Porous electrically conductive three-dimensional network, porous electrically conductive three-dimensional network manufacturing method and use

Abstract

The invention relates to a porous electrically conductive three-dimensional network, characterised in that the porous electrically conductive three-dimensional network is formed from a three-dimensionally formed chemically inert and electrically conductive material, wherein the three-dimensionally formed chemically inert and electrically conductive material has at least one partial or complete coating with an adsorbent.

Description

[0001] Porous electrically conductive three-dimensional network, porous electrically conductive three-dimensional network manufacturing process and use

[0002] The invention relates to a porous, electrically conductive three-dimensional network. Furthermore, the invention relates to a manufacturing process for a porous, electrically conductive three-dimensional network and to its use.

[0003] To separate gases in large industrial plants, pressure or temperature swing adsorbers are most commonly used today. These are containers made of nanoporous materials that are preferentially loaded with one of the gases to be separated in a specific thermodynamic state. Changing the pressure or temperature then releases the gas. By cleverly switching valves, the two gases, for example nitrogen and carbon dioxide, can be separated.

[0004] Pressure swing adsorbers are typically energy-inefficient due to the pumps required to maintain low pressures. Temperature swing adsorbers are also energy-inefficient because the entire container containing the nanoporous material, known as the adsorbent, must also be heated. The adsorbent is usually a large, monolithic block of activated carbon or other technically relevant adsorbents such as zeolites or metal-organic frameworks (MOFs). Their heat capacity must always be factored into the energy budget and is lost during heating and cooling, resulting in very slow cycles and significant heat losses during charging and discharging.

[0005] The same applies to all filters that currently separate or purify gases. This includes, for example, water filters and / or humidity filters, which absorb atmospheric moisture and can only be regenerated by prolonged storage at temperatures up to 120 °C.

[0006] Large-scale temperature swing adsorbers typically operate on the principle of high capacity, resulting in long loading and regeneration cycles. The duration of a cycle depends on the achievable heating and cooling rates and generally ranges from minutes to hours. The energy input per unit mass of product is measured. This energy comprises at least the desorption enthalpy of the stored gas, but in reality, it also includes the heat capacities of the adsorbents, the reactor, the carrier gases, and heat losses due to flow and convection. The slower the heating process, the more energy is consumed in these lossy processes, and the smaller the proportion of energy utilized for the process itself. For example, the adsorption enthalpy for carbon dioxide in a zeolite is specified as 0.5 MJ / kg.However, according to Augustine Ntiamoah et al. (“CO2 Capture by Temperature Swing Adsorption: Use of Hot CO2- Rich Gas for Regeneration”, Ind. Eng. Chem. Res. 2016, 55(3), 703-713), the actual energy used is more than 6 times higher, at over 3 MJ / kg.

[0007] Shortening the desorption times through a clever design of the adsorbents makes the process more efficient in terms of time and energy, and makes the large-scale enrichment of gases such as carbon dioxide, water, nitrogen, hydrogen sulfide and other gases much more attractive.

[0008] According to the state of the art, temperature swing adsorption, also in combination with pressure swing adsorption, is a well-known principle, as already described here, for separating gas mixtures, especially carbon dioxide and water. Temperature swing adsorption is used, for example, in exhaust gas purification for the trace-level removal of contaminants from flue gases of combustion plants.

[0009] The publication EP 3 437 734 A1 discloses an adsorber for indirectly heated temperature cycling adsorption, comprising: at least one channel containing at least one adsorbent in the form of solid adsorbent particles, at least one insert made of a thermally conductive material and into which at least one channel is inserted, wherein the insert has at least one cavity portion and the adsorbent particles at least partially fill the cavity portion of the insert.

[0010] From publication EP 1 291 067 A2, an adsorbent is known with which the temperature-change adsorption of impurities such as water from a gas stream such as air is carried out. The gas stream is packed in the tube-side passages of a shell-and-tube heat exchanger. After a phase of adsorption, during regeneration, heating fluid is passed through the shell-side passage of the adsorber and, upon exiting the adsorber, is returned to the shell via a heater. During the cooling phase, a cooling fluid is passed through the shell-side passage of the adsorber.

[0011] Furthermore, US patent 2018 / 214817 A1 describes a device for adsorbing at least one component from a gas mixture by temperature swing adsorption, comprising a flow chamber and a cooling chamber for receiving a heat transfer fluid, wherein the flow chamber is separate from the cooling chamber, wherein the flow chamber has an adsorbent containing a plurality of (two or more) adsorbent bodies comprising a porous and adsorptively additive first material and a second material with a better thermal conductivity compared to the first material, and wherein the first material is at least partially surrounded by the second material.

[0012] Patent applications US 2012 / 222555 A1 and US 8852322 B2 disclose a gas separation process with a structured particle bed consisting of adsorbent-coated shapes / particles that are arranged in an orderly manner in the bed to simulate a monolith by creating longitudinally extended gas passages through which the gas mixture to be separated can pass along the length of the particles to the adsorbent. The particles can be placed either directly in the bed or in locally structured packets / bundles that are similarly oriented, so that the bed particles behave similarly to a monolith. The adsorbent particles can be shaped with a solid, non-porous core, with the adsorbent forming a thin, adhesive coating on the exposed outer surface. The particles can be cylindrical or hollow to allow easy access to the adsorbent.The separation can be carried out as a kinetic or equilibrium-controlled process.

[0013] Furthermore, the German patent application DE 20 55425 B2 describes an adsorption process for separating gas mixtures in an adsorption system consisting of separate zones I and II connected in series, in which the non-adsorbed gas fraction is removed at the end of the adsorption system, zones I and II are desorbed under pressure reduction, and after regeneration, during the pressure build-up in the adsorption system, the pressure increase in zone II is delayed relative to zone I, characterized in that, when separating gas mixtures containing water vapor in zone I, the water vapor is removed and the adsorbed gas fraction from zone II is withdrawn in the opposite direction to the loading through zone I for the desorption of the water vapor in zone I.

[0014] The publication EP 3 318 321 B1 discloses a method for manufacturing an adsorption device, a conversion method for an adsorption device, and an adsorption device manufactured according to the method. In the method for manufacturing an adsorption device, 1. an adsorbent bed of the adsorption device is filled with a bed of an adsorbent, which is selected from a plurality of adsorbents using a test procedure; 2. a particle of each adsorbent is repeatedly loaded with a sorbate and regenerated, thereby becoming an aged particle; and 3. a fracture property B of the aged particle of each adsorbent is determined, wherein the adsorbent for the bed is selected from the plurality of adsorbents depending on the determined fracture property B.

[0015] Furthermore, German patent application DE 3 702 190 A1 discloses a process for purifying and drying gas mixtures, in particular air upstream of air separation plants, by adsorption. The adsorbers for this purpose are provided with two packings, the first of which binds the water and the second of which binds the component to be separated from the gas stream. The process is carried out in such a way that the heat of adsorption generated during adsorption is largely retained in the adsorber to serve as an aid to desorption during subsequent regeneration.

[0016] German patent application DE 199 35 383 A1 also discloses a method and a device for purifying air of impurities such as water, carbon dioxide, nitrous oxide, ethylene, and / or propane by thermally regenerated adsorption. In an adsorption step, air to be purified is passed successively at a first temperature T1 through a first adsorption zone containing a first adsorbent and through a second adsorption zone containing a second adsorbent. In a regeneration step, a regeneration gas is introduced into the first adsorption zone at a second, higher temperature T2. In the first adsorption zone, water vapor and / or carbon dioxide are essentially completely removed from the air. The second adsorption zone contains an adsorbent that includes strongly nitrogen-binding metal ions.

[0017] The publication EP 3 102 308 B1 describes a process for producing or purifying synthesis gas containing carbon monoxide and at least hydrogen, carbon monoxide, methanol, water, and optionally nitrogen. The synthesis gas is produced according to the prior art by steam reforming or partial oxidation. To increase the carbon monoxide content in the synthesis gas, carbon monoxide separated from the synthesis gas can be recycled as a reactant before gas production.

[0018] Alternative electrical heating methods for temperature change adsorption include, for example, electrical alternating adsorption, which utilizes the Joule effect, induction heating, and microwave heating. In these methods, a conductive adsorbent, such as activated carbon, is heated, particularly without direct contact. These alternative systems can be very fast and simultaneously possess large capacities; however, heat losses occur due to the heat capacity of the substrate or the adsorbent.

[0019] Y. Gomez-Rueda et al., in their publication "Rapid temperature swing adsorption using microwave regeneration for carbon capture," Chemical Engineering Journal, 2022, 446(4), 137345, ISSN 1385-8947, https: / / doi.org / 10.1016 / i.cej.2O22.137345, describe, for example, the use of microwave heating for the thermal regeneration of a porous carbon adsorbent in adsorptive carbon capture. A multimode microwave oven is used here to accelerate the desorption of CO2 after the adsorption of a CO2 / N2 mixture (15 / 85 v / v). The problems with the prior art are essentially that current temperature swing adsorbers are both energetically inefficient and slow. Currently, the operation of temperature swing adsorbers only makes sense if the waste heat from process gases can be used to regenerate the adsorbents.

[0020] In smaller applications, the high temperatures required and the slow regeneration mean that regeneration can only ever take place outside the actual filter process. A filter cartridge filled with zeolites or activated carbon, for example, must be removed from an analytical setup and then heated with highly dry, synthetic air at 300 °C for several hours to ensure that the adsorbate, such as water, is removed from the adsorbents. Therefore, the current state of the art in temperature swing adsorber technology is not suitable for mobile devices and user-friendly applications.

[0021] The operation of temperature swing adsorbers can currently only be implemented practically in large industrial plants and, as described, is not suitable for smaller installations that can enrich gases on a local scale. In many cases, however, direct air capture processes using adsorbents prove to be extremely energy-inefficient even in large-scale plants. There is currently no adequate solution to this problem according to the state of the art, as the energy required for regeneration is too high. Furthermore, for example, the enrichment of water in arid regions to produce drinking water is a particularly difficult task for existing temperature swing adsorbers, as the necessary process gases and equipment are often unavailable.

[0022] The present invention is based on several problems.

[0023] The invention aims to provide a temperature-change adsorber design with improved regeneration. Desorption in the adsorbers is to be simplified and accelerated, enabling short filter cycle times.

[0024] Another objective of the invention is to make the principle of temperature change adsorption more energy-efficient.

[0025] Another task is to provide a temperature swing adsorber setup that allows for regeneration of the adsorber within the setup itself, eliminating the need to remove it for regeneration. Ideally, for mobile applications, the temperature swing adsorber should also be miniaturized.

[0026] A further objective is to heat essentially only the adsorbent and not the entire space around it. These objectives are achieved with a porous, electrically conductive three-dimensional network according to the main claim and two porous, electrically conductive three-dimensional network fabrication methods according to the dependent claims.

[0027] The porous, electrically conductive three-dimensional network is characterized in that the porous, electrically conductive three-dimensional network is formed from a three-dimensionally porous, chemically inert and electrically conductive material, wherein the three-dimensionally formed chemically inert and electrically conductive material has at least a partial or complete coating with an adsorbent.

[0028] In a preferred embodiment, the network can be designed as a temperature change adsorber.

[0029] The three-dimensionally formed, chemically inert and electrically conductive material can also be made of carbon in particular.

[0030] In a preferred embodiment, the individual carbon arms in the network can have a diameter of 0.5 to 8 pm and / or 1 to 5 pm, and the pores between the individual carbon arms can be between 30 and 120 pm and / or 50 and 100 pm in size.

[0031] The adsorbent can be composed of a nanoporous material, in particular a metal-organic framework structure and / or a zeolite and / or a silica gel and / or a porous carbon and / or porous silica and / or porous polymers and / or covalent organic frameworks and / or nanoparticles with high specific surface areas and / or porous salts.

[0032] The network can have a porosity of at least 50% or over 80%. Porosity refers to the ratio of the volume of voids in a porous material to its total volume.

[0033] Furthermore, the adsorbent can exhibit nanoporosity. Nanoporosity means that a material has structural or arbitrary pores that are on the atomic scale. Examples of structural, nanoporous materials are zeolites and MOFs.

[0034] In addition, the network can also contain conductive carbon nanotubes and conductive graphene nanoplatelets.

[0035] The porous, electrically conductive three-dimensional network manufacturing process includes at least the following steps:

[0036] 1. Suspending and / or dispersing adsorbent material and, if necessary,

[0037] Carbon nanotubes in a dispersion medium; 2. Infiltration of a three-dimensionally formed chemically inert and electrically conductive material with the suspension / dispersion from step 1.;

[0038] 3. Drying of the infiltrated three-dimensionally formed chemically inert and electrically conductive material from step 2, wherein the adsorbent material suspended and / or dispersed in step 1. is deposited onto the infiltrated three-dimensionally formed chemically inert and electrically conductive material, thus forming a partial or complete coating.

[0039] In particular, the porous, electrically conductive three-dimensional network produced using the porous, electrically conductive three-dimensional network manufacturing process can preferably be the porous, electrically conductive three-dimensional network according to the invention.

[0040] Drying can be carried out for a duration of 20 to 28 hours and / or 24 hours. Drying can also be carried out in a significantly shorter time, for example in an oven, particularly at temperatures just below the boiling point of the dispersion medium.

[0041] The dispersion medium in step 1 can be, in particular, a solution of water and / or alcohol.

[0042] Furthermore, in step 1, conductive carbon nanotubes can be introduced into the solution in addition to the adsorbent material.

[0043] Another porous, electrically conductive, three-dimensional network fabrication method comprises at least the step of synthesizing an adsorbent as a partial or complete coating on a three-dimensionally formed, chemically inert and electrically conductive material to form a porous, electrically conductive, three-dimensional network. In particular, this porous, electrically conductive, three-dimensional network fabricated by the second porous, electrically conductive, three-dimensional network fabrication method can preferably be the porous, electrically conductive, three-dimensional network according to the invention.

[0044] Both of the described porous, electrically conductive, three-dimensional network fabrication processes result in the formation of a porous, electrically conductive, three-dimensional network with identical properties. The user can therefore obtain an identically formed porous, electrically conductive network with defined properties using either fabrication method.

[0045] A porous, electrically conductive three-dimensional network application involves the following steps: - Feeding a gas mixture with different gas components into a temperature swing adsorber with a porous, electrically conductive three-dimensional network formed as previously described;

[0046] - Adjustable alternating adsorption and desorbing of gas components in the temperature swing adsorber, wherein adsorption is carried out at a lower temperature and desorbing is carried out by applying a power to the chemically inert and electrically conductive material of the porous, electrically conductive, three-dimensional network and thereby heating the network from the inside out and thus at a higher temperature;

[0047] - Removal of gas components from the temperature swing adsorber.

[0048] The temperatures required for adsorption and desorption depend on the adsorbents used and the gases to be adsorbed (host-guest interaction). In any case, however, desorption occurs at higher temperatures than adsorption.

[0049] The process can additionally include the step of rinsing the adsorbent with a purge gas during the desorbing process. The application of power to the chemically inert and electrically conductive material of the porous, electrically conductive three-dimensional network can be carried out in the form of power pulses.

[0050] In particular, the adjustable alternating adsorption and desorption in the temperature change adsorber can be carried out continuously in continuous operation or in batch operation.

[0051] The porous, electrically conductive three-dimensional network can find applications.

[0052] - as temperature change adsorbers and / or

[0053] - for filtering / separating / removing carbon dioxide from the air we breathe and / or

[0054] - for filtering / separating / removing carbon dioxide from ambient air and / or

[0055] - for filtering / separating / removing carbon dioxide from a gas mixture and / or airflow and / or

[0056] - for filtering gases and / or

[0057] - for the purification of gases and / or

[0058] - for the separation of gases and / or

[0059] - for drying air in analytical instruments and / or

[0060] - for drying air in consumer products and / or

[0061] - for water enrichment and / or water extraction in water-scarce areas. Existing gas filters or adsorber cartridges, including temperature-change adsorbers, according to the prior art can be replaced by networks according to the invention.

[0062] In a particularly preferred embodiment, the networks consist of micrometer-thin carbon arms coated with a desired adsorbent micro- or nanoparticle system. Applying an external voltage heats the entire network from within. The adsorbents absorb this heat, forcing the trapped gas to desorb. Due to the open structure of the adsorbents, this process is straightforward, allowing the entire unit to be regenerated in just a few seconds.

[0063] This approach makes the temperature swing adsorber / filter more energy-efficient. It eliminates the need to heat the container and a large quantity of the material, as the heat capacity of all structures is low, and heat can be transferred directly from the porous, electrically conductive, three-dimensional network to the adsorbent via short paths. During desorption, the gas loses the energy required to break the bond and therefore does not heat up significantly. This prevents the generation of excess heat that reduces energy efficiency. Furthermore, the absence of structure heating allows for short cycle times, as the structure can be recharged with process gas immediately after desorption.

[0064] The porous, electrically conductive, three-dimensional network can be purged with gas as a complete system after fabrication and thus used as a temperature swing adsorber and / or filter. When a gas mixture flows through the network, the adsorbents, due to their large and accessible surface area, absorb the preferred gas, and the less preferred gas is therefore concentrated in the gas phase.

[0065] By switching valves in the reactor, it is possible to separate the reaction chamber from the gas mixture. If the network according to the invention, located in the reaction chamber, is now electrically contacted and heated, the heat is transferred from the three-dimensionally formed, chemically inert and electrically conductive material to the adsorbents, and the gases stored therein are desorbed.

[0066] It is now possible to regenerate adsorbents from the inside out using controlled electrical heating, eliminating the need to introduce heat from the outside through the material. Power pulses can even be used to release large quantities of adsorbed gas suddenly, without significantly and continuously heating the temperature-change adsorber and / or filter itself. During pulsed operation, the heat is transferred directly to the adsorbents, resulting in minimal energy loss due to heat dissipation. Simultaneously, the material can be purged with gas to transport the desorbed gas out of the framework. Due to the rapid desorption and the low heat capacity of the framework, the filter can then cool down quickly without active cooling, making it immediately ready for another adsorption / desorption cycle.

[0067] Ideally, the temperature change adsorber can also be miniaturized for mobile applications.

[0068] This allows for the continuous operation of filters in small, non-large-scale industrial setups, enabling the energy-efficient cleaning, filtering, or separation of gases. This is not possible with conventional filters, which always require complex regeneration outside their installation. This opens up a wide range of applications, such as drying air for analytical instruments, drying air in consumer products like plastic drying in 3D printers, and filtering and potentially removing carbon dioxide from the air we breathe.

[0069] The invention is described below with reference to the accompanying figure in the figure description, which is intended to illustrate the invention and is not to be considered limiting. The figure shows:

[0070] Fig. 1 shows an exemplary scanning electron microscope image of a three-dimensionally formed chemically inert and electrically conductive material made of carbon.

[0071] Fig. 2 shows an exemplary schematic representation of the porous, electrically conductive three-dimensional network manufacturing process according to the invention.

[0072] Fig. 3 shows exemplary scanning electron micrographs of a) a three-dimensionally formed chemically inert and electrically conductive carbon material, b) a porous, three-dimensional electrically conductive network with a three-dimensionally formed chemically inert and electrically conductive carbon material and with zeolite as an adsorbent, c) an enlarged section from Fig. 3b), and d) an exemplary thermographic image of a porous, three-dimensional electrically conductive network according to the invention.

[0073] Fig. 4 shows an exemplary scanning electron microscope image of a section of a porous, three-dimensional electrically conductive network with a three-dimensionally formed chemically inert and electrically conductive carbon material and with a metal-organic framework structure as an adsorbent. Fig. 5 shows an exemplary photographic representation of a porous, three-dimensional electrically conductive network according to the invention with a three-dimensionally formed chemically inert and electrically conductive carbon material.

[0074] Fig. 6 shows an exemplary schematic representation of the use of a porous, three-dimensional electrically conductive network according to the invention as a temperature change adsorber and

[0075] Fig. 7 Exemplary scanning electron micrographs of the porous, three-dimensional electrically conductive network with a three-dimensionally formed chemically inert and electrically conductive material made of carbon and with a metal-organic framework structure (MOF) as adsorbent with a) CAU-10 H, b) MOF 303 and c) MOF 801 as metal-organic framework structure.

[0076] Fig. 1 shows an exemplary scanning electron micrograph of a three-dimensionally structured, chemically inert and electrically conductive carbon material 2. The individual carbon arms have a diameter of approximately 1–5 pm, and the pores between the carbon arms are between 50 and 100 pm in size. The microscopic image shows the high connectivity of the carbon arms, which leads to the macroporous network.

[0077] Fig. 2 shows an exemplary schematic representation of the porous, electrically conductive three-dimensional network fabrication process according to the invention. In Fig. 2a), an adsorbent 3 and optionally carbon nanotubes 5 are added to a solution of water and alcohol as the dispersion medium 4 in this example. Subsequently, the micro- and / or nanoparticles of the adsorbent 3 are dispersed and / or suspended in the dispersion medium 4, so that a dispersion and / or suspension 6 is formed. One possible method for this is the use of ultrasound. In Fig. 2c), a three-dimensionally formed chemically inert and electrically conductive material 2 is infiltrated with the dispersion and / or suspension 6 from Fig. 2b).2d) The drying of the infiltrated three-dimensionally formed chemically inert and electrically conductive material 2 takes place, wherein the suspended and / or dispersed adsorbent material 3 is deposited on the infiltrated three-dimensionally formed chemically inert and electrically conductive material 2 and thus forms a coating, so that the porous, electrically conductive three-dimensional network 1 according to the invention is formed.

[0078] The three-dimensionally formed, chemically inert and electrically conductive material 2 can preferably be made of carbon and its surface can be loaded with micro- or nanoparticles of any adsorbent 4. For example, the zeolite class of materials, which is already used on an industrial scale, can be employed. The conductive carbon nanotubes 5, which may be used, serve to fix the particles and entangle them with the surface.

[0079] Figure 3 shows exemplary scanning electron micrographs of a) a three-dimensionally formed chemically inert and electrically conductive material 2 made of carbon, b) a porous three-dimensional electrically conductive network with a three-dimensionally formed chemically inert and electrically conductive material 2 made of carbon and with zeolite as an adsorbent 3, c) an enlarged section from Figure 3c), and d) an exemplary thermographic image of a porous, three-dimensional electrically conductive network 2 according to the invention in which the different temperature zones present when a voltage is applied are visible.

[0080] In Fig. 3b), the three-dimensionally formed chemically inert and electrically conductive material 2 was coated with zeolite 13X particles with a size of approximately 2 pm.

[0081] Figure 3c) shows an enlarged image of a single coated carbon arm from Figure 2b). The particles are tightly packed together. The smaller the particles, the better the individual carbon arms can be coated.

[0082] Figure 3d) shows the three-dimensionally formed, chemically inert and electrically conductive material 2, here made of carbon, of the porous, electrically conductive three-dimensional network 1 according to the invention. It is a material with a volume of 20 mm x 20 mm x 5 mm, which is contacted from its flat sides. By applying power, the material can be heated from the inside. The temperature distribution is very uniform and limited only by heat dissipation at the contacts.

[0083] Furthermore, Fig. 4 shows an exemplary scanning electron micrograph of a section of a porous three-dimensional electrically conductive network 1 with a three-dimensionally formed chemically inert and electrically conductive material 2 made of carbon and with a metal-organic framework structure as adsorbent 3.

[0084] As shown here, in addition to zeolites, other adsorbents 3 can also be applied to the carbon arms. The figure shows a porous salt of the type CAll-55. These particles are significantly smaller and can therefore adhere much more closely to the carbon arms present here. This adsorbent 3 consists of carbon with a metal-organic framework structure.

[0085] Fig. 5 shows an exemplary photographic representation of a porous three-dimensional electrically conductive network 1 according to the invention with a three-dimensionally formed chemically inert and electrically conductive material 2 made of carbon and the adsorbent zeolite 13X.

[0086] Figure 6 shows an exemplary schematic representation of the use of a porous three-dimensional electrically conductive network 1 according to the invention as a temperature change adsorber.

[0087] A gas mixture A+B enters a left and a right reaction chamber 8 of a reactor via a valve. Each of these chambers is filled with the porous, three-dimensional, electrically conductive network 1 according to the invention. A voltage source is connected to each reaction chamber 8 via a circuit 7. The circuit 7 at the left reaction chamber 81 is open. No voltage is applied. Adsorption takes place in the left reaction chamber 81, which is filled with the porous, three-dimensional, electrically conductive network 1. The circuit 7 at the right reaction chamber is closed. Voltage is applied, and the porous, three-dimensional, electrically conductive network 1 is heated from the inside out. Desorption takes place in the right reaction chamber 82, which is also filled with the porous, three-dimensional, electrically conductive network 1.

[0088] During adsorption, the adsorbents 3 absorb the preferred gas A due to their large and accessible surface area, and the non-preferred gas B is enriched in the gas phase.

[0089] By switching valves, the reaction chamber can be separated from the gas mixture A+B.

[0090] During desorption, the gas A stored in the adsorbents 3 is desorbed by heating them, which leads to the regeneration of the adsorbent 3 and thus of the porous, three-dimensional electrically conductive network 1 according to the invention.

[0091] Fig. 7 shows exemplary scanning electron micrographs of the porous, three-dimensional electrically conductive network 1 with a three-dimensionally formed chemically inert and electrically conductive material 2 made of carbon and with a metal-organic framework structure (MOF) as adsorbent 3 with a) CAll-10 H, b) MOF 303 and c) MOF 801 as metal-organic framework structure.

[0092] The porous, three-dimensional electrically conductive networks 1 have a three-dimensionally formed chemically inert and electrically conductive material 2 made of carbon and are covered with adsorbent crystallites 3.

[0093] The figures show that the particles of the metal-organic framework structures densely cover the surface of the carbon sponge 2, while a considerable amount of free space remains between the carbon arms. This arrangement is highly advantageous because energy transfer between adsorbent 3 and the carbon framework can occur directly, without heating additional space or relying on the poor thermal conductivity of adsorbent 3.

[0094] Furthermore, the free space of the network allows for faster diffusion of air through the material and maximizes the exposed surface area of ​​the adsorbents 3.

[0095] In Fig. 7a), the MOF crystallites appear to agglomerate into larger particles with diameters of up to 5 pm. This results in a slightly reduced surface contact compared to the networks 1 in Figs. 7b) and 7c). However, since the individual particles are uniformly distributed on the surface of the carbon sponge 2, the macropores do not become clogged.

[0096] Adsorbent 3 (MOF-303, shown in Fig. 7b) exhibits the densest coverage of the carbon arms, leaving almost no open surface area and thus ensuring good thermal contact. Furthermore, the MOF-303 particles are located very close to the carbon arms, maximizing the space available for diffusion. The enlarged section shows the close contact between the MOF-303 crystallites and the carbon arms.

[0097] In Fig. 7c), the crystallites of the adsorbent 3 MOF-801 adhere tightly to the surface of the carbon sponge 2 without blocking the macropores, although some agglomeration of the MOF particles is visible.

[0098] Another example:

[0099] The invention is described below using a specific embodiment and the previously explained illustrations:

[0100] The porous electrically conductive three-dimensional network fabrication process was carried out as an example to produce the porous electrically conductive three-dimensional networks according to Figure 7.

[0101] Carbon sponges were produced by heating Basotect melamine foam to a temperature of 1000 °C for 90 minutes in a nitrogen atmosphere. The temperature was maintained for 20 minutes to completely carbonize the polymer. Before further use, the sponges were thoroughly washed with deionized water.

[0102] The carbon sponges and the metal-organic framework structures were bonded to form a composite material by liquid infiltration. For this purpose, 100 mg of MOF particles were suspended in 20 mL of water together with 10 wt% of the polysiloxane binder SILRES® MP 50 E by ultrasonic treatment for 30 minutes. The dispersion was then dripped onto the carbon substrate, which was heated to 50 °C to accelerate solvent evaporation. This procedure was repeated until a loading of approximately 70 wt% was achieved, taking care not to exceed the free volume of the substrate during infiltration to prevent the dispersion from drying out at the surface. The wt% of MOFs in the final networks according to the invention, as shown in Figure 7, were 70% for CAU-10-H, 71% for MOF-303, and 74% for MOF-801.

[0103] The exemplary porous, electrically conductive three-dimensional networks produced in this embodiment can be used in particular for water extraction from gaseous water, water vapor, or moisture, since the water sorption isotherms of the exemplary porous, electrically conductive three-dimensional networks are almost identical to those of MOF powders, and these MOF powders are simultaneously very well suited for water enrichment due to their sorption behavior. However, this represents only one of many applications.

[0104] Due to the porous structure of the network according to the invention and the associated increased surface area compared to monoliths in particular, it is possible to reduce the times required for adsorption with the network according to the invention and thus accelerate the cycle times.

[0105] In addition to the sorption performance, the thermal desorption behavior is also an important parameter for the regeneration of the network according to the invention.

[0106] The percolation property of the three-dimensionally formed chemically inert and electrically conductive material, especially carbon, enables uniform and rapid heating and cooling of the materials.

[0107] The regeneration temperature of approximately or at least T = 70°C, preferably desired in the networks produced according to the invention as shown in Figure 7, can be reached, depending on the network configuration, for example, in less than two minutes at a heating power of 0.9 W (6 V and 0.15 A). Cooling occurs within a similar timeframe, so that the network reaches a temperature of T < 30°C, for example, in less than three minutes.

[0108] By skillfully selecting the adsorbents, it is possible to adapt the porous, electrically conductive three-dimensional network according to the invention, in particular for use as a temperature swing adsorber and / or as a filter, to the respective requirements in each individual case.

[0109] A wide variety of adsorbents are available for use. For example, adsorbents can be used to separate sulfur dioxide, nitrogen oxides, or volatile organic compounds, i.e., pollutants such as acetone, hydrocarbons, formaldehyde, and others. The separation of propene / propane, for instance, represents a large-scale, industrially important example.

[0110] A very interesting application possibility can be seen in the formation of a carbon dioxide-binding porous electrically conductive three-dimensional network, wherein this carbon dioxide-binding porous electrically conductive three-dimensional network is designed as a temperature change adsorber and wherein it has a three-dimensionally formed chemically inert and electrically conductive material and a carbon dioxide-binding adsorbent.and wherein the three-dimensionally formed chemically inert and electrically conductive material has at least a partial or complete coating with the carbon dioxide-binding adsorbent, and the three-dimensionally formed chemically inert and electrically conductive material is made of carbon, and the carbon dioxide-binding adsorbent is made of a metal-organic framework structure and / or a zeolite and / or a silica gel and / or a porous carbon and / or porous silica and / or porous polymers and / or covalent organic frameworks and / or nanoparticles with high specific surface areas and / or porous salts.

[0111] Reference symbol list:

[0112] 1 Porous electrically heated three-dimensional network

[0113] 2 Three-dimensionally formed chemically inert and electrically conductive material, carbon sponge

[0114] 3 Adsorbents

[0115] 4 Dispersion medium

[0116] 5 carbon nanotubes

[0117] 6 Dispersion and / or suspension of 3+4 or of 3+4+5

[0118] 7 Circuit with voltage source

[0119] 8 reaction chamber

[0120] A+B gas mixture with the gas components A+B

[0121] A Gas component A

[0122] B Gas component B

Claims

REQUIREMENTS 1. Porous electrically conductive three-dimensional network (1), characterized in that the porous electrically conductive three-dimensional network (1) is formed from a three-dimensionally formed chemically inert and electrically conductive material (2), wherein the three-dimensionally formed chemically inert and electrically conductive material (2) has at least a partial or complete coating with an adsorbent (3).

2. Network (1) according to claim 1 characterized in that the network (1) is designed as a temperature change adsorber.

3. Network (1) according to claim 1 or 2, characterized in that - the three-dimensionally formed chemically inert and electrically conductive material (2) is made of carbon and / or - the adsorbent (3) is formed from a metal-organic framework structure and / or a zeolite and / or a silica gel and / or a porous carbon and / or porous silica and / or porous polymers and / or covalent organic frameworks and / or nanoparticles with high specific surface areas and / or porous salts.

4. Network (1) according to claim 3, characterized in that the individual carbon arms in the network have a diameter of 0.5 to 8 pm and / or 1 to 5 pm and the pores between the individual carbon arms are between 30 and 120 pm and / or 50 and 100 pm in size.

5. Network (1) according to one of the preceding claims, characterized in that the network (1) has a porosity of at least 50% or over 80% and / or the adsorbent has a nanoporosity.

6. Network (1) according to one of the preceding claims, characterized in that the network (1) additionally comprises conductive carbon nanotubes (5).

7. Porous electrically conductive three-dimensional network (1 ^Manufacturing process comprising at least the following steps:

1. Suspending and / or dispersing adsorbent material (3) in a dispersion medium (4); 2. Infiltrating a three-dimensionally formed chemically inert and electrically conductive material (2) with the dispersion medium (4) from step 1.; 3. Drying the infiltrated three-dimensionally formed chemically inert and electrically conductive material (2) from step 2, wherein the adsorbent material (3) suspended and / or dispersed in step 1. is deposited onto the infiltrated three-dimensionally formed chemically inert and electrically conductive material (2) and thus forms a partial or complete coating.

8. Manufacturing process according to claim 7, characterized in that - drying is carried out for a duration of 20 to 28 hours and / or 24 hours and / or - the dispersion medium (4) in step 1 is formed as a solution of water and / or alcohol and / or - in step 1, in addition to the adsorbent material (3), conductive carbon nanotubes (5) are introduced into the dispersion medium (4).

9. Porous electrically conductive three-dimensional network (1 ^Manufacturing process at least comprising the step: Synthesizing adsorbent (3) as a section-by-section or complete coating on a three-dimensionally formed chemically inert and electrically conductive material (2) to form a porous electrically conductive three-dimensional network (1).

10. Porous electrically conductive three-dimensional network (I)-using the following steps: - Feeding a gas mixture with different gas components into a temperature swing adsorber with a porous, electrically conductive three-dimensional network (1) according to any one of claims 1 to 5; - Adjustable alternating adsorption and desorbing of gas components in the temperature swing adsorber, wherein adsorption is carried out at a lower temperature and desorbing is carried out by applying a power to the chemically inert and electrically conductive material (2) of the porous electrically conductive three-dimensional network (1) and thereby heating the network (1) from the inside out to a higher temperature; - Removal of gas components from the temperature swing adsorber.

11. Use according to claim 10, characterized in that - during the desorption process the adsorbent (3) is purged with a purge gas and / or - the application of power is carried out in the form of power pulses and / or - the adjustable alternating adsorption and desorption in the temperature change adsorber is carried out continuously in continuous operation or in batch operation.

12. Use of the porous electrically conductive three-dimensional network (1) according to any one of claims 1 to 6 - as temperature change adsorbers and / or - for filtering carbon dioxide from the air we breathe and / or - for filtering carbon dioxide from the ambient air and / or - for filtering carbon dioxide from a gas mixture and / or airflow and / or - for filtering gases and / or - for the purification of gases and / or - for the separation of gases and / or - for drying air in analytical instruments and / or - for drying air in consumer products and / or - for water enrichment and / or water extraction in water-scarce areas.

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