Ionically conductive gauze separator structure

Abstract

The application discloses an ion-conducting gauze screen, which comprises a screen frame and a water inflow hole, a cavity is arranged in the middle of the screen frame for water and ion exchange membrane to contact, a screen is arranged in the cavity to avoid direct contact of two layers of membranes and ensure smooth water flow, and the screen is composed of ion-conducting screen wires. The ion-conducting screen wires are twisted by fine yarns with good hydrophilicity, or the ion-conducting screen wires are twisted by solid core yarns, and micropores are formed on the solid core yarns. Or the ion-conducting screen wires are connected with chemical functional groups which are beneficial to ion conduction on the surface. The ion-conducting screen wires are used to replace common solid core wires on the screen, so that the effective area of ion migration channels is increased, and the blocking effect of ion electromigration of the solid core screen wires of the traditional membrane screen is reduced.

Description

Technical Field

[0001] This invention relates to the field of electrodialysis technology, specifically to an ion-conducting mesh partition. Background Technology

[0002] Electroosmosis is a technology that transfers salt ions from one solution to another, and it is widely used in brine desalination or the extraction of useful ions. For example... Figure 6 As shown, when an electric field is applied across many cation and anion membranes, cations (Na+) are driven to migrate from the anode to the cathode; simultaneously, anions migrate towards the anode. When cations encounter the anion membrane, they are blocked, and similarly, anions are blocked by the cation membrane. In this way, dilute and concentrated chambers of ions (salts) are formed at each interval.

[0003] like Figure 5 As shown, typical electrodialysis modules use mesh separators to separate two adjacent ion exchange membranes. The function of the separators is to ensure that the two adjacent membranes are separated to maintain unobstructed flow channels, thereby ensuring unimpeded ion migration between the two electrodes.

[0004] like Figure 5 As shown, the membrane separator in electrodialysis is generally made by hot-pressing a rubber-like material around the perimeter of a mesh. Currently, all membrane separator meshes are made of solid threads, such as polypropylene, polyethylene, and polyester. Their common characteristic is that they are solid cores and do not themselves facilitate ion channels. They obstruct ion channels perpendicular to the mesh plane, increasing resistance during electrodialysis operation, reducing the effective ion channel membrane area, and thus increasing energy consumption or module volume. Therefore, there is a need to propose an ion-conducting mesh separator. Summary of the Invention

[0005] The purpose of this invention is to solve the problems in the background art and provide an ion-conducting mesh partition structure.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0007] An ion-conducting mesh partition includes a partition frame and a water inlet hole. A cavity is provided in the middle of the partition frame, and a partition mesh is provided in the cavity to prevent two adjacent membranes from directly contacting each other and to ensure smooth water flow. The partition mesh is composed of ion-conducting mesh wires.

[0008] This invention replaces the ordinary solid wires on the partition mesh with ion-conducting mesh wires, thereby increasing the effective area of ​​the ion migration channel and reducing the blocking effect of the solid wires on ion electromigration.

[0009] Preferably, the ion-conducting mesh is made of finely twisted yarn with good hydrophilicity. The yarn can be made of finely twisted fibers with good hydrophilicity, and the diameter of the mesh is 0.2-5 mm. The diameter of the yarn is the finest in industrial spinning technology: for example, 0.1 micrometers to 50 micrometers.

[0010] The mesh fabric of this invention has a diameter of 0.2-5 mm. As long as the diameter of the twisted wires is smaller than that of the mesh fabric, it will have a certain degree of barrier-removing effect. The ideal diameter of the wires referred to here can be between 10 micrometers and 200 micrometers; it can also be between 1 micrometer and 500 micrometers; or it can be between 0.02 micrometers and 700 micrometers.

[0011] This invention uses fine yarn with good hydrophilicity. Since the fine yarn itself is permeable to water, the prepared partition mesh can be permeated by water, thereby reducing the blocking effect of solid core wire on ion migration.

[0012] Preferably, the ion-conducting mesh can also be made of solid yarn twisted together, and the solid yarn has micropores formed on it.

[0013] The surface of the ion-conducting mesh 3 can be bombarded with high-speed sand particles to create an uneven surface shape, thereby reducing the contact area between the membrane and the mesh and increasing ion conductivity.

[0014] In addition to using the above-mentioned twisting method to prepare water-permeable conductive mesh, this invention can also generate micropores in the solid core of the mesh, so that the prepared partition mesh can conduct ions, thereby reducing the blocking effect of the solid core on ion migration.

[0015] A method for preparing microporous ion-conductive wires includes the following steps:

[0016] (a) Melt production, which involves melting a plastic material to form a melt. The plastic material here is the melt of mesh yarn commonly used in the production of mesh, such as polyethylene, polypropylene, polyester, etc.

[0017] (b) Mixing: The alkali-soluble particles are mixed evenly with the melt using a high-efficiency mixing device, so that the alkali-soluble particles are mixed in the melt;

[0018] (c) Stretching: drawing the melt containing alkali-soluble particles into a fine filament;

[0019] (d) Alkali-soluble particle treatment: The filaments are treated with alkali to dissolve the mixed particles, thereby forming micropores on the filaments.

[0020] (e) Ion-conducting mesh fabrication: fine filaments are woven into solid yarn, and the solid yarn is twisted into ion-conducting mesh fabric.

[0021] This invention mixes alkali-soluble particles with the melt, so that the stretched filament contains alkali-soluble particles. Then, through alkali treatment, the alkali-soluble particles are dissolved, and micropores are formed on the filament. This results in the twisted solid yarn having micropores, which allows the prepared separator mesh to conduct ions, thereby reducing the blocking effect of the solid yarn on ion migration.

[0022] Preferably, the alkali-soluble particles can be, for example, Al (aluminum); the acid-soluble particles can be, for example, calcium carbonate or certain oxides.

[0023] Preferably, this invention may also use acid-soluble or heat-decomposable particles such as Na2CO3 or KNO3. 3等 After being heated, the mixed particles will dissolve or volatilize, thus achieving the purpose of forming pores.

[0024] Preferably, the high-efficiency mixing device includes an outer cylinder and a rotating shaft rotatable within the outer cylinder. The rotating shaft includes a melt conveying zone, a preliminary mixing zone, and a secondary mixing zone sequentially from the feed end to the discharge end. A particle feed inlet is provided above the melt conveying zone. The preliminary mixing zone includes stirring rods, and several stirring rods are evenly distributed on the outer circumference of the rotating shaft. The stirring rods are provided with arc-shaped protrusions. Ball grooves with a diameter of R are provided at the secondary mixing zone and the corresponding outer cylinder. The ball grooves arranged on the rotating shaft are offset by a length of R / 2 from the ball grooves arranged on the adjacent outer cylinder. The portion of the rotating shaft located in the melt conveying zone may be provided with helical blades to convey the melt.

[0025] This invention compresses the melt into a secondary mixing zone via a melt conveying zone. Alkali-soluble particles are conveyed to the melt conveying zone via a particle feed inlet. During the compression process, the particles pass through a preliminary mixing zone and are initially stirred by a stirring rod. Then, they enter the secondary mixing zone where three-dimensional flow is generated through a ball socket, and they are subjected to a combination of shearing, peeling, coordination, and kneading effects, which ensures that the alkali-soluble particles are fully mixed with the melt, resulting in more uniform pores formed later.

[0026] Preferably, the particle inlet is provided with a dispersing plate, the dispersing plate including a fixing plate, the sidewall of the fixing plate being fixedly connected to the sidewall of the particle inlet, and the fixing plate having dispersing holes. This invention, through the dispersing plate, makes the alkali-soluble particles entering the shell more uniform, facilitating subsequent fusion.

[0027] Preferably, the surface of the ion-conducting mesh is coated with chemical functional groups that facilitate ion conduction. The ion-conducting mesh is made of polypropylene mesh, which is sulfonated to form -SO3H functional groups on its surface. This facilitates the migration of cations at the water-solid interface, making the surface (interface) of the mesh more ion-conducting.

[0028] In addition, the present invention can also bombard the surface of solid mesh with yarn particles (or other ions) to create unevenness on the surface of the mesh fibers. When such unevenness is in close contact with the membrane, the aqueous solution ions can still conduct at the interface of the mesh, reducing the "covering effect" of the mesh.

[0029] This invention discloses a twisted, water-permeable conductive mesh, a method for producing porous mesh yarn, and physical modifications such as surface chemical modification and surface unevenness to improve the ion-conducting ability of the water-solid (mesh) interface. The methods listed above can be used individually or in combination of at least two methods.

[0030] After reading this invention, a reader with a background in various science or engineering disciplines will be able to expand to other means of increasing the ionic conductivity of the mesh of the electrodialysis separator, thereby benefiting the operation of the relevant process.

[0031] In summary, the beneficial effects of this invention are as follows:

[0032] 1. This invention replaces the ordinary solid wire on the partition mesh with a water-permeable, ion-conducting wire, thereby reducing the blocking effect of the solid wire on ion migration and solving the problem that the solid wire hinders the ion channel, increases the resistance in the electrodialysis operation, reduces the effective membrane area, and thus increases energy consumption or module size.

[0033] 2. This invention uses fine yarn with good hydrophilicity. Since the fine yarn itself is permeable to water, the finished partition mesh can be permeated by water, thereby reducing the blocking effect of solid core wire on ion migration.

[0034] 3. This invention mixes alkali-soluble particles with the melt, so that the stretched filament contains alkali-soluble particles. Then, through alkali treatment, the alkali-soluble particles are dissolved, and micropores are formed on the filament. This results in the twisted solid yarn having micropores, which allows the prepared partition mesh to conduct ions and reduces the blocking effect of the solid yarn on ion migration.

[0035] 4. In this invention, the melt is extruded to the secondary mixing zone through the melt conveying zone, and the alkali-soluble particles are conveyed to the melt conveying zone through the particle feed inlet. During the extrusion process, the particles pass through the preliminary mixing zone and are initially stirred by the stirring rod. Then, they enter the secondary mixing zone and generate three-dimensional flow through the ball socket. They are subjected to a combination of shearing, peeling, coordination, and kneading, which makes the alkali-soluble particles and the melt fully mixed, resulting in more uniform pores formed later. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the present invention;

[0037] Figure 2 This is a schematic diagram of the preparation method of Embodiment 1 of the present invention;

[0038] Figure 3 This is a cross-sectional schematic diagram of the high-efficiency mixing device of the present invention;

[0039] Figure 4 This is the present invention. Figure 3 An enlarged view of point A;

[0040] Figure 5 This is a schematic diagram of the membrane dialysis membrane of the present invention;

[0041] Figure 6 This is a schematic diagram illustrating the principle of the existing electroosmosis technology of this invention;

[0042] Figure 7 This is a schematic diagram of the comparative experiment of the present invention. Detailed Implementation

[0043] The following specific embodiments are merely illustrative of the present invention and are not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to these embodiments without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of the present invention.

[0044] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0045] Example 1

[0046] like Figure 1-4As shown, an ion-conducting mesh partition includes a partition frame 1 with a cavity 11 in the middle. A partition mesh 2 is provided inside the cavity 11 to avoid direct contact between the two membrane layers while ensuring smooth water flow. Liquid guiding holes are provided at the upper and lower ends of the partition frame 1. The liquid guiding holes are divided into two groups: one group is an open liquid guiding hole 102 that communicates with the central cavity of the partition frame through a water distribution channel, and the other group is a closed liquid guiding hole 101 that does not communicate with the central cavity of the partition frame. The partition mesh 2 is composed of ion-conducting mesh wires 3, which are made of solid yarn twisted together, and micropores are formed on the solid yarn.

[0047] The method for preparing the mesh partition includes the following steps:

[0048] (a) Melt production, which involves melting a plastic material to form a melt;

[0049] (a) Mixing: The alkali-soluble particles are mixed evenly with the melt using a high-efficiency mixing device 4, so that the acid or alkali-soluble particles are mixed in the melt;

[0050] (b) Stretching: drawing the melt containing alkali-soluble particles into a fine filament;

[0051] (c) Alkali-soluble particle treatment: The filaments are treated with alkali to dissolve the mixed particles, thereby forming micropores on the filaments.

[0052] (d) Partition mesh production: fine filaments are woven into mesh, and then the mesh is made into mesh partitions.

[0053] like Figure 3-4 As shown, the high-efficiency mixing device 4 includes an outer cylinder 41 and a rotating shaft 42 rotatable within the outer cylinder 41. The rotating shaft 42, from the inlet end to the outlet end, sequentially includes a melt conveying zone 43, a preliminary mixing zone 44, and a secondary mixing zone 45. The outer cylinder 41 is provided with a particle inlet 46 above the melt conveying zone 43. The preliminary mixing zone 44 includes stirring rods 441, with several stirring rods 441 evenly distributed on the outer circumferential surface of the rotating shaft 42. The stirring rods 441 are provided with arc-shaped protrusions. The granulation unit 442 is provided with a ball groove 451 of diameter R at the rotating shaft 42 and the corresponding outer cylinder 41 in the secondary mixing zone 45. The ball grooves 451 arranged on the rotating shaft 42 are offset by a length of R / 2 from the ball grooves 451 arranged on the adjacent outer cylinder 41. The particle feed inlet 46 is provided with a dispersing plate 47, which includes a fixing plate 471. The side wall of the fixing plate 471 is fixedly connected to the side wall of the particle feed inlet 46. The fixing plate 471 is provided with a dispersing hole 472.

[0054] Working principle: such as Figure 1-4As shown, plastic materials are melted to form a melt, which is then extruded through a melt conveying zone to a secondary mixing zone 45. Simultaneously, alkali-soluble particles are conveyed to the melt conveying zone via a particle feed inlet. During the extrusion process, the particles pass through a preliminary mixing zone 44 and are initially stirred by a stirring rod 441. After entering the secondary mixing zone 45, three-dimensional flow is generated through a ball-and-socket joint, and the particles are subjected to a combination of shearing, peeling, coordination, and kneading, ensuring thorough mixing between the alkali-soluble particles and the melt. The melt containing the alkali-soluble particles is then drawn into fine filaments. These filaments are treated with alkali to dissolve the mixed particles, resulting in micropores on the filaments. The micropores are then woven into a mesh, which is then used to create a mesh partition. This mesh partition is placed between the anion and cation membranes in the electrodialysis process, allowing the partition mesh to conduct ions and reducing the barrier effect of the solid wire on ion electromigration.

[0055] Example 2

[0056] like Figure 1 As shown, an ion-conducting mesh partition includes a partition frame 1, a cavity 11 is provided in the middle of the partition frame 1, and a partition mesh 2 is provided in the cavity 11. The partition mesh 2 is composed of ion-conducting mesh wires 3.

[0057] The ion-conducting mesh 3 is made of fine yarn with good hydrophilicity twisted together. The fine yarn is made of fine fibers with good hydrophilicity twisted together. The diameter of the mesh is 0.2-5 mm.

[0058] Example 3

[0059] .like Figure 1 As shown, an ion-conducting mesh partition includes a partition frame 1, a cavity 11 is provided in the middle of the partition frame 1, and a partition mesh 2 is provided in the cavity 11. The partition mesh 2 is composed of ion-conducting mesh wires 3.

[0060] The surface of the ion-conducting wire 3 is grafted with chemical functional groups that facilitate ion conduction. The ion-conducting wire 3 is made of polypropylene mesh, which is sulfonated to form -SO3H functional groups on its surface, which is beneficial for the migration of cations at the water-solid interface.

[0061] Example 4

[0062] like Figure 1 As shown, an ion-conducting mesh partition includes a partition frame 1, a cavity 11 is provided in the middle of the partition frame 1, and a partition mesh 2 is provided in the cavity 11. The partition mesh 2 is composed of ion-conducting mesh wires 3.

[0063] Bombarding the surface of the ion-conducting mesh 3 with particles such as yarn (or other ions) will create unevenness on the surface of the ion-conducting mesh 3. When such unevenness is in close contact with the membrane, the aqueous solution ions can still conduct at the mesh interface, reducing the "covering effect" of the mesh.

[0064] This invention can combine Examples 1, 3, and 4 to modify and alter the mesh fibers in order to reduce the obstruction of ion migration channels by the mesh fibers.

[0065] Comparative experiment

[0066] like Figure 7 As shown, a cylindrical tube with a cross-sectional area of ​​7 square centimeters was filled with 0.50 M NaCl solution. A 7.0 square centimeter sample was placed in the center of the tube. Two Ag / AgCl reference electrodes were placed at either end of the sample plate, approximately 1 mm away from the sample. The distance between the two reference electrodes remained constant each time the sample was changed. A current of 10 mA was then applied between the two electrode plates, and the voltage reading was recorded. This allows the calculation of the resistance of the solution in the cylinder between the two reference electrodes. The resistance measurements were taken without a mesh sample, with a solid 15-mesh non-conductive mesh, and with a 15-mesh conductive mesh made of spun yarn. The table below shows the resistance measurements:

[0067] sample None (solution resistance) 15-mesh solid core mesh 10-mesh spinning netting Total resistance (ohms) 1.2 1.8 1.5

[0068] This fully demonstrates that mesh made from spun yarn has better electrical conductivity or a smaller ion current blocking effect.

Claims

1. An ion-conducting mesh partition, characterized in that, It includes a partition frame (1), the partition frame (1) has a cavity (11) in the middle, the cavity (11) is provided with a partition mesh (2), and the partition mesh (2) is composed of ion-conducting mesh wires (3); The ion-conducting mesh (3) is made of solid yarn twisted together, and micropores are formed on the solid yarn; The method for preparing this ion-conductive wire includes the following steps: Melt production involves melting plastic materials to form a melt. Mixing: The alkali-soluble particles are mixed evenly with the melt using a high-efficiency mixing device (4), so that the acid or alkali-soluble particles are mixed in the melt. Stretching involves drawing a melt containing alkali-soluble particles into a fine filament. Alkali-soluble particle treatment involves treating the filaments with alkali, causing the mixed particles to dissolve and creating micropores on the filaments. The production of ion-conducting mesh wire involves weaving fine filaments into solid yarn and twisting the solid yarn into ion-conducting mesh wire. The high-efficiency mixing device (4) includes an outer cylinder (41) and a rotating shaft (42) that can rotate inside the outer cylinder (41). The rotating shaft (42) includes a melt conveying zone (43), a preliminary mixing zone (44) and a secondary mixing zone (45) from the feed end to the discharge end. The outer cylinder (41) is provided with a particle feed inlet (46) above the melt conveying zone (43). The preliminary mixing zone (44) includes a stirring rod (441), and several stirring rods (441) are evenly distributed on the outer peripheral surface of the rotating shaft (42). The stirring rod (441) is provided with an arc-shaped protrusion (442). The rotating shaft (42) and the corresponding outer cylinder (41) in the secondary mixing zone (45) are provided with ball grooves (451) with a diameter of R. The ball grooves (451) arranged on the rotating shaft (42) are offset from the ball grooves (451) arranged on the adjacent outer cylinder (41) by a length of R / 2. The particle feed inlet (46) is provided with a dispersing plate (47), the dispersing plate (47) includes a fixing plate (471), the side wall of the fixing plate (471) is fixedly connected to the side wall of the particle feed inlet (46), and the fixing plate (471) is provided with a dispersing hole (472).

2. The ion-conducting mesh partition according to claim 1, characterized in that, The ion-conducting mesh (3) is made of fine yarn with good hydrophilicity twisted together.

3. The ion-conducting mesh partition according to claim 1, characterized in that, The surface of the ion-conducting mesh (3) is coated with chemical functional groups that facilitate ion conductivity.

4. The ion-conducting mesh partition according to claim 3, further characterized in that, The surface of the ion-conducting mesh (3) is bombarded by high-speed sand particles to create an uneven surface shape, thereby reducing the contact area between the membrane and the mesh and increasing ion conductivity.

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