are able to dissolve the polymers mentioned, such as. B. toluene, Gasoline fractions, THF, but also water and other known solvents.

In the second embodiment of the method according to the invention, the polymer layer is formed by precipitation in a precipitant bath. In this procedure, a highly viscous solution of a polymer applied to the inorganic carrier material and this arrangement then in a precipitation bath, which contains a precipitant such. B. water, contains, given. Through contact with the precipitant falls out of the highly viscous Polymer solution from a polymer layer. Depending on the precipitation conditions and selected solvent has a certain average pore size.

The polymer layer is particularly preferably precipitated from a polymer solution which at least one polymer selected from a polyimide, a polyamide, Polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyolefin, polyamideimide, Has polyetherimide, polysulfone and / or polyethersulfone. Are suitable as solvents all known solvents that are able to dissolve the polymers, and with the Precipitants can be mixed in any ratio. In particular, when using the Precipitant water N-methylpyrrolidone, dimethylacetamide or dimethylformamide used.

It can be advantageous if the precipitated polymer layer is added in a subsequent step a temperature of 50 to 500 ° C, preferably at a temperature of 50 to 150 ° C, from 151 to 250 ° C or from 251 to 500 ° C and particularly preferably at one temperature is dried from 300 to 450 ° C.

The polymer material used for the formation of the polymer layer can by the mentioned temperature treatments in both types of Chemically change the inventive method. Such a chemical change can e.g. B. a radical, thermal or photo-induced crosslinking reaction or partially pyrolysis with crosslinking of the polymer. This subsequent change in Polymers causes the polymer layer to become insoluble in most solvents. A subsequent crosslinking reaction as a chemical change can also be caused by a Irradiation with electrons or other radiation can be initiated, such. B. by a UV radiation if the starting polymer layers contain UV-crosslinkable groups or by low energy electron beams.

The hybrid membranes according to the invention are used in many areas. by virtue of there is the possibility of tailoring the selective layer to a separation task Advantages in gas permeation, pervaporation, nanofiltration, ultra and Microfiltration. There are also applications as a membrane reactor, even at higher ones Temperatures, well imaginable.

The hybrid membrane according to the invention can therefore, for. B. as a membrane in pressure driven membrane processes, in nanofiltration, in reverse osmosis, in Ultrafiltration or used in microfiltration.

Likewise, the hybrid membrane according to the invention can be used as a membrane in pervaporation or used in vapor permeation and as a membrane in a membrane reactor become.

The use of a hybrid membrane according to the invention, in particular one Hybrid membrane, which has a gas-tight separation layer, as a membrane in the gas separation also possible.

The advantages of the hybrid membranes according to the invention are above all the larger ones Resistance of the membranes at high pressures, at high temperatures or in Solvents and acids and bases. The greater resistance to high pressures is at of gas separation, since the hybrid membranes according to the invention are more stable and do not compact at pressures of up to 40 bar. In pervaporation and the Vapor permeation becomes the better resistance to various organic solvents as well as the improved temperature resistance. at filtration applications also take advantage of the significantly better pressure resistance, since most polymer membranes at pressures of 20 bar in nanofiltration applications compact strongly and therefore the flows through the membrane are significantly lower than this only from the selective interface.

Due to the flexibility of the invention, which is still present despite the ceramic carrier Hybrid membrane and its small thickness, this is also accessible to applications up to now only with the soft or flexible polymer membranes or polymer membranes inorganic fillers were accessible.

The following examples are intended to illustrate the hybrid membranes according to the invention and the Explain the process for producing such hybrid membranes in more detail without the invention should be limited to these designs.

Examples

• 1. In a coating system, an inorganic flexible ceramic CREAFILTER Z25S membrane (Creavis GmbH, Marl) as the material to be coated submitted. An approx. 50 µm thick layer of a PDMS solution is then passed through Recoating system applied and then in a drying oven at 110 ° C. dried. The web speed was 1.0 m / min Membrane rolled up again and processed further. The coating solution consisted of 8.5% PDMS, 1.37% crosslinker and 0.084% of a catalyst in THF. As The following chemicals available from Wacker were used: Dehesive 930; Crosslinker V93 and the catalyst oil. It became a gas-tight Get hybrid membrane that can be used for gas separation.
• 2. The membrane obtained according to Example 1 is in a subsequent step with a Radiation dose of 69 kGy from a low-energy accelerator of the type LEA (institute for surface modification Leipzig e. V.) irradiated in an air atmosphere. there has been a obtained in organic solvents insoluble crosslinked PDMS membrane, which none Has delamination tendencies and for gas separation but also in the Nanofiltration in organic solvents can be used.
• 3. A piece of approximately A4 size of a CREAFILTER membrane of the type Z100S (Creavis GmbH, Marl) was composed of a 50 µm thick layer of a polymer solution 15% polyetherimide (Ultem 1000, GE Plastics) in N-methylpyrrolidone by a Squeegee coated. After a predrying of 10 minutes, this was Membrane precipitated in an aqueous precipitant bath. The membrane thus obtained can be dried after a solvent exchange and then for the UF be used.
• 4. An approximately A4 piece of a CREAFILTER membrane type Z25S was made with a PVA solution treated in the dip-coating technique. The solution consists of: 2.5% Polyvinyl alcohol and 1.0% β-cyclodextrin in an aqueous sodium hydroxide solution has a pH of 9. After coating, the membrane is still about 1 h cross-linked at 150 ° C and can then be used in pervaporation. For a more detailed description of the substances used, see DE 199 25 475 A1.
• 5. A membrane produced according to Example 2 was used to retain polystyrene with a molecular weight of 2,000 g / mol to 100,000 g / mol. The polystyrene was present in tetrahydrofuran as a solvent. The retention rate was 99.2% with a material flow of 10 L m ^-2 h ^-1 bar ^-1 at a pressure of 20 bar. The retention rate of a ceramic nanofiltration comparison membrane was significantly lower at 92%. The manufacturer specified a pore radius of 1 nm for this membrane, which should correspond to a cut-off of approx. 500 g / mol. Polymer solvent-resistant nanofiltration membranes always had a retention of> 99% at the beginning. However, this fell over time (after 2 days) to values below 90% retention. This was always accompanied by a significant drop in river.
• 6. A membrane produced according to Example 1 was used for the same separation task as used under I. The polymer layer dissolved very quickly and none could Separation can be observed.
• 7. A membrane produced according to Example 2 with a PVDF support was used for the same separation task as under I. The retention rate was 98% with a material flow of 3 L m ^-2 h ^-1 bar ^-1 .
• 8. A membrane produced according to Example 2 with a polypropylene carrier instead of the ceramic CREAFILTER membrane was used for the same separation task as under I. The retention rate was 98% with a material flow of 3 L m ^-2 h ^-1 bar ^-1 . However, this deteriorated after 48 hours, since the carrier material was slowly attacked by the solvent.
• 9. A membrane produced according to Example 2 was used for the separation of polystyrene from an N-methylpyrrolidone solution. The retention rate was 98% with a material flow of 1.2 L m ^-2 h ^-1 bar ^-1 . This was constant over 48 hours.
• 10. One according to Example 2 with a polyetherimide carrier instead of the ceramic CREAFILTER membrane was made for the same separation task as used under V. No support could be determined because of the carrier material was dissolved by the solvent.
• 11. A membrane produced according to Example 3 was used to separate catalyst residues (average particle size approx. 0.05 µm) from a gasoline fraction. The retention was 99% with a material flow of 15 L m ^-2 h ^-1 bar ^-1 . This was constant over 48 hours.
• 12. A membrane produced according to Example 3 with a polypropylene carrier instead of the ceramic CREAFILTER membrane was also used for the removal of catalyst residues from a gasoline fraction. The retention was initially 99% with a material flow of 5 L m ^-2 h ^-1 bar ^-1 . The river rose after a few hours. This was accompanied by a decrease in backing. After the experiment, a change (swelling) of the carrier material was found.
• 13. A membrane produced according to Example 4 was used for the separation of water and acetonitrile in the pervaporation at 70 ° C. The flow of water was 0.24 kg m ^-2 h ^-1 with a separation factor of 2300.
• 14. A membrane produced according to Example 4 with a polyacrylonitrile (PAN) support instead of the ceramic CREAFILTER membrane was used for the separation of water and acetonitrile in the pervaporation at 70 ° C. The flow of water was 0.18 kg m ^-2 h ^-1 with a separation factor of 2390.

As can easily be seen from the examples, membranes show a carrier material made of polymer material have a significantly poorer long-term stability than that hybrid membrane according to the invention.

Fig. 1 shows the surface of a hybrid membrane of the invention prepared according to Example 2. Clearly the unevenness of the polymer surface can be seen, which results from the underlying ceramic particles.

Claims (22)

1. Hybrid membrane with a selective separation layer, wherein the membrane has an inorganic permeable carrier material and polymeric material, characterized in that the selective separation layer is formed by the polymeric material. 2. hybrid membrane according to claim 1, characterized, that the inorganic permeable carrier material is a ceramic Composite is. 3. hybrid membrane according to claim 2, characterized, that the ceramic composite is based on an inorganic carrier on which and / or in which a suspension of an inorganic component and a sol was solidified. 4. Hybrid membrane according to at least one of claims 1 to 3, characterized, that the separation layer is a gas-tight polymer layer. 5. hybrid membrane according to claim 4, characterized, that the gas-tight polymer layer made of polydimethylsiloxane (PDMS), polyvinyl alcohol, Methyl cellulose or cellulose acetate. 6. hybrid membrane according to at least one of claims 1 to 3, characterized, that the selective separation layer is a porous separation layer with defined pores. 7. hybrid membrane according to claim 6, characterized, that the pores have a size of 0.5 to 100 nm. 8. Hybrid membrane according to claim 7, characterized, that the pores have a size of 1 to 50 nm. 9. hybrid membrane according to at least one of claims 6 to 8, characterized, that the selective layer of a polyimide, a polyamide, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyolefin, polyamideimide, polyetherimide, Polysulfone or polyethersulfone exists. 10. Hybrid membrane according to at least one of claims 1 to 9, characterized in that the inorganic carrier material has an oxide selected from Al ₂ O ₃ , TiO ₂ , ZrO ₂ or SiO ₂ . 11. Hybrid membrane according to at least one of claims 1 to 9, characterized in that the inorganic carrier material has a material selected from ceramic, SiC, Si ₃ N ₄ , C, glass, metal or semimetal. 12. Hybrid membrane according to at least one of claims 1 to 9, characterized, that the hybrid membrane is flexible. 13. Process for producing a hybrid membrane with a selective separation layer, wherein the membrane is an inorganic permeable carrier material and has polymeric material, and the selective separation layer by the polymeric material is formed characterized, that a solution of an organic polymer on the inorganic carrier material applied and a polymer layer is formed on the carrier material. 14. The method according to claim 13, characterized, that the polymer layer by removing the solvent at a temperature of 50 up to 350 ° C is formed. 15. The method according to claim 13, characterized, that the polymer layer is formed by precipitation in a precipitant bath. 16. The method according to claim 15, characterized in that the precipitated polymer layer is dried in a subsequent step at a temperature of 50 to 500 ° C. 17. The method according to any one of claims 14 to 16, characterized, that the polymer material changes chemically during the temperature treatment. 18. Use of a hybrid membrane according to one of claims 1 to 12 as a membrane in pressure-driven membrane processes. 19. Use of a hybrid membrane according to one of claims 1 to 12 as a membrane in nanofiltration, reverse osmosis, ultrafiltration or microfiltration. 20. Use of a hybrid membrane according to one of claims 1 to 12 as a membrane in pervaporation or vapor permeation. 21. Use of a hybrid membrane according to one of claims 1 to 12 as a membrane in a membrane reactor. 22. Use of a hybrid membrane according to one of claims 1 to 12 as a membrane in gas separation.