Carbon-containing membrane for water and gas separation

Abstract

The invention relates to a new membrane for the separation of gas mixtures, vapor mixtures and liquid mixtures, the membrane comprising a layer of thermally stabilized (preferably carbonized) polymerized catecholamines, and to methods for producing membranes of this type and the use thereof as molecular sieve membranes.

Description

CARBONATE MEMBRANE FOR WATER AND GAS SEPARATION INTRODUCTION The invention relates to a novel membrane for the separation of gas, vapor and liquid mixtures with one or more layers comprising carbonized polymerized catecholamines, as well as processes for the preparation of such membranes, and their use as molecular sieve membranes. TECHNICAL BACKGROUND AND STATE OF THE ART Separation membranes can, in principle, be porous or non-porous layers. Separation membranes are divided into homogeneous and asymmetric membranes. Homogeneous membranes are generally very thin in order to achieve the highest possible permeability per unit area. However, the mechanical stability of these thin membranes is often insufficient. In contrast, asymmetric membranes have a very thin separation layer arranged on a mechanically stable, porous substructure with high permeability. Separation processes can be classified according to the phases involved (solid, liquid, gas) and are widely used in industrial applications. Membrane processes are increasingly being considered as alternatives to conventional separation methods, such as distillation, crystallization, cryogenic separation, adsorption, or extraction. Membrane technology is considered an energy-efficient alternative for the separation of numerous gases and solvent mixtures compared to mature technologies such as pressure swing adsorption and cryogenic distillation. Specific examples include the separation of hydrogen from gasification, off-gas treatment, and the dewatering of organic solvents. In this context, inorganic microporous membranes have been intensively investigated due to their thermal and chemical stability. Known candidates for membrane materials include silica, zeolites, carbon and graphene / graphene oxide, modifications of carbon with a 2D structure. The membrane separation is shown schematically in Fig. 1. In principle, there are three mechanisms by which membrane separation can occur: Knudsen diffusion, the molecular sieve effect, or adsorption combined with surface diffusion and capillary condensation. These are schematically illustrated in Fig. 2. Knudsen diffusion is a type of diffusion that occurs when the pore diameter is smaller than the mean free path of the diffusing gas molecules. In this case, the gas molecules collide more frequently with the pore walls than with each other, resulting in Knudsen diffusion and separation. However, this mechanism results in limited separation efficiency (< 5) and is generally not suitable for industrial applications. Molecular sieving is the process that replaces Knudsen diffusion when the pore diameter is similar to that of the gases to be separated. The molecular sieve mechanism is based on size exclusion, with smaller molecules permeating through the membrane at a much higher rate than larger molecules. In an ideal molecular sieve process, the membrane selectivity would be 100%. Organic polymers or ceramic materials are typically used to manufacture membranes for the separation of gas, vapor, and liquid mixtures. Polymers, due to their ease of manufacture, account for the majority of membrane materials used. However, many currently very interesting but also demanding applications, such as working at high temperatures, high pressures, with aggressive chemicals, and in hydrothermal environments, require ceramic materials. Carbon is generally included in the category of ceramic materials (and for the purposes of the present invention). Ceramic microporous membranes are already known, which have a functional layer of zeolite, silica (SiO2), or carbon, as well as so-called hybrid SiO2 membranes, which contain carbon atoms in addition to SiO2. These membranes are proposed as an alternative to polymer membranes. They can be used in a wider range of applications and also have a significantly longer service life. They are often resistant to most organic solvents and are usually temperature-stable up to approximately 300 °C for hybrid membranes, and possibly even higher temperatures. Zeolite membranes, in particular, are suitable for use in solvent separation processes, both on a pilot scale and on an industrial scale, e.g., in the liquid phase (pervaporation (PV)) or in the vapor phase (vapor permeation (VP)). Some of these membranes exhibit an extremely narrow pore size distribution of approximately 0.5 nm and are particularly suitable for separating water from all types of organic solvents. Microporous amorphous SiO2 membranes have been known for more than 25 years. These membranes typically have a microporous SiO2 membrane layer with a pore size < 0.5 nm, which is deposited onto a mesoporous, y-ALOa Since their introduction, these membranes have attracted increasing interest because they exhibit sufficiently good separation properties for both water and gas separation. Currently available ceramic membranes generally offer only limited selectivity for the smallest molecules. This is generally due to the difficulty of processing microporous ceramic materials into defect-free thin films and achieving uniform pores with molecular dimensions. Especially for the separation of the smallest gases, such as helium (He) or hydrogen (H2), the membranes must exhibit molecular sieving properties. This means that the pore size must be comparable to the dimension of the molecule to be separated. Carbon-based membranes, particularly those with a stable graphite-like structure, appear to be suitable for the demanding applications mentioned above. Carbon membranes have been known for a long time and have been researched and developed for gas separation since the 1970s. Initially, self-supporting membranes were produced by the controlled pyrolysis of hollow polymer fibers. The resulting hollow-fiber carbon membranes exhibit much higher chemical and thermal stability than the starting polymer membrane, but proved to be mechanically insufficient for practical applications. Therefore, a thin carbon layer is now generally applied to a porous support (e.g., metallic supports or α-aluminum oxide) using conventional processes such as dip coating or spin coating.For this purpose, a thin polymer membrane layer made from a solution of a polymer in a suitable solvent is applied to the support and, if necessary, the polymer layer is cured (e.g., by cross-linking) and then pyrolyzed. This manufacturing method has been known for a long time and has already been used for some polymers. However, the membranes obtained with it are not yet sufficient as true molecular sieve membranes for the clear separation of the smallest gases by molecular sieving. The reason for this lies in the amorphous structure of such membranes, which generally do not have structural pore openings / channels with a size in the range of the gases to be separated. The separation mechanism of such membranes is mainly based on Knudsen diffusion and the adsorption of the more polar gas (e.g., CO2) on the pore walls, which can also be the largest gas in the mixture. Therefore, such membranes do not allow for targeted separation based on molecular size. Both zeolite membranes and amorphous SiO2-based membranes, which were considered as potential alternatives to polymer membranes, have the disadvantage of generally having limited resistance to acidic and alkaline solutions. Furthermore, it has been shown that a number of zeolite membranes, and in particular the classic amorphous SiO2 membranes, are not long-term resistant to hydrothermal conditions. In practice, the use of amorphous SiC membranes is often limited to dry applications due to the material's particular sensitivity to water. To increase material stability, a variety of modified SiC>2 membranes have been produced. These include, for example, in addition to amorphous SiO2, oxides such as ZrO2 or TiO2, or metals such as Ni or Co as a second component. However, even these have not resulted in suitable membranes with sufficient stability and a suitable pore size distribution for water or gas separation. In the microporous ceramic membranes known from the literature (e.g., amorphous SiO2, hybrid carbonaceous SiO2, carbon), the mesoporous layer usually comprises γ-aluminum oxide (γ-ALOa), titanium dioxide (TiO2), zirconium dioxide (ZrO2), silicon oxide (SiO2), or mixtures of the aforementioned materials, which can be produced, for example, using a sol-gel coating process. However, these layers usually exhibit only limited chemical (γ-ALOa, SiOa), thermal (TiOa, ZrOa), or hydrothermal stability. Hybrid carbon-containing SiOa membranes with improved resistance to liquid water and water vapor at temperatures up to 150°C (Hybsi®) are now also known. However, due to the partial SiOa character of these membranes, their practical application in water is also limited. Furthermore, their thermal stability is limited to a maximum of 300°C, which limits their application in gas separation. Such membranes are also generally unable to separate the smallest gas molecules (He, H2) from other gas molecules (e.g., CO2, N2, CH4) using a molecular sieve process, as their pore size typically exceeds 0.5 nm. As a starting material for carbon membranes, graphene, and especially its oxidized form, graphene oxide (GO), has received enormous attention as a potential membrane material. Graphene and graphene oxide can be considered a membrane that is, strictly speaking, only one atomic layer thick. This makes them the thinnest artificially produced membranes ever. Graphene is a 2-dimensional, single-layer carbon sheet made of sp 2- hybridized carbon, in which the carbon atoms are arranged in a honeycomb structure. Due to this honeycomb network, in which very strong bonds exist, graphene is also a very strong and chemically stable material, which is why it is particularly interesting for the development of new separation membranes. Graphene oxide represents the functionalized form of graphene, in which numerous oxygen-containing groups, such as hydroxyl, epoxy, carbonyl, carboxyl, lactone, and quinone, are attached both at the edges and in the plane. Graphene oxide exhibits both sp 2 - as well as sp 3 -hybridized carbon. Graphene oxide, for example, can be obtained from graphite oxide. Graphite oxide is a non-stoichiometric compound of carbon, oxygen, and hydrogen, whose molecular formula varies greatly depending on the production conditions. Graphite oxide, in turn, can be obtained from graphite using strong oxidizing agents, for example, using the well-known synthesis methods of Brodie-, Hummer-, or Staudenmaier. During the production of graphite oxide, the graphene layers in the graphite are oxygenated, resulting in a hydrophilic material. A special property of graphite oxide is that it can be colloidally dispersed in water, leading to the formation of colloidal dispersions. The detachment of individual layers of graphite oxide, e.g., using ultrasonic energy, leads to monolayer graphene oxide. In pure, single-layer graphene or GO, the carbon atoms are arranged so densely that all molecules, even the smallest gas, He, cannot penetrate it. Consequently, it can potentially act as a one-atom-thick barrier layer, but not as a molecular sieve. To achieve a permeable membrane, it has been proposed to provide such a membrane with small perforations, which can be achieved, for example, through etching processes. However, no methods are yet known to precisely control pore formation. Other technological challenges include the large-scale production of such membranes and their robustness. Theoretically, a membrane composed of only a few graphene layers or a membrane composed of several stacked graphene or graphene oxide layers appears to be particularly well suited for the separation of smaller molecules (He, H2) from a gas mixture (e.g., with CO2, N2, CO, or even CH4), since the interlayer spacing between graphene layers is on the order of 0.335 nm. It is assumed that the interlayer spacing between graphene oxide monolayers in few-layer graphene oxide and graphite oxide is larger than that between graphene layers. Depending on the presence of water (liquid, vapor), interlayer spacing between graphene oxide monolayers ranging from 0.6 nm to over 1 nm has been reported in the literature. Therefore, it has already been proposed to stack several graphene or graphene oxide layers to obtain so-called few-layer graphene or graphene oxide. If the layers are stacked compactly and densely, lateral nanochannels form, which can be passed through by small molecules, such as He, H2, or water, but are impermeable to larger molecules. A schematic representation of this principle is shown in Fig. 3. Aggregates of fewer than 10 graphene or graphene oxide layers are usually referred to as few-layer graphene or graphene oxide. Layers with more layers could regularly be referred to as graphite or graphite oxide layers. Such membranes have a layered structure comparable to graphite. The exact structure and composition of the individual graphene oxide layers is, in contrast to graphene layers, not clearly defined. Unlike graphene, graphene oxide contains sp 2 and sp 3Carbon atoms and therefore the layers show a non-planar, irregularly wavy structure. To date, known graphene oxide membranes have been produced at room temperature or treated at only slightly elevated temperatures up to 220 °C. The support materials used for graphene oxide membranes, such as polymeric materials or very thin anodic alumina with a honeycomb structure, limit the operating temperatures for such membranes. The typical production route for this type of membrane involves applying individual graphene oxide layers to a support material using vacuum filtration methods. A colloidal dispersion consisting of monolayer graphene oxide and water is typically used for the coating. The manufacturing route for GO and graphene membranes is partially identical and involves the deposition of individual GO layers on a porous support material using known coating techniques, such as dip coating. A colloidal dispersion consisting of monolayer GO and water is used for the coating. The resulting GO membranes exhibit properties that are of interest for industrial gas and water separation processes. However, for applications involving water or humid conditions, concerns remain regarding the stability of the membrane material. Evidence suggests that GO is readily dispersed in water due to the presence of ionizable functionalities. This is advantageous from a process engineering perspective, as it facilitates the preparation of stable dispersions for membrane formation.On the other hand, it also suggests that coated GO laminates can redisperse and disintegrate in water. Depending on the application, instead of a top layer comprising GO, a design with a top layer at least partially or completely reduced to graphene may be desirable. For example, if sensitivity to water is to be reduced and water permeability is not absolutely necessary, the production of a laminated graphene membrane with a structure similar to graphite is another option. With such a membrane, instability in water is not an issue, since the graphene layers are held together by stacking interactions. The first step in the synthesis of such a membrane is identical to that of GO membranes, comprising the formation of a laminated GO film on a support material using known coating processes, such as dip coating, followed by complete or partial reduction of the resulting GO film to a laminated graphene structure.This makes the membrane more resistant to chemical reactions and also leads to improved permeability of the permeating gases (He, H2), since after reduction, the graphene layers carry only a small number of functional groups, thus reducing the steric barrier to gas transport into the microchannels. The choice of method for achieving the reduction (chemical, thermal) depends on the material used for the support layer and the Intermediate layers. If the membrane structure can withstand the higher temperatures required for reduction, a thermal process is preferably used because it is much simpler. The oxygen-containing groups of the cover layer are eliminated in a vacuum or under a reducing atmosphere (e.g. Ar / H2). Higher temperatures between 500 and 1000 °C are necessary for complete reduction. To make this possible, a multilayer support structure was developed which, in addition to the thermally stable macroporous support, also contains thermally stable mesoporous layers. Such a multilayer membrane is the subject of WO2016 / 177355. The support structures described therein consist of zirconium dioxide, in particular yttrium-stabilized zirconium dioxide (YSZ), with so-called 8YSZ proving particularly advantageous due to its exceptional thermal stability. WO2016 / 177355 describes a membrane comprising a graphene, graphene oxide, or graphite cover layer on a carrier material, which is stable and usable even at higher temperatures, pressures, and under hydrothermal conditions, as well as methods for its production. If thicker cover layers are to be applied using the methods described therein, they must be applied in multiple process steps, as the cover layers regularly tend to crack during the drying process and thermal treatment. This effect limits the layer thickness. Although the single- or multi-layer (supported) graphene and graphene oxide membranes already known from the state of the art have very advantageous properties, they are currently not sufficiently interesting for commercial applications due to several disadvantages. These include: a) The membranes, e.g. the GO or graphene separation layers, are generally not firmly (e.g. chemically) bonded to the support. b) The membranes, e.g. the GO or graphene separation layers, cannot be applied to the support in an ultra-thin and sufficiently defect-free manner. c) The layer thickness of GO or graphene layers is limited due to instability during the drying process. d) The membranes currently do not have the size and dimensions required in industrial plants. e) In particular, the membranes do not yet have the tubular shape and dimensions (50 - 150 cm) required in industrial plants. The multilayer supported graphene and graphene oxide membranes already known from the state of the art are limited in terms of the thickness of the GO or graphene membrane and thus restricted to extremely thin layers (approximately 10 nm). Therefore, such membranes can currently only be coated defect-free on laboratory supports with a very smooth surface. When using commercial supports, which are usually tubular and have a much lower surface quality, the membrane suffers from surface defects and thus poor separation performance. US2022 / 0032240A1 describes a membrane for liquid-phase transport, comprising a porous substrate and a selective transport layer comprising 2D material flakes present in the porous substrate. The porous substrate has surface pores with dimensions of more than 2 micrometers and is coated with the selective transport layer. The 2D flake material can be graphene or graphene oxide, and it is described that graphene oxide can be crosslinked with crosslinking agents comprising polydopamine. The publications CN116272439A, CN114950154A, and CN105536563A describe separation membranes based on porous substrates with polydopamine coatings, which may also contain graphene oxide films. The polydopamine layers applied therein are heated to a maximum of 50 °C or 60 °C during the manufacturing process. In view of the aforementioned state of the art, it is therefore particularly important to provide separation membranes for the selective separation of the smallest molecules / atoms (especially H2), in which the membrane separation layer is stably and defect-free, preferably chemically bonded, to the other layers, e.g., carrier layers. This membrane separation layer remains stably bonded even when used as a microporous gas or water separation membrane and does not detach, thereby losing its functionality. The separation membranes should exhibit high mechanical and / or chemical stability overall in order to be resistant and operate reliably under the required conditions, e.g., high temperatures, pressures, humid, corrosive conditions, or under the influence of chemicals, in particular against all types of organic liquids, as well as (non-strongly oxidizing) acids and alkalis. TASK The object of the present invention was therefore to provide improved membranes for the separation of gas, vapor, and liquid mixtures. In particular, the improved membranes should no longer have disadvantages that known membranes from the prior art have. In a particular aspect, the object was to provide membranes for the separation of gas, vapor, and liquid mixtures which are characterized by a defined and uniform pore size / width of the transport channel with molecular dimensions. The membranes should have a high selectivity towards the smallest molecules, in particular He, H2, and H2O. The membranes should therefore be suitable for acting as true molecular sieves. In a further aspect of the invention, a novel membrane should be provided which enables the separation of water (e.g. in the form of vapor) from solvent mixtures, which is of great industrial interest.In a particular aspect of the invention, the object was to provide membranes for the separation of gas, vapor, and liquid mixtures that can be manufactured very thin (ultra-thin) and essentially defect-free, without significant cracks or fissures. In a further aspect. According to the invention, the membranes should also be usable in the form of supported membranes. A particular aspect of the invention is to provide supported membranes that enable defect-free and stable (chemical) anchoring between the membrane layers and support layers. The membranes should be particularly chemically and mechanically stable and preferably also usable under humid conditions or in liquid systems. It should be possible to produce membranes that do not have the above-described limitations on the thickness of GO / graphene layers due to the instability in the manufacturing process. Furthermore, the membranes should be easy to produce and ultimately also suitable for use on an industrial scale. DESCRIPTION OF THE INVENTION The objects of the present invention were surprisingly achieved by the membranes as described in the claims. In particular, the above-mentioned objects were achieved by the development of membranes comprising at least one layer of carbonized polymerized catecholamines. The present invention is described in more detail below and particularly includes the following aspects: [1] Membrane for the separation of gas, vapor and liquid mixtures (1), comprising one or more porous ceramic support layers (2) and at least one layer (3) containing carbonized polymerized catecholamines. [2] Membrane for the separation of gas, vapor and liquid mixtures according to [1], which further comprises one or more porous intermediate layers (4) arranged between a porous support layer (2) and the layer (3) containing the carbonized polymerized catecholamines. [3] Membrane for the separation of gas, vapor and liquid mixtures according to [1] or [2], wherein the layer containing the carbonized polymerized catecholamines forms an outer cover layer (3a). [4] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to [3], further comprising one or more layers (5) which comprise graphene oxide, partially reduced graphene oxide or graphene. [5] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to [4], wherein the layer containing the carbonized polymerized catecholamines forms an adhesive layer (3b) which connects a porous ceramic carrier layer (2) or a porous intermediate layer (4) to a cover layer comprising graphene oxide, partially reduced graphene oxide or graphene (5). [6] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to [5], wherein the carbonized polymerized catecholamines are in the form of a mixed matrix (3c) with graphene oxide, partially reduced graphene oxide or graphene, which forms an outer covering layer of the membrane. [7] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to [6], wherein the carbonized polymerized catecholamines are selected from the group comprising carbonized polydopamine, carbonized polynoradrenaline, and carbonized polyadrenaline. [8] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to [7], wherein carbonized polydopamine (cPDA) is selected as the carbonized polymerized catecholamine. [9] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to [8], wherein the porous ceramic support layers (2) are macroporous layers with pores having a pore diameter > 50 nm.

[0010] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to [9], wherein porous ceramic support layers (2) are selected from the group of macroporous ceramic support layers comprising aA^Oa, TiOa, ZrOa, YSZ, SiOa, CeO2, MgO, Y2O3, GdaOa, mullite, cordierite, zeolite, BaTiOs, metallic components, carbon, SiC, Sial^, SiOC, SiCN, AIN or mixtures of the aforementioned materials.

[0011] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to

[0010] , which comprises one or more porous intermediate layers (4) which are mesoporous layers with pores having an average pore diameter of 2 nm to 50 nm, preferably with an average pore diameter of 2 to 10 nm.

[0012] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to

[0011] , wherein porous intermediate layers (4) are selected from the group comprising porous ceramic intermediate layers.

[0013] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to

[0012] , wherein porous intermediate layers (4) are selected from the group of mesoporous ceramic intermediate layers with pores having an average pore diameter of 2 nm to 10 nm, preferably with an average pore diameter of 2 to 6 nm.

[0014] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to

[0013] , wherein porous intermediate layers (4) are selected from the group of mesoporous ceramic intermediate layers comprising Y-Al2O3, TiO2, ZrO2, YSZ, SiO2, CeO2, MgO, Y2O3, Gd2O3, ZnO, SnO2, mullite, cordierite, zeolite, metal-organic framework materials (MOF), clay, BaTiOs, carbon, SiC, SiSn4, SiOC, SiCN, AlN or mixtures of the aforementioned materials.

[0015] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to

[0014] , which comprises one or more layers (5) which comprise graphene oxide, partially reduced graphene oxide or graphene and which are microporous layers with pores / transport channels with an average diameter < 1 nm.

[0016] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to

[0015] , wherein the layers (5) comprising graphene oxide, partially reduced graphene oxide or graphene are monolayer or multilayer.

[0017] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to

[0016] , comprising at least two porous intermediate layers (4), in which both the particle size, the roughness and the pore size decrease in the direction of the layer (3, 3a, 3b, 3c) containing the carbonized polymerized catecholamines.

[0018] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to

[0017] , comprising at least two porous intermediate layers (4), of which a first porous intermediate layer (4) is in contact with a porous ceramic carrier layer (2) and a second porous intermediate layer (4) is in contact with the layer (3, 3a, 3b, 3c) containing the carbonized polymerized catecholamines, and wherein at least one intermediate layer (4) has pores with an average pore diameter of less than 5 nm.

[0019] Membrane for the separation of gas, vapor and liquid mixtures according to

[0018] , wherein the first porous intermediate layer (4) has a layer thickness between 1 pm and 20 pm and / or wherein the second porous intermediate layer (4) has a layer thickness between 0.1 pm and 2 pm.

[0020] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to

[0019] , which has a microporous layer (5) comprising graphene oxide, partially reduced graphene oxide or graphene, and wherein this layer (5) has a layer thickness between 3 nm and 2 pm, preferably between 5 nm and 300 nm, more preferably between 5 nm and 10 nm.

[0021] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to

[0020] , comprising a multilayer microporous layer (5) which has between 5 and 1000 layers of graphene oxide, partially reduced graphene oxide or graphene.

[0022] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to

[0021] , wherein the layer (3, 3a, 3b, 3c) containing the carbonized polymerized catecholamines has a layer thickness between 3 nm and 500 nm, preferably between 5 nm and 300 nm, more preferably between 10 nm and 200 nm, most preferably around 25 to 80 nm.

[0023] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to

[0022] , wherein the layer (5) comprising graphene oxide, partially reduced graphene oxide or graphene is arranged as the outer cover layer of the membrane

[0024] Membrane for the separation of gas, vapor and liquid mixtures according to [1] to

[0023] , which is obtainable by producing a multilayer arrangement of the layers (2, 4, 5) provided according to [1] to

[0022] and a layer of polymerized catecholamines and heating the multilayer arrangement to a temperature between 60 and 450°C, preferably between 100 and 400°C, more preferably between 150 and 250°C, in air to obtain a thermally stable layer of polymerized catecholamines (3, 3a, 3b, 3c), and wherein after heating the multilayer layered arrangement to a temperature between 60 and 450 °C, preferably between 100 and 400 °C, more preferably between 150 and 250 °C, in air, a further thermal treatment is carried out with heating to at least 300 °C, preferably to at least 500 °C, preferably to a temperature between 500 and 1000 °C, with carbonization of the polymerized catecholamines and obtaining the layer of carbonized polymerized catecholamines (3, 3a, 3b, 3c).

[0025] Membrane according to

[0024] wherein the carbonization is carried out in an inert or reductive atmosphere.

[0026] Membrane according to [1] to

[0024] , which is in the form of a cylindrical tube.

[0027] Process for producing the membranes according to [1] to

[0026] , comprising the steps (a) providing or producing a porous ceramic carrier layer (2), (b) optionally applying one or more porous intermediate layers (4) to the porous ceramic carrier layer (2), (c) applying catecholamines or their derivatives, or precursors thereof such as DOPA, to the porous ceramic carrier layer (2) or an optionally provided porous intermediate layer (4), either o in the form of an aqueous solution of the catecholamine or its derivative, followed by in-situ polymerisation, or o in the form of an aqueous dispersion or suspension of already polymerised catecholamine particles, (d) thermal treatment at 60 to 450°C, preferably 100 to 400°C, more preferably 150 to 250°C, in air, and (e) optionally (preferably) carbonization of the polymerized catecholamines at a temperature between 300 and 100 °C, preferably between 500 and 1000 °C to obtain a layer of carbonized polymerized catecholamines (3).

[0028] Method according to

[0027] , further comprising a step of applying a layer (5) comprising graphene oxide, partially reduced graphene oxide or graphene.

[0029] Process according to

[0027] , wherein after step (d) an aqueous colloidal dispersion of graphene oxide is applied to the layer of polymerized catecholamines and then optionally (preferably) step (e) of carbonization is carried out to obtain a membrane with a layer of thermally stabilized (preferably carbonized) polymerized catecholamines in the form of an adhesive layer (3b) and a cover layer (5) arranged thereover comprising graphene oxide, partially reduced graphene oxide or graphene.

[0030] Process according to

[0027] , wherein in step (c) graphene oxide particles are mixed into an aqueous solution of the catecholamines and this mixture is then polymerized in situ, followed by the thermal treatment in step (d) and optionally (preferably) the carbonization in step (e) to obtain a membrane with a layer of thermally stabilized (preferably carbonized) polymerized catecholamines in the form of a mixed matrix with graphene oxide, partially reduced graphene oxide or graphene (3c).

[0031] Process according to

[0027] to

[0030] , wherein graphene oxide is used in the form of an aqueous colloidal dispersion of graphene oxide particles with a particle size between 10 nm and 5 pm.

[0032] Process according to

[0027] to

[0031] , wherein graphene oxide is used in the form of an aqueous colloidal dispersion with a solids content of graphene oxide particles between 20 mg and 2 g per liter of colloidal dispersion.

[0033] Process according to

[0027] to

[0032] , comprising step (e), wherein the carbonization takes place in a reducing atmosphere under argon / 3% H2 and, in the case of the presence of a layer containing graphene oxide, this is at least partially reduced to graphene.

[0034] Process according to

[0027] to

[0033] , wherein the application of the layer (3) containing the catecholamines and / or the layer (5) containing graphene oxide, partially reduced graphene oxide or graphene is carried out independently of one another in each case by means of immersion, dipping, dip coating, spin coating, spraying, roller coating, inkjet printing or vacuum filtration.

[0035] Process according to

[0027] to

[0034] , wherein carrier materials in the form of cylindrical tubes are used in the coating process.

[0036] Process according to

[0027] to

[0035] , wherein in step (c) an oxidizing agent, preferably ammonium persulfate, is also added.

[0037] Membrane obtainable from step (d) of a process according to

[0027] to

[0032] and

[0034] to

[0036] , comprising a layer of thermally stabilized polymerized catecholamines (3).

[0038] Use of the membranes according to [1] to

[0026] , which have a layer of carbonized polymerized catecholamines, as a molecular sieve membrane for the separation of He or H2 or H2O.

[0039] Use of a membrane according to

[0037] , which has a layer of thermally stabilized polymerized catecholamines (3), as a membrane for separating H2O from solvent mixtures or from vapor mixtures or moist gas mixtures. DETAILED DESCRIPTION OF THE INVENTION The objects of the invention are achieved by the use of carbonized polymerized catecholamines, in particular carbonized polydopamine (PDA), in membranes for the separation of gas, vapor and liquid mixtures. The inventors of the present invention surprisingly found that carbonized polymerized catecholamines are particularly suitable for adhering to solid inorganic (ceramic) substrates and for forming a strong and stable bond, in particular with the porous layers of known membranes. Using polydopamine (PDA) as an example, it was shown how such carbonized polymerized catecholamines can be advantageously used to improve known membranes, in particular graphene oxide and graphene membranes. The group of catecholamines includes not only dopamine but also noradrenaline and adrenaline, as well as their derivatives, as well as precursors such as DOPA (3,4-dihydroxyphenylalanine). DOPA is the precursor for the biosynthesis of naturally occurring catecholamines and has a nearly identical structure. DOPA is also the main component of the foot polymer responsible for the adhesion of mussels to a surface. Consequently, the group of polymerized catecholamines used in the invention includes polydopamine, polynoradrenaline, polyadrenaline, and derivatives thereof. Derivatives of catecholamines or polymerized catecholamines essentially encompass all chemically possible and reasonable modifications of these compounds, provided that the functional groups of the primary and secondary amines, as well as catechol (3,4-dihydroxybenzene), which are crucial for the strong surface adhesion of this class of compounds, are retained in sufficiently high quantities in the derivatives.In addition to the group of naturally occurring catecholamines, synthetic catecholamines can also be used in principle. Currently, these generally come from the pharmaceutical sector and, due to their high price, are not suitable for industrial use. Application in separation membranes is less interesting. For example, dopamine hydrochloride can be used as a starting material for synthesis. By intense heating and pyrolysis, the polymerized catecholamines are converted to carbon or nitrogen-containing carbon, which is referred to herein as “carbonized polymerized catecholamines” (cPDA). According to the invention, carbonized polydopamine (cPDA) is preferably selected as the carbonized polymerized catecholamine. DOPA (3,4-dihydroxyphenylalanine), the precursor for the formation of dopamine and, consequently, other naturally occurring catecholamines, is the main component of the foot polymer responsible for the adhesion of mussels to a surface. This polymer is capable of forming a kind of biological superglue in water. DOPA is the most important component for the adhesive properties of mussel secretion [H. Lee et al., Science, 2007, 5849, 426-430; J. Zhang et al., RSC Adv., 2020, 10, 12035]. Lee et al. (2007) also describe a simple synthesis method for producing synthetic PDA for applications in materials science. Numerous research groups have demonstrated the suitability of PDA as a highly adhesive coating material for a wide range of surface treatments on various types of surfaces using the same method.Due to the use of a polymer and its special properties, which are derived from nature, PDA is often referred to as a "bio-inspired polymer" or "bio-glue" or simply "shell glue". In particular, Lee et al. (2007) demonstrated that dopamine, the monomeric form of PDA, oxidizes and self-polymerizes in a mildly alkaline aqueous solution (pH 8–9) and in the presence of (atmospheric) oxygen, spontaneously forming a PDA coating with strong adhesion. This behavior is attributed to the chemical composition of PDA, which has two key features: a high content of primary and secondary amines and a high content of catechol (3,4-dihydroxybenzene). The coexistence of these two types of functional groups is thought to contribute to the strong surface adhesion of PDA. Although, following the work of Lee et al. (2007), the mussel-inspired coating technique has been applied in many areas of materials science, only a few studies have been conducted in the field of separation membranes, and these are limited to polymer membranes. In these studies, PDA coating typically serves to change the hydrophobic character of membrane surfaces into a hydrophilic one. PDA is therefore used as a surface modifier and not as an adhesive or separation layer. Such known polymer membrane applications with PDA coatings are characterized by the fact that only a wet application of the PDA Layers without temperature treatment have been described, which makes the resulting PDA layers (thermally) unstable. The inventors of the present invention have used PDA from the group of polymerized catecholamines in processes for producing ceramic separation membranes, in which they are subjected to a thermal treatment and are also exposed to elevated temperatures (> 100 °C). This thermal treatment, which is carried out according to the invention at temperatures between 25 and 500 °C, preferably at temperatures > 60 °C and 500 °C in air, produces thermally stable layers of polymerized catecholamines. This thermal treatment step according to the invention is preferably carried out at temperatures > 25°C, more preferably e 50°C, more preferably > 60°C, more preferably e 100°C, even more preferably e 200°C. The upper limit of this thermal treatment step is generally a maximum of 500°C, preferably a maximum of 450°C, more preferably a maximum of 400°C, even more preferably a maximum of 350°C. Suitable temperature ranges for this thermal treatment step according to the invention are between 60 and 450°C or between 100 and 450°C, preferably between 100 and 400°C or between 150 and 400°C, more preferably between 200 and 350°C, even more preferably between 150 and 250°C, whereby in a further aspect, a preferred range between 250 and 300°C can also be selected. When using support materials in the form of cylindrical tubes, temperatures around 200°C, for example, can be used. Membranes containing a layer of polymerized catecholamines subjected to such a thermal treatment are surprisingly well suited as separation membranes for the separation of water, for example, in the form of water vapor, from solvent mixtures or from water and vapor mixtures. Surprisingly and unexpectedly, they were also found to function as molecular sieves for the separation of He or H2. For example, if a GO layer of ceramic separation membranes is converted into a graphene layer by reduction, temperatures of over 500 °C are required. Upon thermal treatment at temperatures of at least 300 °C, preferably between 500 and 1000 °C, in an inert or reductive atmosphere, the polymerized catecholamine, e.g., PDA, carbonizes and forms a layer with a layered carbon structure. Such a material is called carbonized polydopamine [carbonized PDA (cPDA)] and exhibits properties comparable to reduced graphene oxide. To obtain such a carbon membrane from carbonized polymerized catecholamines, work must be carried out at sufficiently high temperatures in an inert atmosphere; otherwise there is a risk that the carbon membrane will burn. In principle, the inert atmosphere can be nitrogen or a vacuum, for example, in addition to an aerosol atmosphere. If this carbonization step is carried out in a reducing atmosphere, conversion of the polymerized catecholamines into pure carbon or nitrogen-containing carbon can also be achieved at lower temperatures. This is particularly relevant if the membrane has additional layers that are limited with regard to thermal treatment at very high temperatures. For example, the structure of mesoporous interlayers made of zirconium dioxide can begin to change at temperatures above 800 °C. The inventors of the present invention have surprisingly discovered that when polymerized catecholamines, such as PDA, are used in the production of ceramic separation membranes, the high process temperatures during production carbonize (pyrolyze) the polymerized catecholamine (e.g. PDA) and form a layer with outstanding adhesive properties without negatively affecting the separation properties of the membrane with its layer structure or even impairing or preventing the permeability for the atoms or molecules to be separated. It was not foreseeable that a PDA layer used in ceramic separation membranes would form a carbonized PDA layer that has at least the same gas permeability as a functional GO / graphene cover layer and therefore does not represent an obstacle to gas transport through the separation membrane. The inventors also surprisingly found that when a membrane according to the invention with a layer of polymerized catecholamines was produced at a temperature between 200 and 300 °C in an air atmosphere, for example at 200 °C or at 250 °C in an air atmosphere, i.e., under temperature conditions under which the carbon does not burn, a hydrophilic membrane with high water selectivity and high water permeability was obtained. Membranes produced in this way with thermally stabilized polymerized catecholamine layers also showed good He and H2 selectivity, but they were also permeable to CO2 at a lower rate. Therefore, such membranes are not yet suitable as perfect molecular sieves, for example, for the separation of H2 and CO2, but are surprisingly particularly suitable for the separation of water from water / steam mixtures. In one aspect, the invention relates to a membrane for the separation of gas, vapor and liquid mixtures, which membrane has one or more porous ceramic support layers and at least one layer based on polymerized catecholamines, which are thermally treated layers of polymerized catecholamines, the thermal treatment generally being carried out in a temperature range up to a maximum of 500°C (as defined above). Such membranes are particularly suitable for the separation of water / water vapor. In a further preferred aspect, the invention relates to a membrane for the separation of gas, vapor, and liquid mixtures, which comprises one or more porous ceramic support layers and at least one layer based on carbonized polymerized catecholamines. These layers are made of carbonized polymerized catecholamines, which are subjected to an additional heat treatment at temperatures > 300°C, preferably at temperatures > 500°C (as defined above). Such membranes are particularly suitable for the selective separation of the smallest molecules / atoms such as He or H2 and can be used as true molecular sieves. In further aspects, the invention relates to a multilayer porous membrane comprising at least one layer based on thermally stabilized (preferably carbonized) polymerized catecholamines. The coating step can be repeated, for example, to obtain a coating that is as uniform and complete as possible without possible holes or other defects. This allows any holes or defects in the previously applied layer to be repaired and, if necessary, filled in a second (and possibly further) coating step. As a rule, one or two coating steps should be sufficient. In a preferred embodiment of the membrane according to the invention, it further comprises one or more porous intermediate layers. These intermediate layers are then arranged between the porous ceramic support layer and a layer containing thermally stabilized (preferably carbonized) polymerized catecholamines. If several such layers of thermally stabilized (preferably carbonized) polymerized catecholamines are present in the membrane structure, the porous ceramic support layers, porous intermediate layers, and the layers of thermally stabilized (preferably carbonized) polymerized catecholamines can be arranged in alternating layers in a variable order. The term “membrane” used herein refers in particular to multi-layer, porous membranes with a pore structure which, depending on the application, is capable of passing water or smaller gas molecules, such as He or H2, and thus separating them from a gaseous or liquid mixture. The membranes according to the invention comprise one or more porous ceramic support layers, which are preferably macroporous supports. For example, a porous 0C-Al2O3 support can be used as the macroporous support layer of the multilayer membrane device according to the invention, which can be produced using conventional ceramic powder technology methods. Furthermore, the already known support materials, such as titanium dioxide, can also be used. (TiO2), zirconium dioxide (ZrO2), yttrium-stabilized zirconium dioxide (YSZ), silicon oxide (SiO2), cerium oxide (CeO2), magnesium oxide (MgO), yttrium oxide (Y2O3), gadolinium oxide (Gd2O3), silicon carbide (SiC), carbon, or metallic components can be used as supports. Other suitable ceramic materials for the support structure include mullite, cordierite, zeolite, barium titanium oxide (BaTiO2), silicon nitride (SiO2), silicon oxycarbide (SiO2), silicon carbonitride (SiCN), aluminum nitride (AlN), or mixtures of the aforementioned materials. The macroporous support can be monolayer or multilayer. If multiple macroporous layers are provided, the layer located further away from the support generally has a smaller average pore size than the intermediate layer located closer to the support. The previously mentioned support materials can be used for the macroporous layers. The macroporous layers can be applied to the support using conventional methods, such as suspension coating or doctor blade coating. The support itself can be present in all known geometries, i.e., as a flat layer, a cylindrical tube, a hollow fiber, or even a capillary. If the support is in the form of a cylindrical tube, a hollow fiber, or a capillary, the remaining layers and the cover layer can be arranged on both the inside and the outside. Furthermore, the support itself can also be designed as a multi-channel element, for example, as a multi-channel plate or multi-channel tube, or in a honeycomb structure. Supports in the form of cylindrical tubes are preferred with regard to industrial applications and large-scale embodiments. In one aspect, the invention comprises a membrane for the separation of gas, vapor and liquid mixtures as described herein, wherein the porous ceramic support layers are macroporous layers having pores with a pore diameter > 50 nm. In a further aspect, the invention comprises a membrane for the separation of gas, vapor and liquid mixtures as described herein, wherein porous ceramic support layers are selected from the above-mentioned group. In a further aspect, the invention comprises a membrane for the separation of gas, vapor and liquid mixtures as described herein, wherein porous ceramic support layers are selected from the group of macroporous ceramic support layers with pores having a pore diameter > 50 nm. In a further aspect, the invention comprises a membrane for the separation of gas, vapor and liquid mixtures as described herein, wherein porous ceramic support layers are selected from the group of macroporous ceramic Support layers comprising aA^Os, TiOa, ZrO2, YSZ, SiO2, CeO2, MgO, Y2O3, Gd2O3, mullite, cordierite, zeolite, BaTiOs, metallic components, carbon, SiC, SisN4, SiOC, SiCN, AIN or mixtures of the aforementioned materials. The membranes according to the invention may also have one or more porous intermediate layers, which are preferably mesoporous layers. If mesoporous intermediate layers are provided, they exhibit a smaller average pore size and a lower surface roughness when viewed from the direction of the carrier layer. The average pore size of the mesoporous intermediate layer arranged on the carrier layer is typically between 2 nm and 50 nm. If multiple mesoporous intermediate layers are provided, the intermediate layer located further away from the carrier layer generally has a smaller average pore size and surface roughness than the intermediate layer located closer to the carrier. Advantageously, if multiple mesoporous intermediate layers are provided, at least one intermediate layer has an average pore diameter of < 5 nm, preferably the one intended for contact with the subsequent separating layer, e.g., the final cover layer. Alternatively, the aforementioned mesoporous intermediate layers can also be designed as a graded layer. Suitable materials for the intermediate layer(s) are, in addition to y-ALOs, titanium dioxide (TiOa), zirconium dioxide (ZrOa), yttrium-stabilized zirconium dioxide (YSZ), silicon oxide (SiOa), cerium oxide (CeOa), magnesium oxide (MgO), yttrium oxide (Y2O3), gadolinium oxide (GdaOa), zinc oxide (ZnO), tin oxide (SnOa), mullite, cordierite, zeolite, metal-organic framework materials (MOF), clay, barium titanium oxide (BaTiOs), carbon, silicon carbide (SiC), silicon nitride (Sis1^ ), silicon oxycarbide (SiOC), silicon carbonitride (SiCN), aluminum nitride (AIN) or mixtures of the aforementioned materials. Mesoporous intermediate layers can also be applied to the carrier layer using conventional methods, such as coating with a colloidal dispersion, a sol-gel coating process, or hydrothermal synthesis. For this purpose, particles with average particle diameters of 5 to 200 nm are advantageously used together with typical binders, e.g., polyvinyl alcohol, polyethylene glycol, or cellulose compounds dissolved in water. Due to the small particle sizes required for the starting material, metallic materials are less suitable for producing mesoporous layers. After the coating process, drying takes place at temperatures up to 100 °C. Following the drying process, a thermal treatment step follows at temperatures up to 300 °C to calcine the layer. In an advantageous embodiment of the invention, a mesoporous layer comprising 8 mol% yttrium oxide-stabilized zirconium dioxide (8YSZ) is applied to a macroporous support by means of a dip-coating process. When using supports in the form of cylindrical tubes, such intermediate layers are preferably applied to the inside of the tubular supports, for example, by means of a dipping process. It has been shown that such a layer can withstand temperatures of up to 1000°C without damage. Temperatures in the range of 500°C to 900°C are required to effect a partial or complete reduction of graphene oxide by high-temperature treatment in a later process step in one aspect of the invention. In any case, such high temperatures of 500°C to 1000°C are also necessary to achieve carbonization of the inventive layer of carbonized polymerized catecholamines. In a further aspect, a membrane according to the invention has at least one macroporous carrier layer with pores in the range > 50 nm and at least one mesoporous intermediate layer with pores in the range 2 nm to < 50 nm with a layer thickness between 0.1 and 10 .m. In a further aspect, the invention comprises a membrane for the separation of gas, vapor and liquid mixtures as described herein, which comprises one or more porous intermediate layers which are mesoporous layers with pores having an average pore diameter of 2 nm to 10 nm. In a further aspect, the invention comprises a membrane for the separation of gas, vapor and liquid mixtures as described herein, wherein porous intermediate layers are selected from the above-mentioned group, particularly preferred are ceramic intermediate layers. In a further aspect, the invention comprises a membrane for the separation of gas, vapor and liquid mixtures as described herein, wherein porous interlayers are selected from the group of mesoporous ceramic interlayers having pores with an average pore diameter of 2 nm to 5 nm. In a further aspect, the invention comprises a membrane for the separation of gas, vapor and liquid mixtures as described herein, wherein porous intermediate layers are selected from the group of mesoporous ceramic layers comprising Y-Al2O3, TiO2, ZrO2, YSZ, SiO2, CeO2, MgO, Y2O3, Gd2O3, ZnO, SnO2, mullite, cordierite, zeolite, metal-organic framework materials (MOF), clay, BaTiOs, carbon, SiC, SiSn4, SiOC, SiCN, AlN or mixtures of the aforementioned materials. The inventors of the present invention have surprisingly found that the membranes described herein, which comprise a layer of thermally stabilized (preferably carbonized) polymerized catecholamines, enables the provision of a stable separation membrane which can be used to separate water from water / steam mixtures and can be used as a He- and H2-selective membrane. In principle, the application of such a layer of thermally stabilized (preferably carbonized) polymerized catecholamines can be achieved using the same coating processes as described below. Using the selected application process, a layer of polymerized catecholamines (e.g., a PDA layer) is first created on the underlying layers. This layer is then converted into a robust and thermally stable layer of polymerized catecholamines in a thermal treatment at temperatures between 60 and 450°C, preferably between 100 and 450°C (as defined above) in air. To produce the membranes according to the invention with carbonized polymerized catecholamines, the layer of polymerized catecholamines is then carbonized (pyrolyzed) in an additional heat treatment at temperatures > 300°C, preferably > 500°C.The catecholamines can be applied directly as a solution to the underlying layer, and polymerization then occurs in situ on the surface of the underlying support material. It is also possible to first synthesize a dispersion / suspension of polymerized catecholamine particles (e.g., PDA particles) in water and apply this to the surface of the underlying support material. An additional GO / graphene cover layer, as found in prior art membranes, is not absolutely necessary for the novel membranes of the present invention. The present invention thus provides novel membranes for the separation of gas, vapor, and liquid mixtures, which have a thermally stabilized (preferably carbonized) polymerized catecholamine-containing separation layer and enable the selective separation of the smallest molecules / atoms such as He, H2, and water. The layer containing the thermally stabilized (preferably carbonized) polymerized catecholamines is generally provided as an outer cover layer. Fig. 4 shows a schematic representation of such embodiments according to the invention. Due to the above-described good adhesive properties of the thermally stabilized (preferably carbonized) polymerized catecholamines, these are also suitable for improving the membranes known from the prior art, which are characterized by a layer of graphene oxide, partially reduced graphene oxide or graphene. If such a layer of graphene oxide, partially reduced graphene oxide or graphene is provided in the membrane, it is preferably a layer comprising graphene oxide, partially reduced graphene oxide or graphene. Such a layer of graphene oxide, partially reduced graphene oxide or graphene then preferably forms a cover layer of the membranes according to the invention, which is bonded by an adhesive layer intended layer of thermally stabilized (preferably carbonized) polymerized catecholamines is firmly bonded to the porous carrier and / or intermediate layer (if provided). For the purposes of this invention, a layer of graphene oxide, partially reduced graphene oxide, or graphene is understood to mean a layering of superimposed graphene and / or graphene oxide monolayers. The number of monolayers varies between approximately 5 and 1000. Assuming that 1000 monolayers of graphene have a layer thickness of approximately 600 nm and 1000 monolayers of graphene oxide have a layer thickness of approximately 1 to 2 pm, the layer thickness of such a layer is typically less than 2 pm, advantageously even less than 300 nm. The layer thickness of this layer is preferably less than 2 pm, more preferably between 5 nm and 1 pm, advantageously between 5 nm and 300 nm. The permeability of such a covering layer is essentially determined by the interlayer spacing between the graphene or graphene oxide layers of the covering layer. The individual graphene oxide layers usually have an interlayer spacing of 0.6 nm to 1.3 nm, depending on the humidity. Graphene oxide itself is hydrophilic. Such a functional layer is therefore particularly suitable for separation tasks in which water in the liquid or gas phase is to be separated from other larger molecules. Such a functional GO layer is also suitable for conventional gas separation. The advantage of such a layer is that the distance between the individual layers can be advantageously adjusted by adjusting the humidity. It has been shown that the membrane is selective for He and H2 under dry conditions.Larger molecules are retained. Under humid conditions, water molecules intercalate between the graphene oxide layers. This enables the membrane to selectively separate water-soluble gas molecules from less soluble molecules. For example, water-soluble CO2 can permeate through the membrane, while less soluble molecules such as N2 are retained. To apply such a microporous top layer to the membrane, it is applied in the form of a colloidal dispersion consisting of monolayer graphene oxide particles and water onto the layer of polymerized catecholamines applied to the mesoporous intermediate layer. Generally, conventional methods such as dip coating, spin coating, spraying, flooding, drop coating, roller coating, inkjet printing, or vacuum filtration are possible. Apart from aqueous dispersions, dispersions consisting of graphene oxide particles and polar organic solvents, such as alcohols, ethers, cyclic ethers (THF, DMF), N-methyl-2-pyrrolidone (NMP) can also be used. A drying step can then be carried out at a temperature of approximately 25°C. The dried layers are then subjected to a heat treatment in air at a temperature between 60 and 450°C, preferably between 100 and 450°C (as defined above), resulting in a robust and thermally stable top layer. As described above, the GO top layer tends to crack, peel, or detach during drying. This is prevented by the layer of (optionally carbonized) polymerized catecholamines provided according to the invention, which acts as an adhesive layer between a porous carrier or intermediate layer and the top layer of graphene oxide, partially reduced graphene oxide, or graphene. Thus, one possible embodiment of the invention relates to a membrane for the separation of gas, vapor, and liquid mixtures, which membrane comprises one or more layers of graphene oxide, partially reduced graphene oxide, or graphene. In such embodiments, the layer of thermally stabilized (preferably carbonized) polymerized catecholamines according to the invention has surprisingly proven to be a particularly suitable adhesive layer, ensuring a firm and stable bond between the porous carrier layer or an optionally provided porous intermediate layer and the layer comprising graphene oxide, partially reduced graphene oxide, or graphene. In such embodiments, the layer comprising graphene oxide, partially reduced graphene oxide, or graphene is preferably provided as an outer cover layer. Fig. 5 shows a schematic representation of such an embodiment of the invention. As demonstrated by the inventors in experiments, applying a layer of polymerized catecholamines to the support layer or a possibly provided upper (mesoporous) intermediate layer prior to applying a GO or graphene top layer enables the GO / graphene top layer to better withstand the corrosion and pressure conditions typical of industrial separation processes and significantly reduces or even completely prevents the risk of the top layer peeling off under such conditions. Due to the heat treatment in the coating process, the layer of polymerized catecholamines forms a strong chemical bond with the underlying porous layers on one side and the GO / graphene top layer applied on the other side, thus forming a kind of connection or bridge between them without compromising permeability or gas diffusion. A further embodiment of the invention thus relates to a membrane for the separation of gas, vapor and liquid mixtures as described herein, which comprises one or more layers comprising graphene oxide, partially reduced graphene oxide or graphene. In such embodiments, the layers comprising graphene oxide, partially reduced graphene oxide or graphene may be monolayer or multilayer. Particularly suitable ceramic separation membranes, in a preferred aspect of the invention, are those as described in detail in WO2016 / 177355, which are then modified or improved with the inventive layers of thermally stabilized (preferably carbonized) polymerized catecholamines. The membranes described in WO2016 / 177355 and the processes for their production are thus fully encompassed by the scope of the present invention. As mentioned above, supports in the form of cylindrical tubes are preferred. Further embodiments of the membranes according to the invention include those with the following configurations: Membrane for the separation of gas, vapor and liquid mixtures as described herein, comprising at least two porous intermediate layers in which both the particle size, the roughness and the pore size decrease towards the layer containing the (optionally carbonized) polymerized catecholamines. Membrane for the separation of gas, vapor and liquid mixtures as described herein, comprising at least two porous intermediate layers, of which a first porous intermediate layer is in contact with a porous support layer and a second porous intermediate layer is in contact with the layer containing the thermally stabilized (preferably carbonized) polymerized catecholamines, and wherein at least one intermediate layer has pores with an average pore diameter of less than 10 nm. Membrane for the separation of gas, vapor and liquid mixtures as described herein, wherein the first porous intermediate layer has a layer thickness between 1 pm and 20 pm and / or wherein the second porous intermediate layer has a layer thickness between 0.1 pm and 2 pm. Membrane for the separation of gas, vapor and liquid mixtures as described herein, which has a layer comprising graphene oxide, partially reduced graphene oxide or graphene, and wherein this layer has a layer thickness between 3 nm and 2 pm, preferably between 5 nm and 300 nm, more preferably between 5 nm and 20 nm. Membrane for the separation of gas, vapor and liquid mixtures as described herein, comprising a multilayer film having between 5 and 1000 layers of graphene oxide, partially reduced graphene oxide or graphene. Membrane for the separation of gas, vapor and liquid mixtures as described herein, wherein the layer containing the thermally stabilized (preferably carbonized) polymerized catecholamines has a layer thickness between 3 and 500 nm, preferably between 5 and 300 nm, more preferably between 10 and 200 nm, even more preferably between 25 and 80 nm. It is also possible for the layer containing the thermally stabilized (preferably carbonized) polymerized catecholamines to have a layer thickness between 3 nm and 200 nm, preferably between 5 nm and 100 nm, more preferably between 10 nm and 50 nm, most preferably around 25 nm or 80 nm. The suitable layer thickness can vary depending on the selected shape of the carrier materials to be coated. In order to coat rougher surfaces, e.g. tubular substrates, as defect-free and homogeneously as possible, layer thicknesses > 25 nm, for example around 80 nm, are preferred. The suitable layer thickness can also vary depending on the surface quality of the substrate to be coated and can be selected accordingly. Membrane for the separation of gas, vapor, and liquid mixtures as described herein, wherein the layer comprising graphene oxide, partially reduced graphene oxide, or graphene is arranged as the outer cover layer of the membrane In principle, the various layers in such multilayer membranes can be applied using immersion, dip coating, spin coating, spraying, roller coating, inkjet printing, or vacuum filtration, as well as other known coating methods. All of the intended layers can be applied using the same method from the aforementioned methods, or the individual layers can be applied using different methods from the aforementioned methods. In another possible embodiment of the invention, a GO / graphene cover layer can be in the form of a kind of mixed matrix of thermally stabilized (preferably carbonized) polymerized catecholamine and the GO / graphene. For this purpose, the graphene or graphene oxide is added to the starting solution of the catecholamines before the polymerization of the catecholamines, and this mixture is then applied to the surface of the underlying layer using one of the coating methods mentioned herein. This allows the graphene / graphene oxide to be integrated into the layer of polymerized catecholamines during the polymerization of the catecholamines, forming a kind of composite layer with it. This composite layer is then thermally treated in the manner described above and preferably carbonized and / or optionally reduced, resulting in the formation of the robust and stable layer of the thermally stabilized (preferably carbonized) polymerized catecholamine. Thus, a further embodiment of the invention relates to a membrane for the separation of gas, vapor, and liquid mixtures as described herein, wherein the thermally stabilized (preferably carbonized) polymerized catecholamines are present in the form of a mixed matrix with graphene oxide, partially reduced graphene oxide, or graphene, which is preferably formed as the outer cover layer of the membrane. Figure 6 shows a schematic representation of such an embodiment of the invention. The membranes according to the invention for the separation of gas, vapor and liquid mixtures as described herein are basically obtainable by producing a multi-layer arrangement of one or more (identical or different) of the layers described herein as well as at least one layer of polymerized catecholamines and heating the multi-layer arrangement to a temperature > 50 °C, preferably > 60 °C, more preferably between 60 and 450 °C (as described above) in air to obtain a thermally stable layer of polymerized catecholamines, and optionally(preferred) carrying out a further heat treatment at temperatures > 250 °C, preferably > 300 °C, more preferably at least 500 °C, preferably at temperatures between 500 and 1000 °C, more preferably at temperatures between 500 and 750 °C, and carbonization of the polymerized catecholamines to obtain a layer of carbonized polymerized catecholamines, wherein the carbonization can optionally be carried out under reducing conditions (as described above). According to the invention, the carbonization of the polymerized catecholamines is preferably carried out in an inert and / or reductive atmosphere. A further aspect of the invention relates to a process for producing the membranes according to the invention as described herein, comprising the steps (a) providing or producing at least one porous ceramic carrier layer, (b) optionally applying one or more porous intermediate layers to the porous carrier layer, (c) applying catecholamines to the porous ceramic carrier layer or an optionally provided porous intermediate layer, either o in the form of an aqueous solution of the catecholamine and subsequent polymerisation in situ, or o in the form of an aqueous dispersion or suspension of already polymerised catecholamine particles, (d) thermal treatment at 60 to 450°C, preferably 100 to 400°C, more preferably 150 to 250°C, in air, (e) optionally (preferably) carbonization of the polymerized catecholamines at a temperature > 300 °C, preferably between 500 and 1000 °C to obtain a layer of carbonized polymerized catecholamines. The method according to the invention may further comprise a step of applying a layer of graphene oxide, partially reduced graphene oxide or graphene. In order to produce membranes according to the invention with a cover layer of graphene oxide, partially reduced graphene oxide or graphene, in the inventive In a process as described herein, after the above-described step (d), an aqueous colloidal dispersion of graphene oxide is applied to the layer of polymerized catecholamines to obtain a membrane with a layer of polymerized catecholamines in the form of an adhesive layer and a cover layer comprising graphene oxide, partially reduced graphene oxide, or graphene arranged thereover. Optionally, step (e) of carbonization and / or optionally a reduction of the GO layer is also carried out. In order to produce membranes according to the invention with a mixed cover layer (composite layer) of graphene oxide, partially reduced graphene oxide or graphene and polymerized catecholamine, in the process according to the invention as described herein, graphene and / or graphene oxide particles are mixed into an aqueous solution of the catecholamines in step (c) and this mixture is then polymerized in situ, followed by the thermal treatment in step (d) and optionally (preferably) followed by carbonization in step (e) to obtain a membrane with a layer of thermally stabilized (preferably carbonized) polymerized catecholamines in the form of a mixed matrix with graphene oxide, partially reduced graphene oxide or graphene. In order to produce membranes according to the invention on an industrially attractive scale, it is preferable to use supports with a tubular geometry. On a laboratory scale, tubular supports can have a length of at least 10 cm to 50 cm. Commercially available tubular support materials, such as those used in the examples described below, have, for example, a length of at least 10 to at least 25 cm. However, the tubular supports can certainly also be larger, since the process according to the invention is freely scalable. For industrial membrane applications, significantly larger membrane housings are generally used, which can accommodate, for example, tubular membranes with a length of 100 to 150 cm. Due to the free scalability of the process according to the invention, the conditions described in the examples section can be easily transferred to such large scales. Support materials within the meaning of the invention can be coated, for example, in a suitable tank using a dipping process. As described in the experimental section, tubular support materials, for example, can be placed in a sufficiently large tank containing liquid solutions or dispersions of the coating materials. The tank system is set in motion, for example, using a suitable shaking device, so that the coating solutions flow around and through the support materials placed therein, resulting in a uniform coating. In the coating tanks, the carrier materials placed therein can be fixed by suitable fastening devices. Traditional dip coaters can also be used. A common variant of dip coating, used by some membrane manufacturers, involves pumping the coating fluid into the tubular substrates to be coated and then evacuating the tubes. The polymerization of catecholamines usually occurs spontaneously, preferably under oxygen / air and, if necessary, in the presence of a buffer. It is also possible to trigger or accelerate the polymerization of catecholamines by adding an oxidizing agent, especially a strong oxidizing agent. The use of oxidizing agents also makes it possible to carry out the process in the absence of oxygen / air, for example, in a closed system. This is particularly interesting in industrial production. Thus, in addition to atmospheric air, pure oxygen or other oxidizing reagents such as ammonium persulfate, potassium persulfate, sodium persulfate, sodium periodate, potassium permanganate, hydrogen peroxide, Cu 2+ -salts (e.g. CUSO4), Fe 3+ Salts (e.g., FeCh) or mixtures thereof are used. Oxidizing agents are preferably selected from the group comprising ammonium persulfate, hydrogen peroxide, and CuSO4; ammonium persulfate is particularly preferred. The amount of oxidizing agent added to the catecholamine solution, e.g., dopamine, can vary depending on the strength. For example, they can be added in a molar ratio of 1:10 to 10:1 (dopamine:oxidizing agent), preferably in a molar ratio of 5:10 to 10:2, more preferably in a molar ratio of 10:10 (or 1:1). Preferably, in the process according to the invention as described herein, graphene oxide is used in the form of an aqueous colloidal dispersion of graphene oxide particles with a particle size between 10 nm and 5 pm. Preferably, in the process according to the invention as described herein, graphene oxide is used in the form of an aqueous colloidal dispersion having a solids content of graphene oxide particles between 20 mg and 2 g per liter of colloidal dispersion. Preferably, in the process according to the invention as described herein, in step (e) the carbonization is carried out in a reducing atmosphere under argon / 3% H2 and, in the case of the presence of a layer containing graphene oxide, this is at least partially reduced to graphene. In the process according to the invention as described herein, the layer containing the catecholamines and / or the layer containing graphene oxide, partially reduced graphene oxide or graphene is applied independently of one another, in each case by means of Dipping processes (e.g., by immersion or submersion), dip coating, spin coating, spraying, roller coating, inkjet printing, or vacuum filtration, and other known coating processes. In principle, the same equipment for dipping processes can be used as described above in connection with coating with the intermediate layer. If a reduction step is carried out, the selection of the method used to achieve the reduction (chemical or thermal) can depend on the material selected for the carrier layer and the intermediate layers. If the membrane structure can withstand the higher temperatures required for the reduction, a thermal method is preferably used because it is simpler. The oxygen-containing groups of the cover layer are eliminated in a vacuum or under a reducing atmosphere (e.g. Ar / H2). For complete reduction, higher temperatures > 300 °C, preferably between 500 °C and 1000 °C are necessary. To enable this, multilayer membrane structures such as those described in WO2016 / 177355, which contain thermally stable mesoporous layers in addition to a thermally stable macroporous carrier, are particularly suitable.In preferred embodiments, these consist of zirconium dioxide, in particular yttrium-stabilized zirconium dioxide (YSZ), and particularly advantageous is the so-called 8YSZ, which is particularly thermally stable. In the process according to the invention as described herein, the structure of the membrane with respect to the carrier and / or intermediate layer(s) and an optionally provided cover layer of graphene oxide, partially reduced graphene oxide or graphene is as described in WO2016 / 177355 and these process steps and parameters are fully encompassed here. The invention also relates to the use of thermally stabilized (preferably carbonized) polymerized catecholamines as molecular sieve membranes for the separation of He, H2 or H2O. Furthermore, the invention relates to the use of the multilayer membranes described herein as molecular sieve membranes for the separation of He, H2 or H2O. A particular aspect of the invention relates to the use of the membranes described herein, which have a layer of carbonized polymerized catecholamines, as a molecular sieve membrane for the separation of He or H2 or H2O. Membranes according to the invention, in which the layer of polymerized catecholamines is subjected only to the thermal treatment according to process step (d) described herein, but not to the carbonization according to step (e), i.e., it is not in the form of carbonized polymerized catecholamines, are particularly intended for use as a membrane for separating H2O from solvent mixtures. In the sense of the invention, the separation of gas, vapor and liquid mixtures comprises in particular the separation of the smallest molecules / atoms from gas and vapor mixtures and / or the separation of water, in particular in the form of water vapor, from liquid mixtures, such as from solvent mixtures, in liquid or vapor form. To further clarify the invention, it is explained in more detail with reference to some figures, diagrams and exemplary embodiments, without this being intended to limit the invention. DESCRIPTION OF THE CHARACTERS Fig. 1 schematic representation of membrane separation [Scholes, CA et al., Recent Patents on Chemical Engineering 2008, 52-66, p. 53] . Fig. 2 schematic representation of the three basic separation mechanisms on membranes [Scholes, CA et al., Recent Patents on Chemical Engineering 2008, 52- 66, p. 53], Fig. 3 Schematic representation of the molecular sieve function of graphene / GO separation membranes Fig. 4 schematic representation of the layers of a membrane according to the invention, in which the layer of thermally stabilized (preferably carbonized) polymerized catecholamines forms the cover layer. Fig. 5 schematic representation of the layers of a membrane according to the invention, wherein the layer of thermally stabilized (preferably carbonized) polymerized catecholamines forms an adhesive layer connecting a porous intermediate layer to a cover layer of graphene oxide, partially reduced graphene oxide or graphene. Fig. 6 schematic representation of the layers of a membrane according to the invention, wherein the layer of thermally stabilized (preferably carbonized) polymerized catecholamines with graphene oxide, partially reduced graphene oxide or graphene in the form of a mixed matrix / composite layer forms the cover layer applied on a porous intermediate layer. Fig. 7 Gas permeation of He, H2, CO2, N2 and CH4 of membranes according to the invention with a bilayer (double coating) of polydopamine (Polydopamine 2x / internally also referred to as “PDA reduced No. 2”) and a layer of polydopamine and graphene (PDA + graphene) in comparison to conventional graphene separation membranes according to WO2016 / 177355 (Graphene 2x), each measured at 200°C and 5 bar. Fig. 8 Temperature dependence of the gas permeation of He, H2, CO2, N2 and CH4 of membranes according to the invention with a double layer (double coating) of polydopamine (Polydopamine 2x / PDA 2) compared to conventional graphene separation membranes according to WO2016 / 1773 (graphene), each measured at 5 bar and at 22°C, 50°C, 100°C, 150°C and 200°C. REFERENCE SYMBOL (1) Membrane for the separation of gas, vapor and liquid mixtures (2) porous ceramic carrier layer (3) Layer of thermally stabilized (preferably carbonized) polymerized catecholamines (3a) Layer of thermally stabilized (preferably carbonized) polymerized catecholamines in the form of a cover layer (3b) Layer of thermally stabilized (preferably carbonized) polymerized catecholamines in the form of an adhesive layer (3c) Layer of thermally stabilized (preferably carbonized) polymerized catecholamines in the form of a mixed matrix / composite layer with graphene oxide, partially reduced graphene oxide or graphene (4) porous intermediate layer(s) (5) Layer of graphene oxide, partially reduced graphene oxide or graphene EXAMPLES Example 1 - Preparation of a membrane with cPDA adhesive layer For the production of a membrane according to the invention, in which the carbonized polymerized catecholamine layer acts as an adhesive layer connecting a porous intermediate layer with a graphene cover layer, a basic membrane structure consisting of a porous carrier and intermediate layer (e.g. according to WO2016 / 177355) is first provided. In the present example, a structure with a mesoporous interlayer of an 8YSZ support was used, which consists of several layers (e.g., four layers) of yttrium-stabilized zirconia (8YSZ) with a pore size of 5 to 3 nm. These mesoporous layers were deposited on a macroporous support in the form of an aA^Oa support disk or a support tube. A diluted aqueous dopamine solution (or another aqueous catecholamine solution) was dip-coated onto the topmost mesoporous 8YSZ interlayer (side facing away from the support layer). The diluted catecholamine solution has a solids content between 0.3 and 10 mg / ml, preferably between 0.3 and 5 mg / ml, and preferably between 0.5 and 2 mg / ml. Dopamine hydrochloride was used as the starting compound for the synthesis. In a specific preparation example, a macroporous aA^Ch support disc was immersed in a mildly alkaline (pH 8.5; Tris buffer) aqueous dopamine solution (2 mg / ml) for 24 hours with continuous stirring. It was then removed from the solution, washed thoroughly with water, and the coating was subsequently dried at room temperature for one hour. The carrier disk used was coated with a mesoporous 8YSZ interlayer, which consisted of 4 layers of yttrium-stabilized zirconia (8YSZ) with a pore size of 5 nm (2 layers) to 3 nm (2 layers). Alternative application methods include well-known coating processes such as dip coating, spin coating, spraying, roller coating, inkjet printing or vacuum filtration. After applying the dopamine solution and polymerizing the dopamine to PDA, a thermal treatment is performed at temperatures above 60°C and below 300°C in air. A water-based colloidal GO dispersion is then dip-coated onto the 8YSZ support layer coated with the dopamine solution. The resulting layered assembly was then treated in air (<300°C) to produce a graphene oxide-based membrane. Optionally, it was subsequently exposed to a reducing atmosphere (750°C, Ar / H2 (3%)), which causes the carbonization of the PDA layer and completely or partially reduces the GO layer to a graphene functional layer. The cPDA layer firmly bonds the mesoporous 8YSZ layer to the graphene layer, thus acting as an adhesive layer. The thickness of the cPDA layer on the support discs was approximately 25 nm. Gas permeation tests on a correspondingly manufactured prototype (sample PDA + graphene in Fig. 7) showed the same permeation behavior for He, H2, CO2, N2, and CH4 as unmodified graphene-based membranes without a cPDA adhesive layer (sample graphene 2x in Fig. 7), with molecular sieving behavior and He and H2 as permeating gases, while CO2 and the larger gases are retained. The results of these permeation tests are shown in Fig. 7. The (individual) gas permeances (permeation) of the membrane prototypes were measured in dead-end mode. The smallest gas molecules, He (kinetic diameter 0.26 nm), H2 (0.289 nm), CO2 (0.33 nm), N2 (0.364 nm), and CH4 (0.38 nm), were used as test gases. The gas permeability was measured for temperatures between 50°C and 200°C and a feed pressure of 0.3 to 5 bar. The results of the temperature-dependent permeation tests are shown in Fig. 8. The average permeances at 200°C and 5 bar are shown in Fig. 7. It can be seen that the membrane allows the smallest gases, He and H2, to pass through, while preventing the transport of CO2, N2, and CH4. Thus, the membranes exhibited clear molecular sieve behavior, and the sharp drop in permeance between H2 and CO2 also indicates that the effective transport channels in the membrane are in the range of 0.3 to 0.4 nm. In an alternative process, it is possible to first prepare a dispersion / suspension of PDA particles in water before applying the dopamine and GO / graphene layer and apply this to the porous layer, instead of polymerizing the dopamine in situ on the surface of the porous support to PDA. The dispersion / suspension can also be applied to the 8YSZ support layer using known coating methods as described herein and then thermally treated (carbonized) and, if necessary, reduced. Example 2 - Preparation of a membrane with cPDA cover layer The production of an embodiment without a GO / graphene cover layer was carried out in principle as described in Example 1, in which only the additional coating step with GO / graphene was omitted. It was shown that the sole application of a PDA layer followed by thermal treatment at 750 °C in Ar / H2 (3%) also leads to a He- and H2-selective separation membrane (result not shown). A membrane according to the invention equipped with two PDA layers shows comparably good results (sample "Polydopamine 2x" in Fig. 7). SEM cross-sectional images (not shown) showed that a very thin, yet clearly visible, layer is formed, which is firmly bonded to the underlying 8YSZ layer. High-resolution images (not shown) also showed that such a PDA-based cover layer is approximately 25 nm thick. Furthermore, the same exponential increase of He and H2 with increasing operating temperature is observed. The results of the temperature-dependent permeation tests are shown in Fig. 8. The temperature influence on gas transport through the membrane was investigated by measuring the He and H2 permeability at various temperatures (20°C to 200°C) (Fig. 8). It was found that the permeance of these gases was activated by the membranes according to the invention and increased exponentially with temperature. Fig. 8 also shows that the temperature-dependent behavior is essentially the same for both embodiments of the invention according to Example 1 (PDA + graphene) and 2 (polydopamine 2x). He and H2 increase exponentially, the other gases CO2, N2 and CH4 show only a low permeation as shown in the lower part of the diagram in Fig. 8. This behavior confirms that gas transport through the membrane is mainly dominated by micropore diffusion and that Knudsen diffusion plays no role. SEM surface images (not shown) also showed that the 8YSZ layer is homogeneously covered with the cPDA top layer and shows no visible cracks. Example 3 - Fabrication of a membrane with cPDA / graphene composite layer The preparation of an embodiment in which the GO / graphene capping layer forms a mixed matrix or composite layer with the cPDA can in principle be prepared as described in Example 1. For this purpose, graphene oxide platelets are mixed into the dopamine starting solution prior to the dopamine polymerization process. This mixture is applied to the porous support layer as described in Examples 1 and 2, and then polymerized as described in Example 1. During polymerization, the graphene oxide platelets are integrated into the PDA layer. The PDA layer is then thermally treated and, if necessary, reduced as described above, thus forming a type of mixed layer or composite layer that serves as a cover layer. Example 4 - Preparation of a membrane in the form of a cylindrical tube with cPDA cover layer In analogy to Example 2, an embodiment of the invention without a GO / graphene cover layer was fabricated in a tubular configuration, which is the usual shape in real industrial membrane applications. The membrane layers from Example 2 were applied to the inside of macroporous, tubular α-AhOa supports with a length of 25 cm using a dipping process. A commercially available α-AhOa microfiltration membrane was used as the support material. This membrane features a multilayer structure. The pore size of the outermost layer on the inside of the tubular support materials was approximately 70 nm. The outer diameter of the tubular support materials was 10 mm and the inner diameter was 6 mm. The tubular supports were coated with a mesoporous 8YSZ interlayer consisting of four layers of yttrium-stabilized zirconia (8YSZ) with a pore size of 5 nm (2 layers) to 3 nm (2 layers). These were applied to the a-AhOs supports by dip coating using a special dip coating device. For this purpose, a device with a holder for the tubular carrier material and a holder for a container with the coating liquid. Coating was performed by vertically moving the container containing the coating liquid upwards while the tubular substrate remained fixed. After a holding time of 30 s, the container containing the coating liquid was moved downwards again. The vertical movement speed was 10 mm / s during both coating and retraction. In an alternative variant, the tubular support materials were coated internally with 8YSZ layers by pumping the coating liquid through the a-AhCh support tubes. The coating liquid was then held in the support tube for another 30 s and then evacuated from the system. In both variants, the tubular supports with the 8YSZ coating were then immersed in a mildly alkaline (pH 8.5; Tris buffer) aqueous dopamine solution (4 mg / ml) in a suitable tank for 24 hours. The support tubes were fixed horizontally on a glass base plate, and the tank was shaken on a shaking table such that a visible wave motion was created in the dopamine solution, allowing the dopamine solution to flow through the tubular supports. The PDA-coated support tubes were then removed from the solution, washed thoroughly with water, and the PDA coating was then dried for one hour at room temperature. Afterwards, this process step of the PDA coating was completely repeated once again and then a thermal treatment was carried out at a temperature of more than 60 °C and less than 300 °C in air and then a thermal treatment in a reducing atmosphere (300 - 750 °C, Ar / H2 (3%)), which caused the carbonization of the PDA coating. It was shown that the application of a PDA coating on tubular a-AhCh supports by immersion and subsequent thermal treatment at 500 °C in Ar / H2 (3%) also leads to a He- and H2-selective separation membrane. SEM cross-sectional images (not shown) showed that a thin, uniform layer is formed, which is also tightly bonded to the underlying 8YSZ layer. High-resolution images (not shown) showed that such a PDA-based top layer is approximately 80 nm thick. For these tubular membranes, reduced (carbonized) at 500°C, the average ideal permeation selectivity was in the range of 22–35 and 25–40 for the gas pairs H2 / N2 and H2 / CH4, respectively (based on measurements at 200°C and 1 bar with a series of 20 samples). These values ​​are significantly higher than the Knudsen selectivity, demonstrating that the number of membrane defects was kept to a minimum. In addition, hydrogen permeances in the range of 15 to 30 m 3 / (m 2 .h.bar) measured. In another possible process variant, the tubular support materials with the 8YSZ coating were immersed in the dopamine solution. The tubular support materials were fixed using a holder, for example, a revolver-shaped carousel attachment held by a conventional dip-coating system. The tubular support materials thus fixed were immersed in a container containing a mildly alkaline (pH 8.5; Tris buffer) aqueous dopamine solution (4 mg / ml) for 24 hours. After the coating process, they were rinsed with water and thermally treated in the same way as described above. Example 5 - Preparation of a membrane in the form of a cylindrical tube with cPDA cover layer with addition of an additional oxidant Oxygen is known to play a crucial role in the polymerization of dopamine to polydopamine, as a lack of sufficient oxygen slows the kinetics of polymerization. To enable efficient and rapid polymerization and deposition of a PDA membrane layer, e.g., in an industrial context, a strong oxidant is helpful. The present Example 5 was carried out analogously to Example 4, whereby ammonium persulfate was added to the dopamine starting solution as a water-soluble strong oxidizing agent. For this purpose, the tubular supports coated with a mesoporous 8YSZ interlayer with a length of 25 cm were immersed in a mildly alkaline (pH 8.5; Tris buffer) aqueous dopamine solution (4 mg / ml) to which ammonium persulfate was added in a molar ratio of 1:1. The coating, thermal treatment and carbonization were carried out according to the same method as described in Example 4. Definitions The pore size can be determined by permporosimetry using conventional methods.

Claims

PATENT CLAIMS [1] Membrane for the separation of gas, vapor and liquid mixtures (1), comprising one or more porous ceramic support layers (2) and at least one layer (3) containing carbonized polymerized catecholamines, and which optionally also comprises one or more porous intermediate layers (4) arranged between a porous ceramic support layer (2) and the layer (3) containing the carbonized polymerized catecholamines. [2] Membrane for the separation of gas, vapor and liquid mixtures according to claim [1], wherein the layer containing the carbonized polymerized catecholamines forms an outer cover layer (3a). [3] Membrane for the separation of gas, vapor and liquid mixtures according to claim [1] or [2], further comprising one or more layers (5) comprising graphene oxide, partially reduced graphene oxide or graphene. [4] Membrane for the separation of gas, vapor and liquid mixtures according to one of claims [1] to [3], wherein the layer containing the carbonized polymerized catecholamines forms an adhesive layer (3b) which connects a porous support layer (2) or a porous intermediate layer (4) to a cover layer comprising graphene oxide, partially reduced graphene oxide or graphene (5). [5] Membrane for the separation of gas, vapor and liquid mixtures according to any one of claims [1] to [4], wherein the carbonized polymerized catecholamines are in the form of a mixed matrix (3c) with graphene oxide, partially reduced graphene oxide or graphene, which forms an outer covering layer of the membrane. [6] Membrane for the separation of gas, vapor and liquid mixtures according to any one of claims [1] to [5], wherein the carbonized polymerized catecholamines are selected from the group comprising carbonized Polydopamine, carbonated polynoradrenaline, and carbonated polyadrenaline, of which carbonated polydopamine (cPDA) is preferred. [7] Membrane for the separation of gas, vapor and liquid mixtures according to one of claims [1] to [6], wherein the porous ceramic support layers (2) are selected from the group of macroporous ceramic support layers comprising aAlO3O5, TiO4, ZrO2, YSZ, SiO4, CeO4, MgO, Y2O3, GdaO4, mullite, cordierite, zeolite, BaTiO5, metallic components, carbon, SiC, SiS4N4, SiOC, SiCN, AlN or mixtures of the aforementioned materials. [8] Membrane for the separation of gas, vapor and liquid mixtures according to one of claims [1] to [7], wherein the porous ceramic support layers (2) are macroporous layers with pores having a pore diameter > 50 nm. [9] Membrane for the separation of gas, vapor and liquid mixtures according to one of claims [1] to [8], which comprises one or more porous intermediate layers (4) which are selected from the group of mesoporous ceramic intermediate layers comprising Y-Al2O3, TiO2, ZrO2, YSZ, SiO2, CeO2, MgO, Y2O3, GdaOa, ZnO, SnO2, mullite, cordierite, zeolite, metal-organic framework materials (MOF), clay, BaTiOs, carbon, SiC, SiSn4, SiOC, SiCN, AlN or mixtures of the aforementioned materials. [10] Membrane for the separation of gas, vapor and liquid mixtures according to one of claims [1] to [9], which comprises one or more porous intermediate layers (4) which are mesoporous layers with pores having an average pore diameter of 2 nm to 50 nm. [11] Membrane for the separation of gas, vapor and liquid mixtures according to one of claims [1] to [10], which comprises one or more layers (5) comprising graphene oxide, partially reduced graphene oxide or graphene. [12] Membrane for the separation of gas, vapor and liquid mixtures according to one of claims [1] to [11], which has one or more layers (5) comprising graphene oxide, partially reduced graphene oxide or graphene, which are monolayer or multilayer. [13] Membrane for the separation of gas, vapor and liquid mixtures according to one of claims [1] to [12], which is in the form of a cylindrical tube. [14] A process for producing the membranes according to any one of claims [1] to [13], comprising the steps (a) providing or producing a porous ceramic carrier layer (2), (b) optionally applying one or more porous intermediate layers (4) to the porous ceramic carrier layer (2), (c) applying catecholamines to the porous ceramic carrier layer (2) or an optionally provided porous intermediate layer (4), either o in the form of an aqueous solution of the catecholamine and subsequent polymerization in situ, or o in the form of an aqueous dispersion or suspension of already polymerized catecholamine particles, (d) thermal treatment at 60 to 450°C, preferably 100 to 400°C, more preferably 150 to 250°C, in air, (e) optionally (preferably) carbonization of the polymerized catecholamines at a temperature > 300 °C, preferably between 500 and 1000 °C to obtain a layer of carbonized polymerized catecholamines (3). [15] Method according to claim [14] further comprising a step of applying a layer (5) comprising graphene oxide, partially reduced graphene oxide or graphene. [16] Process according to claim [14] or [15], wherein after step (d) an aqueous colloidal dispersion of graphene oxide is applied to the layer of polymerized catecholamines and optionally (preferably) subsequently the step (e) of carbonization is carried out to obtain a membrane with a layer of thermally stabilized (preferably carbonized) polymerized catecholamines in the form of an adhesive layer (3b) and a cover layer (5) arranged thereover comprising graphene oxide, partially reduced graphene oxide or graphene; or wherein in step (c) graphene oxide particles are mixed into an aqueous solution of the catecholamines and this mixture is subsequently polymerized in situ, followed by the thermal treatment in step (d) and optionally (preferably) the carbonization in step (e) to obtain a membrane with a layer of thermally stabilized (preferably carbonized) polymerized catecholamines in the form of a mixed matrix with graphene oxide, partially reduced graphene oxide or graphene (3c). [17] A process according to any one of claims [14] to [16], wherein graphene oxide is used in the form of an aqueous colloidal dispersion of graphene oxide particles having a particle size between 10 nm and 5 pm; and / or wherein graphene oxide is used in the form of an aqueous colloidal dispersion having a solids content of graphene oxide particles between 20 mg and 2 g per liter of colloidal dispersion. [18] Process according to one of claims [14] to [17], comprising step (e) wherein the carbonization takes place in a reducing atmosphere under argon / 3% H2 and in the case of the presence of a layer containing graphene oxide, this is at least partially reduced to graphene. [19] A process according to any one of claims [14] to [18], wherein support materials in the form of cylindrical tubes are used in the coating process. [20] A process according to any one of claims [14] to [19], wherein in step (c) an oxidizing agent, preferably ammonium persulfate, is further added. [21] Membrane obtainable from step (d) of a process according to any one of claims [14] to [17], [19] or [20], comprising a layer of thermally stabilized polymerized catecholamines (3). [22] Use of a membrane according to any one of claims [1] to [13], which comprises a layer of carbonized polymerized catecholamines, as a molecular sieve membrane for the separation of He or H2 or H2O. [23] Use of a membrane according to claim [21], which has a layer of thermally stabilized polymerized catecholamines (3), as a membrane for separating H2O from solvent mixtures or from vapor mixtures or moist gas mixtures.

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