Porous moisture-absorbing material, porous moisture-absorbing member, dehumidifying device, method for producing porous moisture-absorbing material, and method for producing hydrogel

Abstract

The application discloses a porous hygroscopic material, a porous hygroscopic piece, a dehumidification device and a preparation method of the porous hygroscopic material. The porous hygroscopic material comprises a porous adsorption net and a hydrogel-hygroscopic salt composite material; the porous adsorption net is in a single-layer net shape, and the material is hydrophilic; the hydrogel-hygroscopic salt composite material covers at least part of the grid lines of the porous adsorption net and makes at least part of the net holes keep through all the time, the hydrogel-hygroscopic salt composite material comprises hydrogel and hygroscopic salt which are integrated with each other, and the hydrogel is an ionic hydrogel. The porous hygroscopic piece and the dehumidification water collecting device comprise the porous hygroscopic material. The preparation method of the porous hygroscopic material is used for preparing the porous hygroscopic material. In the technical scheme, the porous hygroscopic material has higher hygroscopic efficiency than the first prior art and the second prior art.

Description

Technical Field

[0001] This application relates to the field of air dehumidification or air water collection, specifically to porous moisture-absorbing materials, porous moisture-absorbing components, dehumidification devices, methods for preparing porous moisture-absorbing materials, and methods for preparing hydrogels. Background Technology

[0002] Adsorption-based air dehumidification achieves its effect by capturing moisture from the air through the physical or chemical action of hygroscopic materials. Adsorption-based water collection, building upon adsorption-based dehumidification, uses energy to desorb the hygroscopic material, releasing and collecting the water. In both dehumidification and water collection processes, the hygroscopic material plays a crucial role. During water adsorption, the adsorption capacity primarily involves the adsorption rate and equilibrium adsorption capacity under different humidity levels. During water collection, the daily average water collection volume is the main consideration, which is related to the equilibrium adsorption capacity and the number of adsorption-desorption cycles per day. The number of adsorption-desorption cycles per day is closely related to the adsorption rate. Therefore, in both air dehumidification and water collection, the goal is to improve the adsorption rate of the hygroscopic material, followed by its equilibrium adsorption capacity.

[0003] The first prior art related to this application is Chinese Patent Application Publication CN119019610A, which discloses a hygroscopic transparent hydrogel, its preparation method, and its application. The hygroscopic transparent hydrogel is polymerized from zwitterionic monomers and hydrophilic monomers in a hygroscopic salt solution. The zwitterionic monomers enable the hygroscopic transparent hydrogel to contain both cations and anions, thereby effectively preventing the leakage and migration of the hygroscopic salt. This hygroscopic transparent hydrogel, acting as a hygroscopic material, autonomously adheres to the surface of a solar panel, thereby cooling the solar panel. Under a relative humidity of 90%, the hygroscopic material exhibits an adsorption capacity of 0.5 g / g after 9 hours, with an equilibrium adsorption capacity of 0.56 g / g.

[0004] The second prior art related to this application is Chinese patent application publication CN116180446A, which discloses a method for preparing a super-hygroscopic and water-releasing PNIPAAm hydrogel-based napped fabric. The method involves first preparing a napped fabric, then placing it in a solution containing monomers to undergo a polymerization reaction, thereby coating the surface of the napped fabric with a porous PNIPAAm hydrogel. Finally, polydopamine nanoparticles and polypyrrole are coated onto the surface of the napped fabric, and the fabric is then immersed in a lithium chloride solution using alternating hot and cold treatments to obtain a hygroscopic material. This hygroscopic material has a three-dimensional structure, allowing for maximum light absorption through multiple reflections and scatterings. The fiber gaps after PNIPAAm hydrogel treatment are directly filled with a large amount of highly interconnected porous hydrogel. The purpose is to rapidly evaporate and collect moisture collected overnight under light conditions. The hygroscopic curve of the above-mentioned hygroscopic material is shown in the appendix to its specification.Figure 5 As shown, under an environment with a relative humidity of 30%, the equilibrium adsorption capacity was not reached after 12 hours. The equilibrium adsorption capacity was no higher than 0.7 g / g. The adsorption time was not disclosed, but it is estimated to be no less than 4 hours. Summary of the Invention

[0005] The purpose of this application is to overcome the above-mentioned defects or problems in the prior art and to provide a porous hygroscopic material, a porous hygroscopic component, a dehumidification device, a method for preparing a porous hygroscopic material, and a method for preparing a hydrogel, wherein the porous hygroscopic material has a higher adsorption rate than the two existing technologies mentioned above.

[0006] To achieve the above objectives, the following technical solution is adopted:

[0007] The first technical solution relates to a porous hygroscopic material, comprising: a porous adsorption mesh, which is a single-layer mesh and is made of a hydrophilic material; and a hydrogel-hygroscopic salt composite material, which covers at least part of the mesh lines of the porous adsorption mesh and keeps at least part of the mesh pores connected at all times, wherein the hydrogel-hygroscopic salt composite material comprises a hydrogel and a hygroscopic salt that are fused together, and the hydrogel is an ionic hydrogel.

[0008] The second technical solution is based on the first technical solution, wherein in the part of the hydrogel-hygroscopic salt coated grid lines, the proportion of the number of mesh holes that are always connected is greater than or equal to 60%.

[0009] The third technical solution is based on the first technical solution, wherein the mesh size of the porous adsorption mesh is between 100 mesh and 300 mesh.

[0010] The fourth technical solution is based on the third technical solution, wherein the mesh size of the porous adsorption mesh is preferably 200 mesh.

[0011] The fifth technical solution is based on the first technical solution, wherein the material of the porous adsorption mesh is preferably nylon, polyurethane, glass, or silicon carbide.

[0012] The sixth technical solution is based on the first technical solution, wherein the mass percentage of the hygroscopic salt in the hydrogel-hygroscopic salt composite material is between 20% and 70%.

[0013] The seventh technical solution is based on the sixth technical solution, wherein the mass percentage of the hygroscopic salt in the hydrogel-hygroscopic salt composite material is between 35% and 70%.

[0014] The eighth technical solution is based on the first technical solution, wherein the hygroscopic salt is one or more of lithium chloride, calcium chloride, magnesium chloride and lithium bromide.

[0015] The ninth technical solution is based on the eighth technical solution, wherein the hygroscopic salt is preferably lithium chloride.

[0016] The tenth technical solution is based on any one of the first to ninth technical solutions, wherein the hydrogel contains cations.

[0017] The eleventh technical solution is based on the tenth technical solution, wherein the cation is preferably a quaternary ammonium cation.

[0018] The twelfth technical solution is based on any one of the first to ninth technical solutions, wherein the hydrogel contains anions.

[0019] The thirteenth technical solution is based on the twelfth technical solution, wherein the anion is preferably one or more of carboxyl, carboxylate, sulfonate and phosphate groups.

[0020] The fourteenth technical solution is based on any one of the first to ninth technical solutions, wherein the hydrogel contains cations and anions.

[0021] The fifteenth technical solution is based on the fourteenth technical solution, wherein the cation is preferably a quaternary ammonium cation, and the anion is preferably one or more of carboxyl, carboxylate, sulfonate and phosphate groups.

[0022] The sixteenth technical solution is based on the fifteenth technical solution, wherein the anion is more preferably a carboxyl group and / or a carboxylate group.

[0023] The seventeenth technical solution relates to a porous moisture-absorbing component, which includes a support and a porous moisture-absorbing material as described in any one of the first to sixteenth technical solutions, wherein the support supports the porous moisture-absorbing material.

[0024] The eighteenth technical solution is based on the seventeenth technical solution, wherein the porous moisture-absorbing material is planar, the number of the porous moisture-absorbing material is at least two, and each porous moisture-absorbing material is spaced apart along a direction perpendicular to its plane.

[0025] The nineteenth technical solution relates to a dehumidification device, which includes a heater, a condenser, and a porous moisture-absorbing element as described in the seventeenth or eighteenth technical solutions; the heater desorbs the porous moisture-absorbing material on the porous moisture-absorbing element by heating, and the condenser is used to condense the water vapor formed after the porous moisture-absorbing material is desorbed into condensate.

[0026] The twentieth technical solution is based on the nineteenth technical solution, and it also includes a water collector, which is connected to the condenser to collect the condensate produced by the condenser.

[0027] The twenty-first technical solution is based on the nineteenth technical solution, and it also includes a fan, which is used to cause the air heated by the heater to form convection so as to desorb the porous moisture-absorbing material on the porous moisture-absorbing element.

[0028] The twenty-second technical solution is based on the twenty-first technical solution, wherein the porous moisture-absorbing material is arranged vertically, and the heated air passes through each of the porous moisture-absorbing materials.

[0029] The 23rd technical solution is based on the 19th technical solution, and it further includes a control unit. The control unit controls the heater to start when the amount of water adsorbed by the porous hygroscopic material reaches or exceeds a first threshold, and controls the heater to shut down when the amount of water adsorbed reaches or falls below a second threshold; the first threshold is higher than the second threshold.

[0030] The twenty-fourth technical solution is based on the twenty-third technical solution, wherein the control unit includes a gravimeter and a controller, the gravimeter is used to detect the weight of the porous moisture-absorbing element, and the controller characterizes the amount of water adsorbed by the porous moisture-absorbing material based on the weight of the porous moisture-absorbing element.

[0031] The 25th technical solution is based on the 23rd technical solution. In this solution, the control unit includes a hygrometer and a controller. The hygrometer is used to detect the ambient humidity. The controller, based on the ambient humidity detected by the hygrometer, characterizes the amount of water adsorbed by the porous moisture-absorbing material according to the period experienced after the heater is turned off and the period experienced after it is turned on.

[0032] The twenty-sixth technical solution relates to a method for preparing porous hygroscopic materials, which is used to prepare porous hygroscopic materials as described in any one of the first to sixteenth technical solutions, and includes the following steps:

[0033] Step 1: Place the hydrogel in an aqueous solution of hygroscopic salt;

[0034] Step 2: After the hydrogel swells, it is mechanically broken down to form a micron-sized hydrogel-hygroscopic salt coating; and

[0035] Step 3: Coat the hydrogel-hygroscopic salt coating onto a hydrophilic, single-layer porous adsorption network and dry it.

[0036] The twenty-seventh technical solution is based on the twenty-sixth technical solution, wherein, in step 1, the mass ratio of the hydrogel to the aqueous solution of the hygroscopic salt is between 1:40 and 1:20; and the molar ratio of the hygroscopic salt in the aqueous solution is between 0.5 mol / L and 3 mol / L.

[0037] The twenty-eighth technical solution is based on the twenty-seventh technical solution, wherein, in step 1, the mass ratio of the hydrogel to the aqueous solution of the hygroscopic salt is preferably between 1:25 and 1:35; and the molar ratio of the hygroscopic salt in the aqueous solution is preferably between 1 mol / L and 2 mol / L.

[0038] The twenty-ninth technical solution is based on the twenty-sixth technical solution, wherein in step 2, the mechanical crushing is carried out by stirring.

[0039] The thirtieth technical solution is based on the twenty-sixth technical solution. In step 3, the method of coating the hydrogel-hygroscopic salt coating onto the porous adsorption network includes dip coating, spraying, brushing, rod coating, and spin coating.

[0040] The thirty-first technical solution is based on the thirty-first technical solution, wherein, in step 3, the method of coating the hydrogel-hygroscopic salt coating onto the porous adsorption mesh is preferably dip coating.

[0041] The thirty-second technical solution relates to a method for preparing hydrogels, which is used to prepare porous hygroscopic materials as described in the sixteenth technical solution. The hydrogel is obtained by a free radical polymerization reaction of a first monomer containing a quaternary ammonium salt cationic group and a second monomer containing a carboxyl and / or carboxylate anionic group, a crosslinking agent, and an initiator under conditions containing a first solvent, followed by purification and drying. The free radical polymerization reaction is a front-end polymerization reaction. Both the crosslinking agent and the initiator are hydrophilic. The first and second monomers are monomers containing carbon-carbon double bonds. The first solvent is water or a hydrophilic alcohol.

[0042] The thirty-third technical solution relates to the thirty-second technical solution, wherein the crosslinking agent is preferably an acrylamide crosslinking agent; the initiator is preferably a peroxide or azo initiator; the first monomer is preferably acryloyloxyethyltrimethylammonium chloride and / or (3-acrylamidopropyl)trimethylammonium chloride; and the second monomer is preferably acrylic acid and / or sodium acrylate.

[0043] The thirty-fourth technical solution is based on the thirty-second technical solution, wherein the molar ratio of the second monomer to the first monomer is less than or equal to 5:3.

[0044] The thirty-fifth technical solution is based on the thirty-fourth technical solution, wherein the molar ratio of the second monomer to the first monomer is preferably 1:3.

[0045] The thirty-sixth technical solution is based on the thirty-second technical solution, wherein the free radical polymerization reaction also includes a third monomer, which is a monomer without ionic groups and containing carbon-carbon double bonds; the third monomer is preferably a monomer of acrylate, methacrylate, acrylamide or methacrylamide.

[0046] Compared with existing technologies, the above solution has the following beneficial effects:

[0047] In the first technical solution, the hydrogel is an ionic hydrogel, which can form valence bonds with hygroscopic salts, thereby having a stronger salt-carrying capacity, making it less likely for the hygroscopic salts to leak or decompose, and thus dispersed in the hydrogel skeleton.

[0048] In the first technical solution, the porous adsorption mesh material is hydrophilic, which can better combine with the hydrogel-hygroscopic salt composite material, thereby more effectively preventing the aggregation of the hydrogel-hygroscopic salt composite material.

[0049] The most important technical contribution of this application lies in determining, through creative hypotheses, experiments, and comparative analysis, that using a single-layer porous adsorption mesh to support the hydrogel-hygroscopic salt composite material achieves the highest adsorption rate compared to existing technologies. The most significant technical feature distinguishing this application from existing technologies is that the hydrogel-hygroscopic salt composite material coats at least a portion of the mesh lines of the porous adsorption mesh while ensuring that at least some of the mesh pores remain interconnected.

[0050] Here, "coating" refers to the three-dimensional coating of the hydrogel-hygroscopic salt composite material with the mesh lines of a single-layer porous adsorption network. This not only maximizes the specific surface area of ​​the hydrogel-hygroscopic salt composite material but also ensures maximum contact area between the hydrophilic porous adsorption network and the hydrogel-hygroscopic salt composite material, thus more effectively preventing aggregation of the hydrogel-hygroscopic salt composite material. It is important to note that in this structure, a single-layer porous adsorption network provides the largest surface area of ​​the hydrogel-hygroscopic salt composite material in contact with air compared to a three-dimensional porous adsorption material.

[0051] The phrase "the mesh remains open throughout" means that the mesh remains open throughout the process from before moisture absorption until the equilibrium adsorption capacity is reached. This openness provides ample space for the hydrogel-hygroscopic salt composite material to expand during the moisture absorption and swelling process, minimizing agglomeration and stacking, which would otherwise reduce the contact area with air.

[0052] In the first existing technical solution, firstly, the polymerization reaction takes place in a hygroscopic salt solution. This not only reduces the conversion rate of the polymerization reaction but also makes it more difficult to purify the polymerized hydrogel. This results in toxic crosslinking agents, initiators, and monomers remaining in the hygroscopic material, which then volatilize into the air during desorption, affecting human health. Secondly, coating the solar panel with the hygroscopic salt-containing hydrogel forms a single-layer structure, which has a much smaller specific surface area than coating a mesh structure. Therefore, its adsorption rate is also far lower than that of the technical solution in this application.

[0053] In the second prior art solution, the pile fabric is placed in a solvent for polymerization. Since the various monomers are dissolved in the solvent, they penetrate into the microstructure of the pile fabric. After polymerization, the polymer also fills all the microstructures of the pile fabric. During the process of moisture absorption and swelling, the outer hydrogel swells and blocks the pores formed by the pile fabric, which hinders the hydrogel attached to the inner structure from contacting the air. Therefore, the process of reaching the equilibrium adsorption amount is particularly long, and the adsorption rate is far lower than that of the technical solution of this application.

[0054] In summary, the single-layer mesh structure of the porous adsorption mesh, the hydrophilicity of the porous adsorption mesh, the use of ionic hydrogels, and the coating of the mesh lines of the porous adsorption mesh with hydrogel-hygroscopic salt composite materials are organically combined and mutually supportive to ensure that the mesh remains interconnected, thereby enabling the porous hygroscopic material of this application to have an extremely high adsorption rate. Specifically, the single-layer mesh structure of the porous adsorption mesh increases the contact area between the porous adsorption mesh and the hydrogel-hygroscopic salt composite material, as well as the contact area between the hydrogel-hygroscopic salt composite material and the air. The binding force of the hydrophilic porous adsorption mesh on the hydrogel-hygroscopic salt composite material prevents the composite material from agglomerating. The ionic hydrogel, through its valence bond with the hygroscopic salt, makes the hygroscopic salt less prone to leakage and crystallization. Therefore, these technical means all make significant contributions to ensuring that the mesh remains interconnected.

[0055] The porous hygroscopic material defined by the first technical solution generally exhibits a higher equilibrium adsorption capacity than both the first and second prior art technologies, especially when the hydrogel properties are the same. This is because the hydrogel-hygroscopic salt composite material in the first technical solution has a higher specific surface area, allowing for a greater mass ratio of substances that can fully swell.

[0056] Another important technical advantage of using the porous hygroscopic material defined in the first technical solution is that, after multiple adsorption-desorption cycles, the hydrogel-hygroscopic salt composite material is less prone to agglomeration than existing technologies, and the hygroscopic salt is also less prone to leakage and crystallization. Therefore, its effective service life is longer, and it does not require frequent replacement.

[0057] It should also be noted that, under current technological conditions, the preparation method of the porous hygroscopic material defined in the first technical solution can only be achieved through the preparation method defined in the twenty-sixth technical solution. The preparation method defined in the twenty-sixth technical solution is completely different from the first and second existing technologies. First, compared to the first existing technology, the polymerization reaction is not carried out in the hygroscopic salt solution, thus making purification easier and reducing the likelihood of toxic substances volatilizing into the air during the adsorption-desorption cycle. Furthermore, the conversion rate is higher, resulting in a more efficient polymerization reaction. Second, compared to the second existing technology, the porous adsorption mesh is not immersed in the solvent during the polymerization stage, thus ensuring the mesh remains interconnected. Most importantly, in step 2, the hydrogel is fully swollen directly in the hygroscopic salt solution and then mechanically broken down to form a micron-sized hydrogel-hygroscopic salt coating. This not only reduces the hydrogel-hygroscopic salt particle size to the micron level but also allows the hygroscopic salt to be more uniformly dispersed in the hydrogel, resulting in a more complete valence bond between the hygroscopic salt and the ions in the hydrogel. Here, "micron-scale" refers to the fact that the particle size of the hydrogel-hygroscopic salt is mostly distributed between 0.1 micrometers and 10 micrometers, with the portion between 0.1 micrometers and 1 micrometer being the main part. In step 3, the micron-scale hydrogel-hygroscopic salt coating obtained in step 2 is coated onto the porous adsorption network to achieve the porous hygroscopic material defined in the first technical solution. Therefore, the preparation methods in the first and second prior art cannot produce the porous hygroscopic material defined in the first technical solution.

[0058] Therefore, it is clear that the first technical solution cannot be achieved simply by replacing the solar panel in the first prior art with a hydrophilic single-layer mesh porous adsorption net. Nor can the first technical solution be achieved simply by replacing the three-dimensional napped fabric in the second prior art with a single-layer mesh structure or what the second prior art calls a "2D structure," and by replacing the hydrogel with an ionic hydrogel. In fact, more importantly, neither the first nor the second prior art pursues the adsorption rate as a performance indicator. Since both of the aforementioned prior art employ sunlight to achieve desorption, they only require one adsorption-desorption cycle per 24 hours. In this application, however, the adsorption-desorption cycle is generally completed within half an hour, and at most within one and a half hours, thus enabling dozens of adsorption-desorption cycles per 24 hours, resulting in a significantly higher efficiency in moisture absorption and collection.

[0059] To better understand the differences and effects between the preparation method defined in the twenty-sixth technical solution and existing technologies, refer to the existing technical literature "Hygroscopic-Microgels-Enabled Rapid Water Extraction from Arid Air," published in *Advanced Materials* in 2022. This technical solution involves obtaining micron-sized hydrogels through stirring during the polymerization reaction, then drying the micron-sized hydrogels in a hygroscopic salt solution to obtain powdered micron-sized hydrogel-hygroscopic salt composite materials. Finally, these composite materials are spread onto a monolayer adsorption bed to obtain the hygroscopic material. However, even with a porous adsorption mesh, the hydrogel-hygroscopic salt composite material cannot completely cover the mesh of the adsorption bed obtained by this method. In fact, the hygroscopic material prepared by this method is prone to aggregation and stacking after multiple adsorption-desorption cycles due to insufficient bonding between the adsorption bed and the micron-sized hydrogel-hygroscopic salt composite material. Of course, for single-use adsorption, this hygroscopic material has one of the best moisture absorption effects among the literature available to the applicant. In an environment with a relative humidity of 30%, the equilibrium adsorption capacity reaches 0.8 grams of water per gram of material, and the time to reach 80% equilibrium adsorption capacity is approximately 20 minutes, with an adsorption rate of 1.92 L / kg. -1 h -1 However, its adsorption rate is still significantly lower than that of this application.

[0060] The second technical solution is a preferred option of the first technical solution. The ratio of continuous mesh openings is greater than 60%, which can better ensure a larger specific surface area and is conducive to improving the balance between adsorption capacity and moisture absorption efficiency.

[0061] In the third and fourth technical solutions, if the mesh size of the porous adsorption mesh is greater than 300 mesh, the ratio of consistently permeable pores tends to decrease. If the mesh size of the porous adsorption mesh is less than 100 mesh, the absolute amount of water that can be adsorbed per unit area of ​​the porous adsorption mesh will decrease. Therefore, a mesh size between 100 and 300 mesh, particularly around 200 mesh, is a preferred implementation.

[0062] The fifth technical solution provides a preferred embodiment of a porous adsorption mesh material that is hydrophilic and capable of being woven into a mesh.

[0063] In the sixth and seventh technical solutions, if the mass percentage of hygroscopic salt in the hydrogel-hygroscopic salt composite material is greater than 70%, the hygroscopic salt is prone to leakage after absorbing moisture. If the mass percentage of hygroscopic salt in the hydrogel-hygroscopic salt composite material is less than 20%, not only will the equilibrium adsorption capacity be smaller, but the hydrogel-hygroscopic salt composite material will also be more prone to clogging the pores when coated onto the porous adsorption mesh due to its excessive thickness. If a higher equilibrium adsorption capacity is required for the hygroscopic material, the mass percentage of hygroscopic salt in the hydrogel-hygroscopic salt composite material should preferably be greater than 35%.

[0064] The eighth and ninth technical solutions provide preferred options for hygroscopic salts, among which lithium chloride is selected to achieve a better balance adsorption capacity.

[0065] The tenth to thirteenth technical solutions represent two cases: hydrogels containing cations and hydrogels containing anions, respectively, and provide preferred options.

[0066] In the fourteenth and fifteenth technical solutions, the hydrogel contains both cations and anions. Through the valence bond between the cations in the hydrogel and the anions in the hygroscopic salt, and the valence bond between the anions in the hydrogel and the cations in the hygroscopic salt, the hydrogel can have a stronger salt-carrying capacity, and the hygroscopic salt is less likely to leak and crystallize, thereby ensuring a larger equilibrium adsorption capacity and a higher adsorption rate.

[0067] The porous hygroscopic material defined in the sixteenth technical solution enables the preparation of hydrogels through a pre-polymerization reaction by selecting anions and cations, thereby reducing the energy consumption in the hydrogel preparation process. Here, "pre-polymerization reaction" refers to a polymerization reaction that requires additional energy during the initiation stage but not during the maintenance stage.

[0068] The seventeenth technical solution uses a support member to support the porous moisture-absorbing material, so that the porous adsorption mesh can maintain a single-layer shape and avoid curling or changing shape after absorbing moisture.

[0069] In the eighteenth technical solution, the porous moisture-absorbing material is planar and there are at least two of them. Each porous moisture-absorbing material is spaced apart along a direction perpendicular to the plane, so as to form a multi-layer planar structure. This can increase the overall water adsorption capacity of the porous moisture-absorbing element, while also making it easy to maintain the specific surface area of ​​the porous moisture-absorbing material by utilizing the spacing between each layer of porous moisture-absorbing material. It also facilitates the acceleration of desorption efficiency by hot air flow and shortens the time used for adsorption-desorption cycle.

[0070] In the nineteenth technical solution, moisture in the air is adsorbed by a porous moisture-absorbing element, desorption is achieved by a heater, and water vapor is converted into liquid water by a condenser, thereby achieving the dehumidification function.

[0071] In the twentieth technical solution, water is collected through a water collector connected to the condenser, thereby enabling the dehumidifier to have a water collection function.

[0072] In the twenty-first technical solution, a fan is used to create convection currents in the heated air to achieve desorption more quickly.

[0073] In the twenty-second technical solution, the porous hygroscopic material is arranged vertically so that the heated airflow can easily carry away the water vapor upwards, thereby achieving faster desorption.

[0074] In the twenty-third technical solution, automatic adsorption and desorption are achieved by automatically controlling the opening and closing of the heater.

[0075] Technical solutions 24 and 25 are two specific implementations of technical solution 23.

[0076] In the twenty-seventh and twenty-eighth technical solutions, if the mass ratio of hydrogel to hygroscopic salt aqueous solution is too small, there will be too little hydrogel, and the viscosity of the broken hydrogel-hygroscopic salt coating will be too low, making it difficult to adhere to the porous adsorption network; if the mass ratio of hydrogel to hygroscopic salt aqueous solution is too large, the hydrogel-hygroscopic salt coating will be too viscous, making it easier to cause stacking or pore blockage when coated onto the porous adsorption network, thereby reducing the specific surface area.

[0077] In technical solutions 27 and 28, if the molar ratio of hygroscopic salts in the aqueous solution is too small, the equilibrium adsorption capacity of the porous hygroscopic material is prone to decrease. If the molar ratio of hygroscopic salts in the aqueous solution is too large, the hygroscopic salts in the porous hygroscopic material are prone to leakage, crystallization, and agglomeration.

[0078] The twenty-ninth technical solution is the preferred implementation of mechanical crushing in the twenty-sixth technical solution.

[0079] The 30th and 31st technical solutions illustrate alternative embodiments of coating a hydrogel-hygroscopic salt coating onto a porous adsorption mesh. Dip coating, in particular, is preferred because it allows the hydrogel-hygroscopic salt composite material to cover the mesh in a single impregnation.

[0080] In the thirty-second technical solution, the cationic group is a quaternary ammonium salt cationic group and the anionic group is a carboxyl group and / or a carboxylate group; and the crosslinking agent and the initiator are both hydrophilic, the first monomer and the second monomer are monomers containing carbon-carbon double bonds, and the first solvent is water or a hydrophilic alcohol, then polymerization can be achieved through a front-end polymerization reaction, thereby reducing energy consumption.

[0081] The thirty-third technical solution is a preferred solution for the crosslinking agent, initiator, first monomer, and second monomer.

[0082] In the thirty-fourth technical solution, if the molar ratio of the second monomer to the first monomer is greater than 5:3, the hygroscopic salt is prone to leakage.

[0083] The thirty-fifth technical solution is a more preferred molar ratio than the thirty-fourth technical solution.

[0084] The thirty-sixth technical solution is an optional technical solution, meaning that the thirty-second technical solution allows monomers without ionic groups to participate in the polymerization reaction. Attached Figure Description

[0085] To more clearly illustrate the technical solutions of the embodiments, the accompanying drawings used are briefly described below:

[0086] Figure 1 This is a scanning electron microscope image of the porous hygroscopic material in Example 1 under dry conditions;

[0087] Figure 2 The adsorption-desorption curves of the porous hygroscopic material in Example 1 at 30% relative humidity are shown.

[0088] Figure 3 This is a schematic diagram of the moisture absorption device in Example 1;

[0089] Figure 4 This is a schematic diagram of the porous moisture-absorbing component in Example 1;

[0090] Figure 5 This is a schematic diagram of the moisture absorption device in Example 2;

[0091] Figure 6 This is a scanning electron microscope image of the porous hygroscopic material in Example 3 under dry conditions;

[0092] Figure 7 This is a scanning electron microscope image of the porous hygroscopic material in Example 4 under dry conditions;

[0093] Figure 8 This is a metallographic microscope image of the porous hygroscopic material in Example 4 after it has reached adsorption equilibrium.

[0094] Explanation of key figure labels:

[0095] 1. Porous moisture-absorbing component; 2. Gravity meter; 3. Fan; 4. Heater; 5. Air collector hood; 6. Condenser; 7. Water collector; 8. Housing; 9. Door; 10. Door actuator; 11. Controller; 12. Support frame; 13. Porous moisture-absorbing material; 14. Lower frame; 15. Upper frame; 16. Support column; 17. Air vent; 18. Hygrometer. Detailed Implementation

[0096] Unless otherwise specified, the terms “first,” “second,” or “third,” etc., in the claims and description are used to distinguish different objects and not to describe a particular order.

[0097] Unless otherwise specified, in the claims and description, the terms “center,” “lateral,” “longitudinal,” “horizontal,” “vertical,” “top,” “bottom,” “inner,” “outer,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “clockwise,” “counterclockwise,” etc., indicate the orientation or positional relationship based on the orientation and positional relationship shown in the drawings, and are only for the purpose of simplifying the description, and do not imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation.

[0098] Unless otherwise specified in the claims and description, the terms "fixed connection" or "fixed connection" shall be interpreted broadly to mean any connection in which there is no displacement or relative rotation relationship between the two parties, including non-removable fixed connection, detachable fixed connection, integral connection, and fixed connection by other means or components.

[0099] Unless otherwise specified, the terms “comprising,” “having,” and variations thereof in the claims and description shall mean “including but not limited to.”

[0100] In the claims and description, unless otherwise specified, the term "have" means that a technical feature that follows is part of a technical feature that precedes it.

[0101] Unless otherwise specified in the claims and description, the term "coating" refers to the mesh lines of a single layer of porous adsorption network that is three-dimensionally coated by the hydrogel-hygroscopic salt composite material.

[0102] Unless otherwise specified in the claims and description, the term "mesh remains open at all times" means that the mesh remains open at all times before absorbing moisture until the equilibrium adsorption capacity is reached.

[0103] Unless otherwise specified in the claims and description, the term "micron-scale" means that the particle size of the hydrogel-hygroscopic salt water is mostly distributed between 0.1 micrometers and 10 micrometers, of which the portion between 0.1 micrometers and 1 micrometer is the main part.

[0104] Unless otherwise specified in the claims and description, the term "front-end polymerization" refers to a polymerization reaction in which additional energy is required during the initiation phase but not during the maintenance phase.

[0105] Unless otherwise specified in the claims and description, the term "equilibrium adsorption capacity" refers to the number of grams of water adsorbed per gram of hydrogel-hygroscopic salt composite material when the adsorption capacity of the porous hygroscopic material reaches equilibrium, expressed in g / g.

[0106] Unless otherwise specified in the claims and description, the term "adsorption time" refers to the time required for the adsorption capacity of a porous hygroscopic material to increase from 0% to 80% equilibrium adsorption capacity, and the unit in this application is min or h (minutes or hours).

[0107] Unless otherwise specified in the claims and description, the term "desorption time" refers to the time required for the adsorption amount of a porous hygroscopic material to decrease from 80% equilibrium adsorption amount to 0, and the unit in this application is min or h (minutes or hours).

[0108] Unless otherwise specified in the claims and description, the term "adsorption rate" refers to the volume of water adsorbed per kilogram of hydrogel-hygroscopic salt composite material per hour, in Lkg. -1 h -1 (liters per kilogram per hour) is calculated by dividing the volume of water corresponding to the adsorption capacity of the porous hygroscopic material from 0 to 80% equilibrium adsorption capacity by the adsorption time and then by the mass of the hydrogel-hygroscopic salt composite material.

[0109] Unless otherwise specified in the claims and description, the term "desorption rate" refers to the volume of water desorbed per kilogram of hydrogel-hygroscopic salt composite material per hour, in Lkg. -1 h -1 (liters per kilogram per hour) is calculated by dividing the volume of water corresponding to the desorption of the porous hygroscopic material from 80% equilibrium adsorption to 0 by the desorption time and then by the mass of the hydrogel-hygroscopic salt composite material.

[0110] The technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings.

[0111] Example 1

[0112] I. Preparation of Hydrogels

[0113] The hydrogel in Example 1 was prepared by free radical polymerization of a first monomer containing a quaternary ammonium salt cationic group, a second monomer containing a carboxyl anionic group, a crosslinking agent, and an initiator under conditions with a first solvent, followed by purification and drying. The free radical polymerization is a front-end polymerization reaction; both the crosslinking agent and the initiator are hydrophilic; the first and second monomers are monomers containing carbon-carbon double bonds; and the first solvent is water or a hydrophilic alcohol. Here, "front-end polymerization reaction" refers to a polymerization reaction that requires additional energy during the initiation phase but not during the maintenance phase. Specifically, in this example, the first monomer is acryloyloxyethyltrimethylammonium chloride; in other examples, (3-acrylamidopropyl)trimethylammonium chloride can also be used. The second monomer is acrylic acid; the crosslinking agent is an acrylamide crosslinking agent, specifically N,N-methylenebisacrylamide; the initiator is a peroxide or azo initiator, specifically ammonium persulfate; and the first solvent is water.

[0114] The specific preparation process is as follows:

[0115] Dissolve 0.013g of N,N-dimethylbisacrylamide in 0.5g of acrylic acid by stirring / manual shaking at room temperature, then add 4.66g of acryloyloxyethyltrimethylammonium chloride (80wt% aqueous solution) and dissolve by stirring / manual shaking at room temperature. Label this solution A.

[0116] Prepare an ammonium persulfate aqueous solution by adding 0.041 g of ammonium persulfate to 0.082 g of water, stirring / manually shaking at room temperature to dissolve, and label this solution as solution B;

[0117] Add solution B to solution A, stir / shake manually at room temperature to dissolve, and label as solution C;

[0118] Add solution C into a glass test tube with a diameter of 1.5 cm and a height of 20 cm;

[0119] Heat the test tube wall with a 300°C soldering iron until the polymerization reaction starts, then remove the soldering iron and let the polymerization reaction proceed spontaneously until it is complete.

[0120] After the polymerization reaction was completed, water was added until it swelled completely and then removed. Anhydrous ethanol was then added in three portions to wash away unreacted reactants for purification. The polymer was then dried in an 80°C oven for 12 hours to obtain a hydrogel.

[0121] In this embodiment, the molar ratio of the second monomer to the first monomer is 1:3.

[0122] The prepared hydrogel is porous and fragmented, and easily broken. The prepared hydrogel contains cations and anions; the cations are quaternary ammonium cations, and the anions are carboxyl groups.

[0123] II. Preparation of porous hygroscopic materials

[0124] The process of preparing porous hygroscopic materials mainly includes:

[0125] Step 1: Place the hydrogel in an aqueous solution of hygroscopic salt;

[0126] Step 2: After the hydrogel swells, it is mechanically broken down to form a micron-sized hydrogel-hygroscopic salt coating; and

[0127] Step 3: Coat the hydrogel-hygroscopic salt coating onto a hydrophilic, single-layer porous adsorption network and dry it.

[0128] In step 1, the hygroscopic salt is one or more of lithium chloride, calcium chloride, magnesium chloride, and lithium bromide, preferably lithium chloride; the mass ratio of the hydrogel to the aqueous solution of the hygroscopic salt is between 1:40 and 1:20; and the molar ratio of the hygroscopic salt in the aqueous solution is between 0.5 mol / L and 3 mol / L. Preferably, the mass ratio of the hydrogel to the aqueous solution of the hygroscopic salt is between 1:25 and 1:35; and the molar ratio of the hygroscopic salt in the aqueous solution is preferably between 1 mol / L and 2 mol / L.

[0129] In step 2, mechanical crushing is carried out by stirring.

[0130] In step 3, the mesh size of the porous adsorption mesh is between 100 and 300 mesh, preferably 200 mesh, and the material of the porous adsorption mesh is preferably nylon, polyurethane, glass, or silicon carbide; the method of coating the hydrogel-hygroscopic salt coating onto the porous adsorption mesh includes dip coating, spraying, brushing, rod coating, and spin coating, with dip coating being the preferred method.

[0131] Specifically, in this embodiment, in step 1, the hygroscopic salt is lithium chloride; the molar ratio of hygroscopic salt in the hygroscopic salt aqueous solution is 1 mol / L; and the mass ratio of hydrogel to hygroscopic salt aqueous solution is 1:30. In step 2, the stirring speed is 12000 r / min. In step 3, the porous adsorption mesh has a mesh size of 200 mesh, the material of the porous adsorption mesh is nylon, and the method of coating the hydrogel-hygroscopic salt coating onto the porous adsorption mesh is dip coating.

[0132] The specific preparation process is as follows:

[0133] Take 4.239g of lithium chloride and add it to 10g of deionized water to dissolve by stirring / manual shaking at room temperature. Then transfer it to a 250ml graduated cylinder and continue to add deionized water until 100ml is reached to prepare a 1mol / L lithium chloride aqueous solution, that is, 42.39g of lithium chloride in 1000ml of salt solution.

[0134] Add 1g of the prepared hydrogel to 30g of the prepared lithium chloride aqueous solution and let it stand for 12h to allow it to swell completely.

[0135] The fully swollen hydrogel-lithium chloride mixture was homogenized at 12,000 rpm for 4 minutes to obtain a micron-sized ionic hydrogel-lithium chloride coating. Here, "micron-sized" means that the particle size of the hydrogel-hygroscopic salt is mostly distributed between 0.1 microns and 10 microns, with the portion between 0.1 microns and 1 micron being the main part.

[0136] A 200-mesh single-layer porous nylon mesh with a length and width of 6.5 cm was immersed in a prepared ion hydrogel-lithium chloride aqueous solution coating, and then immediately removed and dried in an oven at 110°C for 30 minutes; thus, the porous moisture-absorbing material in this embodiment was obtained.

[0137] III. Structure of Porous Hygroscopic Materials

[0138] See Figure 1 , Figure 1 The structure of the porous hygroscopic material in the dry state of Example 1 is shown. For example... Figure 1 As shown, the porous hygroscopic material includes a porous adsorption network and a hydrogel-hygroscopic salt composite material. The porous adsorption network is a single-layer mesh with a hydrophilic material. The hydrogel-hygroscopic salt composite material coats at least a portion of the network lines of the porous adsorption network while maintaining at least some of the mesh pores interconnected. The hydrogel-hygroscopic salt composite material comprises a hydrogel and a hygroscopic salt fused together, wherein the hydrogel is an ionic hydrogel. Here, "coating" refers to the hydrogel-hygroscopic salt composite material three-dimensionally coating the mesh lines of the single-layer porous adsorption network.

[0139] Specifically, in this embodiment, the porous adsorption mesh in the porous hygroscopic material is a single-layer nylon mesh with a mesh size of 200. In the portion where the hydrogel-hygroscopic salt composite material adheres to the porous adsorption mesh, the hydrogel-hygroscopic salt composite material completely covers the mesh lines of the porous adsorption mesh, and the proportion of interconnected mesh pores is greater than or equal to 60%.

[0140] IV. Adsorption and desorption curves of porous hygroscopic materials

[0141] In this application, "equilibrium adsorption capacity" refers to the number of grams of water adsorbed per gram of hydrogel-hygroscopic salt composite material when the adsorption capacity of the porous hygroscopic material reaches equilibrium, expressed in g / g. "Adsorption time" refers to the time required for the adsorption capacity of the porous hygroscopic material to increase from 0% to 80% of the equilibrium adsorption capacity, expressed in min or h. "Desorption time" refers to the time required for the adsorption capacity of the porous hygroscopic material to decrease from 80% to 0%, expressed in min or h. "Adsorption rate" refers to the volume of water adsorbed per kilogram of hydrogel-hygroscopic salt composite material per hour, expressed in Lkg. -1 h -1(L / kg / hour) is specifically calculated as the volume of water corresponding to the adsorption capacity of the porous hygroscopic material from 0% to 80% equilibrium adsorption capacity, divided by the adsorption time, and then divided by the mass of the hydrogel-hygroscopic salt composite material. "Dehygroscopic rate" refers to the volume of water desorbed per kilogram of hydrogel-hygroscopic salt composite material per hour, expressed in L / kg. -1 h -1 (liters per kilogram per hour) is calculated by dividing the volume of water corresponding to the desorption of the porous hygroscopic material from 80% equilibrium adsorption to 0 by the desorption time and then by the mass of the hydrogel-hygroscopic salt composite material.

[0142] The specific methods for measuring adsorption and desorption curves are as follows:

[0143] The porous hygroscopic material was placed in a constant temperature and humidity chamber (temperature 25℃, relative humidity 30% or 60%). The material was then heated on a hot plate at 110℃ for 30 minutes, and subsequently rapidly transferred to an electronic balance with an accuracy of 0.1 mg for weighing. The electronic balance was used for automatic data recording and reading at 5-second intervals to test its adsorption curve.

[0144] The sample that has reached adsorption equilibrium is heated on a hot plate at 70°C. The sample is weighed every 1 minute using an electronic balance. The measurement is performed for 30 minutes to test its desorption curve.

[0145] See Figure 2 , Figure 2 The adsorption-desorption curves of the porous hygroscopic material in Example 1 at 30% relative humidity are shown. Figure 2 As shown, at 30% relative humidity, the equilibrium adsorption capacity of the porous hygroscopic material in this embodiment is 0.92 g / g, the adsorption time is 12.98 min, the desorption time is 9.99 min, and the adsorption rate is 3.4 L / kg. -1 h -1 The desorption rate was 4.42 L / kg. -1 h -1 .

[0146] Tests showed that, at 60% relative humidity, the equilibrium adsorption capacity of the porous hygroscopic material in this embodiment was 1.56 g / g, and the adsorption rate was 4.7 L / kg. -1 h -1 The desorption rate was 5.4 L / kg. -1 h -1 .

[0147] V. Dehumidification device and porous adsorption element

[0148] See Figure 3 , Figure 3 The dehumidification device in this embodiment is shown. Figure 3 As shown, in this embodiment, the dehumidification device includes a porous moisture-absorbing element 1, a gravimeter 2, a fan 3, a heater 4, an air collector 5, a condenser 6, a water collector 7, a housing 8, a door 9, a door actuator 10, and a controller 11.

[0149] See Figure 4 , Figure 4 The porous moisture-absorbing element 1 in this embodiment is shown, such as Figure 4 As shown, the porous moisture-absorbing component 1 in this embodiment includes a support 12 and porous moisture-absorbing material 13, wherein the support 12 is used to support the porous moisture-absorbing material 13. In this embodiment, the porous moisture-absorbing material 13 is planar, and the number of porous moisture-absorbing materials 13 is at least two, specifically five, although one porous moisture-absorbing material 13 may also be used. The porous moisture-absorbing materials 13 are spaced apart along a direction perpendicular to the plane. In this embodiment, the porous moisture-absorbing materials 13 are vertically arranged. The support 12 includes a lower frame 14, an upper frame 15, and a support column 16 fixedly connected to each other. The support column 16 is arranged at four corners and is used to connect the lower frame 14 and the upper frame 15. The lower frame 14 and the upper frame 15 are respectively used to tension and support each porous moisture-absorbing material 13. Both the lower frame 14 and the upper frame 15 are provided with a number of air passage holes 17. The air passage holes 17 are arranged parallel to the porous moisture-absorbing material 13, and air passage holes 17 are provided on both sides of each porous moisture-absorbing material 13.

[0150] like Figure 3As shown, the gravimeter 2 supports the porous absorbent element 1 and measures its weight to characterize the amount of water adsorbed by the porous absorbent material 13. The fan 3 is located below the porous absorbent element 1 and creates convection currents in the air heated by the heater 4 to desorb the porous absorbent material 13 on the absorbent element 1. In this embodiment, the heated airflow generated by the fan 3 flows upward through each air passage 17 and each porous absorbent material 13. The heater 4 desorbs the porous absorbent material 13 on the absorbent element 1 by heating it. In this embodiment, the heater 4 is located below the fan 3. The air collector 5 is located above the porous absorbent element 1 and collects the hot water vapor generated during the desorption of the porous absorbent material 13. The condenser 6 is connected to the air collector 5 and condenses the water vapor generated after the desorption of the porous absorbent material 13 into condensate. The water collector 7 is connected to the condenser 6 to collect the condensate produced by the condenser 6. The housing 8 houses the porous moisture-absorbing element 1, the gravimeter 2, the fan 3, the heater 4, the air collector 5, the condenser 6, and the water collector 7. The housing 8 has an opening. A door 9 is located at the opening for closing or opening the opening. A door actuator 10 drives the door 9 to close or open the opening. A controller 11 is housed within the housing 8. The controller 11 is electrically connected to the gravimeter 2, the fan 3, the heater 4, and the door actuator 10. It controls the opening and closing of the fan 3, the heater 4, and the door actuator 10 based on the amount of water adsorbed by the porous moisture-absorbing material 13, as indicated by the weight of the porous moisture-absorbing element 1 detected by the gravimeter 2.

[0151] Specifically, when the amount of water adsorbed by the porous hygroscopic material 13 reaches or exceeds a first threshold, the controller 11 controls the door actuator 10 to close the door 9 at the opening of the housing 8, and controls the fan 3 and heater 4 to start to achieve desorption of the porous hygroscopic material 13; when the amount of water adsorbed by the porous hygroscopic material 13 reaches or falls below a second threshold, the controller 11 controls the door actuator 10 to open the door 9 at the opening of the housing 8, and controls the fan 3 and heater 4 to turn off to achieve adsorption of the porous hygroscopic material 10. Thus, the dehumidification device achieves an automatic adsorption-desorption cycle.

[0152] Example 2

[0153] The difference between Example 2 and Example 1 lies in the structure of the dehumidification device. All other parts are the same as in Example 1.

[0154] See Figure 5 , Figure 5 The dehumidification device in Embodiment 2 is shown. For example... Figure 5 As shown, the dehumidification device in Embodiment 2 differs from that in Embodiment 1 in that the dehumidification device in Embodiment 2 no longer has the gravity meter 2 as in Embodiment 1, but instead has a hygrometer 18 fixed to the housing 8 and extending out of the housing 8. The controller 11 is also electrically connected to the hygrometer 18.

[0155] Hygrometer 18 is used to detect ambient humidity. Based on the ambient humidity detected by hygrometer 18, controller 11 characterizes the amount of water adsorbed by porous hygroscopic material 13 according to the period elapsed after heater 4 is turned off and the period elapsed after heater 4 is turned on. Similarly, when the amount of water adsorbed by porous hygroscopic material 13 reaches or exceeds a first threshold, controller 11 controls door actuator 10 to close the opening of housing 8 by door 9, and controls fan 3 and heater 4 to start to achieve desorption of porous hygroscopic material 13; when the amount of water adsorbed by porous hygroscopic material 13 reaches or falls below a second threshold, controller 11 controls door actuator 10 to open the opening of housing 8 by door 9, and controls fan 3 and heater 4 to turn off to achieve adsorption of porous hygroscopic material 10.

[0156] The rest of the dehumidification device in Example 2 is the same as in Example 1.

[0157] Example 3

[0158] The difference between Example 3 and Example 1 is that the porous adsorption mesh has a mesh size of 100. The rest of Example 4 is the same as Example 1.

[0159] See Figure 6 , Figure 6 The structure of the porous hygroscopic material in the dry state of Example 4 is shown. Figure 6 As shown, when the mesh size of the porous adsorption mesh reaches 100 mesh, the proportion of mesh holes that remain connected in the part of the mesh line of the porous adsorption mesh covered by the hydrogel-hygroscopic salt composite material is also greater than or equal to 60%.

[0160] Example 4

[0161] The difference between Example 4 and Example 1 is that, in preparing the porous hygroscopic material, the molar ratio of hygroscopic salt in the hygroscopic salt aqueous solution is 0.5 mol / L; the mass ratio of hydrogel to hygroscopic salt aqueous solution is 1:20. Therefore, in the prepared porous hygroscopic material, the mass percentage of hygroscopic salt in the hydrogel-hygroscopic salt composite material is 35%. The mesh size of the porous adsorption mesh in Example 4 is 300 mesh. The rest of Example 5 is the same as Example 1.

[0162] See Figure 7 and Figure 8 , Figure 7 The structure of the porous hygroscopic material in the dry state in Example 4 is shown. Figure 8 The structure of the porous hygroscopic material in Example 5 after reaching adsorption equilibrium is shown. Figure 7 As shown in Example 5, in the portion of the porous adsorption mesh coated with the hydrogel-hygroscopic salt composite material, the proportion of interconnected pores remaining in the dry state is also greater than or equal to 60%. Figure 8As shown in Example 5, in the portion of the porous adsorption mesh coated with the hydrogel-hygroscopic salt composite material, the number of interconnected pores after reaching adsorption equilibrium did not change significantly, remaining greater than or equal to 60%. Since the mass percentage of hygroscopic salt in the hydrogel-hygroscopic salt composite material was not high in Example 4, implying a higher proportion of hydrogel and a more viscous hydrogel-hygroscopic salt composite material, and the porous adsorption mesh had a mesh size of 300, the fact that the number of interconnected pores in the porous hygroscopic material in Example 4 remained at or equal to 60% after reaching adsorption equilibrium means that in all examples, the porous hygroscopic material maintained interconnected pores throughout the process from before adsorption to reaching adsorption equilibrium.

[0163] In Example 4, the porous hygroscopic material had an equilibrium adsorption capacity of 0.65 g / g at 30% relative humidity, an adsorption time of 6.95 min, a desorption time of 6.47 min, and an adsorption rate of 3.9 L / kg. -1 h -1 The desorption rate was 4.8 L / kg. -1 h -1 .

[0164] The rest of Example 4 is the same as Example 1.

[0165] Example 5

[0166] The difference between Example 5 and Example 1 is that, in preparing the porous hygroscopic material, the molar ratio of hygroscopic salt in the hygroscopic salt aqueous solution is 3 mol / L; the mass ratio of hydrogel to hygroscopic salt aqueous solution is 1:30. Therefore, in the prepared porous hygroscopic material, the mass percentage of hygroscopic salt in the hydrogel-hygroscopic salt composite material is 70%.

[0167] In Example 5, the porous hygroscopic material had an equilibrium adsorption capacity of 1.52 g / g at 30% relative humidity, an adsorption time of 30.02 min, a desorption time of 23.31 min, and an adsorption rate of 2.4 L / kg. -1 h -1 The desorption rate was 3.1 L / kg. -1 h -1 .

[0168] The remainder of Example 5 is the same as that of Example 1.

[0169] Example 6

[0170] The difference between Example 6 and Example 1 is that, in the preparation of the hydrogel, the second monomer is sodium acrylate, so the anionic group in the hydrogel is carboxylate.

[0171] In Example 6, the porous hygroscopic material had an equilibrium adsorption capacity of 0.9 g / g at 30% relative humidity, an adsorption time of 13.42 min, a desorption time of 10.05 min, and an adsorption rate of 3.2 L / kg. -1 h -1 The desorption rate was 4.3 L / kg. -1 h -1 .

[0172] The remainder of Example 6 is the same as that of Example 1.

[0173] Example 7

[0174] The difference between Example 7 and Example 1 is that calcium chloride is used as the hygroscopic salt in the preparation of the porous adsorbent material.

[0175] In Example 7, the porous hygroscopic material had an equilibrium adsorption capacity of 0.6 g / g at 30% relative humidity, an adsorption time of 9.82 min, a desorption time of 7.02 min, and an adsorption rate of 2.9 L / kg. -1 h -1 The desorption rate was 4.1 L / kg. -1 h -1 .

[0176] The rest of Example 7 is the same as Example 1.

[0177] Example 8

[0178] The difference between Example 8 and Example 1 is that, in the preparation of the hydrogel, the molar ratio of the second monomer to the first monomer is 5:3.

[0179] In Example 8, the porous hygroscopic material had an equilibrium adsorption capacity of 0.85 g / g at 30% relative humidity, an adsorption time of 12.1 min, a desorption time of 9.69 min, and an adsorption rate of 3.4 L / kg. -1 h -1 The desorption rate was 4.2 L / kg. -1 h -1 .

[0180] The remainder of Example 8 is the same as that of Example 1.

[0181] Example 9

[0182] The difference between Example 9 and Example 1 is that, in preparing the hydrogel, the molar ratio of the second monomer to the first monomer is 1:5.

[0183] In Example 9, the porous hygroscopic material had an equilibrium adsorption capacity of 0.91 g / g at 30% relative humidity, an adsorption time of 14 min, a desorption time of 10.92 min, and an adsorption rate of 3.1 L / kg.-1 h -1 The desorption rate is 4.0 L / kg. -1 h -1 .

[0184] The remainder of Example 9 is the same as that of Example 1.

[0185] Example 10

[0186] The difference between Example 10 and Example 1 is that no second monomer was used in the preparation of the hydrogel, so neither the hydrogel nor the hydrogel-hygroscopic salt composite material contains anionic groups.

[0187] In Example 10, the porous hygroscopic material had an equilibrium adsorption capacity of 0.8 g / g at 30% relative humidity, an adsorption time of 14.0 min, a desorption time of 10.8 min, and an adsorption rate of 3.1 L / kg. -1 h -1 The desorption rate is 4.0 L / kg. -1 h -1 .

[0188] The remainder of Example 10 is the same as that of Example 1.

[0189] Example 11

[0190] The difference between Example 11 and Example 1 is that no first monomer was used in the preparation of the hydrogel, so neither the hydrogel nor the hydrogel-hygroscopic salt composite material contains cationic groups.

[0191] In Example 11, the porous hygroscopic material had an equilibrium adsorption capacity of 0.8 g / g at 30% relative humidity, an adsorption time of 40.9 min, a desorption time of 32.3 min, and an adsorption rate of 0.9 L / kg. -1 h -1 The desorption rate is 1.2 L / kg. -1 h -1 .

[0192] The rest of Example 11 is the same as Example 1.

[0193] In addition to the above embodiments, in other embodiments, when preparing the hydrogel, the free radical polymerization reaction may also include a third monomer, which is a monomer without ionic groups and containing carbon-carbon double bonds; the third monomer is preferably an acrylate, methacrylate, acrylamide or methacrylamide monomer.

[0194] In addition to the above embodiments, if the polymerization reaction for preparing the hydrogel is not considered to be a front-end polymerization reaction, the anionic groups contained in the second monomer during the hydrogel preparation process can also be sulfonate and / or phosphate groups.

[0195] From the above embodiments, it can be seen that:

[0196] In each embodiment, the hydrogel is an ionic hydrogel, which can form valence bonds with the hygroscopic salt, thereby having a stronger salt-carrying capacity, making the hygroscopic salt less likely to leak or decompose, and thus dispersed in the hydrogel skeleton.

[0197] In each embodiment, the porous adsorption mesh material is hydrophilic, which can better combine with the hydrogel-hygroscopic salt composite material, thereby more effectively preventing the aggregation of the hydrogel-hygroscopic salt composite material.

[0198] In each embodiment, the hydrogel-hygroscopic salt composite material three-dimensionally coats the mesh lines of a single-layer porous adsorption network. This not only maximizes the specific surface area of ​​the hydrogel-hygroscopic salt composite material but also maximizes the contact area between the hydrophilic porous adsorption network and the hydrogel-hygroscopic salt composite material, thereby more effectively preventing the aggregation of the hydrogel-hygroscopic salt composite material. It should be noted that, in this structure, a single-layer porous adsorption network provides the largest surface area of ​​the hydrogel-hygroscopic salt composite material in contact with air compared to a three-dimensional porous adsorption material.

[0199] In each embodiment, the mesh remains open, providing sufficient volume expansion space for the hydrogel-hygroscopic salt composite material during the moisture absorption and swelling process, minimizing agglomeration and stacking, which would reduce the contact area with air.

[0200] In each embodiment, the single-layer mesh structure of the porous adsorption mesh, the hydrophilicity of the porous adsorption mesh, the use of ionic hydrogels, and the coating of the mesh lines of the porous adsorption mesh with hydrogel-hygroscopic salt composite materials are organically combined and mutually supportive to ensure that the mesh remains interconnected, thereby enabling the porous hygroscopic material of this application to have an extremely high adsorption rate. Specifically, the single-layer mesh structure of the porous adsorption mesh increases the contact area between the porous adsorption mesh and the hydrogel-hygroscopic salt composite material, as well as the contact area between the hydrogel-hygroscopic salt composite material and the air. The binding force of the hydrophilic porous adsorption mesh on the hydrogel-hygroscopic salt composite material prevents the hydrogel-hygroscopic salt composite material from agglomerating. The ionic hydrogel, through its valence bond with the hygroscopic salt, makes the hygroscopic salt less prone to leakage and crystallization. Therefore, these technical means all contribute to ensuring that the mesh remains interconnected.

[0201] In most embodiments, the equilibrium adsorption capacity is also higher than that of the prior art, especially when the properties of the hydrogel are the same. This is because the hydrogel-hygroscopic salt composite material in each embodiment has a higher specific surface area, allowing for a greater mass ratio of substances that can swell sufficiently.

[0202] In each embodiment, after multiple adsorption-desorption cycles, the hydrogel-hygroscopic salt composite material is less prone to aggregation than in the prior art, and the hygroscopic salt is also less prone to leakage and crystallization. Therefore, its effective service life is longer, and it does not require frequent replacement.

[0203] The preparation methods of the porous hygroscopic materials in each embodiment are completely different from the prior art. First, compared with the first prior art, the polymerization reaction is not carried out in the hygroscopic salt solution, thus making purification easier and reducing the likelihood of toxic substances volatilizing into the air during the adsorption-desorption cycle. Simultaneously, the conversion rate is higher, and the polymerization reaction efficiency is higher. Second, compared with the second prior art, the porous adsorption mesh is not immersed in the solvent during the polymerization reaction stage, thus ensuring that the mesh pores remain interconnected. Most importantly, in step 2, the hydrogel is fully swollen directly in the hygroscopic salt solution and then mechanically broken down to form a micron-sized hydrogel-hygroscopic salt coating. This not only reduces the hydrogel-hygroscopic salt particle size to the micron level but also allows the hygroscopic salt to be more uniformly dispersed in the hydrogel, resulting in more complete valence bond binding between the hygroscopic salt and the ions in the hydrogel. In step 3, the micron-sized hydrogel-hygroscopic salt coating obtained in step 2 is coated onto the porous adsorption mesh to achieve the porous hygroscopic materials defined in each embodiment. Therefore, the preparation methods in the first and second prior art cannot prepare the porous hygroscopic materials of each embodiment.

[0204] In each embodiment, the adsorption-desorption cycle is generally completed within half an hour, and at most within one and a half hours, so that dozens of adsorption-desorption cycles can be performed in a day and night, and its efficiency in moisture absorption and water collection is self-evident.

[0205] In each embodiment, the ratio of continuous mesh openings is greater than 60%, which can better ensure a larger specific surface area and is conducive to balancing the adsorption capacity and moisture absorption efficiency.

[0206] In each embodiment, lithium chloride is selected as the hygroscopic salt, which has a better equilibrium adsorption capacity.

[0207] In Examples 1 to 10, the selection of anions and cations enables the hydrogel to be prepared via a front-end polymerization reaction, thereby reducing the energy consumption in the hydrogel preparation process. Here, "front-end polymerization reaction" refers to a polymerization reaction that requires additional energy during the initiation phase but not during the maintenance phase.

[0208] In each embodiment, the porous moisture-absorbing material is supported by a support member, so that the porous adsorption mesh can maintain a single-layer shape and avoid curling or changing shape after absorbing moisture.

[0209] In each embodiment, the porous moisture-absorbing material is planar and there are at least two of them. The porous moisture-absorbing materials are spaced apart along a direction perpendicular to the plane, so as to form a multi-layer planar structure. This can increase the overall water adsorption capacity of the porous moisture-absorbing element, while also making it easy to maintain the specific surface area of ​​the porous moisture-absorbing material by utilizing the spacing between the layers of porous moisture-absorbing material. It also facilitates the acceleration of desorption efficiency by hot air flow and shortens the time required for adsorption-desorption cycle.

[0210] In each embodiment, moisture in the air is adsorbed by a porous moisture-absorbing element, desorption is achieved by a heater, and water vapor is converted into liquid water by a condenser, thereby achieving the dehumidification function.

[0211] In each embodiment, a fan is used to create convection currents in the heated air to achieve desorption more quickly.

[0212] In each embodiment, the porous hygroscopic material is arranged vertically so that the heated airflow can easily carry away the water vapor upwards, thereby desorbing more quickly.

[0213] In each embodiment, automatic adsorption and desorption are achieved by automatically controlling the opening and closing of the heater.

[0214] In each embodiment, the cationic group is a quaternary ammonium salt cationic group and the anionic group is a carboxyl group and / or a carboxylate group; and the crosslinking agent and the initiator are both hydrophilic, the first monomer and the second monomer are monomers containing carbon-carbon double bonds, and the first solvent is water or a hydrophilic alcohol, then polymerization can be achieved through a front-end polymerization reaction, thereby reducing energy consumption.

[0215] The description of the above specification and embodiments is used to explain the scope of protection of this application, but does not constitute a limitation on the scope of protection of this application.

Claims

1. A porous hygroscopic material, characterized in that its... include: Porous adsorption mesh, which is a single-layer mesh and is made of hydrophilic material; and A hydrogel-hygroscopic salt composite material, which covers at least part of the mesh lines of a porous adsorption network and keeps at least part of the mesh pores always connected, the hydrogel-hygroscopic salt composite material comprising a hydrogel and a hygroscopic salt fused together, wherein the hydrogel is an ionic hydrogel.

2. The porous moisture-absorbing material as described in claim 1, characterized in that, In the portion of the hydrogel-hygroscopic salt composite material coated with mesh lines, the proportion of mesh openings that remain continuous is greater than or equal to 60%.

3. The porous moisture-absorbing material as described in claim 1, characterized in that, The mesh size of the porous adsorption mesh is between 100 and 300 mesh.

4. The porous moisture-absorbing material as described in claim 3, characterized in that, The mesh size of the porous adsorption mesh is preferably 200 mesh.

5. The porous moisture-absorbing material as described in claim 1, characterized in that, The porous adsorption mesh is preferably made of nylon, polyurethane, glass, or silicon carbide.

6. The porous moisture-absorbing material as described in claim 1, characterized in that, The hygroscopic salt in the hydrogel-hygroscopic salt composite material has a mass percentage between 20% and 70%.

7. The porous moisture-absorbing material as described in claim 6, characterized in that, The hygroscopic salt in the hydrogel-hygroscopic salt composite material has a mass percentage between 35% and 70%.

8. The porous moisture-absorbing material as described in claim 1, characterized in that, The hygroscopic salt is one or more of lithium chloride, calcium chloride, magnesium chloride, and lithium bromide.

9. The porous moisture-absorbing material as described in claim 8, characterized in that, The hygroscopic salt is preferably lithium chloride.

10. The porous hygroscopic material according to any one of claims 1 to 9, characterized in that, The hydrogel contains cations.

11. The porous moisture-absorbing material as described in claim 10, characterized in that, The cation is preferably a quaternary ammonium cation.

12. The porous hygroscopic material according to any one of claims 1 to 9, characterized in that, The hydrogel contains anions.

13. The porous moisture-absorbing material as described in claim 12, characterized in that, The anion is preferably one or more of carboxyl, carboxylate, sulfonate and phosphate groups.

14. The porous hygroscopic material according to any one of claims 1 to 9, characterized in that, The hydrogel contains both cations and anions.

15. The porous moisture-absorbing material as described in claim 14, characterized in that, The cation is preferably a quaternary ammonium cation, and the anion is preferably one or more of carboxyl, carboxylate, sulfonate and phosphate groups.

16. The porous moisture-absorbing material as described in claim 15, characterized in that, More preferably, the anion is a carboxyl group and / or a carboxylate group.

17. A porous moisture-absorbing component, characterized in that, It includes a support and a porous moisture-absorbing material as described in any one of claims 1 to 16, wherein the support supports the porous moisture-absorbing material.

18. The porous moisture-absorbing element as described in claim 17, characterized in that, The porous moisture-absorbing material is planar, and there are at least two porous moisture-absorbing materials, which are spaced apart along a direction perpendicular to their plane.

19. A dehumidification device, characterized in that, It includes a heater, a condenser, and a porous moisture-absorbing element as described in claim 17 or 18; the heater desorbs the porous moisture-absorbing material on the porous moisture-absorbing element by heating, and the condenser is used to condense the water vapor formed after the porous moisture-absorbing material is desorbed into condensate.

20. The dehumidification device as described in claim 19, characterized in that, It also includes a water collector connected to the condenser to collect the condensate produced by the condenser.

21. The dehumidification device as described in claim 19, characterized in that, It also includes a fan used to create convection currents in the air heated by the heater to desorb the porous moisture-absorbing material on the porous absorbent.

22. The dehumidification device as described in claim 21, characterized in that, The porous moisture-absorbing materials are arranged vertically, and the heated air passes through each of the porous moisture-absorbing materials.

23. The dehumidification device as described in claim 19, characterized in that, It also includes a control unit, which controls the heater to start when the amount of water adsorbed by the porous hygroscopic material reaches or exceeds a first threshold, and controls the heater to shut down when the amount of water adsorbed reaches or falls below a second threshold; the first threshold is higher than the second threshold.

24. The dehumidification device as described in claim 23, characterized in that, The control unit includes a gravimeter and a controller. The gravimeter is used to detect the weight of the porous moisture-absorbing element, and the controller characterizes the amount of water adsorbed by the porous moisture-absorbing material based on the weight of the porous moisture-absorbing element.

25. The dehumidification device as described in claim 23, characterized in that, The control unit includes a hygrometer and a controller. The hygrometer is used to detect the ambient humidity. The controller, based on the ambient humidity detected by the hygrometer, characterizes the amount of water adsorbed by the porous hygroscopic material according to the period experienced after the heater is turned off and the period experienced after it is turned on.

26. A method for preparing porous hygroscopic materials, characterized in that, It is used to prepare the porous hygroscopic material as described in any one of claims 1 to 16, and comprises the following steps: Step 1: Place the hydrogel in an aqueous solution of hygroscopic salt; Step 2: After the hydrogel swells, it is mechanically broken down to form a micron-sized hydrogel-hygroscopic salt coating; and Step 3: Coat the hydrogel-hygroscopic salt coating onto a hydrophilic, single-layer porous adsorption network and dry it.

27. The method for preparing the porous hygroscopic material as described in claim 26, characterized in that, In step 1, the mass ratio of the hydrogel to the aqueous solution of the hygroscopic salt is between 1:40 and 1:20; the molar ratio of the hygroscopic salt in the aqueous solution is between 0.5 mol / L and 3 mol / L.

28. The method for preparing the porous hygroscopic material as described in claim 27, characterized in that, In step 1, the mass ratio of the hydrogel to the aqueous solution of the hygroscopic salt is preferably between 1:25 and 1:35; the molar ratio of the hygroscopic salt in the aqueous solution is preferably between 1 mol / L and 2 mol / L.

29. The method for preparing the porous hygroscopic material as described in claim 26, characterized in that, In step 2, the mechanical crushing is carried out by stirring.

30. The method for preparing porous hygroscopic material as described in claim 26, characterized in that, In step 3, the methods for coating the hydrogel-hygroscopic salt coating onto the porous adsorption mesh include dip coating, spray coating, brush coating, rod coating, and spin coating.

31. The method for preparing porous hygroscopic material as described in claim 30, characterized in that, In step 3, the preferred method for coating the hydrogel-hygroscopic salt coating onto the porous adsorption mesh is dip coating.

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