WO2003013708A2 - Hybrid membrane, method for the production thereof and use of said membrane - Google Patents

Abstract

The invention relates to a hybrid membrane combining the advantages of inorganic membranes such as solvent resistance and stability with the advantages of organic membrane materials. Said hybrid membrane consists of a ceramic carrier layer and an organic, selectively separating layer. The separating properties of the membrane can be regulated in a targeted manner by varying the polymers or the method of treatment of the polymer materials or the conditions under which the polymer selective separating layer is produced.

Description

Hybrid membrane, process for its manufacture and the use of the membrane

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

Ceramic membranes have been known for more than 10 years and due to their rather high price are always used where either good temperature resistance (> 80 ° C) or good chemical resistance must be guaranteed. These membranes are commercially available for microfiltration and for ultrafiltration applications. Various applications in pervaporation and nanofiltration have recently been reported (K.-V. Peinemann and S.P. Nunes, Membrane Technology; 2001, VCH-Verlag).

The ceramic materials of the separating layers, which are used in the latter applications, are nanoparticulate and have a very large surface area. This and the limitation to materials such as γ-aluminum oxide or silicon dioxide means that these membranes do not have the required acid or alkali resistance. Reverse osmosis 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 available relatively cheaply for wide pH ranges and many applications. However, most materials are not solvent-resistant or not resistant at temperatures above 80 ° C.

There are currently many studies to improve these properties on polymer membranes and new polymer materials with a wider range of applications are constantly being developed. However, there are two points that stand in the way of a significant expansion of the area of application for polymer membranes. On the one hand, there are no sufficiently stable polymeric carrier materials such as nonwovens and, on the other hand, all polymers are plastically deformable at higher temperatures. This causes the entire membrane to compact when it is under pressure operated at higher temperatures. This compacting then leads so far that the pore structure of a membrane is completely compressed and then no more filtrate can pass through the membrane. If such a membrane is used in a medium temperature range, the user will accept a drop in flow.

Another disadvantage of polymer materials is that they can be dissolved or dissolved by solvents or oils, or that the oils have a softening effect. These three effects all lead to the fact that the separating capacity of the membrane is impaired or that the membrane is compacted even at very low temperatures. Ultimately, compacting always means that the membrane has lower 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 currently do. The weak point of the polymeric membranes is not the materials or the selective layers. These can be tailored to the separation task by skillful selection of materials and chemical modification. 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 (with pore sizes of up to 5μm) do not meet the requirements.

DE 199 12 582 attempts to increase the stability of the membranes by mixing inorganic metal oxide powder into the polymer matrix, which increases the stability. The admixture of the inorganic filler ensures that the pore structure of the membrane is retained even if it is dried in an air stream, for example. A compacting of the membrane at higher temperatures is also not avoided by this method.

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

WO 99/62624 describes composite materials with hydrophobic properties which can be used as a membrane and which can have polymers on the inner and outer surfaces. These polymers do not represent the release-active layer, but serve to produce the hydrophobicity of the composite material. In the production of these composite materials, the polymers are added to the sol, from which a suspension, which is applied to a support and solidified, is added. In this way, the polymer is distributed over the entire cross section of the composite material. The pore size of this composite material is determined by the inorganic particles.

The task was therefore to develop a membrane with the positive separation properties of a polymer membrane, which has a sufficiently high stability at higher temperatures and when exposed to oils or solvents, and which can be manufactured inexpensively.

Surprisingly, it was found that a hybrid membrane, which has a polymeric separating layer and a ceramic carrier material, has the separating properties of a polymer membrane and largely the chemical resistance and the pressure resistance of a ceramic membrane. It has also surprisingly been found that the methods of producing polymeric membranes are very easily applicable to a flexible inorganic, chemically stable and pressure-stable carrier material.

The present invention therefore relates to a hybrid membrane according to claim 1, with a selective separating layer, the membrane having an inorganic permeable carrier material and polymeric material, which is characterized in that the selective separating layer is formed by the polymeric material. The present invention also relates to a method for producing a hybrid membrane with a selective separation layer, the membrane having an inorganic permeable carrier material and polymeric material, and the selective separation layer being formed by the polymeric material, which is characterized in that a solution of an organic Polymer applied to a ceramic carrier and a polymer layer is formed on the carrier.

The present invention also relates to the use of a hybrid membrane as claimed in 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 are significantly more temperature and shape stable than pure organic polymer membranes, polymer membranes on polymer supports or as polymer membranes to which inorganic substances have been added. In particular, in the membranes according to the invention, the desired selectivity and the flow of the separating layer are retained even at higher temperatures and at higher pressure, i.e. H. the undesirable phenomenon of compacting the membrane is avoided. In addition, the hybrid membranes according to the invention are tolerant of chemicals and in particular stable against the common solvents.

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

The hybrid membrane according to the invention is described below by way of example, without the invention being restricted to these embodiments.

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

As inorganic permeable carrier materials are z. B. microglass fiber nonwovens, metal nonwovens, dense glass fiber or metal mesh but also ceramic or carbon fiber nonwovens or fabrics. It is clear to the person skilled in the art that all other known, preferably flexible, materials with open pores or openings of the appropriate size can also be present as carrier materials. Expanded metals or laser-punctured metal sheets or foils may be mentioned as examples.

The hybrid membranes according to the invention preferably have inorganic carrier materials which have pore sizes of less than 20 μm. The carrier materials particularly preferably have a pore size of less than 1 μm and very particularly preferably 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, inorganic, material-permeable composite material which is based on an inorganic carrier, on which and / or in which a suspension of an inorganic component and a sol has been solidified. The carrier material present in the membrane according to the invention can comprise metal, glass, ceramic or a combination of these materials. The permeable carrier material preferably has woven fabrics, nonwovens, sintered powder or sintered fibers made of metal, glass, ceramic or a combination of these materials. Likewise, 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 a microfiltration membrane, ultrafiltration membrane, nanofiltration membrane or Gas separation membrane can be used. It is therefore also possible to use such material combinations as carrier materials in which a micro, nano and / or ultrafiltration membrane has been applied as a layer on and / or in a carrier or in and / or on 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, which are available under the name CREAFILTER from Creavis GmbH, Mari. Under the type designations CREAFILTER Z240S; Z100S and Z25S are composite materials based on steel mesh, on which a suspension of aluminum oxide particles has been solidified in a zirconium sol. According to their type designation, these composite materials have 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 have an inorganic or ceramic material applied to and in a porous carrier. The hybrid membrane according to the invention can have both the composite materials described below and the carriers on which they are based as the carrier material.

The composite materials have at least one perforated and permeable support as the basis. On at least one side of the carrier and in the interior of the carrier, the carrier has at least one inorganic component which essentially has at least one compound composed of a metal, a semimetal or a mixed metal with at least one element from the 3rd to 7th main group. The interior of a carrier is understood to mean 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 having inorganic component and a sol, on an openwork and permeable carrier, and through heating at least once, in which the suspension having at least one inorganic component is solidified on or in or on and in the carrier.

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 carriers, which may have the aforementioned materials, may have been modified by a chemical, thermal or mechanical treatment method or a combination of the treatment methods. The composite materials preferably have a carrier which has at least one metal which can be formed by at least one mechanical deformation technique or treatment method, such as, for. B. drawing, upsetting, milling, rolling, stretching or forging was modified. The composite materials very particularly preferably have at least one carrier which has at least woven, bonded, matted or ceramic-bonded fibers, or at least sintered or bonded shaped bodies, balls or particles. In a further preferred embodiment, a perforated carrier can be used. Permeable supports can also be those which become permeable or have been made by laser treatment or ion beam treatment.

It may be advantageous if the carrier 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. Carriers are preferably used which have at least interwoven fibers made of glass, metal or alloys. Wires can also serve as fibers made of metal. The composite materials very particularly preferably have a carrier which has at least one fabric made of steel or stainless steel, such as, for. B. from steel wires, steel fibers, stainless steel wires or stainless steel fibers by woven fabric, which preferably have a mesh size of 5 to 500 microns, particularly preferably mesh sizes from 50 to 500 microns and most preferably mesh sizes from 70 to 120 microns. The carrier of the composite materials can also have at least one expanded metal with a pore size of 5 to 500 μm. According to the invention, however, the carrier can also have at least one granular, sintered metal, a sintered glass or a metal fleece with a pore size of 0.1 μm to 500 μm, preferably 3 to 60 μm.

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 a material coated with Au, Ag, Pb, Ti, Ni, Cr, Pt, Pd, Rh, Ru and / or Ti.

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, AI 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, TI, 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 present in a grain size fraction with a grain size of 1 to 250 nm or with a grain size of 260 to 10,000 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 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 quantity ratio of the grain size fractions in the composite material can preferably be from 0.01 to 1 to 1 to 0.01.

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

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

The composite material which is preferably used as the carrier material in the hybrid membrane according to the invention is preferably designed to be bendable or flexible without destroying the composite material. The composite material can preferably be bent to a radius down to 5 m, particularly preferably down to 500 mm and very particularly preferably down to 25 mm. The hybrid membrane according to the invention can have a gas-tight polymer layer as the separating layer. In the context of the present invention, gas-tight is understood to mean that a gas cannot pass through the separating layer in a laminar flow. Rather, the separation takes place e.g. B. of gas mixtures at the separation layer instead of the gases of the gas mixture to be separated diffusing or being transported through the membrane at different speeds.

The gas-tight polymer layer can e.g. B. of polydimethylsiloxane (PDMS), polyvinyl alcohol, methyl cellulose or cellulose acetate or a polymer mixture which comprises at least one of the compounds mentioned, or these compounds or modifications of these compounds. In addition, the polymeric starting materials for forming the gas-tight layers can contain crosslinkable, in particular UV-crosslinkable, groups.

It is also possible that the hybrid membrane has a porous separation layer with defined pores instead of the gas-tight separation layer. The hybrid membrane preferably has a porous separating layer with pores with a size of 0.5 to 100 nm, particularly 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 comprises 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 another membrane-forming polymer or its Modifications.

The hybrid membranes according to the invention preferably have a polymer layer with a thickness of 0.5 to 10 μm, preferably 1 to 8 μm, the porous separating layers having thicker layers than the gas-tight separating layers. Preferred gas-tight polymer layers have layer thicknesses from 0.5 to 5 μm, preferably from 1.25 to 3.75 μm and very particularly 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 preferably the membrane according to 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 preferably down to a radius of 5 mm to bend.

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

The method can be carried out in various ways. The process is preferably carried out in the systems and devices for producing polymer membranes known from the prior art, with the difference that the inorganic carrier material is used instead of the polymer carrier membrane or instead of the polymer carrier fleece. This inorganic carrier material is preferably such that the pores, meshes or openings are less than 20 μm in diameter. The carrier material is particularly preferably flexible and has a correspondingly good tensile strength in the machine direction, preferably a tensile strength of at least 5 N / cm, particularly preferably of at least 20 N / cm. The carrier material very particularly preferably has a tensile strength in the machine direction of at least 50 N / cm, preferably 100 N / cm, in particular when using glass or steel fabrics.

The use of carrier materials with a high tensile strength means that the hybrid membrane also has a similarly high tensile strength as the carrier material. Micro-fiber non-woven fabrics, metal non-woven fabrics, dense glass fiber fabrics or metal fabrics, but also ceramic or carbon fiber non-woven fabrics and fabrics are preferably used as carrier materials. It is clear to the person skilled in the art that all other known flexible materials provided with open pores or openings of the appropriate size can also be used.

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, Al ₂ O ₃ , TiO ₂ , ZrO ₂ or SiO ₂ and a carrier which preferably 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 are available under the name CREAFILTER from Creavis, Mari. We mainly used the Z240S for our tests; Z100S and Z25S.

Limiting the pore size as small as possible for the support materials used is advantageous since too large pores would suck the polymer solution too far into the membrane, which leads to an unnecessarily large flow resistance in the finished membrane. However, pores that are too small can also have an adverse effect, since in some cases the adhesion of the polymer layer becomes too low and delamination and thus complete destruction of the membrane occur during use. For this reason, the carrier materials preferably used have a minimum pore size of 5 nm, preferably 10 nm and very particularly preferably 25 nm.

The production of such composite materials that can be used as carrier materials is used, for. B. described in detail in WO 99/15262 and is based on the application of a suspension having at least one, a compound of at least one metal, a semimetal or a mixed metal with at least one element of the 3rd to 7th main group, inorganic component and a sol has an openwork and permeable carrier, and solidifying the suspension by at least one heating, in which the suspension having at least one inorganic component is solidified on or in or on and in the carrier. 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. It may be advantageous if the carrier 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. Carriers are preferably used which have at least interwoven fibers made of glass, metal or alloys. Wires can also serve as fibers made of metal. The composite materials very particularly preferably have a carrier which has at least one fabric made of glass, steel or stainless steel, such as, for. B. from steel wires, steel fibers, stainless steel wires or stainless steel fibers by woven fabric, which preferably have a mesh size of 5 to 500 microns, particularly preferably mesh sizes from 50 to 500 microns and most preferably mesh sizes from 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 minutes. up to 5 hours or at a temperature of 101 to 800 ° C for 1 second to 10 min., very particularly preferably at a temperature of 350 to 550 ° C.

The coating of the carrier material with the solution, which has at least one polymer, for producing the hybrid membranes can be carried out according to the prior art by knife coating, spraying, rolling, printing or by dip-coating techniques. 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 embodiment of the method according to the invention, the polymer layer is removed of the solvent at a temperature of 50 to 350 ° C, preferably at a temperature of 50 to 125 ° C, from 126 to 250 ° C or from 251 to 350 ° C and particularly preferably at a temperature of 260 to 340 ° C. A solution of polydimethylsiloxane (PDMS), polyvinyl alcohol, methyl cellulose or cellulose acetate or a polymer mixture which has at least one of the compounds mentioned is preferably used as the polymer solution. Suitable solvents are the known solvents, which 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 method, a highly viscous solution of a polymer is applied to the inorganic carrier material and this arrangement is then placed in a precipitation bath which contains a precipitation agent, such as, for. B. water contains. Due to the contact with the precipitant, a polymer layer precipitates out of the highly viscous polymer solution. Depending on the precipitation conditions and the solvent selected, this has a certain average pore size.

The polymer layer is particularly preferably precipitated from a polymer solution which has at least one polymer selected from a polyimide, a polyamide, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyolefin, polyamideimide, polyetherimide, polysulfone and / or polyether sulfone. Suitable solvents are all known solvents which are able to dissolve the polymers and are miscible with the precipitant in any ratio. In particular, when using the precipitant water, N-methylpyrrolidone, dimethylacetamide or dimethylformamide are used.

It can be advantageous if the precipitated polymer layer in a subsequent step at 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 is dried at a temperature of 300 to 450 ° C. The polymer material used to form the polymer layer can change chemically as a result of the temperature treatments mentioned in both embodiments of the method according to the invention. Such a chemical change can e.g. B. a radical, thermal or photo-induced crosslinking reaction or a partial pyrolysis with crosslinking of the polymer. This subsequent change in the polymer results in the polymer layer becoming insoluble in most solvents. A subsequent crosslinking reaction as a chemical change can also be initiated by irradiation with electrons or other radiation. B. by 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. Due to the possibility of tailoring the selective layer to a separation task, there are advantages in gas permeation, pervaporation, nanofiltration, ultrafiltration and microfiltration. Applications as a membrane reactor are also conceivable, even at higher temperatures.

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 in microfiltration.

The hybrid membrane according to the invention can also be used as a membrane in pervaporation or in vapor permeation and as a membrane in a membrane reactor.

It is also possible to use a hybrid membrane according to the invention, in particular a hybrid membrane which has a gas-tight separation layer, as a membrane in gas separation.

The advantages of the hybrid membranes according to the invention lie above all in the greater resistance of the membranes at high pressures, at high temperatures or in Solvents and acids and bases. The greater resistance at high pressures is used in 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 vapor permeation, the better resistance to various organic solvents as well as the improved temperature resistance are used. Filtration applications also take advantage of the significantly better pressure resistance, since at polymer pressures of 20 bar in most nanofiltration applications, most polymer membranes are highly compact and therefore the flows through the membrane are significantly lower than they would be from the selective separation layer alone.

Due to the flexibility of the hybrid membrane according to the invention and its small thickness, which is still present despite the ceramic support, this is also accessible to applications which until now have only been accessible to the soft or flexible polymer membranes or polymer membranes with inorganic fillers.

The following examples are intended to explain the hybrid membranes according to the invention and the process for producing such hybrid membranes in more detail, without the invention being restricted to these embodiments.

Examples:

1.) An inorganic flexible ceramic CREAFILTER membrane of the type Z25S, (Creavis GmbH, Mari) is presented as the material to be coated in a coating system. An approx. 50μm thick layer of a PDMS solution is then applied by a recoating system and then dried in a drying oven at 110 ° C. The web speed was 1.0 m / min. After drying, the membrane was 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. The following chemicals available from Wacker were used as feed products: 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 irradiated 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 eN) in an air atmosphere. A PDMS membrane which was insoluble in organic solvents and had no tendency to delaminate, but which was also used for gas separation, was obtained

Nanofiltration in organic solvents can be used.

3.) A piece of approximately A4 size of a CREAFILTER membrane of the type Z100S (Creavis GmbH, Mari) was coated with a 50 μm thick layer of a polymer solution consisting of 15% polyetherimide (Ultem 1000, GE Plastics) in N-methylpyrrolidone

Squeegee coated. After predrying for 10 minutes, this membrane was precipitated in an aqueous precipitant bath. The membrane thus obtained can be dried after a solvent exchange and then used for the UF.

4.) An approximately DIN A4 piece of a CREAFILTER membrane type Z25S was treated with a PVA solution using the dip-coating technique. The solution consists of: 2.5% polyvinyl alcohol and 1.0% β-cyclodextrin in an aqueous sodium hydroxide solution which has a pH of 9. After coating, the membrane is crosslinked for another 1 hour at 150 ° C and can then be used in pervaporation.

For a more detailed description of the substances used, see DE 19925475 AI.

I.) A membrane produced according to Example 2 was used to retain polystyrene with a molar mass of 2 OOOg / 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 ^ l 'bar ^"1 at a pressure of 20 bar. The retention rate of a ceramic nanofiltration comparison membrane was significantly lower at 92%. The manufacturer had specified a pore radius of lnm for this membrane, which resulted in a cut off of approx. 500g / 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% Back off. This was always accompanied by a significant drop in river.

II.) A membrane produced according to Example 1 was used for the same separation task as under I. The polymer layer dissolved very quickly and no separation was observed.

III.) 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 ^' Vbar ^"1 .

IV.) 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 1 1

3 L m ^" h ^" bar ^' . However, this deteriorated after 48 h because the carrier material was slowly attacked by the solvent.

V.) 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 1 1 a material flow of 1, 2 L m ^" h ^" bar ^" This was constant over 48 hours.

VI.) A membrane produced according to Example 2 with a polyetherimide support instead of the ceramic CREAFILTER membrane was used for the same separation task as under V. No retention could be determined since the carrier material was dissolved by the solvent.

VII.) A membrane produced according to Example 3 was used to separate catalyst residues (average particle size approx. 0.05 μm) from a gasoline fraction

") 1 1 used. The retention was 99% with a stream of 15 Lm ^" h ^" bar ^" . This was constant over 48 hours.

VIII.) One according to Example 3 with a polypropylene carrier instead of the ceramic CREAFILTER membrane manufactured membrane was also used for the separation of catalyst residues from a gasoline fraction. The retention was initially 99% with a stream of 5 lm ^"2 h ^{" 1} bar ^"1. However, the flow increased after a few hours. This was accompanied by a decrease in the retention

A change (swelling) of the carrier material was found in the experiment.

IX.) 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 ^" h ^" with a separation factor of 2300.

X.) 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 1 was 0.18 kg m ^" h ^' with a separation factor of 2390.

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

1 shows the surface of a hybrid membrane according to the invention, produced according to Example 2. The unevenness of the polymer surface, which results from the ceramic particles underneath, can be clearly seen.

Claims

claims: 1. Hybrid membrane with a selective separation layer, the membrane having 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 in that the inorganic permeable carrier material is a ceramic composite material. 3. Hybrid membrane according to claim 2, characterized in that the ceramic composite material is based on an inorganic carrier on and / or in which a suspension of an inorganic component and a sol has been solidified. 4. Hybrid membrane according to at least one of claims 1 to 3, characterized in that the separating layer is a gas-tight polymer layer. 5. Hybrid membrane according to claim 4, characterized in 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 in that the selective separation layer is a porous separation layer with defined pores. 7. Hybrid membrane according to claim 6, characterized in that the pores have a size of 0.5 to 100 nm. 8. Hybrid membrane according to claim 7, characterized in 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 in that the selective layer consists of a polyimide, a polyamide, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyolefin, polyamideimide, polyetherimide, polysulfone or polyether sulfone. 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 in that the hybrid membrane is flexible. 13. A method for producing a hybrid membrane with a selective separation layer, the membrane having an inorganic permeable carrier material and polymeric material, and the selective separation layer through the polymeric material is formed, characterized in that a solution of an organic polymer is applied to the inorganic carrier material and a polymer layer is formed on the carrier material. 14. The method according to claim 13, characterized in that the polymer layer is formed by removing the solvent at a temperature of 50 to 350 ° C. 15. The method according to claim 13, characterized in 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 in 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 in 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.