SE2250929A1 - Device for removal of a liquid from a cellulose nanoparticle slurry and a method thereof - Google Patents

Abstract

A device (10) for removing a liquid phase from a suspension or dispersion (5) comprising cellulose nanoparticles and containing at least 75 wt-% liquid, comprising:a container (1) adapted to be pressurized, having at least one inlet (2) adapted to receive said suspension or dispersion (5), at least one outlet (3) adapted to discharge a filtrate (7) solution; wherein said at least one filter arrangement (8) is provided inside the container (1) having a pore size adapted to retain solid material (4) in the dispersion while allowing said filtrate (7) to pass through and be discharged, and an arrangement adapted to provide a pressure onto said cellulose nanoparticle suspension or dispersion (5) such that said filtrate (7) is discharged from said suspension or dispersion.

Description

DEVICE FOR REMOVAL OF A LIQUID FROM A CELLULOSE NANOPARTICLE SLURRY AND A METHOD THEREOF Technical field The present invention relates to a device and method for efficient removal of a liquid phase of a cellulose nanofiber (CNF) slurry such as a colloid, co||oida| dispersion, dispersion or suspension.

Background A general problem for both the production of cellulose nanoparticles (CNP), such as nanocellulose or cellulose nanofibers (CNF), cellulose nanocrystals (CNC), cellulose nanofibrils (CNF) from wood and bacterial nanocellulose, tunicates and materials therefrom is the large amount of liquid, such as water or a solvent, often above 98 wt-%, associated with the cellulose nanoparticles. Having a low dry content, often below 2 wt-%, is necessary for two major reasons i) feasible processing of the dispersions and ii) achieve efficient liberation and thereby high quality of the cellulose nanoparticles.

By being unable to produce high quality nanocellulose at higher concentrations means that water needs to be removed when forming sheet like products from the cellulose nanoparticles, such as membranes. The removal of water from nanocellulose colloids, suspensions or dispersions is difficult due to the morphology of the CNFs, their intrinsic hydrophilicity and the chemical modifications performed to liberate the CNFs from e.g. wood fibres.

For example, to prepare a 50 um thick membrane from a 1wt-% cellulose nanoparticle dispersion a dispersion equivalent to a several millimetre water column has to be deposited, retain its form and dried, without changes in lateral dimensions. The rheological properties of such a nanocellulose dispersion leads to that the effect that he material is difficult to deposit for restrained drying conditions, which means conventional papermaking techniques cannot be used.

The deposition and dewatering are therefore one of the largest obstacles that need overcoming in order to efficiently produce nanocellulose membranes. Conventional techniques include simply evaporating the water from the dispersions, but this is an expensive and relatively uncontrolled method which often produces uneven membranes due to curling. A technique which produces reproducible membranes of high quality is simple filtration where the water is removed by vacuum filtration and the CNFs are collected on a filter having pore sizes small enough to collect the CNFs. The formed filter cake has a substantially higher CNF-concentration compared to the original colloid, suspension or dispersion, and the final water can be removed by constrained drying in various sheet dryers. A problem associated with vacuum assisted dewatering is that it is a time consuming process, and for a high quality chemically modified CNF dispersion the dewatering time can be several hours.

There is thus a need for an improved device and method for dewatering CNF dispersions, that produces high quality membranes and is both quicker and less energy consuming than conventional techniques.

Summary lt is an object of the present disclosure, to provide an improved device and method of removing a liquid phase from a colloid, colloidal dispersion, dispersion or suspension comprising cellulose nanoparticles.

The invention is defined by the appended independent claims. Embodiments are set forth in the appended dependent claims and in the following description.

According to a first aspect there is provided a device for removing a liquid phase from a suspension or dispersion comprising cellulose nanoparticles and containing at least 75 wt-% liquid, comprising, a container adapted to be pressurized, having at least one inlet adapted to receive said dispersion, at least one outlet adapted to discharge a filtrate solution, wherein said at least one filter arrangement is provided inside the container having a pore size adapted to retain solid material in the dispersion while allowing said filtrate to pass through and be discharged, and an arrangement adapted to provide a pressure onto said cellulose nanoparticle dispersion such that said filtrate is discharged from said dispersion.

By this device, it is possible to provide a pressure onto the dispersion, thus pushing water out of the dispersion and forming a filter cake onto the filter arrangement. This device thus provides for a quicker and more energy efficient way of forming a substantially dry CNF filter cake preferably removing at least 90 % of the water content of the dispersion. The amount of water removed can be controlled volumetrically by either knowing the volume left in the pressurized vessel or by measurement of the discharged amount of liquid.lt has surprisingly been found that this device provides for a dewatering time which is radically shorter, and in the range of around 1 to around 60 minutes, compared to conventional dewatering devices and methods.

Said cellulose nanoparticles may be anyone of cellulose nanocrystals, cellulose nanofibrils, bacterial cellulose and tunicates, or a combination thereof.

The dispersion may contains or comprise at least 80 wt-% liquid, or at least 90 wt-% liquid or at least 95 wt-% liquid and the liquid may be any one of water and a solvent.

According to the first aspect the arrangement for providing pressure may be any one of a static and a dynamic pressure arrangement.

The arrangement for providing pressure may be a mechanical pressure device.

According to another alternative the arrangement for providing pressure may be a gas pressure device.

The device may further comprise a stirring arrangement.

The filter arrangement may be a sheet filter media.

According to another alternative the filter arrangement may be a substantially tubular filter media. The filter may for instance be a circumferential filter arrangement along the sides of vertical side portions of the container.

The arrangement for providing a pressure is adapted to provide pressure difference across the filter arrangement, which pressure difference is sufficient to push the liquid in the colloid, colloidal dispersion, dispersion or suspension through the pores of the filter arrangement or media and leave the cellulose nanoparticles on the filter media, preferably in less than 20 minutes, or even more preferably in less than 10 minutes, or most preferably in less than 5 minutes.

The filter arrangement or media may have a substantially smooth surface on a side facing the cellulose nanoparticle dispersion. This allows for the formation of a smooth membrane surface.

According to one alternative of the first aspect said retained solids form a filter cake, and wherein said filter cake is an intermediate form of a membrane comprising a crosslinked cellulose nanomaterial, wherein the cellulose nanomaterial is chemically modified to exhibit, on surfaces of the nanomaterial, aldehyde groups within the range of 0.5-1 mmol/g nanomaterial, preferably within the range of 0.7-0.9 mmol/g, and sulfo groups in an amount providing a charge within the range of 200-1500 umol/g nanomaterial, preferably within the range of 300-1400 umol/g, wherein at least some of the aldehyde groups have reacted with respective hydroxy groups on the surfaces to form crosslinks. To form the final membrane subsequent and further drying is necessary.

According to a second aspect there is provided a method for removing a liquid phase from a suspension or dispersion comprising cellulose nanoparticles and containing at least 75 wt-% liquid, comprising: providing a container adapted to be pressurized, having at least one in|et adapted to receive said dispersion, and at least one outlet adapted to discharge a filtrate solution, and at least one filter arrangement having a pore size adapted to retain solid material in the dispersion while allowing said filtrate to pass through and be discharged,providing said suspension or dispersion comprising cellulose nanoparticles into said container, providing a pressure onto said cellulose nanoparticle suspension or dispersion such that said filtrate is discharged from said dispersion and wherein a solid content of said dispersion is retained onto said filter arrangement.

By providing pressure on the colloid, colloidal dispersion, dispersion or suspension the liquid phase, such as water, is physically pushed out of the dispersion while the solid material is collected on the filter media. When most of the water has been removed the container may be depressurized and opened. The collected solid materials, in the form of a filter cake may then be removed and may be further dried completely by for instance restrained drying methods. lt has been surprisingly found that this method of dewatering is applicable to all types of cellulose nanoparticle slurries, such as colloids, dispersions or suspensions, comprising at least one of cellulose nanocrystals, cellulose nanofibrils, bacterial cellulose and tunicates and combinations of dissolved polymers in such a dispersion or colloid.

According to the second aspect the method may further comprise stirring said dispersion.

The method may further comprise discharging a filtrate solution from the at least one outlet of the container.

The collected nanocellulose fibers may have a dry content of at least 10 g/l after being subjected to said pressure.

According to the second aspect the pressure may be provided for a period of less than 30 minutes, or less than 20 minutes, or less than 10 minutes, or less than 5 minutes, or less than 1 minute or less than 30 seconds.

This means that through the inventive method of pushing water out of the CNF-dispersion the time for dewatering is radically shortened compared to using conventional techniques, such as vacuum or heat. Further to this, using pressure to push water out of the dispersion requires less energy than using vacuum or heat.

According to a third aspect there is provided a product comprising cellulose nanoparticles obtained through the method according to the second aspect, wherein said product is an intermediate product.

The intermediate product may subsequently be dried to form a membrane comprising a crosslinked cellulose nanomaterial, wherein the cellulose nanomaterial is chemically modified to exhibit, on surfaces of the nanomaterial, aldehyde groups within the range of 0.5-1 mmo|/g nanomaterial, preferably within the range of 0.7-0.9 mmo|/g, and su|fo groups in an amount providing a charge within the range of 200-1500 umol/g nanomaterial, preferably within the range of 300-1400 umol/g, wherein at least some of the aldehyde groups have reacted with respective hydroxy groups on the surfaces to form crosslinks.

Brief description of drawinqs Embodiments of the present solution will now be described, by way of example, with reference to the accompanying schematic drawings.

Fig 1 shows a schematic cross-section of one device according to the invenüon.

Fig 2 shows a schematic cross-section of another device according to the invenflon.

Description of Embodiments Definitions As used herein, and in accordance with the TAPPI document "Roadmap for the Development of International Standards for Nanocellulose" of October 24, 2011, as well as the ISO TC 229 protocols, the term "cellulose nanomaterials" includes plant based nanocellulose as well as nanocellulose from bacteria, algae, tunicates, and other sources. Examples of nanocellulose, and thus of cellulose nanomaterials, include herein mentioned cellulose nanofibrils (CNF), cellulose nanocrystals (CNC) and cellulose microfibrils (CMF). CNPs are thus defined as a class of bio-based nanoscale materials, having unique structural features and properties such as biocompatibility, biodegradability, and renewability. The term "nanocellulose" is commonly used to define a material from any source of cellulose such as wood pulp. The cellulose nanofibrils can be isolated from wood by mechanicalmethods which applies high shear and acceleration forces, or chemical methods or a combination thereof. Cellulose nanofibrils may also be isolated from bacteria and tunicates. High-pressure homogenizers, ultrasonic homogenizers grinders or microfluidizers can be used for the preparation of nanocellulose materials. ln the sense of this application the term cellulose nanoparticles encompasses any one of a cellulose nanocrystals, cellulose nanofibrils, bacterial cellulose and tunicates, or a mixture thereof.

Further, the wordings and expressions cellulose nanoparticles and nanocellulose may be used interchangeably.

As used herein is a colloidal heterogeneous mixture where the dispersed particles have at least in one direction a dimension roughly between 1 nm and 1 um or that in a system discontinuities are found at distances of that order.

As used herein is a suspension a heterogeneous dispersion of larger particles in a medium. Unlike solutions and colloids, if left undisturbed for a prolonged period of time, the suspended particles will settle out of the mixture. ln general, dispersions of particles sufficiently large for sedimentation are called suspensions, while those of smaller particles are called colloids and solutions.

A solution is meant a homogenous mixtures of two or more components in which the molecules of one component is dissolved into the other. Solutions require complete miscibility between the components and create a single phase mixture.

By dispersion is meant a mixture of two or more compounds. A dispersion may contain more than one phase. Dispersions can also be defined as mixtures in which particles of one compound are scattered throughout a continuous phase of another component. Unlike solutions, the components of dispersions are immiscible which is the reason for the formation of different phases.

By a suspension is meant a heterogeneous mixture in which the solid particles are spread throughout the liquid without dissolving in it. ln the present invention commonly colloid, suspension or a dispersion comprising the above mentioned cellulose nanoparticles may be present. ln the suspension or dispersion according to the present invention further, additional substances or compounds may be present. These substances or compounds may for instance be adapted to provide desired characteristics of a membrane for use in energy storage applications, such as the membrane of the not yet published ep21198305.1, which is hereby incorporated by reference.

These substances and compounds may for instance be soluble polymers, e.g. water soluble polymers. They may also be other nanoparticle materials or even a mixture of different nanoparticle materials. The nanoparticle materials may be cellulose based, or based on other bio-derivable materials, or be synthetic nanoparticles, or chemical nanoparticles. The substances or compounds may also be for instance clay or silica. The substances may also be monomeric materials which may subsequently polymerize, for instance during subsequent treatment of the filter cake.

Fig 1 illustrates a schematic arrangement 10 for removing a liquid or liquid phase, such as dewatering, from a cellulose nanoparticle dispersion or suspension 5 is disclosed. The arrangement 10 comprises a vesse| or container 1, which is adapted to be pressurized, i.e. a pressurized container or vesse|.

The means or devices for providing pressure may be dynamic or static, and may for instance include mechanical means such as a piston and rod, or be a regulated gas pressure source, such for instance an inert gas, e.g. pressurized Nz gas.

The container may also be an open container, which is subsequently closes or sealed to be able to be pressurized.

The container 1 is provided with at least one inlet 2. The inlet may according to one embodiment be arranged at a top portion of the container 1, but may also be provided at any suitable location in the container 1. The container 1 is further provided with at least one outlet 3. ln Fig. 1 this outlet is depicted at a bottom part of the container, but may be arranged at any suitable location in the container. ln one embodiment the container 1 further comprises at least two chambers, wherein one first chamber is adapted for storage of a suspension or dispersion and which is in fluid connection with another or second chamber which is chamber is adapted to be pressurized.

The container 1 further comprises at least one filter arrangement 8. ln Fig. 1 the filter arrangement is depicted as a sheet filter at a bottom part of the container. ln a different embodiment, schematically illustrated in Fig. 2, the filter arrangement 8 may be arranged as a circumferential or substantially tubular filter on the inside of the container, or even as a combination of a sheet filter and a circumferential filter (not shown).

The filter arrangement 8 may further have a substantially smooth surface on a side facing the cellulose nanoparticle suspension. This is in particular advantageous when the dewatering device is used for manufacturing of a membrane. The surface pattern of the filter arrangement may influence the surface pattern on the filter cake, however the filter cake may also have a relatively low dry contents, in which case the filter cake is not as influenced by the actual surface pattern of the filter arrangement. By surface pattern is meant a topographical pattern of the surface. ln other embodiments the filter arrangement may have any surface pattern or shape desirable for the final filter cake.

The filter arrangement may comprise any type of filter media having a pore size which is adapted to allow for a solvent, such as water to pass through the pores, while retaining the solid materials of the suspension or dispersion on a surface thereof. The filter may also preferably be dimensioned to withstand pressure, and a pressure difference across the filter in the range of 1 to 80 bar. The filter may also be of a material which is able to withstand solvents, acids and hydrocarbons. The filter may be of a material able to withstand for instance organic solvents, such as toluene.

A preferable pore size is less than 1 um.

The desired pore-size may be adapted after the hydrodynamic volume of the cellulose nanoparticle suspension to be dewatered.

The filter media may also be a ceramic filter media or ceramic membrane able to withstand a high load. The advantage of such a filter media or membrane is that it may be reused and cleaned.

Both Bubble Point Tests and Capillary Flow Porometry are commonly used to assess the through pores present in filtration media. These techniques are based on a well-known relationship between a size of a pore and the associated pressure drop necessary to evacuate a wetted fluid from that pore, and are well-known to the skilled person defining the pore-size of a filter media. 11 According to one embodiment the filter is a polyvinylidene fluoride (PVDF) filter having a pore size of 650 nm.

The at least one inlet is adapted to receive a flow of a dispersion or suspension 5 comprising cellulose nanoparticies. The dispersion or suspension 5 is contained inside the container.

The at least one outlet 3 is arranged to receive a flow of a filtrate 7 from the container.

A pressure arrangement or means, is provided to provide a pressure inside of the container, which pushes the dispersion or suspension 5 towards the filter arrangement, and thus pushes the water out of the dispersion 5, thus retaining the solids content of the dispersion or suspension onto the filter, and leaving a filter cake 4 on the filter arrangement.

This means that a pressure difference is created over the filter arrangement, and that the dispersion or suspension is dewatered against a surface which allows for the water to pass through, while collecting the solid particles of the dispersion or suspension on the filter surface facing the dispersion or suspension.The amount of solvent or water removed can be controlled volumetrically by either measuring or knowing the volume left in the pressurized vessel or by measurement of the discharged amount of liquid.

The suspension or dispersion 5 may initially have a liquid content of at least 75 wt-%. The liquid content depends mainly on the type of CNP dispersion or suspension, i.e. which particles that are contained therein. ln a CNC suspension the liquid content may be around 80 wt-%. The liquid content in the dispersion or suspension may thus be at least 80 wt-%, or at least 90 wt-% or at least 95 wt-%.

The liquid content may comprise, or consist of, water, as a solvent.

The liquid may in other embodiments comprise a solvent, or mixtures of solvents. The solvent may for instance be an organic solvent, including aliphatic hydrocarbons, aromatic hydrocarbons, amines, esters, ethers, 12 ketones, and nitrated or chlorinated hydrocarbons. Examples of organic solvents are ethanol, acetone, benzene and toluene.

The pressure is exerted onto the suspension or dispersion, or provided inside the container, until a dry content in the collected so|ids material or filter cake of at least 10 g/l has been achieved. The dry content of the collected solid material or filter cake is preferably higher than in the original suspension or dispersion. According to one embodiment, one portion of the suspension, dispersion or colloid is pressed until a filter cake has been obtained, and the remaining portion is re-introduced after the filter cake has been removed to be pressed.

After pressurization of the container and dispersion to reach the desired dry content of the solid filter material filter cake, container may be depressurized and the filter cake removed to be further dried, for instance through restrained drying operations. This may also be performed within the container.

The filter cake 4 may also be an intermediate product to form a membrane comprising a crosslinked cellulose nanomaterial, wherein the cellulose nanomaterial is chemically modified to exhibit, on surfaces of the nanomaterial, aldehyde groups within the range of 0.5-1 mmol/g nanomaterial, preferably within the range of 0.7-0.9 mmol/g, and sulfo groups in an amount providing a charge within the range of 200-1500 umol/g nanomaterial, preferably within the range of 300-1400 umol/g, wherein at least some of the aldehyde groups have reacted with respective hydroxy groups on the surfaces to form crosslinks. The cellulose nanomaterial of the membrane may comprise or consists of cellulose nanofibrils, CNF; cellulose nanocrystals, CNC; and/or cellulose microfibrils, CMF; preferably CNF.

When the membrane has been dried to a suitable dry content, it may consist or comprise to 100% of the crosslinked cellulose nanomaterial, and may have a thickness within the range of 5-100 um. The membrane, may also, when dried, have a density preferably within the range of 1.4-1.5 g/cm3, 13 or if additional materials have been added to the nanoparticle cellulose, such as clay, a density within the range of 1 .2-2.5 g/cm3.

The pressurization may be preferable be performed in a temperature range of 0 to 100°C, i.e. it may be performed in either cold or warm conditions, as long as water is in a liquid, or substantially liquid phase.

The container may also be provided with temperature regulating arrangement, such that the temperature or temperature gradient of the container may be optimized for the dewatering process. ln Fig. 1 a support structure 6 is arranged beneath the filter arrangement 8 as a support structure. The support structure may be arranged on a side of the filter arrangement not facing the dispersion or suspension 5. The support structure or frit may for instance be made of a stainless steel, onto which a filter paper or stainless steel mesh may be placed. The support structure may also be a polymer grid. The support structure is sized and dimensioned to withstand the pressure inside the container and support the filter arrangement. The support structure is provided with a pore structure having large pore size, i.e. allows for liquid to flow through it easily. The support structure, such as the frit, further provides a distance between the filter cake and the container, which allows for liquid such as water to be pushed out of the dispersion or suspension more easily. ln one embodiment, not shown in the figures, a stirring device may also provided to stir the dispersing or suspension during the pressurization step, in order to provide for a more homogenous mixture of CNP. ln the below a process or method for removing a liquid phase from a dispersion or suspension 5 comprising cellulose nanoparticles will be described. The dispersion 5 is introduced into a container 1, which is then closed and pressurized, by any of the means described above. The pressurization pushes liquid or water contained in the dispersion or suspension through the filter arrangement 8, thus leaving a filter cake 4 onto 14 the filter arrangement. The pressure is provided until a desired dry content of the filter cake has been achieved. lt has surprisingly been found that dewatering of CNP dispersions or suspension through this method shortens the time needed for dewatering. Depending on the water content of the dispersion, the desired dry content of the filter cake, and the size of the container the time for dewatering the dispersion or suspension may be in the range of 30 seconds up to 60 minutes.

Preferably, the time for dewatering is in the lower range and around 1 to 20 minutes or in the range of 1 to 10 minutes.

A short time period for the dewatering process is desirable from an industrial manufacturing perspective as it allows for a higher through-put of material.

Further using the inventive device and method for removing a liquid phase or dewatering also reduces the cost of dewatering the CNP dispersion or suspension as compared to other conventional dewatering techniques.

The above described method and device also provides for an intermediate product in the manufacture of for instance membrane for energy storage applications, or other types of biobased products comprising cellulose nanoparticles.

The filter cake 4 may for instance be used as an ion-selective bio-based membrane for applications such PEM electrolyzers, redox flow batteries and fuel cells. The filter cake 4 may be an intermediate product for the manufacture of such as membrane. The filter cake 4 may subsequently be dried or treated in any other way to obtain the desired membrane.

A membrane may comprise a crosslinked cellulose nanomaterial, wherein the cellulose nanomaterial is chemically modified to exhibit, on surfaces of the nanomaterial, aldehyde groups within the range of 0.5-1 mmol/g nanomaterial,preferably within the range of 0.7-0.9 mmol/g, and sulfo groups in an amount providing a charge within the range of 200-1500 umol/g nanomaterial, preferably within the range of 300-1400 umol/g, wherein at least some of the aldehyde groups have reacted with respective hydroxy groups on the surfaces to form crosslinks.

According to one embodiment a membrane may be manufactured through the following method: oxidation of cellulose fibres by means of sodium meta periodate, NalO4, to provide aldehyde groups on surfaces of CNF within fibre walls of the fibres; sulfonation of some of the aldehyde groups, e.g. by means of sodium metabisulfite, NazSzOs, to provide sulfo groups on the surfaces of the CNF, thus obtaining chemically modified CNF within fibre walls; obtaining the chemically modified CNF in free form from the fibres by means of processing of the fibres, e.g. comprising mechanical processing by means of high pressure homogenization; and forming the membrane by dewatering an aqueous slurry, such as colloid, suspension or dispersion, comprising the separated chemically modified CN F, according to the above described pressurization method.

Membranes are a key component in energy storage devices. The membrane has a high ion-selectivity, high ion-conductivity, good barrier properties such as low crossover, high thermal, mechanical and chemical stability. The membrane may further be easily activated without any pre- treatment and has tunable properties through the inventive manufacturing process as described above. By tunable is meant that the CNP dispersion or suspension may be adapted to provide for specific characteristics of the membrane after the dewatering process. The nanocellulose membrane may thus be used for fabrication of renewable energy storage devices, such as hydrogen fuel cells and redox flow batteries. The bio-based membranes may be made of nanocellulose fibrils. The membrane as obtained in the inventive method is usually integrated between two electrodes (anode and cathode). This allows for only specific selected ions to be transported across it, whilst at the same time, separating the redox active species in the catholyte and anolyte, or separating oxygen and hydrogen in a hydrogen fuel cell. 16 Moreover, an ion-selective membrane allows for specific ion selection through chemical modifications and size exclusion created by the pores in the membrane. The above device and method allow for a quicker and simpler manufacturing process of these bio-based membranes, or intermediates thereof.

E Aqueous CNP colloids of different concentrations (2-10 g/L) were poured into a stainless steel container (Sterlitech HP4750) fitted in one end with a PVDF filter (Merck) having a pore size of 650 nm. The container was subsequently hermetically sealed and N2-gas was introduced in order to increase the pressure inside the container to a final pressure of 7, 15 or 30 bar.

The pressure gradient resulted in the dewatering of the CNF suspension and the build up a CNF-filter cake on the PVDF membrane. Upon having pushed out water equivalent to >90% of the initial volume of CNP dispersion was the pressure released and the formed filter cake collected and completely dried in a Rapid Köthen sheet dryer.

The result of the trial is shown in Table 1 below. ln the trials a dewatering time of 20 minutes was achieved.

Table 1. Dewatering time for a CNP dispersion CNP concentration Dewatering pressure Dewatering time [g/L] [bar] [min] 2 30 135 5 30 30 30 20 17 Modifications and other variants of the described embodiments will come to mind to one skilled in the art having benefit of the teachings presented in the foregoing description and associated drawings. Therefore, it is to be understood that the embodiments are not limited to the specific example embodiments described in this disclosure and that modifications and other variants are intended to be included within the scope of this disclosure. Furthermore, although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Therefore, a person skilled in the art would recognize numerous variations to the described embodiments that would still fall within the scope of the appended claims. As used herein, the terms "comprise/comprises" or "include/includes" do not exclude the presence of other elements or steps. Furthermore, although individual features may be included in different claims (or embodiments), these may possibly advantageously be combined, and the inclusion of different claims (or embodiments) does not imply that a combination of features is not feasible and/or advantageous. ln addition, singular references do not exclude a plurality. Finally, reference signs in the claims are provided merely as a clarifying example and should not be construed as limiting the scope of the claims in any way.

Claims (1)

1.A device (10) for removing a liquid phase from a suspension or dispersion (5) comprising cellulose nanoparticlesand containing at least 75wt-% liquid, comprising: a container (1) adapted to be pressurized, having at least one inlet (2) adapted to receive said suspension or dispersion (5), at least one outlet (3) adapted to discharge a filtrate (7) solution; wherein said at least one filter arrangement (8) is provided inside the container (1 )having a pore size adapted to retain solid material (4) in the dispersion while allowing said filtrate (7) to pass through and be discharged,and an arrangement adapted to provide a pressure onto said cellulose nanoparticlesuspension or dispersion (5) such that said filtrate (7) is discharged from said suspension or dispersion. _ The device (10) according to claim 1, wherein said suspension or dispersion contains at least 80 wt-% liquid, or at least 90 wt-% liquid or at least 95 wt-% liquid. The device (10) according to any of the preceding claims, wherein the liquid is any one of water and a solvent. _ The device (10) according to claim 1, wherein said arrangement for providing pressure is any one of a static and a dynamic pressure arrangement.5. The device (10) according to claim 1, wherein said arrangement for providing pressure is a mechanical pressure device. 6. The device (10) according to claim 1, wherein said arrangement for providing pressure is a gas pressure device. 7. The device (10) according to any one of the preceding claims further comprising a stirring arrangement. 8. The device (10) according to claim 1, wherein said filter arrangement (8) is a sheet filter media. 9. The device (10) according to claim 1, wherein said filter arrangement (8) is a substantially tubular filter media. 10.The device (10) as claimed in any of the preceding claims wherein said arrangement for providing a pressure is adapted to provide pressure difference across said filter arrangement (8). 11.The device (10) according to any one of claims 1 to 11, wherein said filter arrangement has a substantially smooth surface on a side facing the cellulose nanoparticle dispersion. 12. The device (10) according to any one of the preceding claims, wherein said retained solids (4) form a filter cake, and wherein said filter cake is a membrane comprising a crosslinked cellulose nanomaterial, wherein the cellulose nanomaterial is chemically modified to exhibit, on surfaces of the nanomaterial, aldehyde groups within the range of 0.5- 1 mmol/g nanomaterial, preferably within the range of 0.7-0.9 mmol/g, and sulfo groups in an amount providing a charge within the range of 200-1500 umol/g nanomaterial, preferably within the range of 300- 1400 umol/g, wherein at least some of the aldehyde groups have reacted with respective hydroxy groups on the surfaces to form crosslinks. 13.A method for removing a liquid phase from a suspension or dispersion (5) comprising cellulose nanoparticles and containing at least 75 wt-% liquid, comprising: providing a container (1) adapted to be pressurized,having at least one inlet (2) adapted to receive said suspension or dispersion (5), and at least one outlet (3) adapted to discharge a filtrate solution (7), and at least one filter arrangement(8) having a pore size adapted to retain solid material in the suspension or dispersion (5) while allowing said filtrate (7) to pass through and be discharged, providing said suspension or dispersion (5) comprising cellulose nanoparticles into said container (1), providing a pressure onto said cellulose nanoparticle suspension or dispersion such that said filtrate (7) is discharged from said dispersion and wherein a solid content (4) of said suspension or dispersion is retained onto said filter arrangement. 14.The method according to claim 13, wherein said method further comprises stirring said dispersion. 15.The method according to claim 13 or 14, wherein the method further comprises: discharging a filtrate solution from the at least one outlet (3) of the container. 16.The method according to any one of claims 13 to 15, wherein said collected cellulose nanoparticles(4) have a dry content of at least 10 g/lafter being subjected to said pressure.17.The method according to any one of claims 13 to 16, wherein said pressure is provided for a period of less than 30 minutes, or less than 20 minutes, or less than 10 minutes, or less than 5 minutes, or less than 1 minute or less than 30 seconds. 18.A product comprising cellulose nanoparticles obtained through the method according to claims 14 to 17, wherein said product is an intermediate product. 19.The product according to claim 18, wherein said intermediate product is a membrane comprising a crosslinked cellulose nanomaterial, wherein the cellulose nanomaterial is chemically modified to exhibit, on surfaces of the nanomaterial, aldehyde groups within the range of 0.5- 1 mmol/g nanomaterial, preferably within the range of 0.7-0.9 mmol/g, and sulfo groups in an amount providing a charge within the range of 200-1500 umol/g nanomaterial, preferably within the range of 300- 1400 umol/g, wherein at least some of the aldehyde groups have reacted with respective hydroxy groups on the surfaces to form crosslinks.