Cellulose binder formulation for adsorbent apparatus

Abstract

The present application discloses a composition comprising an adsorbent and a cellulose based binder that strongly adheres to a support and is flexible.

Description

DescriptionCELLULOSE BINDER FORMULATION FOR ADSORBENT APPARATUSTechnical Field

[0001] The present invention relates to the field of gas capture and more particularly carbon dioxide capture using adsorption processes, specifically focusing on an adsorption apparatus and a composition for an adsorption material. The composition for an adsorption material comprises an adsorbent, such as a metal-organic framework (MOF) adsorbent, and a cellulose based binder comprising a cellulose derivative.Background Art

[0002] Carbon dioxide (CO2) emissions from various industrial processes and combustion of fossil fuels have contributed significantly to the increase of greenhouse gases in the atmosphere, leading to global climate change. As a result, there is a growing need for effective methods to capture and mitigate CO2 emissions and other gases as for example carbon monoxide (CO) or sulfur dioxide (SO2).

[0003] One particularly promising strategy for the capture of CO2 involves the utilization of adsorbents. Adsorbents can be engineered with various supports, such as a monolith, a fiber, or a laminate, to produce adsorption materials. Among these adsorption materials’ supports, laminates are very interesting, especially for air drying application, due to their ease of manufacturing and the low pressure drop, fast heat and mass transfer when stacked to form a large-scale adsorption apparatus. Among the adsorbents, metal organic frameworks are of particular interest since they have shown satisfactory adsorption yield while being industrially easy to manufacture.

[0004] During the adsorption / desorption cycle, which is central to the gas adsorption process, it is important to provide an adsorption material that effectively reduces pressure drop and enhances both mass and heat transfer. The efficiency of the adsorption process is significantly influenced by these factors, as a low pressure drop ensures that the gas flows smoothly through the adsorption material, minimizing energy consumption and operational costs. Enhanced mass transfer facilitates the rapid movement of molecules in gaseous or vapor phase to the adsorbent surface, thereby increasing the rate of adsorption. Similarly, improved heat transfer is crucial for maintaining the thermal stability of the adsorption material, as the adsorption and desorption processes are often exothermic and endothermic, respectively. Efficient heat dissipation prevents localized overheating, which can degrade the adsorbent material and reduce the effectiveness of the adsorption material over time and reduce the time between the adsorption and desorption processes. Efficient heat dissipation thus minimizes energy consumption and operational costs.

[0005] Therefore, selecting an adsorption material that optimizes these parameters is essential for achieving a high-performance, durable, and cost-effective gas adsorption system.

[0006] The process of fabricating an adsorption material begins with coating the support of the adsorption material with a layer of a composition comprising an adsorbent. The support coated withthe layer of composition is then dried to solidify the layer of composition. The layer of composition, once coated and dried, must adhere sufficiently to the support material and must be flexible if the support material is flexible. Indeed, if the layer does not adhere sufficiently and is not flexible when needed, then the adsorption material can be damaged during handling and use.

[0007] Therefore, a composition having unsuitable properties such as insufficient adhesion and / or insufficient flexibility makes the adsorption material difficult to manipulate without risking damage. Additionally, the industrial-scale manufacture of such fragile adsorption material presents a significant burden, as the risk of damage during production, handling and uses increases, complicating the process of manufacturing and the process of capturing CO2, thereby leading to higher costs and lower yields.

[0008] Accordingly, the industry would benefit from the development of enhanced compositions for an adsorption material that surmounts these existing limitations and enables the production of improved adsorption material thereby increasing gas capture efficiency.Summary

[0009] The present invention addresses this need by providing a composition for an adsorption material comprising:- a cellulose based binder, and- an adsorbent, wherein the cellulose based binder comprises a cellulose derivative.

[0010] The composition of the invention is designed for ease of handling, allowing for straightforward manipulation during various stages of use. It can be easily replicated, ensuring consistent quality and performance across different batches.

[0011] Additionally, the composition is formulated to be easily transportable, minimizing the risk of damage or degradation during shipping.

[0012] Furthermore, it has excellent storage stability, in particular when kept in dry environments and without being exposed to the sun. Thanks to this advantage its properties are maintained over extended periods, which makes it convenient for long-term use and inventory management.

[0013] The present invention also concerns an adsorption material comprising:- a support, preferably being a monolith, a laminate, or a fiber, more particularly a laminate, and- the above defined composition, wherein the support is coated with a layer of the composition.

[0014] The adsorption material has advantageously improved gas adsorption properties, in particular CO2 adsorption properties. The lifetime of the adsorption material is also high since the adhesion of the layer of the composition to the support is high and the flexibility of this layer enables it to conform to a flexible support. Therefore, the layer of the composition does not detach easily from the support of the adsorption material. These attributes collectively enhance the overall efficiency of gas capture, in particular CO2 capture, making the adsorption material more effective and durable.

[0015] The present invention also concerns an adsorption apparatus comprising the adsorption material of the present invention as defined above.

[0016] Advantageously, the adsorption apparatus of the present invention is adapted to capture predetermined gases and more particularly CO2 in a more effective and durable manner.

[0017] The present invention also concerns a process for the preparation of the composition for an adsorption material as defined above comprising the step of mixing a cellulose based binder with an adsorbent.

[0018] Advantageously, this process is easy to perform thereby enabling the production of the composition of the present invention at high yield and reduced cost.

[0019] The present invention also concerns a process for the preparation of the adsorption material of the invention comprising the following steps: a) coating a support with a layer of the composition as defined above, or prepared by the process as defined above to obtain a coated support, and b) drying the coated support obtained in step a) to make the adsorption material.

[0020] This process ensures, at high yield, a uniform and complete coating, maximizing the contact surface area between the adsorbent and the gas.

[0021] The present invention also concerns a process to purify a mixture of gas containing an unwanted gas selected from the list consisting of carbon dioxide (CO2), carbon monoxide (CO), sulfur dioxide (SO2), water (H2O), hydrogen sulfide (H2S), nitrogen oxides (NOx), ozone (Os), Volatile Organic Compounds (VOC), ammonia (NH3), methane (CF ) or a mixture thereof, in particular carbon dioxide, water, hydrogen sulfide or a mixture thereof, more particularly CO2, the process comprising the following step: i) contacting the gas containing an unwanted gas with the adsorption material of the present invention as defined above or made by the process of the present invention as defined above to obtain separately a purified gas comprising a reduced concentration of the unwanted gas and an adsorption material containing the unwanted gas, and optionally : ii) desorbing the unwanted gas from the adsorption material containing the unwanted gas.

[0022] Overall, the present invention offers a significant advancement in the field of gas, especially CO2 capture technology by providing a durable, efficient, and scalable solution that addresses the limitations of existing methods. The following detailed description and examples illustrate the various aspects and embodiments of the present invention.Brief Description of Drawings

[0023] Other features, details and advantages will be shown in the following detailed description and on figurel :Fig. 1

[0024] [Fig. 1] is a graph of three curves representing the CO2 adsorption of composition according to the present invention in comparison with the adsorption curve of pure AI-MIL-120.Description of Embodiments

[0025] According to a first aspect of the present invention, it is provided a composition for an adsorption material comprising a cellulose based binder and an adsorbent, wherein the cellulose based binder comprises a cellulose derivative.

[0026] Within the meaning of the present invention, the term “cellulose derivative” refers to a cellulose that has been physically modified, chemically modified from the natural polysaccharide, or physically and chemically modified.

[0027] The cellulose derivative imparts adhesion to the composition, allowing it to firmly attach to a support of an adsorption material. Additionally, it shows flexibility when applied on a flexible support.

[0028] The cellulose derivative used in the present invention may be carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), methyl cellulose (MC) or a mixture thereof, and preferably, the cellulose derivative is CMC.

[0029] The choice of cellulose derivative may depend on the specific properties required for the application, such as solubility, viscosity, adhesive strength, and flexibility of the composition once applied on a support of an adsorption material.

[0030] The choice of the cellulose based binder may also be dependent on the adsorbent used in the composition of the invention.

[0031] The composition of the invention may comprise from 5% to 50% of cellulose derivative by dry weight of the composition, in particular from 9% to 25%, more particularly from 10% to 22.5%.

[0032] When the cellulose derivative content falls within the above ranges, it ensures that the composition adheres properly to the support and / or remains cohesive.

[0033] Within the meaning of the present invention, the term “dry weight” denotes the weight of the composition without the mass of the solvent. The solvent can be an aqueous solvent, more particularly water.

[0034] The composition of the present invention may be free of cellulose. Alternatively, in addition to the cellulose derivate, the cellulose based binder may further comprise cellulose. Also, a cellulose based binder may consist of cellulose, cellulose derivative, or a mixture thereof.

[0035] The cellulose based binder is valued for its biodegradability, non-toxicity, and renewable origin.

[0036] Adding cellulose to the composition enhances the mechanical strength and structural integrity of the composition. Furthermore, the presence of cellulose can contribute to better dispersion of the adsorbent within the cellulose based binder, leading to a more uniform coating of the composition on the support of an adsorption material and improved gas, in particular CO2, adsorption efficiency of the composition.

[0037] Within the meaning of the present invention, the term “cellulose” denotes fibers obtained by means of a chemical or mechanical or thermomechanical pulping process, such as wood fibers, hemp fibers, flax fibers or a mixture thereof, in particular wood fibers.

[0038] The composition of the invention may comprise from 0.1% to 10% of cellulose by dry weight of the composition, in particular from 0.1% to 5%, more particularly from 0.1% to 2.55%, even more particularly from 2% to 3%.

[0039] Good results, in particular in terms of adhesion, flexibility and CO2 capture, are achieved for cellulose amount within these ranges.

[0040] The composition of the invention may comprise from 2% to 50% of cellulose-based binder by dry weight of the composition, in particular from 5% to 40%, more particularly from 10% to 25%.

[0041] According to a preferred embodiment, the cellulose based binder may be CMC.

[0042] According to another preferred embodiment, the cellulose based binder comprises CMC and cellulose.

[0043] According to the present invention, the composition for an adsorption material also comprises an adsorbent.

[0044] Within the meaning of the present invention, the term “adsorbent” refers to a material that can capture and hold molecules of a gas, liquid, or dissolved solid on its surface. This process, known as adsorption, involves the accumulation of substances at the interface between the adsorbent and the surrounding phase, typically resulting in a thin film of the adsorbate on the surface of the adsorbent.

[0045] The adsorbent of the invention is preferably micro-porous or meso-porous particles. Micro- porous adsorbents particles have pore diameters of strictly less than 2 nano meters (nm). Meso- porous adsorbents particles have pore diameters between 2 nm and 50 nm.

[0046] The specific surface area of the adsorbent of the composition of the invention may be greater than 50m2 / g and preferably greater than 100m2 / g.

[0047] Adsorbent of the composition of the present invention can be activated carbon, silica gel, zeolites, metal-organic frameworks (MOFs) or a mixture thereof.

[0048] According to a preferred embodiment, the adsorbent of the composition may be a MOF, a zeolite, or a mixture thereof, in particular an aluminum-based MOF. Indeed, such adsorbent may have acceptable gas adsorption capacity, advantageously in regard to its CO2 adsorption capacity.

[0049] The adsorbent of the composition may preferably be a metal-organic framework (MOF) selected from a list consisting of MOFs known for their CO2 adsorption capacity.

[0050] The MOF of the composition of the present invention may be CALF-20, UTSA-16, KAUST-7, MOF-74 (CPO-27), HKUST-1 (Cu-BTC), MIL-101 , MIL-53, ZIF-8, UiO-66, SIFSIX-3-Cu, Mg-MOF- 74, PCN-250, CAU-10-H, AI-MIL-120, MIL-120(Cr) or a mixture thereof.

[0051] In a preferred embodiment, the adsorbent is an AI-MIL-120. Indeed, very good results in terms of CO2 capture are obtained with this MOF.

[0052] The composition of the invention may comprise from 50% to 98% of adsorbent by dry weight of the composition, in particular from 60% to 95%, more particularly from 75% to 90%.

[0053] The mass ratio of binder: adsorbent in the composition may be from 1 :1 to 1 :20, in particular from 1 :2 to 1 :15, more particularly from 1 :3 to 1 :9.

[0054] These specific ranges of mass ratio ensure an optimal balance between mechanical stability and adsorption capacity of the composition of the invention. A lower ratio enhances the adhesion and flexibility of the composition but could reduce the CO2 capture capacity of the composition. A higher ratio increases the CO2 capture capacity of the composition but may decrease the adhesion and flexibility of the composition.

[0055] In a very preferred embodiment, the composition of the invention comprises:- from 10% to 22,5% of CMC by dry weight of the composition,- from 0% to 2,5% cellulose by dry weight of the composition, and- from 75% to 90% of AI-MIL-120 as adsorbent by dry weight of the composition.

[0056] The composition of the invention may further comprise some additives. The choice of the additive depends on the specific properties required for the application, such as for example solubility and viscosity of the composition to facilitate its coating on a support of an adsorption material or even the thermal conductivity of the adsorption material.

[0057] The additive may be selected among the list consisting of carbon substrates including and not limited to, graphene oxide, activated carbon, carbon black, and thickening agent such as bentonite, rheology modifier, fluidifier, plasticizers or a mixture thereof.

[0058] The composition according to the invention may further comprise a solvent, preferably an aqueous solvent. The aqueous solvent may be water, an ethanol-water mixture, a methanol-water mixture, an acetone-water mixture, an isopropanol-water mixture, a glycerol-water mixture, deionized water, or a mixture thereof. Advantageously, the aqueous solvent is water. The solvent is preferably chosen so that additives are soluble in said solvent.

[0059] According to another aspect of the invention, there is provided an adsorption material comprising:- a support, preferably a support being a monolith, a laminate, or a fiber, more preferably a laminate, and- the composition defined above, wherein the support is coated with a layer of the composition.

[0060] The thickness of the layer of the composition coated onto the support may preferably be from 480 micrometers (pm) to 560pm, in particular from 500pm to 540pm, more particularly around 520pm when the composition comprises 10% by weight of binder.

[0061] The thickness of the layer of the composition coated onto the support may preferably be from 903pm to 983pm, in particular from 923pm to 963pm, more particularly around 943pm when the composition comprises 25% by weight of binder.

[0062] Such a thickness may be measured thanks to different methods known by the skilled person, such as averaging several thicknesses measured on multiple scanning electron microscope pictures of the adsorption material.

[0063] The adsorption material comprises a support that is coated with a layer of the composition comprising an adsorbent. The choice of the support is determined based on the specific adsorbent used and the intended purpose of the adsorption material. Indeed, the support may be selected considering factors such as the quantity of gas to be treated, the desired pressure drops, and the type of molecule to be adsorbed. The support may be a monolith, laminate, fiber, or a mixture thereof.

[0064] Within the meaning of the present invention, the term “monolith” refers to a single, continuous piece of material that is often used as a support structure in various applications. In the context of adsorption materials, a monolith typically refers to a solid, porous structure that provides a large surface area for the adsorbent to interact with the gas or liquid being treated. Monoliths are valued for their mechanical strength, low pressure drop, and high mass transfer efficiency.

[0065] Within the meaning of the present invention, the term “laminate” refers to a flat, thin layer of material that can be used as a support for adsorbents. Laminates can be made from various materials, including metals, polymers, carbon, and fabrics. In adsorption applications, laminates provide a flexible and easily manageable surface for coating with adsorbent compositions. They are often used in configurations where space and weight are considerations. A cloth is a specific laminate.

[0066] Within the meaning of the present invention, the term “fiber” refers to a long, thin strand of material that can be woven or bundled together to form a support structure. Fiber can be made from natural or synthetic materials, such as carbon, glass, or polymers. In adsorption applications, fibers offer a high surface area-to-volume ratio, which enhances the interaction between the adsorbent and the gas or liquid being treated. Fibers are often used in filters, membranes, and other applications where flexibility and high adsorption capacity are required.

[0067] The support of the adsorption material of the invention may be flexible.

[0068] In the context of the present invention, "flexible" refers to the ability of the support to bend, stretch, or be manipulated without breaking or losing its functional integrity, thereby maintaining its performance and structural properties under various conditions.

[0069] A flexible support offers several key benefits. Indeed, flexibility enhances durability by allowing the support to withstand mechanical stresses without breaking, making the adsorption material more robust and less prone to damage during handling, installation, and operation. It also simplifies installation by enabling the support to be easily manipulated and shaped to fit various configurations and spaces. Additionally, flexibility ensures improved contact with irregular or curved surfaces, maximizing the contact area between the adsorbent and the target molecules, thereby enhancing adsorption efficiency.

[0070] Even though the support is flexible, the layer of the composition does not fall from said support thanks to the above-mentioned combination of cellulose based binder and adsorbent because the layer adheres strongly to the support and is flexible. Accordingly, the lifetime of the adsorption material of the invention comprising a flexible support is high.

[0071] The support of the adsorption material of the invention may be thermally conductive.

[0072] According to an embodiment, the support may be metallic, in particular the support is made of stainless steel, aluminum, copper, nickel, titanium, Inconel (nickel-chromium alloy), brass, bronze, carbon steel, galvanized steel, carbon, graphite.

[0073] Metallic supports provide excellent thermal conductivity, enhancing heat transfer during adsorption and desorption cycles, which improves overall efficiency. They are also highly durable and can withstand harsh industrial conditions.

[0074] In another embodiment the support may comprise carbon, in particular activated carbon, more particularly may be made of activated carbon.

[0075] Carbon supports, in particular activated carbon supports offer a high surface area and excellent adsorption properties, making them highly effective in capturing target gases like CO2. Additionally, activated carbon is lightweight, allowing for easy handling and installation.

[0076] In a preferred embodiment, the support of the adsorption material may be a laminate being a cloth. This offers excellent flexibility, allowing it to conform to various shapes and surfaces. Moreover, its porosity and roughness advantageously enhance the contact area between the adsorbent and the gas thereby improving adsorption efficiency. Cloth supports are lightweight, easy to handle, and provide better airflow, further boosting the adsorption process.

[0077] Additionally, cloth supports can be made from various materials, including carbon cloth, or activated carbon cloth, which offer high surface area and excellent adsorption properties. They are durable and reusable, making them cost-effective as they can withstand multiple adsorptiondesorption cycles.

[0078] The cloth of the adsorption material may advantageously be a carbon cloth, in particular an activated carbon cloth. Activated carbon cloth offers several benefits, including a high surface area that enhances its adsorption capacity for various gases and contaminants. The activated carbon cloth's flexibility allows it to conform to different shapes and surfaces, maximizing contact area and improving adsorption efficiency. Additionally, it is lightweight, making it easy to install, handle, and maintain. Furthermore, its porous nature allows for better airflow, further enhancing the adsorption process.

[0079] Finally, a carbon cloth offers superior thermal conductivity, which enhances mass transfer and reduces the pressure drop required to adsorb a large quantity of gas efficiently.

[0080] According to an embodiment, the adsorption material comprises:- a support being a carbon cloth,- a composition comprising:- from 10% to 22,5% of cellulose derivative by dry weight of the composition,- from 0% to 2,5% cellulose by dry weight of the composition, and- from 75% to 90% of a MOF as adsorbent by dry weight of the composition

[0081] According to a particular embodiment, the adsorption material comprises:- a support being an activated carbon cloth, and- a composition comprising:- from 10% to 22,5% of CMC by dry weight of the composition,- from 0% to 2,5% cellulose by dry weight of the composition, and- from 75% to 90% of AI-MIL-120 as adsorbent by dry weight of the composition

[0082] According to another aspect of the invention, it is provided an adsorption apparatus comprising an adsorption material of the invention.

[0083] Within the meaning of the present invention, the term “adsorption apparatus” refers to a device designed to capture and remove an unwanted gas from a mixture of gas using the process of adsorption.

[0084] The adsorption apparatus according to the invention may be an adsorption column.

[0085] An adsorption column is a vertical or horizontal vessel filled with the adsorption material of the present invention through which a gas mixture is passed. The molecules of the unwanted gas are adsorbed onto the surface of the adsorbent of the adsorption material as the gas mixture flows through the column. Adsorption columns are commonly used in gas purification. The adsorption column may further be associated with fans or blowers that draw air through a series of the adsorption material of the present invention that capture unwanted gas. The captured unwanted gas is then desorbed and collected for storage or utilization.

[0086] The adsorption apparatus of the invention may be especially configured for the capture of unwanted gases selected from the list consisting of carbon dioxide (CO2), carbon monoxide (CO), sulfur dioxide (SO2), water (H2O), hydrogen sulfide (H2S), nitrogen oxides (NOx), ozone (Os), Volatile Organic Compounds (VOC), ammonia (NH3), methane (CP ) or a mixture thereof, in particular carbon dioxide, water, hydrogen sulfide or a mixture thereof, more particularly CO2.

[0087] According to another aspect of the invention, it is provided a process for the preparation of a composition for an adsorption material according to the invention comprising the step of mixing a cellulose based binder with an adsorbent.

[0088] Mixing a cellulose based binder with an adsorbent can involve various methods and materials. For instance, the cellulose based binder can be dissolved in a solvent, preferably an aqueous solvent, to form a gel-like solution, and then the adsorbent is added to this gel-like solution while stirring continuously to ensure even distribution. Optionally, the same or another solvent is then added to the composition. The quantity of solvent added can be adjusted based on the desired viscosity of the composition, ensuring optimal consistency for coating and performance

[0089] This process can be performed using mechanical mixers, blenders, or other suitable equipment to achieve a homogeneous blend. The choice of binder and adsorbent, as well as the solvent used, can be adjusted based on the specific requirements of the application.

[0090] These methods ensure that the cellulose based binder effectively coats the adsorbent particles, thereby enhancing the adhesion and the flexibility of the layer of composition on the support of the adsorption material.

[0091] The solvent used to dissolve the cellulose based binder before introduction of the absorbent is preferably an aqueous solvent. The aqueous solvent may be water, an ethanol-water mixture, a methanol-water mixture, an acetone-water mixture, an isopropanol-water mixture, a glycerol-water mixture, deionized water, or a mixture thereof. Advantageously, the aqueous solvent is water. The solvent is preferably chosen to ensure solubility if additives introduced in the composition.

[0092] According to another aspect of the invention, it is provided a process to make an adsorption material according to the invention that comprises the following steps: a) coating a support with a layer of the composition of the invention or prepared by the process of the invention to obtain a coated support, and b) drying the coated support obtained in step a) to make the adsorption material.

[0093] This process ensures a uniform and complete coating, which maximizes the contact surface area between the adsorbent and the gas. The drying step enables the coating to adhere to the support. This step also solidifies the coating, making it robust enough to withstand industrial-scale production and handling without significant risk of damage. Additionally, the process can be easily scaled up, enabling high-yield and cost-effective production of the adsorption material. The resulting material is durable, efficient, and well-suited for various applications, including gas purification and environmental remediation.

[0094] The step a) of process of the invention may be performed by spraying the composition on the support, by dipping the support in the composition, by using a brush or roller to apply the composition on the support, by spreading the liquid composition over the support using a blade.

[0095] The coated support of the invention may be dried, during step b) at a temperature of at least 60°C, preferably at least 80°C.

[0096] During step b), the coated support is preferably dried for at least 6 hours, preferably at least 8 hours. The drying time is counted from the moment the desired temperature is reached.

[0097] The temperature and / or the duration of the drying step b) enables the formation of the layer of the composition that is uniform and not cracked, thereby enabling the adhesion of said layer on the support and, when needed, the flexibility of said layer.

[0098] Step b) of the invention may also be done under vacuum.

[0099] It accelerates the drying process by reducing the boiling point of the solvent, thereby enhancing the efficiency of solvent removal. This also results in a more uniform and complete drying of the coated support, which improves the overall quality and performance of the adsorption material.

[0100] According to another aspect, the invention concerns a process for purifying a mixture of gas containing an unwanted gas comprising the following step: i) contacting the mixture of gas containing an unwanted gas with an adsorption material of the invention or made by the process of the invention to obtain separately a purified mixture of gas comprising a reduced concentration of the unwanted gas and an adsorption material containing the unwanted gas and optionally ii) desorbing the unwanted gas from the adsorption material containing the unwanted gas.

[0101] Within the meaning of the present invention, the term "contacting" refers to bringing the mixture of gas containing the unwanted gas into close proximity with the adsorption material so that the unwanted gas molecules can adhere to the surface of the adsorbent to obtain the adsorption material containing the unwanted gas. This can be achieved by forcing the mixture of gas through or over the adsorption material, ensuring that the gas molecules interact with the adsorbent's surface.

[0102] Step i) of the process may be performed with the adsorption apparatus of the present invention as defined above.

[0103] The process can be carried out in various types of equipment, such as adsorption columns, filters, or chambers, where the gas flow is controlled to maximize the contact time and surface area exposure. The goal is to efficiently capture and remove the unwanted gas molecules, resulting in a purified gas with a reduced concentration of the unwanted gas.

[0104] The unwanted gas may be carbon dioxide (CO2), carbon monoxide (CO), sulfur dioxide (SO2), water (H2O), hydrogen sulfide (H2S), nitrogen oxides (NOx), ozone (Os), Volatile Organic Compounds (VOC), ammonia (NH3), methane (CF ) or a mixture thereof, in particular carbon dioxide, water, hydrogen sulfide or a mixture thereof, more particularly CO2.

[0105] The mixture of gas containing an unwanted gas may be the atmosphere or an industrial exhaust gas.

[0106] The mixture of gas containing an unwanted gas may be pretreated before step i). This pretreatment may involve increasing the concentration of the unwanted gas or removing other gases. Such pretreatment steps can enhance the efficiency of the process of purification of the present invention by ensuring that the unwanted gas is more effectively captured by the adsorption material.

[0107] Once the adsorbent of the adsorption material is saturated or once a predetermined duration is passed, step i) stops and step ii) begins. In this step ii), the adsorbed molecules of unwanted gas are removed from the surface of the adsorbent, typically by applying heat, reducing pressure, or using a purge gas. This step ii) thus regenerates the adsorption capacity of the adsorbent material, making it ready for a new step i). The desorbed molecules are collected and can be further processed or disposed of as needed.

[0108] Steps i) and ii) may be repeated one after the other as long as the adsorption material can adsorb the unwanted gas.

[0109] The cycle of step i) and step ii) allows the adsorption material to be used repeatedly, making it an efficient and cost-effective solution for removing molecules of unwanted gas from gas.Examples

[0110] Example 1 : Adhesion and Flexibility

[0111] Different compositions for an adsorbent material according to the present invention or not according to the invention were made.

[0112] The chemical composition of each composition is shown in the table 1 below.The composition of Ex n°C, not according to the invention, comprises adsorbent and cellulose.The composition of Ex n°6 comprises adsorbent and CMC.The other compositions comprise adsorbent, CMC, and cellulose

[0113] The adsorbent is the AI-MIL-120 and the cellulose is bleached softwood pulp.

[0114] The support is Flexzorb® carbon cloth.

[0115] AI-MIL-120 and CMC and / or cellulose were dispersed into water and a paste was made. The cloth is then dipped into the paste and finally the coated cloth is dried under vacuum at 80°C to form a layer of the composition on the cloth.

[0116] The adherence of the layer of the composition on the cloth after drying is determined by visual and physical inspection from bad, moderate to good.

[0117] Observation of the layer on the cloth is done and a result is given in regard to the flexibility of the cloth from Bad, Flexible to Brittle.

[0118] As evidenced by Table 1 , the adherence, and the flexibility of the layer of the composition of Ex n°C, not according to the invention are bad.

[0119] At least one of the adherence and flexibility of the layer of the composition of Ex n°2 to 10, according to the invention is good.For instance, the compositions of ex n°8 and n°9 have good adherence but are brittle. These two compositions may be use in specific conditions wherein the adherence is mandatory but not the flexibility, for instance if the support is not flexible.The best results are achieved with the composition of Ex n°6 and n°7 which have good adherence and flexibility on the cloth.

[0120] [Table 1]

[0121] Example 2: CO2adsorption capacity

[0122] In the table 2 below, the CO2 adsorption capacity of the cloth comprising a layer of the composition of Ex n°6 and n°7 have been measured and compared to the CO2 adsorption capacity of pure AI-MIL-120 (presented as Ex n° theoretical in Table 2 below).

[0123] [Table 2]

[0124] Reference is now made to Figure 1 of the application, where the CO2 adsorption isotherms of pure AI-MIL-120 are compared to those of Ex n°6 and n°7 from Table 2.

[0125] Figure 1 shows that the isotherms of Ex n°6 and n°7 from Table 2 have a similar shape to that of pure AI-MIL-120, although they are slightly lower in magnitude. This indicates that while the CO2 adsorption capacity of the compositions is somewhat reduced compared to pure AI-MIL-120, the overall adsorption behavior remains consistent.

[0126] It has been shown that the composition according to the invention almost reaches the same result as the pure AI-MIL-120. That is to say, the inventors have surprisingly discovered that the composition of the invention still presents satisfactory CO2 uptake even if the MOF has been mixed with a cellulose based binder.

[0127] It has been demonstrated that the composition according to the invention achieves nearly the same CO2 uptake as pure AI-MIL-120. Remarkably, the inventors have discovered that the composition maintains satisfactory CO2 adsorption performance even when the MOF is mixed with a cellulose based binder. This finding indicates that the addition of the binder does not significantlycompromise the adsorption efficiency of the MOF, making the composition both effective and practical for industrial applications.

Claims

Claims

1. A composition for an adsorption material comprising:- a cellulose based binder, and- an adsorbent, wherein the cellulose based binder comprises a cellulose derivative.

2. The composition according to claim 1 comprising from 5% to 50% of cellulose derivative by dry weight of the composition.

3. The composition according to claim 1 or claim 2, wherein the cellulose based binder further comprises cellulose.

4. The composition according to claim 3 comprising from 0.1% to 10% of cellulose by dry weight of the composition.

5. The composition according to any one of claims 1 to 4 comprising from 2% to 50% of cellulose based binder by dry weight of the composition.

6. The composition according to any one of claims 1 to 5 comprising from 50% to 98% of adsorbent by dry weight of the composition.

7. The composition according to any one of claims 1 to 6, wherein the mass ratio of binder: adsorbent in the composition is from 1 :1 to 1 :20.

8. The composition according to any one of claims 1 to 7, wherein the adsorbent is an activated carbon, a silica gel, a metal organic framework, a zeolite, or a mixture thereof.

9. The composition according to claims 1 to 8, wherein the adsorbent is CALF-20, UTSA-16, KAUST-7, MOF-74, HKUST-1 , MIL-101 , MIL-53, ZIF-8, UiO-66, SIFSIX-3-Cu, Mg-MOF-74, PCN- 250, CAU-10-H, AI-MIL-120, Cr-MIL-120, or a mixture thereof.

10. The composition according to any one of claims 1 to 9, wherein the adsorbent is the AI- MIL-120.

11. The composition according to any one of claims 1 to 10 further comprising a solvent.

12. The composition according to any one of claims 1 to 1 1 , wherein: the cellulose based binder comprises from 10% to 22,5% of CMC by dry weight of the composition and from 0% to 2,5% cellulose by dry weight of the composition, and the adsorbent is AI-MIL-120, and the composition comprises from 75% to 90% of AI-MIL-120 by dry weight of the composition.

13. An adsorption material comprising:- a support, and- a composition as defined in any one of claim 1 to 12, wherein the support is coated with a layer of the composition.

14. The adsorption material according to claim 13, wherein the support is flexible.

15. The adsorption material according to any one of claims 13 to 14, wherein the support is thermally conductive.

16. The adsorption material according to any one of claims 13 to 15, wherein the support is metallic

17. The adsorption material according to any one of claims 13 to 16, wherein the support comprises carbon, preferably activated carbon.

18. The adsorption material according to any one of claims 13 to 17 wherein the support is a laminate being a cloth.

19. The adsorption material according to claim 18 wherein the cloth is a carbon cloth, preferably an activated carbon cloth.

20. The adsorption material according to claim 19, wherein the composition is according to claim 12.

21. An adsorption apparatus comprising an adsorption material as defined in any one of claims 13 to 20.

22. The adsorption apparatus according to claim 21 being an adsorption column.

23. A process to make a composition for an adsorption material as defined in any one of claims 1 to 12 comprising the following step:- mixing a cellulose based binder with an adsorbent.

24. A process to make an adsorption material according to any one of claims 13 to 20 comprising the following steps: a) coating a support with a layer of a composition as defined in any one of claims 1 to 12 or made by the process of claim 23 to obtain a coated support, and b) drying the coated support obtained in step a) to make the adsorption material.

25. A process according to claim 24, wherein, during step b), the coated support is dried at a temperature of at least 60°C.

26. A process according to any one of claims 24 to 25, wherein, during step b), the coated support is dried during at least 6 hours.

27. A process to purify a mixture of gas containing an unwanted gas comprising the following step: i) contacting the gas containing an unwanted gas with an adsorption material as defined in any one of claim 13 to 20 or made by the process according to any one of claim 24 to 26 to obtain separately a purified gas comprising a reduced concentration of the unwanted gas and an adsorption material containing the unwanted gas and optionally ii) desorbing the unwanted gas from the adsorption material containing the unwanted gas.

28. The process according to claim 27, wherein the unwanted gas is carbon dioxide, carbon monoxide, sulfur dioxide, water, hydrogen sulfide, nitrogen oxides, ozone, Volatile OrganicCompounds, ammonia, methane, or a mixture thereof, in particular carbon dioxide, water, hydrogen sulfide, or a mixture thereof, more particularly carbon dioxide.

29. The process according to claim 27 or 28, wherein the gas containing an unwanted gas is the atmosphere or an industrial exhaust gas.

30. The process according to any one of claims 27 to 29, wherein step i) is performed in an adsorption apparatus as defined in claim 21 or claim 22.

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