A gas membrane device

Abstract

A gas membrane device for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species.

Description

[0001] A gas membrane device

[0002] The invention relates to a gas membrane device for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species.

[0003] Respective gas membrane devices have been generally known in the art and can be used in different technical applications requiring separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species.

[0004] An exemplary application is the separation of CO2 (carbon dioxide) from a gas mixture, particularly a flow of a gas mixture, comprising CO2 and other components, such as e.g. oxygen and / or nitrogen, which gas mixture results from an industrial process, such as e.g. an industrial combustion process in which the combustion of carbon-based substances, e.g. fossil fuels, generates a gas mixture comprising CO2 as a by-product. An efficient removal of CO2 from a respective gas mixture can be the basis for an efficient carbon-capturing which can form part of a superordinate approach for reducing greenhouse gas emissions.

[0005] A common approach to separate CC>2 from a respective gas mixture, particularly a flow of a respective gas mixture, is using chemicals, particularly solvents, to remove CO2 from the gas mixture which has several drawbacks, particularly with respect to its efficiency; notably, using chemicals, particularly solvents, to remove CC>2 from a respective gas mixture because typically requires a fairly high amount of energy.

[0006] As such, there exists a need for an improved approach for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species and particularly, a need for an improved gas membrane device for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species.

[0007] It is therefore, the particular objective of the present invention to provide for an improved gas membrane device for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species.

[0008] The objective is achieved by the subject-matter of claim 1 . The subject-matter of the claims depending from claim 1 relate to possible embodiments of the subject-matter of claim 1 . The subject-matter of the remaining claims also enable achieving the objective.

[0009] A first aspect of the invention relates to a gas membrane device for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species. The gas membrane device specified herein is thus, generally configured to separate gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species.

[0010] A respective gas mixture can be or comprise a flow of the gas mixture. A respective gas mixture can thus, comprise a flow of gas molecules of the first species and gas molecules of at least one second species. The flow is typically directed towards the gas membrane device such that gas molecules of the first species can pass or penetrate through the gas membrane device as will be more apparent from below.

[0011] A respective gas mixture can particularly, be a gas mixture resulting from an industrial process. A respective industrial process can generate CO2, e.g. as a main-product or as a by-product. An example of a respective industrial process is a combustion process. A respective combustion process can comprise the combustion of carbon-based substances, e.g. fossil fuels, which generates a gas mixture comprising CO2, for instance.

[0012] Hence, gas molecules of a respective first species can generally be CC>2-molecules. Gas molecules of a respective second species may include but are not limited to at least one of oxygen-molecules, oxygencontaining molecules (except for CO2), nitrogen-molecules, nitrogen-containing molecules, sulfur molecules, sulfur-containing molecules, for instance. The gas membrane device can thus, be generally configured for separating gas molecules of a first species which is CO2, from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species which is not CO2, but oxygen and / or nitrogen and / or sulfur, for instance.

[0013] The gas membrane device comprises at least one two-dimensional membrane layer. The at least one two- dimensional membrane layer comprises one or more penetration openings. The penetration openings are configured such that gas molecules of the first species of a respective gas mixture can pass or penetrate therethrough. Typically, the penetration openings are configured such that gas molecules of the at least one second species of the respective gas mixture cannot pass or penetrate therethrough. Particularly, the penetration openings are sized and / or shaped such that molecules of the first species of a respective gas mixture can pass or penetrate therethrough, e.g. due to the molecule size which allows for that the molecules of the first species can pass or penetrate through the respective penetration openings. Accordingly, the penetration openings are typically, sized and / or shaped such that molecules of the at least one second species of the respective gas mixture cannot pass or penetrate therethrough, e.g. due to the molecule size which does not allow for that the molecules of the at least one second species can pass or penetrate through the respective penetration openings. Hence, the size and / or shape of the penetration openings can be selected based on the size and / or shape of the molecules of the first species such that the molecules of the first species can pass or penetrate through the respective penetration openings which typically, also means that the molecules of the at least one second species cannot pass or penetrate through the respective penetration openings. The at least one two-dimensional membrane layer is functionalized with at least one functionalization agent configured to promote penetration of the gas molecules of the first species through the one or more penetration openings of the at least one two-dimensional membrane layer. Hence, the at least one two- dimensional membrane layer comprises one or more functionalizations, particularly chemical functionalizations, which enable that the penetration of the gas molecules of the first species through the one or more penetration openings is promoted. The at least one two-dimensional membrane layer can thus, also be deemed or denoted a “functionalized membrane layer”. Respective functionalizing agents can thus, be or comprise chemical substances or chemical groups which enable that the penetration of the gas molecules of the first species through the one or more penetration openings is promoted. The at least one functionalizing agent can thus, have chemical and / or physical properties which enable that the penetration of the gas molecules of the first species through the one or more penetration openings is promoted. As an example, a respective functionalizing agents can have a chemical affinity, e.g. due to chemical and / or physical attracting effects, with respect to the gas molecules of the first species and / or a chemical disaffinity, e.g. due to chemical and / or physical repelling effects, with respect to the gas molecules of the at least one second species such that the penetration of the gas molecules of the first species through the one or more penetration openings is promoted. Respective functionalization agents can be provided at portions of the at least one functionalized membrane layer adjacent to respective penetration openings and / or at portions of the at least one functionalized membrane layer not adjacent to respective penetration openings. Particularly, respective functionalization agents can be provided at portions of the at least one functionalized membrane layer adjacent to respective penetration openings, wherein at least some of the functionalization agents are oriented in the plane of the at least one functionalized membrane layer, particularly such that the molecule axes, particularly the longitudinal molecule axes, of respective molecules of the functionalization agents extend (substantially) parallel to the main extension plane of the at least one membrane layer. In either case, the arrangement of respective functionalization agents is chosen and effective such that penetration of gas molecules of the first species through the one or more penetration openings is promoted. In other words, the at least one functionalized membrane layer can have, due to respective functionalizing agents, a specific chemical “design” which promotes penetration of gas molecules of the first species through the one or more penetration openings which forms basis for and supports a highly efficient separation of the gas molecules of the respective first species from a respective gas mixture.

[0014] Alternatively or additionally, the at least one functionalized membrane layer is functionalized with at least one functionalization agent configured to impede penetration of the gas molecules of the first species through the one or more penetration openings of the at least one functionalized membrane layer. Hence, the at least one functionalized membrane layer can comprise one or more functionalizations, particularly chemical functionalizations, which enable that the penetration of the gas molecules of the first species through the one or more penetration openings is impeded. The at least one functionalizing agent can thus, be or comprise chemical substances or chemical groups which enable that the penetration of the gas molecules of the first species through the one or more penetration openings is impeded. The at least one functionalizing agent can thus, have chemical and / or physical properties which enable that the penetration of the gas molecules of the first species through the one or more penetration openings is impeded. As an example, a respective functionalizing agent can have a chemical affinity, e.g. due to chemical and / or physical attracting effects, with respect to the gas molecules of the at least one second species and / or a chemical disaffinity, e.g. due to chemical and / or physical repelling effects, with respect to the gas molecules of the first species such that the penetration of the gas molecules of the at least one second species through the one or more penetration openings is impeded. Respective functionalization agents can be provided at portions of the at least one functionalized membrane layer adjacent to respective penetration openings and / or at portions of the functionalized membrane layers not adjacent to respective penetration openings. Particularly, respective functionalization agents can be provided at portions of the at least one functionalized membrane layer not adjacent to respective penetration openings, wherein at least some of the functionalization agents are oriented angled relative to the plane of the at least one functionalized membrane layer, particularly such that the molecule axes, particularly the longitudinal molecule axes, of respective molecules of the functionalization agents extend at an angle of 15 - 165° relative to the main extension plane of the at least one functionalized membrane layer. In either case, the arrangement of respective functionalization agents is chosen and effective such that penetration of gas molecules of the at least one second species through the one or more penetration openings is impeded. In other words, the at least one functionalized membrane layer can have, due to respective functionalizing agents, a specific chemical “design” which impedes penetration of gas molecules of the first species through the one or more penetration openings which forms basis for and supports a highly efficient separation of the gas molecules of the respective first species from a respective gas mixture.

[0015] As will be apparent from further below, the at least one functionalization agent can generally also be or comprise at least one intercalation agent. As such, the terms “functionalizing” or “functionalization” as used herein can also comprise an intercalation or doping. Intercalation can be or comprise one or more intercalation agents arranged (intercalated) between adjacent membrane layers and / or arranged (intercalated) between adjacent gas membrane layer elements of one or more gas membrane layers of the gas membrane device. Doping can comprise doping the at least one membrane layer and / or one or more membrane layer elements with at least one doping agent.

[0016] The gas membrane device thus, enables due to the provision of at least one functionalized membrane layer which comprises one or more penetration openings and the functionalization with at least one functionalization agent configured to promote penetration of the gas molecules of the first species through the one or more penetration openings and / or to impede penetration of the gas molecules of the at least one second species through the one or more penetration openings, a highly selective and thus, a highly efficient separation gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species.

[0017] According to an exemplary embodiment, the at least one functionalized membrane layer can comprise an arrangement of a plurality of, particularly flake-like, or flake-shaped, membrane layer elements arranged in a two-dimensional plane. Hence, the at least one functionalized membrane layer can be built from a plurality of, particularly flake-like- or flake-shaped, membrane layer elements which can be chemically and / or physically bonded with each other via one or more bonding areas so as to form the at least one functionalized membrane layer. Respective membrane layer elements can also have a two-dimensional basis shape such that respective membrane layer elements can be arranged in a two-dimensional plane so as to form the at least one functionalized membrane layer. In other words, the arrangement of the membrane layer elements in a common plane typically results in the two-dimensional extension of the at least one functionalized membrane layer. The size, shape, and / or arrangement of the membrane layer elements relative to each other has an effect on the properties of the at least one functionalized membrane layer. Generally, the at least one functionalized membrane layer can comprise membrane layer elements of the same size and / or shape and membrane layer elements of different size and / or shape.

[0018] Respective membrane layer elements can be provided with respective functionalization agents, particularly respective intralayer spacing agents and / or respective interlayer spacing agents as will be set forth further below. Notably, respective functionalization agents can thus, be provided as respective intralayer spacing agents and / or respective interlayer spacing agents.

[0019] Respective intralayer spacing agents can particularly, be provided at one or more lateral edges of respective membrane layer elements and extend (substantially) parallel to the main plane of the respective membrane layer elements and the at least one functionalized membrane layer, respectively. As such, the molecule axes of respective interlayer spacing agents can be oriented (substantially) parallel to the main plane of the respective membrane layer elements and the at least one functionalized membrane layer, respectively. This also means that adjacently arranged membrane layer elements can be arranged (substantially) in parallel and can be spaced from each other because their respective lateral edges are provided with respective intralayer spacing agents which can repel each other and thus, repel the respective membrane layer elements from each other. Notably, respective intralayer spacing agents can provide for a stabilized intralayer spacing, particularly due respective chemical and / or physical repelling forces. The parallel arrangement of respective membrane layer elements can result from the manufacturing process of the respective functionalized membrane layer.

[0020] Respective interlayer spacing agents can particularly, be provided at an upper or lower surface portions of respective membrane layer elements and extend (substantially) angled relative to the main plane of the respective membrane layer elements and the at least one functionalized membrane layer, respectively. As such, the molecule axes of respective interlayer spacing agents can be oriented (substantially) at an angle relative to the main plane of the respective membrane layer elements and the at least one functionalized membrane layer, respectively. This also means that adjacently arranged functionalized membrane layers, e.g. in a stacked arrangement, can be spaced from each other because their respective upper and / or lower surfaces are provided with respective interlayer spacing agents which can repel each other and thus, repel the respective functionalized membrane layers from each other. Notably, respective interlayer spacing agents can provide for a stabilized interlayer spacing, particularly due respective chemical and / or physical repelling forces.

[0021] According to a further exemplary embodiment, two or more of the membrane layer elements are arranged with an intralayer spacing, wherein the intralayer spacing forms a respective penetration opening. Hence, the arrangement of two or more respective membrane layer elements can results in an intermediate space between the two or more respective membrane layer elements, which intermediate space forms an intralayer spacing which forms a respective penetration opening. In other words, respective penetration openings of the at least one functionalized membrane layer can be formed by spacing adjacent membrane layer elements of a functionalized membrane layer and thus, by creating intermediate spaces between adjacently arranged membrane layer elements.

[0022] According to a further exemplary embodiment, at least one membrane layer element can comprise at least one intralayer spacing agent configured to repel at least one membrane layer elements from at least one adjacently arranged further membrane layer element, thereby creating a respective intralayer spacing between the membrane layer element and the at least one adjacently arranged further membrane layer element. Hence, respective intralayer spacings can be formed by respective intralayer spacing agents which can comprise functional groups enabling a chemical and / or physical repelling effect between adjacently disposed membrane layer elements such that the membrane layer elements are spaced from each other and do not directly contact each other, thereby forming and / or stabilizing respective intralayer spacings and penetration openings, respectively. As an example, respective intralayer spacing agents can comprise electric charges such that two adjacently arranged membrane layer elements each being provided with intralayer spacing agents having the same electric charge will repel each other, thereby creating an intralayer spacing due to electric or electrostatic repelling effects. As another example, respective intralayer spacing agents can be polar or hydrophilic, e.g. can comprise polarity, or can be apolar (non-polar) or hydrophobic, e.g. can comprise no polarity, such that two adjacently arranged membrane layer elements each being provided with intralayer spacing agents being polar or apolar, respectively will repel each other, thereby creating an intralayer spacing due to electric or electrostatic repelling effects. Generally, respective intralayer spacing agents can also make use of steric effects for creating and / or stabilizing a respective intralayer spacing and penetration opening, respectively.

[0023] According to an exemplary embodiment, the at least one intralayer spacing agent can thus, carry at least one electric charge configured to create an electric or electrostatic repelling force between adjacent membrane layer elements having the same intralayer spacing agents and thus, the same electric charge. Additionally or alternatively, the at least one intralayer spacing agent can thus, be a polar functional group, e.g. a hydrophilic functional group, configured to create a repelling force between adjacent membrane layer elements comprising the same intralayer spacing agents and thus, the same polarity functional groups. Additionally or alternatively, the at least one intralayer spacing agent can thus, be an apolar functional group, e.g. a hydrophobic functional group, configured to create a repelling force between adjacent membrane layer elements comprising the same intralayer spacing agents and thus, the same apolar functional groups. As mentioned before, respective intralayer spacing agents can also make use of steric effects for creating a respective intralayer spacing.

[0024] According to a further exemplary embodiment, the at least one intralayer spacing agent can be or comprise at least one of the following functional groups: a carbonyl-group, a hydroxyl-group, a carboxyl-group, a di- carboxyl-group, an epoxide-group, an amine-group, a diamine-group, an acrylate-group, a sulfonic-group, particularly a sulfonic-acid-group, a phosphonic-group, particularly a phosphonic-acid-group, a silanegroup, an amino-silane-group, a polymeric group, an ionic charge, for instance. Any one of the aforementioned groups can be provided with one or more functional groups; as a non-limiting example, also multi-amine-groups other than diamine groups are conceivable, for instance.

[0025] According to a further exemplary embodiment, at least a respective carbonyl-group (-C=O) or a respective hydroxyl-group (-OH) can be created via an oxidation process of one or more membrane layer elements or the at least one functionalized membrane layer, respectively. As such, respective intralayer spacing agents can generally be created by one or more oxidation reactions which result in that the membrane layer elements or the at least one functionalized membrane layer is provided with at least one carbonyl-group or at least one hydroxyl-group. In same manner, also carboxyl-groups can be created which can also act as respective intralayer spacing agents. As will be further apparent from below, the at least one functionalized membrane layer can be a carbon-based layer, particularly a graphene-based layer, more particularly a graphene-oxide-based layer; as such respective oxidation reactions can comprise oxidation reactions required for transferring graphite into graphene oxide, for instance.

[0026] According to a further exemplary embodiment, at least an epoxide-group (-O-CH2-CH2-) can be created via an epoxidation process of one or more membrane layer elements or the at least one functionalized membrane layer, respectively. As such, respective intralayer spacing agents can generally be created by one or more epoxidation reactions which result in that the membrane layer elements or the at least one functionalized membrane layer is provided with at least one epoxide-group. As will be further apparent from below, the at least one functionalized membrane layer can be a carbon-based layer, particularly a graphene-based layer, more particularly a graphene-oxide-based layer. As such, respective epoxidation reactions can comprise epoxidation reactions required for introducing epoxide-g roups into graphene oxide, for instance. Respective epoxidation reactions can comprise using epichlorohydrin or glycidyl methacrylate to introduce epoxide-groups into graphene oxide, for instance.

[0027] According to a further exemplary embodiment, at least one amine group can be created via an aminization process of one or more membrane layer elements or the at least one functionalized membrane layer, respectively. As such, respective intralayer spacing agents can generally be created by one or more aminization reactions which result in that the membrane layer elements or the at least one functionalized membrane layer is provided with at least one amine-group. As will be further apparent from below, the at least one functionalized membrane layer can be a carbon-based layer, particularly a graphene-based layer, more particularly a graphene-oxide-based layer. As such, respective aminization reactions can comprise aminization reactions required for introducing amine-groups into graphene oxide, for instance. Respective aminization reactions can generally allow for that amine group-containing molecules, such as e.g. amines or amino acids, react with graphene oxide. Respective aminization reactions can comprise using aminobenzoic acid or ethylenediamine to introduce amine-groups into graphene oxide, for instance. Both aminobenzoic acid or ethylenediamine can react with carbonyl groups and hydroxyl groups of graphene oxide, leading to the functionalization with amino groups.

[0028] According to another exemplary embodiment, at least one ionic charge can be created via an ion exchange process of one or more membrane layer elements or the at least one functionalized membrane layer, respectively. As such, respective intralayer spacing agents can generally be created by one or more ionic exchange reactions which result in that the membrane layer elements or the at least one functionalized membrane layer is provided with at least one ionic charge. As will be further apparent from below, the at least one functionalized membrane layer can be a carbon-based layer, particularly a graphene-based layer, more particularly a graphene-oxide-based layer; as such respective ion exchange processes can comprise ion exchange processes required for introducing ions or ionic charges into graphene oxide, for instance. Respective ion exchange reactions can generally allow for that ionic charges can be introduced into the structure of graphene oxide. Respective ion exchange reactions can comprise a treatment of graphene oxide with ionic solutions. Respective ion exchange reactions can comprise using potassium permanganate (KMnC ) or ammonium hydroxide (NH4OH), for instance. Both potassium permanganate and ammonium hydroxide can incorporate ions into the structure of graphene oxide.

[0029] According to another exemplary embodiment, respective intralayer spacing agents can be or comprise at least one functional polymer, e.g. a polymer comprising functional groups carrying an electric charge, which can be chemically and / or physically bonded to the one or more membrane layer elements or the at least one functionalized membrane layer, respectively thereby, introducing charge-bearing functional groups. This can specifically, apply for embodiments in which the at least one functionalized membrane layer is a carbon-based layer, particularly a graphene-based layer, more particularly a graphene-oxide-based layer, since respective functional polymers can react with a carbon-based layer, particularly a graphene-based layer, more particularly a graphene-oxide-based layer, and thus, bond thereto to introduce charge-bearing functional groups.

[0030] According to a further exemplary embodiment, the at least one intralayer spacing agent can comprise one or more groups resulting from an at least partial reduction of graphene oxide. This particularly, applies to embodiments in which the membrane layer is made of or consists of graphene oxide or comprises membrane layer elements made of or consisting of graphene oxide. A respective partial reduction of the graphene oxide can be based on a chemical treatment, particularly with an acid, such as e.g. ascorbic acid, nitric acid, sulfuric acid, etc.

[0031] According to a further exemplary embodiment, the at least one intralayer spacing agent can comprise doped graphene oxide, particularly N-doped graphene oxide, more particularly Nitrogen-doped graphene oxide. As such, an intralayer spacing agent can also be created by doping at least one membrane layer and / or at least one membrane layer element with at least one doping agent. A respective doping of graphene oxide (or generally at least one membrane layer or membrane layer element, respectively) can have an effect on the morphology of the graphene oxide which can promote creating and / or maintaining an intralayer spacing and thus, improve the overall separation properties of the gas membrane device.

[0032] According to a further exemplary embodiment, the at least one intralayer spacing agent can comprise one or more intercalation agents configured to intercalate between adjacent membrane layer elements or intercalated between adjacent membrane layer elements. Also, respective intercalation agents can be configured to promote penetration of the gas molecules of the first species through the one or more penetration openings and / or can be configured to impede penetration of the gas molecules of the at least one second species through the one or more penetration openings and thus, improve the overall separation properties of the gas membrane device.

[0033] Exemplary intercalation agents can comprise at least one of: nanoparticles or nanosheets, particularly Ti- based nanoparticles or Ti-based nanosheets.

[0034] Concrete non-limiting examples of one or more intralayer spacing agents can be or comprise at least one of: ethylene diamine, piperazine, imidazole, p-Phenylenediamine (PPD), trimesoyl chloride (TMC), aminosilane, urea, thiourea, ammonia, hydrazine, ethylene glycol, propylene glycol, oxalic acid, malonic acid, polyethyleneimine, polyvinyl alcohol, polyethylene glycol, 3-aminopropyltriethoxysilane (APTES), tetraethyl orthosilicate (TEOS), polyethylene glycol diamine, polydopamine, and metal salts, such as e.g. Mg2+- and Zn2+-salts, metal (nano)particles, metal oxide (nano)particles, such as e.g. ZnO-particles, TiO2- (nano)particles, and quantum dots, or respective derivatives of at least one of the aforementioned.

[0035] According to a further exemplary embodiment, the gas membrane device can comprise multiple functionalized membrane layers each comprising an arrangement of a plurality of, particularly flake-like or platelet-like shaped, membrane layer elements arranged in a two-dimensional plane. Hence, the gas membrane device can comprise multiple stacked functionalized membrane layers. The overall gas separation properties of the gas membrane device can be defined or at least be influenced by the number of functionalized membrane layers. Particularly, providing multiple functionalized membrane layers can improve the gas separation properties of the gas membrane device. Likewise, providing multiple stacked functionalized membrane layers can improve the stability of the gas membrane device.

[0036] As will be apparent from further below, an interlayer spacing can be provided between adjacently arranged functionalized membrane layers. A respective interlayer spacing can range between 0,1 nm - 1 pm, particularly between 0,1 nm - 0,9 pm, more particularly between 0,1 nm - 0,8 pm, more particularly between 0,1 nm - 0,7 pm, more particularly between 0,1 nm - 0,6 pm, more particularly between 0,1 nm - 0,5 pm, more particularly between 0,1 nm - 0,4 pm, more particularly between 0,1 nm - 0,3 pm, more particularly between 0,1 nm - 0,2 pm, more particularly between 0,1 nm - 0,1 pm, more particularly between 0,1 nm - 75 nm, more particularly between 0,1 nm - 50 nm, more particularly between 0,1 nm - 25 nm, more particularly between 0,1 nm - 20 nm, more particularly between 0,1 nm - 15 nm, more particularly between 0,1 nm - 10 nm, more particularly between 0,1 nm - 9 nm, more particularly between 0,1 nm - 8 nm, more particularly between 0,1 nm - 7 nm, more particularly between 0,1 nm - 6 nm, more particularly between 0,1 nm - 5 nm, more particularly between 0,1 nm - 4 nm, more particularly between 0,1 nm - 3 nm, more particularly between 0,1 nm - 2 nm, more particularly between 0,1 nm - 1 nm, more particularly between 0,1 nm - 0,9 nm, more particularly between 0,1 nm - 0,8 nm, more particularly between 0,1 nm - 0,7 nm, more particularly between 0,1 nm - 0,6 nm, more particularly between 0,1 nm - 0,5 nm, more particularly between 0,1 nm - 0,4 nm, more particularly between 0,1 nm - 0,3 nm, more particularly between 0,1 nm - 0,2 nm. Further, a respective interlayer spacing can range between 1 - 20 nm, particularly between of 1 - 19 nm, more particularly between of 1 - 18 nm, more particularly between of 1 - 17 nm, more particularly between of 1 - 16 nm, more particularly between of 1 - 15 nm, more particularly between of 1 - 14 nm, more particularly between of 1 - 13 nm, more particularly between of 1 - 12 nm, more particularly between of 1 - 11 nm, more particularly between of 1 - 10 nm, more particularly between of 1 - 9 nm, more particularly between of 1 - 8 nm, more particularly between of 1 - 7 nm, more particularly between of 1 - 6 nm, more particularly between of 1 - 5 nm, more particularly between of 1 - 4 nm, more particularly between of 1 - 3 nm, more particularly between of 1 - 2 nm, for instance. Hence, a respective interlayer spacing can be deemed a nano-spacing which typically, enables or at least supports an effective gas separation.

[0037] Two, more than two, or all functionalized membrane layers can have the same interlayer spacing. Alternatively, two, more than two, or all functionalized membrane layers can have a different interlayer spacing. Hence, there is generally high flexibility with respect to the interlayer spacing of respective functionalized membrane layers which is another parameter for influencing the gas separation properties of the gas membrane device.

[0038] Respective functionalized membrane layers can be arranged relative to each other such that their respective penetration openings are aligned and thus, not offset, particularly forming a straight gas penetration channel which extends through the gas membrane device. This can be achieved by arranging respective functionalized membrane layers with no lateral offset, for instance. Alternatively, respective functionalized membrane layers can be arranged relative to each other such that their respective penetration openings are not aligned and thus, offset, particularly not forming a straight gas penetration channel which extends through the gas membrane device. Generally, the arrangement of respective penetration openings of respective functionalized membrane layers relative to each other is another parameter which enables to influence the gas separation properties of the gas membrane device.

[0039] According to a further exemplary embodiment, at least one functionalized membrane layer can comprise at least one interlayer spacing agent configured to repel the at least one functionalized membrane layer from at least one adjacently arranged further functionalized membrane layer, thereby creating and / or stabilizing an interlayer spacing between the at least one functionalized membrane layer and the at least one adjacently arranged further functionalized membrane layer. Hence, respective interlayer spacings can be formed by respective interlayer spacing agents which can comprise functional groups enabling a chemical and / or physical repelling effect between adjacently disposed functionalized membrane layers such that the functionalized membrane layers are spaced from each other and do not directly contact each other, thereby forming respective interlayer spacings. As an example, respective intralayer spacing agents can comprise electric charges such that two adjacently arranged functionalized membrane layers each being provided with interlayer spacing agents having the same electric charge will repel each other, thereby creating an interlayer spacing due to electric or electrostatic repelling effects. As another example, respective interlayer spacing agents can be polar or hydrophilic, e.g. can comprise polarity, or can be apolar (non-polar) or hydrophobic, e.g. can comprise no polarity, such that two adjacently arranged functionalized membrane layers each being provided with interlayer spacing agents being polar or apolar, respectively will repel each other, thereby creating an interlayer spacing due to electric or electrostatic repelling effects. Generally, respective interlayer spacing agents can also make use of steric effects for creating and / or stabilizing a respective interlayer spacing.

[0040] According to a further exemplary embodiment, the at least one interlayer spacing agent can thus, carry at least one electric charge configured to create an electric or electrostatic repelling force between adjacent functionalized membrane layers having the same interlayer spacing agents and thus, the same electric charge. Additionally or alternatively, the at least one interlayer spacing agent can thus, be a polar functional group, e.g. a hydrophilic functional group, configured to create a repelling force between adjacent functionalized membrane layers comprising the same interlayer spacing agents and thus, the same polarity functional groups. Additionally or alternatively, the at least one interlayer spacing agent can thus, be an apolar functional group, e.g. a hydrophobic functional group, configured to create a repelling force between adjacent functionalized membrane layers comprising the same interlayer spacing agents and thus, the same apolar functional groups. As indicated before, respective interlayer spacing agents can also make use of steric effects for creating and / or stabilizing a respective interlayer spacing.

[0041] According to a further exemplary embodiment, the at least one interlayer spacing agent can be or comprise at least one of the following functional groups: a carbonyl-group, a hydroxyl-group, a carboxyl-group, a di- carboxyl-group, an epoxide-group, an amine-group, a diamine-group, an acrylate-group, a sulfonic-group, particularly a sulfonic-acid-group, a phosphonic-group, particularly a phosphonic-acid-group, a silanegroup, an amino-silane-group, a polymeric group, an ionic charge, for instance. Any one of the aforementioned groups can be provided with one or more functional groups; as a non-limiting example, also multi-amine-groups other than diamine groups are conceivable, for instance.

[0042] According to a further exemplary embodiment, at least a respective carbonyl-group (-C=O) or a respective hydroxyl-group (-OH) can be created via an oxidation process of one or more functionalized membrane layers. As such, respective interlayer spacing agents can generally be created by one or more oxidation reactions which result in that the functionalized membrane layers are provided with at least one carbonyl- group or at least one hydroxyl-group. In same manner, also carboxyl-groups can be created which can also act as respective interlayer spacing agent. As will be further apparent from below, respective functionalized membrane layers can be carbon-based layers, particularly graphene-based layers, more particularly graphene-oxide-based layers; as such respective oxidation reactions can comprise oxidation reactions required for transferring graphite into graphene oxide, for instance.

[0043] According to a further exemplary embodiment, at least an epoxide-group (-O-CH2-CH2-) can be created via an epoxidation process of one or more functionalized membrane layers. As such, respective interlayer spacing agents can generally be created by one or more epoxidation reactions which result in that the functionalized membrane layers are provided with at least one epoxide-group. As will be further apparent from below, the respective functionalized membrane layers can be carbon-based layers, particularly a graphene-based layers, more particularly graphene-oxide-based layers. As such, respective epoxidation reactions can comprise epoxidation reactions required for introducing epoxide-g roups into graphene oxide layers, for instance. Respective epoxidation reactions can comprise using epichlorohydrin or glycidyl methacrylate to introduce epoxide-groups into graphene oxide, for instance.

[0044] According to a further exemplary embodiment, at least one amine group can be created via an aminization process of one or more functionalized membrane layers. As such, respective interlayer spacing agents can generally be created by one or more aminization reactions which result in that the functionalized membrane layers are provided with at least one amine-group. As will be further apparent from below, the functionalized membrane layers can be carbon-based layers, particularly a graphene-based layers, more particularly graphene-oxide-based layers. As such, respective aminization reactions can comprise aminization reactions required for introducing amine-groups into graphene oxide layers, for instance. Respective aminization reactions can generally allow for that amine group-containing molecules, such as e.g. amines or amino acids, react with graphene oxide. Respective aminization reactions can comprise using aminobenzoic acid or ethylenediamine to introduce amine-groups into graphene oxide, for instance. Both aminobenzoic acid or ethylenediamine can react with carbonyl groups and hydroxyl groups of graphene oxide layers, leading to the functionalization with amino groups.

[0045] According to a further exemplary embodiment, at least one ionic charge can be created via an ion exchange process of one or more functionalized membrane layers. As such, respective interlayer spacing agents can generally be created by one or more ionic exchange reactions which result in that the functionalized membrane layers are provided with at least one ionic charge. As will be further apparent from below, the functionalized membrane layers can be carbon-based layers, particularly graphene-based layers, more particularly graphene-oxide-based layers. As such, respective ion exchange processes can comprise ion exchange processes required for introducing ions or ionic charges into graphene oxide, for instance. Respective ion exchange reactions can generally allow for that ionic charges can be introduced into the structure of graphene oxide layers. Respective ion exchange reactions can comprise a treatment of graphene oxide layers with ionic solutions. Respective ion exchange reactions can comprise using potassium permanganate (KMnC ) or ammonium hydroxide (NH4OH), for instance. Both potassium permanganate and ammonium hydroxide can incorporate ions into the structure of graphene oxide layers. According to a further exemplary embodiment, respective interlayer spacing agents can be or comprise at least one functional polymer, e.g. a polymer comprising functional groups carrying an electric charge, which can be chemically and / or physically bonded to one or more functionalized membrane layers thereby, introducing charge-bearing functional groups between adjacent functionalized membrane layers. This can specifically, apply for embodiments in which the functionalized membrane layers are carbon-based layers, particularly graphene-based layers, more particularly graphene-oxide-based layers, since respective functional polymers can react with carbon-based layers, particularly graphene-based layers, more particularly graphene-oxide-based layers, and thus, bond thereto to introduce charge-bearing functional groups.

[0046] According to a further exemplary embodiment, the at least one interlayer spacing agent can comprise one or more groups resulting from an at least partial reduction of graphene oxide. This particularly, applies to embodiments in which the membrane layer is made of or consists of graphene oxide or comprises membrane layer elements made of or consisting of graphene oxide. A respective partial reduction of the graphene oxide can be based on a chemical treatment, particularly with an acid, such as e.g. ascorbic acid, nitric acid, sulfuric acid, etc.

[0047] According to a further exemplary embodiment, the at least one interlayer spacing agent can comprise doped graphene oxide, particularly N-doped graphene oxide, more particularly Nitrogen-doped graphene oxide. As such, an intralayer spacing agent can also be created by doping at least one membrane layer and / or at least one membrane layer element with at least one doping agent. A respective doping of graphene oxide (or generally at least one membrane layer or membrane layer element, respectively) can have an effect on the morphology of the graphene oxide which can promote creating and / or maintaining an interlayer spacing and thus, improve the overall separation properties of the gas membrane device.

[0048] According to a further exemplary embodiment, the at least one interlayer spacing agent can comprise one or more intercalation agents configured to intercalate between adjacent membrane layer elements or intercalated between adjacent membrane layer elements. Also, respective intercalation agents can be configured to promote penetration of the gas molecules of the first species through the one or more penetration openings and / or can be configured to impede penetration of the gas molecules of the at least one second species through the one or more penetration openings and thus, improve the overall separation properties of the gas membrane device.

[0049] Exemplary intercalation agents can comprise at least one of the following: nanoparticles or nanosheets, particularly Ti-based nanoparticles or Ti-based nanosheets.

[0050] Concrete non-limiting examples of one or more interlayer spacing agents can be or comprise at least one of: ethylene diamine, piperazine, imidazole, p-Phenylenediamine (PPD), trimesoyl chloride (TMC), aminosilane, urea, thiourea, ammonia, hydrazine, ethylene glycol, propylene glycol, oxalic acid, malonic acid, polyethyleneimine, polyvinyl alcohol, polyethylene glycol, 3-aminopropyltriethoxysilane (APTES), tetraethyl orthosilicate (TEOS), polyethylene glycol diamine, polydopamine, and metal salts, such as e.g. Mg2+- and Zn2+-salts, metal (nano)particles, metal oxide (nano)particles, such as e.g. ZnO-particles, TiO2- (nano)particles, and quantum dots, or respective derivatives of at least one of the aforementioned.

[0051] As indicated above, the at least one functionalized membrane layer (which also applies to embodiments in which the gas membrane device comprises multiple functionalized membrane layers, particularly in a stacked arrangement) can be or comprise a carbon-based layer (which also applies to embodiments in which the gas membrane device comprises multiple functionalized membrane layers, particularly in a stacked arrangement). A respective carbon-based layer can comprise a plurality of carbon-atoms in a lattice-arrangement. Hence, the carbon-based layer can comprise carbon-atoms forming edge-points and / or node-points of the lattice-arrangement.

[0052] Particularly, the at least one functionalized membrane layer (which also applies to embodiments in which the gas membrane device comprises multiple functionalized membrane layers, particularly in a stacked arrangement) can be or comprise a graphene-based layer. Graphene-based layers can comprise layers of graphene or layers of e-graphene, for instance. Graphene-based layers are of specific advantage for the purpose of gas separation, e.g. because they can be functionalized with diverse functionalizing agents, and because they exhibit high stability.

[0053] More particularly, the at least one functionalized membrane layer (which also applies to embodiments in which the gas membrane device comprises multiple functionalized membrane layers, particularly in a stacked arrangement) can be or comprise a graphene-oxide-based layer. Graphene-oxide-based layers can comprise layers of e-graphene-oxide, for instance. Hence, respective functionalized membrane layer elements can be or comprise graphene-oxide flakes. Also graphene-oxide-based layers are of specific advantage for the purpose of gas separation, e.g. because they can be functionalized with diverse functionalizing agents, and because they exhibit high stability.

[0054] According to a further exemplary embodiment, the at least one functionalized membrane layer (which also applies to embodiments in which the gas membrane device comprises multiple functionalized membrane layers, particularly in a stacked arrangement) can have a layer thickness of 1 - 20 nm, particularly a thickness of 1 - 19 nm, more particularly a thickness of 1 - 18 nm, more particularly a thickness of 1 - 17 nm, more particularly a thickness of 1 - 16 nm, more particularly a thickness of 1 - 15 nm, more particularly a thickness of 1 - 14 nm, more particularly a thickness of 1 - 13 nm, more particularly a thickness of 1 - 12 nm, more particularly a thickness of 1 - 11 nm, more particularly a thickness of 1 - 10 nm, more particularly a thickness of 1 - 9 nm, more particularly a thickness of 1 - 8 nm, more particularly a thickness of 1 - 7 nm, more particularly a thickness of 1 - 6 nm, more particularly a thickness of 1 - 5 nm, more particularly a thickness of 1 - 4 nm, more particularly a thickness of 1 - 3 nm, more particularly a thickness of 1 - 2 nm. Also, respective upper limits can be higher than 20 nm. Particularly, respective upper limits can comprise 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, 950 nm or more. It is even conceivable that the upper limit is at least 50 pm, particularly at least 100 pm, more particularly at least 150 pm, more particularly at least 200 pm, more particularly at least 250 pm, more particularly at least 300 pm, more particularly at least 350 pm, more particularly at least 400 pm, more particularly at least 450 pm, more particularly at least 500 pm, more particularly at least 550 pm, more particularly at least 600 pm, more particularly at least 650 pm, more particularly at least 700 pm, more particularly at least 750 pm, more particularly at least 800 pm, more particularly at least 850 pm, more particularly at least 900 pm, more particularly at least 950 pm. Hence, a respective functionalized membrane layer can be deemed a nanolayer. Respective nanolayers generally exhibit good gas separation properties and typically, enable or at least support an effective gas separation. The thickness of respective functionalized membrane layers is another parameter to influence the gas separation properties of the gas membrane device. Hence, by selecting specific thicknesses, the gas separation properties of the gas membrane device can be adjusted.

[0055] In exemplary embodiments with multiple functionalized membrane layers, two, more than two, or all functionalized membrane layers can have the same thickness. Alternatively, two, more than two, or all functionalized membrane layers can have a different thickness. Hence, there is generally high flexibility with respect to the thickness of respective functionalized membrane layers and thus, the thickness of the gas membrane device.

[0056] According to a further exemplary embodiment, the at least one functionalized membrane layer can have an area of at least 4 cm2, particularly at least 5 cm2, more particularly at least 6 cm2, more particularly at least 7 cm2, more particularly at least 8 cm2, more particularly at least 9 cm2, more particularly at least 10 cm2, more particularly at least 11 cm2, more particularly at least 12 cm2, more particularly at least 13 cm2, more particularly at least 14 cm2, more particularly at least 15 cm2, more particularly at least 16 cm2, more particularly at least 17 cm2, more particularly at least 18 cm2, more particularly at least 19 cm2, more particularly at least 20 cm2. However, the area of the at least one functionalized membrane layer can even be larger. As such, it is conceivable that the at least one functionalized membrane layer has an area of at least 25 cm2, particularly at least 30 cm2, more particularly at least 35 cm2, more particularly at least 40 cm2, more particularly at least 45 cm2, more particularly at least 50 cm2, more particularly at least 55 cm2, more particularly at least 60 cm2, more particularly at least 65 cm2, more particularly at least 70 cm2, more particularly at least 75 cm2, more particularly at least 80 cm2, more particularly at least 85 cm2, more particularly at least 90 cm2, more particularly at least 95 cm2, more particularly at least 100 cm2, more particularly at least 105 cm2, more particularly at least 110 cm2, more particularly at least 115 cm2, more particularly at least 120 cm2, more particularly at least 125 cm2, more particularly at least 130 cm2, more particularly at least 135 cm2, more particularly at least 140 cm2, more particularly at least 145 cm22, more particularly at least 150 cm2, more particularly at least 155 cm2, more particularly at least 160 cm2, more particularly at least 165 cm2, more particularly at least 170 cm2, more particularly at least 185 cm2, more particularly at least 190 cm2, more particularly at least 195 cm2, more particularly at least 200 cm2. The aforementioned values can also represent upper and lower threshold values of intervals. The areas of respective functionalized membrane layers is another parameter to influence the gas separation properties of the gas membrane device. Hence, by selecting specific areas, the gas separation properties of the gas membrane device can be adjusted.

[0057] In exemplary embodiments with multiple functionalized membrane layers, two, more than two, or all functionalized membrane layers can have the same area. Alternatively, two, more than two, or all functionalized membrane layers can have a different area. Hence, there is generally high flexibility with respect to the area of respective functionalized membrane layers and thus, the area of the gas membrane device.

[0058] According to a further exemplary embodiment, the at least one penetration opening of the at least one functionalized membrane layer can have, in at least one spatial direction, a size of 0,1 nm, 0,2 nm, 0,3 nm, 0,4 nm, 0,5 nm, 0,6 nm, 0,7 nm, 0,8 nm, 0,9 nm, or 1 nm, for instance. The aforementioned values can also represent upper and lower threshold values of intervals. As indicated further above, the size of the at least one penetration opening is typically, selected such that (only) the gas molecules of the first species of a respective gas mixture from which a respective first species is to be separated. As such, the size of the at least one penetration opening can be selected with regard to the size of the gas molecules which should be able to penetrate therethrough.

[0059] In exemplary embodiments with at least one functionalized membrane layer having multiple penetration openings, two, more than two, or all penetration openings of the at least one functionalized membrane layer can have the same size. Alternatively, two, more than two, or all penetration openings of at least one functionalized membrane layer can have a different size. In exemplary embodiments with multiple functionalized membrane layers, two, more than two, or all functionalized membrane layers can have penetration openings of the same size. Alternatively, two, more than two, or all functionalized membrane layers can have penetration openings of different sizes. Hence, there is generally high flexibility with respect to the size of respective penetration openings and thus, the permissibility of the gas membrane device with regard to gas molecules of a specific species.

[0060] The same applies to the shape of respective penetration openings. As indicated further above, the shape of respective penetration openings can be generally adapted to the shape of the gas molecules of the first species, i.e. the shape of the gas molecules which are meant to penetrate through the respective penetration openings.

[0061] According to a further exemplary embodiment, the at least one functionalized membrane layer can be at least partly, particularly completely, embedded in an embedding material or in an embedding material structure, thereby forming an embedded functionalized membrane layer. Particularly, the embedding material or the embedding material structure is at least arranged laterally so as to stabilize the gas membrane device and so as not to compromise the permeation properties of the membrane. It is conceivable that a plurality of stacked functionalized membrane layers are at least partly, particularly completely, embedded in an embedding material or in an embedding material structure, thereby forming an embedded functionalized membrane layer. Embedding at least one functionalized membrane layer in a respective embedding material or a respective embedding material structure can stabilize and / or protect the at least one functionalized membrane layer, e.g. with respect to electrical, mechanical and / or thermal influences. Also, embedding the at least one functionalized membrane layer in a respective embedding material or a respective embedding material structure can enable further processing steps which can be required for manufacturing the gas membrane device. Respective further processing steps can comprise separating, e.g. via cutting, particularly via microtomy cutting, respective embedded functionalized membrane layers from a bulk embedded structure which comprises multiple functionalized membrane layers embedded therein, for instance. Respective embedded functionalized membrane layers can be separated from a respective bulk embedded structure by cutting slices off the bulk embedded structure, wherein each slice comprises at least one embedded functionalized membrane layer.

[0062] Respective slices can have a thickness of 1 - 1000 pm, particularly a thickness of 1 - 900 pm, more particularly a thickness of 1 - 800 pm, more particularly a thickness of 1 - 700 pm, more particularly a thickness of 1 - 600 pm, more particularly a thickness of 1 - 500 pm, more particularly a thickness of 1 - 500 pm, more particularly a thickness of 1 - 400 pm, a thickness of 1 - 300 pm, more particularly a thickness of 1 - 200 pm, more particularly a thickness of 1 - 100 pm, more particularly a thickness of 1 - 50 pm, more particularly a thickness of 1 - 25 pm, more particularly a thickness of 1 - 20 pm, particularly a thickness of 1 - 19 pm, more particularly a thickness of 1 - 18 pm, more particularly a thickness of 1 - 17 nm, more particularly a thickness of 1 - 16 pm, more particularly a thickness of 1 - 15 pm, more particularly a thickness of 1 - 14 pm, more particularly a thickness of 1 - 13 pm, more particularly a thickness of 1 - 12 pm, more particularly a thickness of 1 - 11 pm, more particularly a thickness of 1 - 10 pm, more particularly a thickness of 1 - 9 pm, more particularly a thickness of 1 - 8 pm, more particularly a thickness of 1 - 7 pm, more particularly a thickness of 1 - 6 pm, more particularly a thickness of 1 - 5 pm, more particularly a thickness of 1 - 4 pm, more particularly a thickness of 1 - 3 pm, more particularly a thickness of 1 - 2 pm, for instance. Generally, the thickness of the slices typically, depends on the overall configuration of a respective embedded functionalized membrane layer, i.e. particularly the number of functionalized membrane layers and / or non-functionalized membrane layers (as will be apparent from further below).

[0063] A respective embedding material or a respective embedding material structure typically, has a specific porosity which enables that gas molecules of a respective first species which are to be separated from a respective gas mixture can penetrate not only through the penetration openings of the at least one functionalized membrane layer but also through the embedding material or a respective embedding material structure. As such, the openings creating the porous structure of the embedding material or a respective embedding material structure can have the same or a similar shape and / or size as the penetration openings of the at least one functionalized membrane layer. According to a further exemplary embodiment, the embedding material or the embedding material structure can be or comprise a polymer, particularly a curable resin. A respective polymer and a respective curable resin, respectively can be based on a thermoplastic polymer, a duroplastic polymer, an elastomer, or a silicone polymer, for instance. According to a concrete, yet non-limiting exemplary embodiment, a respective polymer can be or comprise curable epoxy resin.

[0064] According to a further exemplary embodiment, the embedding material or the embedding material structure can comprise at least one functionalization configured to promote penetration of the gas molecules of the first species through openings of the embedding material or the embedding material structure and / or configured to impede penetration of the gas molecules of the at least one second species through openings of the embedding material or the embedding material structure. Hence, not only the at least one functionalized membrane layer but also a respective embedding material or embedding material structure can be functionalized with at least one functionalization which enables that penetration of the gas molecules of the first species through openings of the embedding material or the embedding material structure is promoted and / or that penetration of the gas molecules of the at least one second species through openings of embedding material or the embedding material structure is impeded. As such, the above annotations regarding the functionalization of the at least one functionalized membrane layer apply in analogous manner. Specifically, a respective embedding material or embedding material structure can be functionalized with functionalization agents which correspond to respective intralayer spacing agents and / or to respective interlayer spacing agents as specified further above.

[0065] According to a further exemplary embodiment, the gas membrane device can further comprise at least one support material providing mechanical support for the at least one functionalized membrane layer. A respective support material can particularly, prevent deformation or damage to respective embedded functionalized membrane layers and can thus, improve handling, mounting, etc. of the gas membrane device. As such, a respective support material can also be provided with one or more interfaces, such as e.g. threaded portions, configured to co-act with a handling tool, a mounting tool, etc.

[0066] According to a further exemplary embodiment, the at least one support material can be or comprise one or more porous substrates or membranes with high mechanical strength. As an example, a respective support material can be or comprise a perforated plate, e.g. made from a ceramic, metal, or polymer material, for instance.

[0067] According to a further exemplary embodiment, the gas membrane device can comprise multiple embedded functionalized membrane layers, particularly in a stacked arrangement. As such, the gas membrane device can comprise a stack of embedded functionalized membrane layers. The overall gas separation properties of the gas membrane device can be defined or at least be influenced by the number of embedded functionalized membrane layers. The above annotations regarding exemplary embodiments of the gas membrane device with multiple functionalized membrane layers, particularly in a stacked arrangement, apply in analogous manner. According to a further exemplary embodiment, the at least one functionalized membrane layer or a respective embedded functionalized membrane layer can be arranged within a sealing structure, particularly configured to seal the free edges of the at least one functionalized membrane layer or the free edges of the at least one embedded functionalized membrane layer, respectively. Sealing the at least one functionalized membrane layer and / or a respective embedded functionalized membrane layer can improve the properties of the gas membrane device because the sealing avoids undesired leakage and / or encapsulates the at least one functionalized membrane layer and / or a respective embedded functionalized membrane layer such that it is protected against e.g. electrical, mechanical, thermal, climate influences which might possibly compromise the gas separation properties of the gas membrane device. Particularly, sealing the at least one functionalized membrane layer and / or a respective embedded functionalized membrane layer can reduce the risk of undesired interactions of the at least one functionalized membrane layer with other gas mixtures, e.g. gas mixtures, such as e.g. air, present in an operating environment of the gas membrane device, which might possibly compromise the separation properties of the gas membrane device.

[0068] Exemplary and thus, not limiting sealing materials can be or comprise a thermoplastic polymer, a duroplastic polymer, an elastomer, or a silicone polymer, for instance. According to a concrete, yet nonlimiting exemplary embodiment, a respective polymer can be or comprise curable epoxy resin.

[0069] According to a further exemplary embodiment, the gas membrane device can further comprise at least one non-functionalized membrane layer, particularly in a parallel arrangement relative to the at least one functionalized membrane layer. A respective non-functionalized membrane layer can particularly, act or serve as a spacer layer in between two adjacent functionalized membrane layers. Hence, providing at least one respective non-functionalized membrane layer can be particularly, beneficial in a stacked arrangement of functionalized membrane layers, wherein at least one non-functionalized membrane layer is arranged between two adjacent functionalized membrane layers to provide, support or stabilize an interlayer spacing. Hence, the gas membrane device can comprise an alternating arrangement of non-functionalized membrane layers and functionalized membrane layers, for instance. A respective non-functionalized membrane layer can be or comprise an intercalated layer, particularly an intercalated nanolayer or nanosheet.

[0070] As such, embodiments of the gas membrane device are contemplated herein which comprise a stack of multiple functionalized membrane layers and multiple non-functionalized membrane layers, wherein at least one non-functionalized membrane layer is arranged between two adjacent functionalized membrane layers. Also, embodiments of the gas membrane device are contemplated herein which comprise a stack of multiple functionalized membrane layers and multiple non-functionalized membrane layers, wherein at least two non-functionalized membrane layers are arranged between two adjacent functionalized membrane layers. Generally, arbitrary stacked arrangements of non-functionalized membrane layers and functionalized membrane layers are conceivable. Also respective non-functionalized membrane layers can comprise an arrangement of a plurality of, particularly flake-like, or flake-shaped, membrane layer elements arranged in a two-dimensional plane. Hence, the at least one non-functionalized membrane layer can be built from a plurality of, particularly flakelike- or flake-shaped, membrane layer elements which can be chemically and / or physically bonded with each other via one or more bonding areas so as to form the at least one non-functionalized membrane layer. Respective membrane layer elements can also have a two-dimensional basis shape such that respective membrane layer elements can be arranged in a two-dimensional plane so as to form the at least one non-functionalized membrane layer. In other words, the arrangement of the membrane layer elements in a common plane typically results in the two-dimensional extension of the at least one non-functionalized membrane layer. The size, shape, and / or arrangement of the membrane layer elements relative to each other has an effect on the properties of the at least one non-functionalized membrane layer. Generally, the at least one non-functionalized membrane layer can comprise membrane layer elements of the same size and / or shape and membrane layer elements of different size and / or shape. However, in contrast to respective membrane layer elements of the at least one functionalized membrane layer, the membrane layer elements of the at least one non-functionalized membrane layer do typically, not comprise any functionalization.

[0071] Also respective non-functionalized membrane layers be carbon-based layers, particularly graphene-based layers, more particularly graphene-oxide-based layers, for instance. However, respective non- functionalized membrane layers can also comprise different materials or different material structures which exhibit, at least to some extent, e.g. due to chemical and / or physical repelling effects, a repelling behavior relative to the functionalized membrane layers.

[0072] The above remarks, e.g. regarding size, shape, and thickness, made in connection with the at least one functionalized membrane layer also apply to the at least one non-functionalized membrane layer in analogous manner. In other words, a respective non-functionalized membrane layer can be a functionalized membrane layer without functionalization.

[0073] In either embodiment, the at least one functionalizing agent can be crosslinked. Crosslinking can comprise that the at least one functionalizing agent is linked via at least one first linking point to a first membrane layer and / or a first membrane layer element and linked via at least one second linking point to a second membrane layer and / or a second membrane layer element. Respective linking points can be created via chemical and / or physical interactions, particularly bonds, between the respective functionalizing agent, particularly respective functional linking groups of the respective functionalizing agent, and a respective membrane layer and / or membrane layer element, respectively. Crosslinking can generally, increase the related effects of promoting penetration of the gas molecules of the first species through the one or more penetration openings and / or impeding penetration of the gas molecules of the at least one second species through the one or more penetration openings. A second aspect of the invention relates to a gas separation apparatus for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species. The gas separation apparatus will be briefly referred to as apparatus in the following and comprises the following components which can be arranged in a common housing structure of the apparatus:

[0074] A first component of the apparatus is at least one gas membrane device according to the first aspect of the invention. As such, all annotations regarding the gas membrane device according to the first aspect of the invention also apply to the apparatus according to the second aspect of the invention.

[0075] The gas membrane device can be arranged in a receiving space of a housing unit. The housing unit can form part of the housing structure of the apparatus.

[0076] A further component of the apparatus is at least one pre-treatment device for pre-treating a gas mixture from which respective gas molecules of a first species are to be separated. The at least one pre-treatment device is thus, generally configured for pre-treating a gas mixture from which respective gas molecules of a first species are to be separated via the at least one gas membrane device. The at least one pre-treatment device can be arranged in a receiving space of a housing unit. The housing unit can form part of the housing structure of the apparatus.

[0077] The at least one pre-treatment device can be arranged upstream of the at least one gas membrane device. Particularly, the at least one gas membrane device and the at least one pre-treatment device can be in fluid communication such that a flow of a gas mixture from which the gas molecules of the first species can be separated can flow through the at least one pre-treatment device to undergo at least one pre-treatment process and subsequently flow through the at least one gas membrane device to undergo a gas separation process. As such, the apparatus can comprise a flow generation unit, such as a blowing unit and / or sucking unit, configured to generate a flow of a gas mixture from which the gas molecules of the first species can be separated through at least the at least one pre-treatment device and / or at least one gas membrane device. Concrete, yet non-limiting examples of a respective flow generation unit can comprise a pump unit.

[0078] An additional or alternative component of the apparatus is at least one control device configured to control at least one parameter influencing the separation of the gas molecules of the first species from the gas mixture. The control device can be embodied in hardware- and / or software-embodied. Particularly, the control device can be configured to process input parameters, which can particularly relate to operational parameters of the at least one pre-treatment device and / or the at least one gas membrane device which operational parameters can e.g. be derived from one or more sensors assigned to the at least one pretreatment device and / or the at least one gas membrane device, and generate, as an output, control information for controlling at least one parameter influencing the separation of the gas molecules of the first species from the gas mixture. More particularly, the control device can be configured to process respective input parameters with respect to one or more target criteria, e.g. a specific target quantity and / or quality criterion of the gas separation process implemented by the apparatus. As an example, a respective target quantity and / or quality criterion of the gas separation process can relate to a specific output of gas from which the gas molecules of the first species have been separated and / or a specific residual concentration of gas molecules of the first and / or at least one second species which is to be achieved in the gas separation process implemented by the apparatus.

[0079] According to a further exemplary embodiment, the at least one pre-treatment device can be configured to remove impurities, particularly particulate impurities, from the gas mixture. The at least one pre-treatment device can thus, comprise one or more impurity removal units for removing impurities, particularly particulate impurities, from a gas mixture from which gas molecules of the first species are to be separated. Respective impurity removal units can be built as or comprise chemical and / or physical sieves, for instance. The at least one pre-treatment device can comprise one or more sensor units configured to generate information on parameters indicative of the impurity removal process implemented by the at least one pretreatment device. Respective information can be transmitted to the at least one control device and used as respective input parameters for controlling purposes as explained further above.

[0080] According to a further exemplary embodiment, the at least one pre-treatment device can be configured to temper a gas mixture. The at least one pre-treatment device can thus, comprise one or more tempering units, particularly heating units, for tempering a gas mixture. Notably, tempering can comprise drying a gas mixture to remove excess moisture from the gas mixture. The at least one pre-treatment device can comprise one or more sensor units configured to generate information on parameters indicative of the tempering process implemented by the at least one pre-treatment device. Respective information can be transmitted to the at least one control device and used as respective input parameters for controlling purposes as explained further above.

[0081] According to a further exemplary embodiment, the at least one control device can be generally configured to detect and / or monitor at least one operational parameter, particularly an operational performance, of the at least one gas membrane device and / or the at least one pre-treatment device and generate an information indicative of at least one detected and / or monitored operational parameter of the at least one gas membrane device and / or the at least one pre-treatment device. The apparatus can thus, comprise one or more detection units, such as e.g. sensors, particularly flow sensors, temperature sensors, impurity sensors, gas sensors, etc., which can generate detection information which can be used for detecting and / or monitoring at least one operational parameter, particularly an operational performance, of the at least one gas membrane device and / or the at least one pre-treatment device and generate a respective information indicative of at least one detected and / or monitored operational parameter of the at least one gas membrane device and / or the at least one pre-treatment device. The control device can be particularly, configured to use a respective information for implementing a control loop, particularly an open control loop or a closed control loop, for controlling operation of the at least one pre-treatment device and / or the at least one gas membrane device and / or a respective flow generation device. According to a further exemplary embodiment, the at least one control device can be configured to output the information to a user and / or to take at least one discrete action concerning the operation of at least the at least one gas membrane device and / or the at least one pre-treatment device based on the information. Outputting can comprise outputting a respective information, which can e.g. be an acoustically perceivable and / or a visually perceivable information, via an outputting means provided with the apparatus and / or transmitting a respective to a user device, such as a computer, smartphone, etc., such that the information, which can e.g. be an acoustically perceivable and / or a visually perceivable information, can be output via an outputting means of the user device. In either case, a respective information can be or comprise a warning to a user in events that the information indicates that at least a part of the gas separation process implemented by the apparatus does not take place as desired. Taking a discrete action can comprise changing at least one operational parameter of at least the at least one pre-treatment device, the at least one gas membrane device and / or the at least one flow generation device, for instance. Taking a discrete action can be implemented automatically such that the operation of the apparatus can be fully automated.

[0082] According to a further exemplary embodiment, the apparatus can further comprise at least one compressor device configured to compress the or a respective gas mixture before it flows through the at least one gas membrane device. As such, the at least one compressor device is typically arranged upstream of the at least one gas membrane device such that a compressed flow of gas mixture can be directed from the at least one compressor device to the at least one gas membrane device. Particularly, the at least one compressor device can be arranged between the at least one pre-treatment device and the at least one gas membrane device such that such that a pre-treated and compressed flow of gas mixture can be directed from the at least one pre-treatment device, if present, via the at least one compressor device, if present, to the at least one gas membrane device.

[0083] According to a further exemplary embodiment, the apparatus can further comprise at least one de-watering device configured to de-water the or a respective gas mixture before it flows through the at least one gas membrane device. As such, the at least one de-watering device is typically arranged upstream of the at least one gas membrane device such that a de-watered flow of gas mixture can be directed from the at least one de-watering device to the at least one gas membrane device. Particularly, the at least one dewatering device can be arranged between the at least one compressor device, if present, and the at least one gas membrane device such that such that a pre-treated, compressed and de-wagered flow of gas mixture can be directed from the at least one pre-treatment device, if present, via the at least one compressor device, if present, and via the at least one de-watering device, if present, to the at least one gas membrane device.

[0084] According to a further exemplary embodiment, the apparatus can comprise at least one storage device configured to capture gas molecules of the first species which have been separated from a respective gas mixture via the at least one gas membrane device. The at least one storage device can be or comprise a tank which defines an inner volume for receiving gas molecules of the first species which have been separated from a respective gas mixture via the at least one gas membrane device. As such, the at least one storage device is typically arranged downstream of the at least one gas membrane device such that a flow of gas molecules of the first species which has been separated from a respective gas mixture can be directed from the at least one gas membrane device to the at least one storage device. The at least one storage device can be provided with tempering and / or pressurizing units configured to temper and / or pressurize the gas molecules stored therein under specified physical conditions. Respective physical conditions can particularly, result in that the gas stored in the at least one storage device is transferred into a liquid.

[0085] A third aspect of the invention relates to a method for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species. The method comprises using at least one gas membrane device according to the first aspect of the invention and / or at least one gas separation apparatus according to the second aspect of the invention for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species. Hence, all annotations regarding the gas membrane device according to the first aspect of the invention and / or the at least one gas separation apparatus according to the second aspect of the invention apply in analogous manner to the method of the third aspect of the invention and vice versa.

[0086] Notably, the method can particularly, comprise generating a flow of the gas mixture which at least partly flows through the gas membrane device or the gas separation apparatus, respectively, wherein the flow of the gas mixture can be pre-treated via the at least one pre-treatment device of the gas separation apparatus and / or the gas molecules of the first species can be removed from the gas mixture via the at least one gas membrane device of the gas separation apparatus.

[0087] A fourth aspect of the invention relates to a method for manufacturing a gas membrane device according to the first aspect of the invention. All annotations regarding the gas membrane device according to the first aspect of the invention apply in analogous manner to the method of the fourth aspect of the invention and vice versa.

[0088] The method can comprise at least the following steps: providing at least one membrane layer, particularly comprising one or more penetration openings configured such that gas molecules of a respective first species of a respective gas mixture can pass our penetrate therethrough; functionalizing the at least one membrane layer with at least one functionalization agent configured to promote penetration of the gas molecules of the first species through the one or more penetration openings and / or configured to impede penetration of the gas molecules of the at least one second species through the one or more penetration openings so as to create a functionalized membrane layer.

[0089] According to an exemplary embodiment, the method can comprise at least one of the following processes for functionalizing the at least one membrane layer with the at least one functionalization agent: a coating process, such as e.g. a dip coating process, a spray coating process, a roll-to-roll coating process, a bar coating process, a chemical and / or physical deposition process, e.g. based on evaporation, a filtration process, such as e.g. a vacuum filtration process or a pressure filtration process, a printing process, etc. Likewise, the one or more of the aforementioned processes could be used for applying the membrane layer on a support layer.

[0090] According to a further exemplary embodiment, the at least one functionalized membrane layer can be generated by dispersing a plurality of, particularly flake-like shaped, membrane layer elements in a dispersion solution, particularly in an electrically conductive dispersion solution, such as e.g. an aqueous dispersion solution, wherein the membrane layer elements arrange in two-dimensional layers in the dispersion solution, particularly based on electric and / or electrostatic interactions effected through a positive and an negative electrode arranged at or in the dispersion solution, thereby creating the at least one functionalized membrane layer.

[0091] According to a further exemplary embodiment, when the membrane layer elements are arranged in respective two-dimensional layers, the dispersion solution is removed or the respective two-dimensionally arranged functionalized membrane layers are removed from the dispersion solution.

[0092] According to a further exemplary embodiment, the method may comprise embedding the at least one functionalized membrane layer in an embedding material or in an embedding material structure.

[0093] According to a further exemplary embodiment, the method may comprise embedding multiple functionalized membrane layers in an embedding material or in an embedding material structure, thereby forming a block comprising multiple embedded functionalized membrane layers, wherein the method further comprises separating, e.g. via cutting, sheet- or slice-like elements from the block, wherein each element comprises at least one functionalized membrane layer embedded in the embedding material or in the embedding material structure.

[0094] According to a further exemplary embodiment, the method may further comprise providing the at least one functionalized membrane layer with a support material providing mechanical support for the at least one two-dimensional layer functionalized membrane layer.

[0095] According to a further exemplary embodiment, the method may comprise arranging at least one nonfunctionalized membrane layer, which can be a functionalized membrane layer without functionalization, between at least two adjacent functionalized membrane layers. In such a manner, layers acting or serving as a spacer layer can be arranged in between two adjacent functionalized membrane layers. Arranging at least one respective non-functionalized membrane layer can be particularly, beneficial in a stacked arrangement of functionalized membrane layers, wherein at least one non-functionalized membrane layer is arranged between two adjacent functionalized membrane layers to provide, support or stabilize an interlayer spacing. Hence, the gas membrane device can comprise an alternating arrangement of non- functionalized membrane layers and functionalized membrane layers, for instance. A respective nonfunctionalized membrane layer can be or comprise an intercalated layer, particularly an intercalated nanolayer or nanosheet.

[0096] The disclosure will also be readily understood by the following description of exemplary embodiments in conjunction with the accompanying drawings in which:

[0097] Fig.1 to 4 each illustrate a principle drawing of a gas membrane device according to an exemplary embodiment;

[0098] Fig. 5 illustrates a gas separation apparatus according to an exemplary embodiment; and

[0099] Fig. 6 and 7 each illustrate a principle drawing of a gas membrane device according to other exemplary embodiments.

[0100] Fig. 1 illustrates a principle drawing of a first exemplary embodiment of a gas membrane device 10 for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species. The gas membrane device 10 is thus, generally configured to separate gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species.

[0101] A respective gas mixture can be or comprise a flow of the gas mixture. A respective gas mixture can thus, comprise a flow of gas molecules of the first species and gas molecules of at least one second species. The flow is typically directed towards the gas membrane device such that gas molecules of the first species can pass or penetrate through the gas membrane device as will be more apparent from below.

[0102] A respective gas mixture can particularly, be a gas mixture resulting from an industrial process, particularly an industrial process which generates CO2, e.g. as a main-product or as a by-product. An example of a respective industrial process is a combustion process. A respective combustion process can comprise the combustion of carbon-based substances, e.g. fossil fuels, which generates a gas mixture comprising CO2, for instance.

[0103] Hence, gas molecules of a respective first species can generally be CC>2-molecules. Gas molecules of a respective second species may include but are not limited to at least one of oxygen-molecules, oxygencontaining molecules (except for CO2), nitrogen-molecules, nitrogen-containing molecules, sulfur molecules, sulfur-containing molecules, for instance. The gas membrane device 10 can thus, be generally configured for separating gas molecules of a first species which is CO2, from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species which is not CO2, but oxygen and / or nitrogen and / or sulfur, for instance. The gas membrane device comprises 10 at least one two-dimensional functionalized membrane layer 11. The at least one functionalized membrane layer 11 comprises one or more penetration openings 12. The penetration openings 12 are configured such that gas molecules of the first species of a respective gas mixture can pass or penetrate therethrough. In the exemplary embodiments, the penetration openings 12 are configured such that gas molecules of the at least one second species of the respective gas mixture cannot pass or penetrate therethrough. Particularly, the penetration openings 12 are sized and / or shaped such that gas molecules of the first species of a respective gas mixture can pass or penetrate therethrough, e.g. due to the molecule size which allows for that the gas molecules of the first species can pass or penetrate through the respective penetration openings 12. Accordingly, the penetration openings 12 are sized and / or shaped such that gas molecules of the at least one second species of the respective gas mixture cannot pass or penetrate therethrough, e.g. due to the molecule size which does not allow for that the gas molecules of the at least one second species can pass or penetrate through the respective penetration openings. Hence, the size and / or shape of the penetration openings 12 is selected based on the size and / or shape of the gas molecules of the first species such that the gas molecules of the first species can pass or penetrate through the penetration openings 12 of the gas membrane device 10 which typically, also means that the gas molecules of the at least one second species cannot pass or penetrate through the penetration openings 12 of the gas membrane device 10.

[0104] The at least one membrane layer 11 is functionalized with at least one functionalization agent 13 configured to promote penetration of the gas molecules of the first species through the one or more penetration openings 12. Hence, the at least one functionalized membrane layer 11 comprises one or more functionalizations, particularly chemical functionalizations, which enable that the penetration of the gas molecules of the first species through the penetration openings 12 is promoted. Respective functionalizing agents can thus, be or comprise chemical substances or chemical groups which enable that the penetration of the gas molecules of the first species through penetration openings 12 is promoted. A respective functionalizing agent 13 can thus, have chemical and / or physical properties which enable that the penetration of the gas molecules of the first species through the penetration openings 12 is promoted. As an example, a respective functionalizing agent 13 can have a chemical affinity, e.g. due to chemical and / or physical attracting effects, with respect to the gas molecules of the first species and / or a chemical disaffinity, e.g. due to chemical and / or physical repelling effects, with respect to the gas molecules of the at least one second species such that the penetration of the gas molecules of the first species through the penetration openings 12 is promoted. Respective functionalization agents 13 can be provided at portions of the at least one functionalized membrane layer 11 adjacent to respective penetration openings 12 and / or at portions of the at least one functionalized membrane layer 11 not adjacent to respective penetration openings 12. As schematically shown in Fig. 1 , respective functionalization agents 13 can be provided at portions of the at least one functionalized membrane layer 11 adjacent to respective penetration openings 12, wherein at least some of the functionalization agents 13 are oriented in the plane of the at least one functionalized membrane layer 11 , particularly such that the molecule axes, particularly the longitudinal molecule axes, of respective molecules of the functionalization agents 13 extend (substantially) parallel to the main extension plane of the at least one functionalized membrane layer 11. In either case, the arrangement of respective functionalization agents 13 is chosen and effective such that penetration of gas molecules of the first species through the penetration openings 13 is promoted.

[0105] Alternatively or additionally, the at least one functionalized membrane layer 11 is functionalized with at least one functionalization agent 14 configured to impede penetration of the gas molecules of the first species through the penetration openings 12 of the at least one functionalized membrane layer 11. Hence, the at least one functionalized membrane layer 11 can comprise one or more functionalizations, particularly chemical functionalizations, which enable that the penetration of the gas molecules of the first species through the penetration openings 12 is impeded. Respective functionalizing agents 14 can thus, be or comprise chemical substances or chemical groups which enable that the penetration of the gas molecules of the first species through the penetration openings 12 is impeded. The at least one functionalizing agent 14 can thus, have chemical and / or physical properties which enable that the penetration of the gas molecules of the first species through the penetration openings 12 is impeded. As an example, a respective functionalizing agent 14 can have a chemical affinity, e.g. due to chemical and / or physical attracting effects, with respect to the gas molecules of the at least one second species and / or a chemical disaffinity, e.g. due to chemical and / or physical repelling effects, with respect to the gas molecules of the first species such that the penetration of the gas molecules of the at least one second species through the penetration openings 12 is impeded. Respective functionalization agents 14 can be provided at portions of the at least one functionalized membrane layer 11 adjacent to respective penetration openings 12 and / or at portions of the at least one functionalized membrane layer 11 not adjacent to respective penetration openings 12. Particularly, respective functionalization agents 14 can be provided at portions of the at least one functionalized membrane layer 11 not adjacent to respective penetration openings 12, wherein at least some of the functionalization agents 14 are oriented angled relative to the plane of the at least one functionalized membrane layer 11 , particularly such that the molecule axes, particularly the longitudinal molecule axes, of respective molecules of the functionalization agents 14 extend at an angle of 15 - 165° relative to the main extension plane of the at least one functionalized membrane layer 11. In either case, the arrangement of respective functionalization agents 14 is chosen and effective such that penetration of gas molecules of the at least one second species through the penetration openings 12 is impeded. In other words, the at least one functionalized membrane layer 11 can have, due to respective functionalizing agents 14, a specific chemical “design” which impedes penetration of gas molecules of the at least one second species through the one or more penetration openings 12 which forms basis for and supports a highly efficient separation of the gas molecules of the respective first species from a respective gas mixture.

[0106] The gas membrane device 10 thus, enables due to the provision of at least one functionalized membrane layer 11 which comprises one or more penetration openings 12 and the functionalization with at least one functionalization agent 13, 14 configured to promote penetration of the gas molecules of the first species through the penetration openings 12 and / or to impede penetration of the gas molecules of the at least one second species through the penetration openings 12, a highly selective and thus, a highly efficient separation gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species.

[0107] As is apparent from Fig. 1 , 2, the at least one functionalized membrane layer 11 can comprise an arrangement of a plurality of, particularly flake-like or flake-shaped, membrane layer elements 11.n arranged in a two-dimensional plane. Hence, the at least one functionalized membrane layer 11 can be built from a plurality of, particularly flake-like- or flake-shaped, membrane layer elements 11.n which are chemically and / or physical bonded with each other via one or more bonding areas so as to form the at least one functionalized membrane layer 11. Respective membrane layer elements 11.n can also have a two- dimensional basis shape such that respective membrane layer elements 11.n can be arranged in a two- dimensional plane so as to form the at least one functionalized membrane layer 11. In other words, the arrangement of the membrane layer elements 11.n in a common plane typically results in the two- dimensional extension of the at least one functionalized membrane layer 11. The size, shape, and / or arrangement of the membrane layer elements 11 .n relative to each other has an effect on the properties of the at least one functionalized membrane layer 11. Generally, the at least one functionalized membrane layer 11 can comprise membrane layer elements 11 .n of the same size and / or shape and membrane layer elements 11 .n of different size and / or shape.

[0108] As is apparent from Fig. 1 , 2, the membrane layer elements 11.n can be provided with respective functionalization agents 13, 14, particularly respective intralayer spacing agents 15 and / or respective interlayer spacing agents 16 which will be set forth further below. Notably, respective functionalization agents 13, 14 can thus, be provided as respective intralayer spacing agents 15 and / or respective interlayer spacing agents 16.

[0109] As is apparent from Fig. 1 , 2, respective intralayer spacing agents 15 can particularly, be provided at one or more lateral edges of respective membrane layer elements 11.n and extend (substantially) parallel to the main plane of the respective membrane layer elements 11 .n and the at least one functionalized membrane layer 11 , respectively. As such, the molecule axes of respective interlayer spacing agents 15 can be oriented (substantially) parallel to the main plane of the respective membrane layer elements 11 .n and the at least one functionalized membrane layer 11 , respectively. This also means that adjacently arranged membrane layer elements 11.n can be arranged (substantially) in parallel and can be spaced from each other because their respective lateral edges are provided with respective intralayer spacing agents 15 which can repel each other and thus, repel the respective membrane layer elements 11 .n from each other. Notably, respective intralayer spacing agents 15 can provide for a stabilized intralayer spacing, particularly due respective chemical and / or physical repelling forces. The parallel arrangement of respective membrane layer elements 11 .n can result from the manufacturing process of the respective functionalized membrane layer 11 .

[0110] Respective interlayer spacing agents 16 can generally, be provided at an upper or lower surface portions of respective membrane layer elements 11.n and extend (substantially) angled relative to the main plane of the respective membrane layer elements 11.n and the at least one functionalized membrane layer 11 , respectively. As such, the molecule axes of respective interlayer spacing agents 16 can be oriented (substantially) at an angle relative to the main plane of the respective membrane layer elements 11 .n and the at least one functionalized membrane layer 11 , respectively. This also means that adjacently arranged functionalized membrane layers 11 , e.g. in a stacked arrangement as shown in Fig. 2, can be spaced from each other because their respective upper and / or lower surfaces are provided with respective interlayer spacing agents 16 which can repel each other and thus, repel the respective functionalized membrane layers 11 from each other. Notably, respective interlayer spacing agents 16 can provide for a stabilized interlayer spacing, particularly due respective chemical and / or physical repelling forces.

[0111] As is apparent from Fig. 1 , 2, two or more of the membrane layer elements 11.n are arranged with an intralayer spacing, wherein the intralayer spacing forms a respective penetration opening 12. Hence, the arrangement of two or more respective membrane layer elements 11.n results in an intermediate space between the two or more respective membrane layer elements 11.n, which intermediate space forms an intralayer spacing which forms a respective penetration opening 12. In other words, respective penetration openings 12 of the at least one functionalized membrane layer 11 can be formed by spacing adjacent membrane layer elements 11.n of at least one functionalized membrane layer 11 and thus, by creating intermediate spaces between adjacently arranged membrane layer elements 11.n.

[0112] A respective intralayer spacing agent 15 can be configured to repel at least one membrane layer element 11.n from at least one adjacently arranged further membrane layer element 11.n within a respective functionalized membrane layer 11 , thereby creating a respective intralayer spacing between the respective membrane layer elements 11.n. Hence, respective intralayer spacings can be formed by respective intralayer spacing agents 15 which can comprise functional groups enabling a chemical and / or physical repelling effect between adjacently disposed membrane layer elements 11 .n such that the membrane layer elements 11 .n are spaced from each other and do not directly contact each other, thereby forming and / or stabilizing respective intralayer spacings and penetration openings 12, respectively. As an example, respective intralayer spacing agents 15 can comprise electric charges such that two adjacently arranged membrane layer elements 11.n each being provided with intralayer spacing agents 15 having the same electric charge will repel each other, thereby creating an intralayer spacing due to electric or electrostatic repelling effects. As another example, respective intralayer spacing agents 15 can be polar or hydrophilic, e.g. can comprise polarity, or can be apolar (non-polar) or hydrophobic, e.g. can comprise no polarity, such that two adjacently arranged membrane layer elements 11.n each being provided with intralayer spacing agents 15 being polar or apolar, respectively will repel each other, thereby creating an intralayer spacing due to electric or electrostatic repelling effects. Generally, respective intralayer spacing agents 15 can also make use of steric effects for creating and / or stabilizing a respective intralayer spacing and penetration opening 12, respectively.

[0113] The at least one intralayer spacing agent 15 can thus, carry at least one electric charge configured to create an electric or electrostatic repelling force between adjacent membrane layer elements 11 .n having the same intralayer spacing agents 15 and thus, the same electric charge. Additionally or alternatively, the at least one intralayer spacing agent 15 can be a polar functional group, e.g. a hydrophilic functional group, configured to create a repelling force between adjacent membrane layer elements 11.n comprising the same intralayer spacing agents 15 and thus, the same polarity functional groups. Additionally or alternatively, the at least one intralayer spacing agent 15 can be an apolar functional group, e.g. a hydrophobic functional group, configured to create a repelling force between adjacent membrane layer elements 11.n comprising the same intralayer spacing agents 15 and thus, the same apolar functional groups. As mentioned before, respective intralayer spacing agents 15 can also make use of steric effects for creating a respective intralayer spacing.

[0114] Particularly, the at least one intralayer spacing agent 15 can be or comprise at least one of the following functional groups: a carbonyl-group, a carboxylic-group, a di-carboxylic-group, a hydroxyl-group, an epoxide-group, an amine-group, a diamine-group, an acrylate-group, a sulfonic-group, particularly a sulfonic-acid-group, a phosphonic-group, particularly a phosphonic-acid-group, a silane-group, an amino- silane-group, a polymeric group, an ionic charge, for instance.

[0115] A respective carbonyl-group (-C=O) or a respective hydroxyl-group (-OH) can be created via an oxidation process of one or more membrane layer elements 11 .n or the at least one functionalized membrane layer 11 , respectively. As such, respective intralayer spacing agents 15 can generally be created by one or more oxidation reactions which result in that the membrane layer elements 1 1 .n or the at least one functionalized membrane layer 11 is provided with at least one carbonyl-group or at least one hydroxyl-group. In same manner, also carboxyl-groups can be created which can also act as respective intralayer spacing agents 15. As will be further apparent from below, the at least one functionalized membrane layer 11 can be a carbon-based layer, particularly a graphene-based layer, more particularly a graphene-oxide-based layer; as such respective oxidation reactions can comprise oxidation reactions required for transferring graphite into graphene oxide, for instance.

[0116] A respective epoxide-group (-O-CH2-CH2-) can be created via an epoxidation process of one or more membrane layer elements 11 .n or the at least one functionalized membrane layer 11 , respectively. As such, respective intralayer spacing agents 15 can generally be created by one or more epoxidation reactions which result in that the membrane layer elements 11.n or the at least one functionalized membrane layer 11 is provided with at least one epoxide-group. As will be further apparent from below, the at least one functionalized membrane layer 11 can be a carbon-based layer, particularly a graphene-based layer, more particularly a graphene-oxide-based layer. As such, respective epoxidation reactions can comprise epoxidation reactions required for introducing epoxide-g roups into graphene oxide, for instance. Respective epoxidation reactions can comprise using epichlorohydrin or glycidyl methacrylate to introduce epoxidegroups into graphene oxide, for instance.

[0117] A respective amine group can be created via an aminization process of one or more membrane layer elements 11.n or the at least one functionalized membrane layer 11 , respectively. As such, respective intralayer spacing agents 15 can generally be created by one or more aminization reactions which result in that the membrane layer elements 11.n or the at least one functionalized membrane layer 11 is provided with at least one amine-group. As will be further apparent from below, the at least one functionalized membrane layer 11 can be a carbon-based layer, particularly a graphene-based layer, more particularly a graphene-oxide-based layer. As such, respective aminization reactions can comprise aminization reactions required for introducing amine-groups into graphene oxide, for instance. Respective aminization reactions can generally allow for that amine group-containing molecules, such as e.g. amines or amino acids, react with graphene oxide. Respective aminization reactions can comprise using aminobenzoic acid or ethylenediamine to introduce amine-groups into graphene oxide, for instance. Both aminobenzoic acid or ethylenediamine can react with carbonyl groups and hydroxyl groups of graphene oxide, leading to the functionalization with amino groups.

[0118] A respective ionic charge can be created via an ion exchange process of one or more membrane layer elements 11.n or the at least one functionalized membrane layer 11 , respectively. As such, respective intralayer spacing agents 15 can generally be created by one or more ionic exchange reactions which result in that the membrane layer elements 11 .n or the at least one functionalized membrane layer 11 is provided with at least one ionic charge. As will be further apparent from below, the at least one functionalized membrane layer 11 can be a carbon-based layer, particularly a graphene-based layer, more particularly a graphene-oxide-based layer; as such respective ion exchange processes can comprise ion exchange processes required for introducing ions or ionic charges into graphene oxide, for instance. Respective ion exchange reactions can generally allow for that ionic charges can be introduced into the structure of graphene oxide. Respective ion exchange reactions can comprise a treatment of graphene oxide with ionic solutions. Respective ion exchange reactions can comprise using potassium permanganate (KMnC ) or ammonium hydroxide (NH4OH), for instance. Both potassium permanganate and ammonium hydroxide can incorporate ions into the structure of graphene oxide.

[0119] Respective intralayer spacing agents 15 can also be or comprise at least one functional polymer, e.g. a polymer comprising functional groups carrying an electric charge, which can be chemically and / or physically bonded to the one or more membrane layer elements 11.n or the at least one functionalized membrane layer 11 , respectively thereby, introducing charge-bearing functional groups. This can specifically, apply for embodiments in which the at least one functionalized membrane layer 11 is a carbon-based layer, particularly a graphene-based layer, more particularly a graphene-oxide-based layer, since respective functional polymers can react with a carbon-based layer, particularly a graphene-based layer, more particularly a graphene-oxide-based layer, and thus, bond thereto to introduce charge-bearing functional groups.

[0120] It is also possible that the at least one intralayer spacing agent 15 can comprise one or more groups resulting from an at least partial reduction of graphene oxide. This particularly, applies to embodiments in which the membrane layer 11 is made of or consists of graphene oxide or comprises membrane layer elements 11.n made of or consisting of graphene oxide. A respective partial reduction of the graphene oxide can be based on a chemical treatment, particularly with an acid, such as e.g. ascorbic acid, nitric acid, sulfuric acid, etc.

[0121] Further, it is also possible that the at least one intralayer spacing agent 15 can comprise doped graphene oxide, particularly N-doped graphene oxide, more particularly Nitrogen-doped graphene oxide. As such, an intralayer spacing agent 15 can also be created by doping at least one membrane layer 11 and / or at least one membrane layer element 11 .n with at least one doping agent. A respective doping of graphene oxide (or generally at least one membrane layer 11 or membrane layer element 11 .n, respectively) can have an effect on the morphology of the graphene oxide which can promote creating and / or maintaining an intralayer spacing and thus, improve the overall separation properties of the gas membrane device.

[0122] Further, it is also possible that the at least one intralayer spacing agent 15 can comprise one or more intercalation agents 31 intercalated between adjacent membrane layer elements 11 .n (see the exemplary embodiment of Fig. 6). Also, respective intercalation agents 31 can be configured to promote penetration of the gas molecules of the first species through the one or more penetration openings 12 and / or can be configured to impede penetration of the gas molecules of the at least one second species through the one or more penetration openings 12 and thus, improve the overall separation properties of the gas membrane device 10. Yet, one or more respective intercalation agents 31 can have no functionalization, as is e.g. the case when unfunctionalized graphene-based layers are used an intercalation agents 31.

[0123] Exemplary intercalation agents can comprise at least one of: nanoparticles or nanosheets, particularly Ti- based nanoparticles or Ti-based nanosheets.

[0124] As is apparent from Fig. 2, the gas membrane device 10 can comprise multiple functionalized membrane layers 11 each comprising an arrangement of a plurality of, particularly flake-like or platelet-like shaped, membrane layer elements 11.n arranged in a two-dimensional plane. Hence, the gas membrane device 10 can comprise multiple stacked functionalized membrane layers 11. The overall gas separation properties of the gas membrane device 10 can be defined or at least be influenced by the number of functionalized membrane layers 11. Particularly, providing multiple functionalized membrane layers 11 can improve the gas separation properties of the gas membrane device 10. Likewise, providing multiple stacked functionalized membrane layers 11 can improve the stability of the gas membrane device 10.

[0125] As is apparent from Fig. 2, an interlayer spacing d can be provided between vertically adjacently arranged functionalized membrane layers 11. A respective interlayer spacing d can range between 0,1 nm - 1 pm, particularly between 0,1 nm - 0,9 pm, more particularly between 0,1 nm - 0,8 pm, more particularly between 0,1 nm - 0,7 pm, more particularly between 0,1 nm - 0,6 pm, more particularly between 0,1 nm - 0,5 pm, more particularly between 0,1 nm - 0,4 pm, more particularly between 0,1 nm - 0,3 pm, more particularly between 0,1 nm - 0,2 pm, more particularly between 0,1 nm - 0,1 pm, more particularly between 0,1 nm - 75 nm, more particularly between 0,1 nm - 50 nm, more particularly between 0,1 nm - 25 nm. Further, a respective interlayer spacing d can range between 1 - 20 nm, for instance. Hence, a respective interlayer spacing d can be deemed a nano-spacing which typically, enables or at least supports an effective gas separation.

[0126] Two, more than two, or all functionalized membrane layers 11 can have the same interlayer spacing d. Alternatively, two, more than two, or all functionalized membrane layers 11 can have a different interlayer spacing d. Hence, there is generally high flexibility with respect to the interlayer spacing d of respective functionalized membrane layers 11 which is another parameter for influencing the gas separation properties of the gas membrane device 10.

[0127] As is exemplarily illustrated in Fig. 2, respective functionalized membrane layers 11 can be arranged relative to each other such that their respective penetration openings 12 are aligned and thus, not offset, particularly forming a straight gas penetration channel (as indicated by the arrow in Fig. 2) which extends through the gas membrane device 10. This can be achieved by arranging respective functionalized membrane layers 11 with no lateral offset, for instance. Alternatively, respective functionalized membrane layers 11 can be arranged relative to each other such that their respective penetration openings 12 are not aligned and thus, offset, particularly not forming a straight gas penetration channel which extends through the gas membrane device 10. Generally, the arrangement of respective penetration openings 12 of respective functionalized membrane layers 11 relative to each other is another parameter which enables to influence the gas separation properties of the gas membrane device 10.

[0128] As indicated above, at least one functionalized membrane layer 11 can comprise at least one interlayer spacing agent 16 configured to repel the at least one functionalized membrane layer 11 from at least one adjacently arranged further functionalized membrane layer 11 , thereby creating and / or stabilizing a respective interlayer spacing d between the respective functionalized membrane layers 11. Hence, respective interlayer spacings d can be formed by respective interlayer spacing agents 16 which can comprise functional groups enabling a chemical and / or physical repelling effect between adjacently disposed functionalized membrane layers 11 such that the functionalized membrane layers 11 are spaced from each other and do not directly contact each other, thereby forming respective interlayer spacings d. As an example, respective intralayer spacing agents 16 can comprise electric charges such that two adjacently arranged functionalized membrane layers 11 each being provided with interlayer spacing agents 16 having the same electric charge will repel each other, thereby creating an interlayer spacing d due to electric or electrostatic repelling effects. As another example, respective interlayer spacing agents 16 can be polar or hydrophilic, e.g. can comprise polarity, or can be apolar (non-polar) or hydrophobic, e.g. can comprise no polarity, such that two adjacently arranged functionalized membrane layers 11 each being provided with interlayer spacing agents 16 being polar or apolar, respectively will repel each other, thereby creating an interlayer spacing d due to electric or electrostatic repelling effects. Generally, respective interlayer spacing agents 16 can also make use of steric effects for creating and / or stabilizing a respective interlayer spacing d. The at least one interlayer spacing agent 16 can thus, carry at least one electric charge configured to create an electric or electrostatic repelling force between adjacent functionalized membrane layers 11 having the same interlayer spacing agents 16 and thus, the same electric charge. Additionally or alternatively, the at least one interlayer spacing agent 16 can be a polar functional group, e.g. a hydrophilic functional group, configured to create a repelling force between adjacent functionalized membrane layers 11 comprising the same interlayer spacing agents 16 and thus, the same polarity functional groups. Additionally or alternatively, the at least one interlayer spacing agent 16 can be an apolar functional group, e.g. a hydrophobic functional group, configured to create a repelling force between adjacent functionalized membrane layers 11 comprising the same interlayer spacing agents 16 and thus, the same apolar functional groups. As indicated before, respective interlayer spacing agents 16 can also make use of steric effects for creating and / or stabilizing respective interlayer spacing d.

[0129] Particularly, the at least one interlayer spacing agent 16 can be or comprise at least one of the following functional groups: a carbonyl-group, a hydroxyl-group, a carboxyl-group, an epoxide-group, an aminegroup, an acrylate-group, an ionic charge, for instance.

[0130] A respective carbonyl-group (-C=O) or a respective hydroxyl-group (-OH) can be created via an oxidation process of one or more functionalized membrane layers 11. As such, respective interlayer spacing agents 16 can generally be created by one or more oxidation reactions which result in that the functionalized membrane layers 11 are provided with at least one carbonyl-group or at least one hydroxyl-group. In same manner, also carboxyl-groups can be created which can also act as respective interlayer spacing agent 16. As will be further apparent from below, respective functionalized membrane layers 11 can be carbon-based layers, particularly graphene-based layers, more particularly graphene-oxide-based layers; as such respective oxidation reactions can comprise oxidation reactions required for transferring graphite into graphene oxide, for instance.

[0131] An epoxide-group (-O-CH2-CH2-) can be created via an epoxidation process of one or more functionalized membrane layers 11. As such, respective interlayer spacing agents 16 can generally be created by one or more epoxidation reactions which result in that the functionalized membrane layers 11 are provided with at least one epoxide-group. As will be further apparent from below, the respective functionalized membrane layers 11 can be carbon-based layers, particularly a graphene-based layers, more particularly graphene- oxide-based layers. As such, respective epoxidation reactions can comprise epoxidation reactions required for introducing epoxide-groups into graphene oxide layers, for instance. Respective epoxidation reactions can comprise using epichlorohydrin or glycidyl methacrylate to introduce epoxide-groups into graphene oxide, for instance.

[0132] An amine group can be created via an aminization process of one or more functionalized membrane layers 11 . As such, respective interlayer spacing agents 16 can generally be created by one or more aminization reactions which result in that the functionalized membrane layers 11 are provided with at least one aminegroup. As will be further apparent from below, the functionalized membrane layers 11 can be carbon-based layers, particularly a graphene-based layers, more particularly graphene-oxide-based layers. As such, respective aminization reactions can comprise aminization reactions required for introducing amine-groups into graphene oxide layers, for instance. Respective aminization reactions can generally allow for that amine group-containing molecules, such as e.g. amines or amino acids, react with graphene oxide. Respective aminization reactions can comprise using aminobenzoic acid or ethylenediamine to introduce amine-groups into graphene oxide, for instance. Both aminobenzoic acid or ethylenediamine can react with carbonyl groups and hydroxyl groups of graphene oxide layers, leading to the functionalization with amino groups.

[0133] An ionic charge can be created via an ion exchange process of one or more functionalized membrane layers 11 . As such, respective interlayer spacing agents 16 can generally be created by one or more ionic exchange reactions which result in that the functionalized membrane layers 11 are provided with at least one ionic charge. As will be further apparent from below, the functionalized membrane layers 11 can be carbon-based layers, particularly graphene-based layers, more particularly graphene-oxide-based layers. As such, respective ion exchange processes can comprise ion exchange processes required for introducing ions or ionic charges into graphene oxide, for instance. Respective ion exchange reactions can generally allow for that ionic charges can be introduced into the structure of graphene oxide layers. Respective ion exchange reactions can comprise a treatment of graphene oxide layers with ionic solutions. Respective ion exchange reactions can comprise using potassium permanganate (KMnC ) or ammonium hydroxide (NH4OH), for instance. Both potassium permanganate and ammonium hydroxide can incorporate ions into the structure of graphene oxide layers.

[0134] A respective interlayer spacing agent 16 can also be or comprise at least one functional polymer, e.g. a polymer comprising functional groups carrying an electric charge, which can be chemically and / or physically bonded to one or more functionalized membrane layers 11 thereby, introducing charge-bearing functional groups between adjacent functionalized membrane layers 11. This can specifically, apply for embodiments in which the functionalized membrane layers 11 are carbon-based layers, particularly graphene-based layers, more particularly graphene-oxide-based layers, since respective functional polymers can react with carbon-based layers, particularly graphene-based layers, more particularly graphene-oxide-based layers, and thus, bond thereto to introduce charge-bearing functional groups.

[0135] It is also possible that the at least one interlayer spacing agent 16 can comprise one or more groups resulting from an at least partial reduction of graphene oxide. This particularly, applies to embodiments in which the membrane layer 11 is made of or consists of graphene oxide or comprises membrane layer elements 11.n made of or consisting of graphene oxide. A respective partial reduction of the graphene oxide can be based on a chemical treatment, particularly with an acid, such as e.g. ascorbic acid, nitric acid, sulfuric acid, etc.

[0136] Further, it is also possible that the at least one interlayer spacing agent 16 can comprise doped graphene oxide, particularly N-doped graphene oxide, more particularly Nitrogen-doped graphene oxide. As such, an interlayer spacing agent 16 can also be created by doping at least one membrane layer 11 and / or at least one membrane layer element 11.n with at least one doping agent. A respective doping of graphene oxide (or generally at least one membrane layer 11 or membrane layer element 1 1 .n, respectively) can have an effect on the morphology of the graphene oxide which can promote creating and / or maintaining an intralayer spacing and thus, improve the overall separation properties of the gas membrane device.

[0137] Further, it is also possible that the at least one interlayer spacing agent 16 can comprise one or more intercalation agents 31 intercalated between adjacent membrane layer elements 1 1 .n (see the exemplary embodiment of Fig. 6). Also, respective intercalation agents can be configured to promote penetration of the gas molecules of the first species through the one or more penetration openings 12 and / or can be configured to impede penetration of the gas molecules of the at least one second species through the one or more penetration openings 12 and thus, improve the overall separation properties of the gas membrane device 10. Yet, one or more respective intercalation agents 31 can have no functionalization, as is e.g. the case when unfunctionalized graphene-based layers are used an intercalation agents 31.

[0138] Exemplary intercalation agents 31 can comprise at least one of: nanoparticles or nanosheets, particularly Ti-based nanoparticles or Ti-based nanosheets.

[0139] As indicated above, the at least one functionalized membrane layer 11 (which also applies to embodiments in which the gas membrane device 10 comprises multiple functionalized membrane layers 11 , particularly in a stacked arrangement as shown in Fig. 2) can be or comprise a carbon-based layer (which also applies to embodiments in which the gas membrane device comprises multiple functionalized membrane layers, particularly in a stacked arrangement). A respective carbon-based layer can comprise a plurality of carbon- atoms in a lattice-arrangement. Hence, the carbon-based layer can comprise carbon-atoms forming edgepoints and / or node-points of the lattice-arrangement.

[0140] Particularly, the at least one functionalized membrane layer 11 (which also applies to embodiments in which the gas membrane device 10 comprises multiple functionalized membrane layers 11 , particularly in a stacked arrangement as shown in Fig. 2) can be or comprise a graphene-based layer. Graphene-based layers are of specific advantage for the purpose of gas separation, e.g. because they can be functionalized with diverse functionalizing agents, and because they exhibit high stability.

[0141] More particularly, the at least one functionalized membrane layer 11 (which also applies to embodiments in which the gas membrane device 10 comprises multiple functionalized membrane layers 11 , particularly in a stacked arrangement as shown in Fig. 2) can be or comprise a graphene-oxide-based layer. Hence, respective membrane layer elements 11 .n can be or comprise graphene-oxide flakes. Also graphene-oxide- based layers are of specific advantage for the purpose of gas separation, e.g. because they can be functionalized with diverse functionalizing agents, and because they exhibit high stability. In either embodiment, a respective functionalized membrane layer 11 can have a layer thickness of 1 - 20 nm or higher, e.g. between 1 nm and 950 pm. Hence, a respective functionalized membrane layer 11 can be deemed a nanolayer. Respective nanolayers generally exhibit good gas separation properties and typically, enable or at least support an effective gas separation. The thickness of respective functionalized membrane layers 11 is another parameter to influence the gas separation properties of the gas membrane device 10. Hence, by selecting specific thicknesses, the gas separation properties of the gas membrane device 10 can be adjusted.

[0142] In exemplary embodiments with multiple functionalized membrane layers 11 , two, more than two, or all functionalized membrane layers 11 can have the same thickness. Alternatively, two, more than two, or all functionalized membrane layers 11 can have a different thickness. Hence, there is generally high flexibility with respect to the thickness of respective functionalized membrane layers 11 and thus, the thickness of the gas membrane device 10.

[0143] In either embodiment, the at least one functionalized membrane layer 11 can have an area of at least 5 cm2. Particularly, the area of the at least one functionalized membrane layer 11 can even be larger. As such, it is conceivable that the at least one functionalized membrane layer 11 has an area of at least 25 cm2, more particularly at least 50 cm2, more particularly at least 100 cm2, more particularly at least 150 cm2, more particularly at least 200 cm2. The areas of respective functionalized membrane layers 11 is another parameter to influence the gas separation properties of the gas membrane device 10. Hence, by selecting specific areas, the gas separation properties of the gas membrane device 10 can be adjusted.

[0144] In exemplary embodiments with multiple functionalized membrane layers 11 , two, more than two, or all functionalized membrane layers 11 can have the same area. Alternatively, two, more than two, or all functionalized membrane layers 11 can have a different area. Hence, there is generally high flexibility with respect to the area of respective functionalized membrane layers 11 and thus, the area of the gas membrane device 10.

[0145] In either embodiment, one, more or all penetration openings 12 of the at least one functionalized membrane layer 11 can have, in at least one spatial direction, a size of 0,1 nm, 0,2 nm, 0,3 nm, 0,4 nm, 0,5 nm, 0,6 nm, 0,7 nm, 0,8 nm, 0,9 nm, or 1 nm, for instance. As indicated further above, the size of the respective penetration openings 12 is typically, selected such that (only) the gas molecules of the first species of a respective gas mixture from which a respective first species is to be separated. As such, the size of the respective penetration openings 12 can be selected with regard to the size of the gas molecules which should be able to penetrate therethrough.

[0146] In exemplary embodiments with at least one functionalized membrane layer 11 having multiple penetration openings 12, two, more than two, or all penetration openings of the at least one functionalized membrane layer 11 can have the same size. Alternatively, two, more than two, or all penetration openings 12 of at least one functionalized membrane layer 11 can have a different size. In exemplary embodiments with multiple functionalized membrane layers 11 , two, more than two, or all functionalized membrane layers 11 can have penetration openings 12 of the same size. Alternatively, two, more than two, or all functionalized membrane layers 11 can have penetration openings 12 of different sizes. Hence, there is generally high flexibility with respect to the size of respective penetration openings 12 and thus, the permissibility of the gas membrane device 10 with regard to gas molecules of a specific species.

[0147] The same applies to the shape of respective penetration openings 12. As indicated further above, the shape of respective penetration openings 12 can be generally adapted to the shape of the gas molecules of the first species, i.e. the shape of the gas molecules which are meant to penetrate through the respective penetration openings 12.

[0148] As indicated by the boxes 17 in Fig. 1 , 2, the at least one functionalized membrane layer 11 can be at least partly, particularly completely, embedded in an embedding material or in an embedding material structure, thereby forming an embedded functionalized membrane layer. It is conceivable that a plurality of stacked functionalized membrane layers 11 are at least partly, particularly completely, embedded in an embedding material or in an embedding material structure, thereby forming an embedded functionalized membrane layer (see Fig. 2). Embedding at least one functionalized membrane layer 11 in a respective embedding material or a respective embedding material structure can stabilize and / or protect the at least one functionalized membrane layer 11 , e.g. with respect to electrical, mechanical and / or thermal influences. Also, embedding the at least one functionalized membrane layer 11 in a respective embedding material or a respective embedding material structure can enable further processing steps which can be required for manufacturing the gas membrane device 10. Respective further processing steps can comprise separating, e.g. via cutting, particularly via microtomy cutting, respective embedded functionalized membrane layers from a bulk embedded structure which comprises multiple functionalized membrane layers 11 embedded therein, for instance. Respective embedded functionalized membrane layers can be separated from a respective bulk embedded structure by cutting slices off the bulk embedded structure, wherein each slice comprises at least one embedded functionalized membrane layer.

[0149] Respective slices can have a thickness of 1 - 1000 pm, particularly between 1 - 500 pm, more particularly between 1 - 100 pm, more particularly between 1 - 50 pm, more particularly between 1 - 25 pm, for instance. The thickness of respective slices typically depends on the overall configuration of a respective slice, i. e. particularly the number of functionalized membrane layers 11 and, as will be apparent from further below, the number of non-functionalized membrane layers 91. One, more or all of the respective nonfunctionalized membrane layers 91 can be or comprise an intercalated layer, particularly an intercalated nanolayer or nanosheet.

[0150] A respective embedding material or a respective embedding material structure typically, has a specific porosity (not explicitly shown in the Fig.) which enables that gas molecules of a respective first species which are to be separated from a respective gas mixture can penetrate not only through the penetration openings 12 of the at least one functionalized membrane layer 11 but also through the embedding material or a respective embedding material structure. As such, the openings creating the porous structure of the embedding material or a respective embedding material structure can have the same or a similar shape and / or size as the penetration openings 12 of the at least one embedded functionalized membrane layer.

[0151] The embedding material or the embedding material structure can be or comprise a polymer, particularly a curable resin. A respective polymer and a respective curable resin, respectively can be based on a thermoplastic polymer, a duroplastic polymer, an elastomer, or a silicone polymer, for instance. According to a concrete, yet non-limiting exemplary embodiment, a respective polymer can be or comprise curable epoxy resin.

[0152] The embedding material or the embedding material structure can comprise at least one functionalization (not shown) configured to promote penetration of the gas molecules of the first species through openings of the embedding material or the embedding material structure and / or configured to impede penetration of the gas molecules of the at least one second species through openings of the embedding material or the embedding material structure. Hence, not only the at least one functionalized membrane layer 11 but also a respective embedding material or embedding material structure can be functionalized with at least one functionalization which enables that penetration of the gas molecules of the first species through openings of the embedding material or the embedding material structure is promoted and / or that penetration of the gas molecules of the at least one second species through openings of embedding material or the embedding material structure is impeded. As such, the above annotations regarding the functionalization of the at least one functionalized membrane layer 11 apply in analogous manner. Specifically, a respective embedding material or embedding material structure can be functionalized with functionalization agents which correspond to respective intralayer spacing agents 15 and / or to respective interlayer spacing agents 16 as specified further above.

[0153] As is exemplarily shown in Fig. 1 , the gas membrane device 10 can further comprise at least one support material 18 providing mechanical support for the at least one functionalized membrane layer 11. A respective support material 18 can particularly, prevent deformation or damage to respective embedded functionalized membrane layers and can thus, improve handling, mounting, etc. of the gas membrane device 10. As such, a respective support material 18 can also be provided with one or more interfaces, such as e.g. threaded portions, configured to co-act with a handling tool, a mounting tool, etc.

[0154] The at least one support material 18 can be or comprise one or more porous substrates or membranes with high mechanical strength. As an example, a respective support material can be or comprise a perforated plate, e.g. made from a ceramic, metal, or polymer material, for instance.

[0155] Returning to Fig. 2, it has to be emphasized that the gas membrane device 10 can comprise multiple embedded functionalized membrane layers 11 , particularly in a stacked arrangement. As such, the gas membrane device 10 can comprise a stack of embedded functionalized membrane layers 11. The overall gas separation properties of the gas membrane device 10 can be defined or at least be influenced by the number of embedded functionalized membrane layers 11. The above annotations regarding exemplary embodiments of the gas membrane device 10 with multiple functionalized membrane layers 11 , particularly in a stacked arrangement, apply in analogous manner.

[0156] In either embodiment, the at least one functionalized membrane layer 11 or a respective embedded functionalized membrane layer can be arranged within a sealing structure 19 (only schematically indicated in Fig. 1 , 2), particularly configured to seal the free edges of the at least one functionalized membrane layer 11 or the free edges of the at least one embedded functionalized membrane layer, respectively. Sealing the at least one functionalized membrane layer 11 and / or a respective embedded functionalized membrane layer can improve the properties of the gas membrane device 10 because the sealing avoids undesired leakage and / or encapsulates the at least one functionalized membrane layer 11 and / or a respective embedded functionalized membrane layer such that it is protected against e.g. electrical, mechanical, thermal, climate influences which might possibly compromise the gas separation properties of the gas membrane device 10. Particularly, sealing the at least one functionalized membrane layer 11 and / or a respective embedded functionalized membrane layer can reduce the risk of undesired interactions of the at least one functionalized membrane layer 11 with other gas mixtures, e.g. gas mixtures, such as e.g. air, present in an operating environment of the gas membrane device 10, which might possibly compromise the separation properties of the gas membrane device 10.

[0157] Exemplary and thus, not limiting sealing materials can be or comprise a thermoplastic polymer, a duroplastic polymer, an elastomer, or a silicone polymer, for instance. According to a concrete, yet nonlimiting exemplary embodiment, a respective polymer can be or comprise curable epoxy resin.

[0158] Fig.3 and 4 each illustrate a principle drawing of a gas membrane device 10 according to another exemplary embodiment which differs from the embodiments of Fig. 1 , 2 in that at least one non-functionalized membrane layer 91 is provided between adjacent functionalized membrane layers 11. Respective nonfunctionalized membrane layers 91 differ from respective functionalized membrane layers 11 in that they do not have a respective functionalization, e.g. provided by respective intralayer spacing agents 15 and interlayer spacing agents 16. Respective non-functionalized membrane layers 91 can be or comprise an intercalated layer, particularly an intercalated nanolayer or nanosheet.

[0159] According to the exemplary embodiment of Fig. 3, the gas membrane device 10 comprises a stack of multiple functionalized membrane layers 11 and multiple non-functionalized membrane layers 91 in alternating arrangement.

[0160] According to the exemplary embodiment of Fig. 4, the gas membrane device 10 comprises a stack of multiple functionalized membrane layers 11 and multiple non-functionalized membrane layers 91 in an arrangement, in which at least two non-functionalized membrane layers 91 are arranged between two adjacent -functionalized membrane layers 11 . Fig. 5 shows a principle drawing of an exemplary embodiment of a gas separation apparatus 20 configured for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species.

[0161] In the exemplary embodiment, the apparatus 20 comprises at least one gas membrane device 10 as specified above in connection with the embodiments of Fig. 1 - 4. The gas membrane device 10 can be arranged in a receiving space of a housing unit 21 . The housing unit 21 can form part of a superordinate housing structure 22 of the apparatus 20.

[0162] The apparatus 20 further comprises at least one pre-treatment device 23 for pre-treating a gas mixture from which respective gas molecules of a first species are to be separated. The at least one pre-treatment device 23 is thus, generally configured for pre-treating a gas mixture from which respective gas molecules of a first species are to be separated via the at least one gas membrane device 10. The at least one pre-treatment device 23 can be arranged in a receiving space of a housing unit 24. The housing unit 24 can form part of the superordinate housing structure 22 of the apparatus 20.

[0163] The at least one pre-treatment device 23 can be configured to remove impurities, particularly particulate impurities, from the gas mixture. The at least one pre-treatment device 23 can thus, comprise one or more impurity removal units (not shown) for removing impurities, particularly particulate impurities, from a gas mixture from which gas molecules of the first species are to be separated. Respective impurity removal units can be built as or comprise chemical and / or physical sieves, for instance. The at least one pretreatment device 23 can comprise one or more sensor units (not shown) configured to generate information on parameters indicative of the impurity removal process implemented by the at least one pre-treatment device 23. Respective information can be transmitted to at least one control device 26 of the apparatus 20 and used as respective input parameters for controlling purposes as explained further below.

[0164] Additionally or alternatively, the at least one pre-treatment device 23 can be configured to temper a gas mixture. The at least one pre-treatment device 23 can thus, comprise one or more tempering units, particularly heating units, for tempering a gas mixture. Notably, tempering can comprise drying a gas mixture to remove excess moisture from the gas mixture. The at least one pre-treatment device 23 can comprise one or more sensor units (not shown) configured to generate information on parameters indicative of the tempering process implemented by the at least one pre-treatment device. Respective information can be transmitted to at least one control device 26 of the apparatus 20 and used as respective input parameters for controlling purposes as explained further below.

[0165] As is apparent from Fig. 5, the at least one pre-treatment device 23 can be arranged upstream of the at least one gas membrane device 10. Particularly, the at least one gas membrane device 10 and the at least one pre-treatment device 23 can be in fluid communication such that a flow of a gas mixture from which the gas molecules of the first species can be separated can flow through the at least one pre-treatment device 23 to undergo at least one pre-treatment process and subsequently flow through the at least one gas membrane device 10 to undergo a gas separation process. As such, the apparatus 20 can comprise a flow generation unit 25, such as a blowing unit and / or sucking unit, configured to generate a flow of a gas mixture from which the gas molecules of the first species can be separated through at least the at least one pre-treatment device 23 and the at least one gas membrane device 10. Concrete, yet non-limiting examples of a respective flow generation unit 25 can comprise a pump unit.

[0166] An additional component ofthe apparatus 20 as shown in Fig. 5, is at least one control device 26 configured to control at least one parameter influencing the separation of the gas molecules of the first species from the gas mixture. The control device 26 can be embodied in hardware- and / or software-embodied. Particularly, the control device 26 can be configured to process input parameters, which can particularly relate to operational parameters of the at least one pre-treatment device 23 and / or the at least one gas membrane device 10 which operational parameters can e.g. be derived from one or more sensors (not shown) assigned to the at least one pre-treatment device 23 and / or the at least one gas membrane device 10, and generate, as an output, control information for controlling at least one parameter influencing the separation of the gas molecules of the first species from the gas mixture. More particularly, the control device 26 can be configured to process respective input parameters with respect to one or more target criteria, e.g. a specific target quantity and / or quality criterion of the gas separation process implemented by the apparatus 20. As an example, a respective target quantity and / or quality criterion of the gas separation process can relate to a specific output of gas from which the gas molecules of the first species have been separated and / or a specific residual concentration of gas molecules of the first and / or at least one second species which is to be achieved in the gas separation process implemented by the apparatus 20.

[0167] The at least one control device 26 can be generally configured to detect and / or monitor at least one operational parameter, particularly an operational performance, of at least the at least one gas membrane device 10 and / or the at least one pre-treatment device 23 and generate an information indicative of at least one detected and / or monitored operational parameter of the at least one gas membrane device 10 and / or the at least one pre-treatment device 23. The apparatus 20 can thus, comprise one or more detection units, such as e.g. sensors, particularly flow sensors, temperature sensors, impurity sensors, gas sensors, etc., which can generate detection information which can be used for detecting and / or monitoring at least one operational parameter, particularly an operational performance, of at least the at least one gas membrane device 10 and / or the at least one pre-treatment device 23 and generate a respective information indicative of at least one detected and / or monitored operational parameter of at least the at least one gas membrane device 10 and / or the at least one pre-treatment device 23. The control device 26 can be particularly, configured to use a respective information for implementing a control loop, particularly an open control loop or a closed control loop, for controlling operation of at least the at least one pre-treatment device 23 and / or the at least one gas membrane device 10 and / or a respective flow generation device 25.

[0168] The at least one control device 26 can be configured to output the information to a user and / or to take at least one discrete action concerning the operation of at least the at least one gas membrane device 10 and / or the at least one pre-treatment device 23 based on the information. Outputting can comprise outputting a respective information, which can e.g. be an acoustically perceivable and / or a visually perceivable information, via an outputting means 27 provided with the apparatus 20 and / or transmitting a respective to a user device, such as a computer, smartphone, etc., such that the information, which can e.g. be an acoustically perceivable and / or a visually perceivable information, can be output via an outputting means of the user device. In either case, a respective information can be or comprise a warning to a user in events that the information indicates that at least a part of the gas separation process implemented by the apparatus 20 does not take place as desired. Taking a discrete action can comprise changing at least one operational parameter of at least the at least one pre-treatment device 23, the at least one gas membrane device 10 and / or the at least one flow generation device 25, for instance. Taking a discrete action can be implemented automatically such that the operation of the apparatus 20 can be fully automated.

[0169] As is apparent from Fig. 5, the apparatus 20 can further comprise at least one compressor device 28 configured to compress the or a respective gas mixture before it flows through the at least one gas membrane device 10. As such, the at least one compressor device 28 is typically arranged upstream of the at least one gas membrane device 10 such that a compressed flow of gas mixture can be directed from the at least one compressor device 28 to the at least one gas membrane device 10. Particularly, the at least one compressor device 28 can be arranged between the at least one pre-treatment device 23 and the at least one gas membrane device 10 such that such that a pre-treated and compressed flow of gas mixture can be directed from the at least one pre-treatment device 23, if present, via the compressor device 28, if present, to the at least one gas membrane device 10.

[0170] As is apparent from Fig. 5, the apparatus 10 can further comprise at least one de-watering device 29 configured to de-water the or a respective gas mixture before it flows through the at least one gas membrane device 10. As such, the at least one de-watering device 29 is typically arranged upstream of the at least one gas membrane device 10 such that a de-watered flow of gas mixture can be directed from the at least one de-watering device 29 to the at least one gas membrane device 10. Particularly, the at least one de-watering device 29 can be arranged between the at least one compressor device 28, if present, and the at least one gas membrane device 10 such that such that a pre-treated, compressed and de-wagered flow of gas mixture can be directed from the at least one pre-treatment device 23, if present, via the at least one compressor device 28, if present, and via the at least one de-watering device 29, if present, to the at least one gas membrane device 10.

[0171] As is apparent from Fig. 5, the apparatus 20 can comprise at least one storage device 30 configured to capture gas molecules of the first species which have been separated from a respective gas mixture via the at least one gas membrane device 10. The at least one storage device 30 can be or comprise a tank which defines an inner volume for receiving gas molecules of the first species which have been separated from a respective gas mixture via the at least one gas membrane device 10. As such, the at least one storage device 30 is typically arranged downstream of the at least one gas membrane device 10 such that a flow of gas molecules of the first species which has been separated from a respective gas mixture can be directed from the at least one gas membrane device 10 to the at least one storage device 30. The at least one storage device 30 can be provided with tempering and / or pressurizing units (not shown) configured to temper and / or pressurize the gas molecules stored therein under specified physical conditions. Respective physical conditions can particularly, result in that the gas stored in the at least one storage device 30 is transferred into a liquid.

[0172] Both the gas membrane devices 10 of Fig. 1 - 4 and the apparatus of Fig. 5 enable implementing a method for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species. The method comprises using at least one gas membrane device 10 and / or at least one gas separation apparatus 20 for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species.

[0173] Notably, the method can particularly, comprise generating a flow of the gas mixture which at least partly flows through the gas membrane device 10 or the gas separation apparatus 20, respectively, wherein the flow of the gas mixture can be pre-treated via the at least one pre-treatment device 23 of the gas separation apparatus 20 and / or the gas molecules of the first species can be removed from the gas mixture via the at least one gas membrane device 10 of the gas separation apparatus 20.

[0174] Further exemplary embodiments of the gas membrane device 10 are illustrated in Fig. 6 and 7.

[0175] Fig. 6 and 7 generally indicate that respective functionalized membrane layers 11 or membrane layer elements 11.n can be arranged relative to each other such that their respective penetration openings 12 are not aligned and thus, offset, particularly not forming a straight gas penetration channel which extends through the gas membrane device 10 (as indicated by the arrows in Fig. 6 - 9 which indicate a possible path along which a gas component or species, respectively may penetrate though the gas membrane device 10).

[0176] Fig. 6 shows an exemplary representation of an embodiment in which intercalation agents 31 are provided between adjacent membrane layers 11 and membrane layer elements 11.n, respectively. As indicated above, respective intercalation agents 31 can acts as intralayer spacing agents 15 and / or interlayer spacing agents 16, respectively.

[0177] Fig. 7 shows an exemplary representation of an embodiment in which both crosslinked functionalization agents 13, 14 and non-crosslinked functionalization agents 13, 14 are present. Particularly, Fig. 7 shows an exemplary representation of an embodiment in which both crosslinked interlayer spacing agents 16 and non-crosslinked interlayer spacing agents 16 are present. However, the same could apply to intralayer spacing agents 15 which could thus, also be crosslinked or non-crosslinked. The crosslinking is indicated for illustrative purposes by a connection between vertically adjacent membrane layers 11 and membrane layer segments 1 1 .n, respectively.

Claims

C LAI MS1 . A gas membrane device for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species, the gas membrane device comprising: at least one two-dimensional functionalized membrane layer comprising one or more penetration openings configured such that gas molecules of the first species can penetrate therethrough, wherein the at least one two-dimensional functionalized membrane layer is functionalized with at least one functionalizing agent configured to promote penetration of the gas molecules of the first species through the one or more penetration openings and / or configured to impede penetration of the gas molecules of the at least one second species through the one or more penetration openings.

2. The gas membrane device of claim 1 , wherein the at least one two-dimensional functionalized membrane layer comprises an arrangement of a plurality of, particularly flake-like shaped, membrane layer elements arranged in a two-dimensional plane.

3. The gas membrane device of claim 2, wherein two or more of the membrane layer elements are arranged with an intralayer spacing, wherein the intralayer spacing forms a respective penetration opening.

4. The gas membrane device of claim 2 or 3, wherein at least one membrane layer element comprises at least one intralayer spacing agent configured to repel the at least one two-dimensional membrane layer elements from at least one adjacently arranged further two-dimensional membrane layer element, thereby creating a respective intralayer spacing between the at least one two-dimensional membrane layer element and the at least one adjacently arranged further two-dimensional membrane layer element.

5. The gas membrane device of claim 4, wherein the at least one intralayer spacing agent carries at least one electric charge configured to create an electrostatic repelling force between the at least one membrane layer element and the at least one adjacently arranged further membrane layer element.

6. The gas membrane device of claim 4 or 5, wherein the at least one intralayer spacing agent comprises at least one of the following: a carbonyl-group, a carboxylic-group, a di-carboxylic-group, a hydroxyl-group, an epoxide-group, an amine-group, a diamine-group, an acrylate-group, a sulfonic-group, particularly a sulfonic-acid-group, a phosphonic-group, particularly a phosphonic-acid-group, a silane-group, an amino- silane-group, a polymeric group, an ionic charge.

7. The gas membrane device of any one of claims 4 - 6, wherein the at least one intralayer spacing agent comprises one or more groups resulting from an at least partial reduction of graphene oxide.

8. The gas membrane device of any one of claims 4 - 7, wherein the at least one intralayer spacing agent comprises doped graphene oxide, particularly N-doped graphene oxide, more particularly Nitrogen-doped graphene oxide.

9. The gas membrane device of any one of claims 4 - 8, wherein the at least one intralayer spacing agent comprises one or more intercalation agents configured to intercalate between adjacent membrane layer elements or intercalated between adjacent membrane layer elements.

10. The gas membrane device of claim 9, wherein the one or more intercalation agents comprise at least one of the following: nanoparticles or nanosheets, particularly Ti-based nanoparticles or Ti-based nanosheets.

11. The gas membrane device of any one of the preceding claims, comprising multiple two-dimensional functionalized membrane layers each comprising an arrangement of a plurality of, particularly flake-like shaped, membrane layer elements arranged in a two-dimensional plane.

12. The gas membrane device of claim 11 , wherein at least one two-dimensional functionalized membrane layer comprises at least one interlayer spacing agent configured to repel the at least one two-dimensional functionalized membrane layerfrom at least one adjacently arranged further two-dimensional functionalized membrane layer, thereby creating In interlayer spacing between the at least one two-dimensional functionalized membrane layer and the at least one adjacently arranged further two-dimensional functionalized membrane layer.

13. The gas membrane device of claim 12, wherein the at least one interlayer spacing agent carries at least one electric charge configured to create an electrostatic repelling force between the at least one functionalized membrane layer and the at least one adjacently arranged further functionalized membrane layer.

14. The gas membrane device of claim 12 or 13, wherein the at least one interlayer spacing agent comprises at least one of the following: a carbonyl-group, a carboxylic-group, a di-carboxylic-group, a hydroxyl-group, an epoxide-group, an amine-group, a diamine-group, an acrylate-group, a sulfonic-group, particularly a sulfonic-acid-group, a phosphonic-group, particularly a phosphonic-acid-group, a silanegroup, an amino-silane-group, a polymeric group, an ionic charge.

15. The gas membrane device of any one of claims 12 - 14, wherein the at least one interlayer spacing agent comprises one or more groups resulting from an at least partial reduction of graphene oxide.

16. The gas membrane device of any one of claims 12 - 15, wherein the at least one interlayer spacing agent comprises doped graphene oxide, particularly N-doped graphene oxide, more particularly Nitrogen- doped graphene oxide.

17. The gas membrane device of any one of claims 12 - 16, wherein the at least one interlayer spacing agent comprises one or more intercalation agents configured to intercalate between adjacent membrane layer elements or intercalated between adjacent membrane layer elements.

18. The gas membrane device of claim 17, wherein the one or more intercalation agents comprise at least one of the following: nanoparticles or nanosheets, particularly Ti-based nanoparticles or Ti-based nanosheets.

19. The gas membrane device of any one of claims 11 - 18, wherein the interlayer spacing can range between 0,1 nm - 1 pm.

20. The gas membrane device of any one of the preceding claims, wherein the at least one two-dimensional layer is a carbon-based layer, particularly comprising a plurality of carbon-atoms in a lattice-arrangement.21 . The gas membrane device of any one of the preceding claims, wherein the at least one two-dimensional functionalized membrane layer is a graphene-based layer.

22. The gas membrane device of any one of the preceding claims, wherein the at least one two-dimensional functionalized membrane layer is a graphene-oxide-based layer.

23. The gas membrane device of any one of the preceding claims, wherein the at least one two-dimensional functionalized membrane layer has a layer thickness between 0,1 nm - 1 pm.

24. The gas membrane device of any one of the preceding claims, wherein the at least one two-dimensional functionalized membrane layer has an area of at least 5 cm2.

25. The gas membrane device of any one of the preceding claims, wherein the at least one penetration opening has in at least one spatial direction a size 0,1 nm - 1 nm.

26. The gas membrane device of any one of the preceding claims, wherein the at least one two-dimensional layer functionalized membrane layer is at least partly, particularly completely, embedded in an embedding material or in an embedding material structure, thereby forming an embedded functionalized membrane layer.

27. The gas membrane device of claim 26, wherein the embedding material or the embedding material structure is or comprises a polymer, particularly a curable resin, more particularly a curable epoxy resin.

28. The gas membrane device of claim 26 or 27, wherein the embedding material orthe embedding material structure comprises at least one functionalization configured to promote penetration of the gas moleculesof the first species through the one or more penetration openings of the at least one two-dimensional layer functionalized membrane layer and / or configured to impede penetration of the gas molecules of the at least one second species through the one or more penetration openings of the at least one two-dimensional layer functionalized membrane layer.

29. The gas membrane device of any one of claims 26 -28, further comprising at least one support material providing mechanical support for the at least one two-dimensional layer functionalized membrane layer.

30. The gas membrane device of claim 28, wherein the at least one support material is or comprises one or more porous substrates or membranes with high mechanical strength.31 . The gas membrane device of any one of claims 27 - 31 , comprising multiple embedded functionalized membrane layers, particularly in a stacked arrangement.

32. The gas membrane device of any one of the preceding claims, wherein the at least one two-dimensional layer functionalized membrane layer or a respective embedded functionalized membrane layer is arranged within a sealing structure, particularly configured to bond the free edges of the at least one two-dimensional layer functionalized membrane layer or the free edges of the at least one embedded functionalized membrane layer.

33. The gas membrane device of any one of the preceding claims, wherein it is configured to separate CO2- molecules from a gas mixture, particularly from a flow of a gas mixture, comprising CC>2-molecules and molecules of at least one other species.

34. The gas membrane device of any one of the preceding claims, further comprising at least one nonfunctionalized membrane layer, particularly in a parallel arrangement relative to the at least one functionalized membrane layer.

35. The gas membrane device of claim 34, further comprising a stack of multiple functionalized membrane layers and multiple non-functionalized membrane layer, wherein at least one non-functionalized membrane layer is arranged between two adjacent functionalized membrane layers.

36. The gas membrane device of any one of the preceding claims, wherein the at least one functionalizing agent is crosslinked.

37. A gas separation apparatus for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species, the gas separation apparatus comprising, particularly arranged in a common housing structure: at least one gas membrane device according to any one of the preceding claims;at least one pre-treatment device for pre-treating a gas mixture from which respective gas molecules of a first species are to be separated; and / or at least one control device configured to control at least one parameter influencing the separation of the gas molecules of the first species from the gas mixture.

38. The gas separation apparatus of claim 37, wherein the at least one pre-treatment device is configured to remove impurities, particularly particulate impurities, from the gas mixture.

39. The gas separation apparatus of claim 37 or 38, wherein the at least one pre-treatment device is configured to temper the gas mixture.

40. The gas separation apparatus of any one of claims 37 to 39, wherein the at least one control device is configured to detect and / or monitor at least one operational parameter, particularly an operational performance, of the at least one gas membrane device and / or the at least one pre-treatment device and generate an information indicative of at least one detected and / or monitored operational parameter of the at least one gas membrane device and / or the at least one pre-treatment device.41 . The gas separation apparatus of claim 40, wherein the at least one control device is configured to output the information to a user and / or to take at least one discrete action concerning the operation of the at least one gas membrane device and / or the at least one pre-treatment device based on the information.

42. A method for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species, the method comprising using at least one gas membrane device according to any one of claims 1- 36 and / or at least one gas separation apparatus according to claim 37 - 41 for separating gas molecules of a first species from a gas mixture, particularly from a flow of a gas mixture, comprising the gas molecules of the first species and gas molecules of at least one second species, particularly by generating a flow of the gas mixture which at least partly flows through the gas membrane device or the gas separation apparatus.

43. A method for manufacturing a gas membrane device according to any one of claims 1 - 36, the method comprising:- providing at least one two-dimensional membrane layer, particularly comprising one or more penetration openings configured such that gas molecules of the first species can penetrate therethrough,- functionalizing the at least one two-dimensional membrane layer with at least one functionalizing agent configured to promote penetration of the gas molecules of the first species through the one or more penetration openings and / or configured to impede penetration of the gas molecules of the at least one second species through the one or more penetration openings to create at least one functionalized membrane layer.

44. The method of claim 43, wherein the at least one two-dimensional functionalized membrane layer is created by dispersing flake a plurality of, particularly flake-like shaped, membrane layer elements in a dispersion solution, particularly in an electrically conductive dispersion solution, wherein the membrane layer elements are arranged in two-dimensional layers in the dispersion solution, particularly based on electric and / or electrostatic interactions effected through a positive and an negative electrode arranged at or in the dispersion solution, thereby creating the at least one two-dimensional functionalized membrane layer.

45. The method of claim 44, wherein, when the membrane layer elements arranged in respective two- dimensional layers, the dispersion solution is removed or the respective two-dimensional functionalized membrane layers are removed from the dispersion solution.

46. The method of claim 44 or 45, further comprising embedding the at least one two-dimensional functionalized membrane layer in an embedding material or in an embedding material structure.

47. The method of claim 46, wherein multiple two-dimensional functionalized membrane layers are embedded in an embedding material or in an embedding material structure, thereby forming a block comprising multiple embedded two-dimensional functionalized membrane layers, wherein the method comprise separating sheet- or slice-like elements from the block, wherein each element comprises at least one two-dimensional functionalized membrane layer embedded in the embedding material or in the embedding material structure.

48. The method of any one of claims 44 - 47, further comprising providing the at least one two-dimensional functionalized membrane layer with a support material providing mechanical support for the at least one two-dimensional layer functionalized membrane layer.

49. The method of any one of claims 44 - 48, further comprising arranging at least one non-functionalized membrane layer between at least two adjacent functionalized membrane layers.

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