Water treatment device based on capacitive deionization technology

Abstract

The utility model discloses a water treatment device based on a capacitive deionization technology, and belongs to the technical field of capacitive deionization. The device comprises a shell and an electrode pair structure, wherein the shell is fixedly connected with the electrode pair structure; the electrode pair structure comprises a silica gel sheet, a first current collector, a cathode electrode sheet, a first hydrophilic diaphragm, a water flow channel, a second hydrophilic diaphragm, a first anode electrode sheet, a second current collector and a second anode electrode sheet which are arranged in a laminated structure; the water flow channel is of a grid-shaped structure. According to the water flow channel with the grid structure, water flow can be evenly distributed in the water flow channel, meanwhile, the effect of separating the electrode plates can be achieved, and short circuit of the device caused by electrode contact in the power-on operation process is prevented.

Description

Technical Field

[0001] The invention belongs to the technical field of capacitive deionization, and in particular relates to a water treatment device based on the capacitive deionization technology. Background Art

[0002] Capacitive deionization (CDI) is an electrosorption desalination technology based on the principle of electrochemical double layer. Under the action of the electric field, the anions and cations in the water move to the electrodes of opposite polarity and are then adsorbed on the surface of the electrode material, thereby achieving the purpose of removing ions from the water. When the electrode adsorption layer is saturated, the adsorbed ions can be released and discharged by simply docking or reversing the electrodes, so that they can continue to work and be recycled. Therefore, CDI technology has broad application prospects in the fields of hard water softening, seawater desalination, heavy metal salt purification and wastewater treatment.

[0003] Although predecessors have done a lot of work in the basic research of CDI technology and have achieved many phased research results, most of the research on CDI is concentrated on small-scale trials, and there is a lack of industrial scale-up research on CDI systems. From the perspective of industrial application, most CDI devices currently still have problems such as low water production and low energy efficiency due to unreasonable module structure design and insufficient contact between electrode materials and water flow. Summary of the invention

[0004] The technical problem solved by the utility model is to provide a water treatment device based on capacitive deionization technology. The device adopts a grid structure water flow channel inside, which can make the water flow evenly distributed in the water flow channel. At the same time, it can also play the role of separating the electrode sheets to prevent the electrodes from contacting during power-on operation and causing the device to short-circuit.

[0005] Technical solution: In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] A water treatment device based on capacitive deionization technology comprises a housing and an electrode pair structure, wherein the housing is fixedly connected to the electrode pair structure;

[0007] The electrode pair structure includes a silica gel sheet, a first current collector, a cathode electrode sheet, a first hydrophilic diaphragm, a water flow channel, a second hydrophilic diaphragm, a first anode electrode sheet, a second current collector, and a second anode electrode sheet, and is arranged in a stacked structure;

[0008] The water flow channel is in a grid structure.

[0009] In the water treatment device based on capacitive deionization technology, the water flow channel is formed by gluing an outer frame support structure and an internal grid-like channel, the material is polyethylene, and the mesh number is 4-200 meshes; the first current collector and the second current collector are made of graphite paper.

[0010] The water treatment device based on capacitive deionization technology has n pairs of electrode pair structures, with n less than 5000 for a single device, which are connected in parallel; multiple electrode pair structures are arranged at intervals to form a first water flow channel, a second water flow channel...an nth water flow channel; the outer shell includes a first outer shell and a second outer shell, which are polypropylene partitions.

[0011] In the water treatment device based on capacitive deionization technology, thick rubber pads are arranged between the first shell, the second shell and the electrode pair structure, and n pairs of electrode pair structures are embedded in the thick rubber pads in an embedded structure.

[0012] The water treatment device based on capacitive deionization technology has a water inlet at the bottom of the first shell, which is connected to the water inlet pipe, and a fresh water outlet at the top of the first shell, which is connected to the water outlet pipe; threaded through holes are arranged around the first shell and the second shell, which are fixedly connected by screws and bolts; the water outlet pipe is connected to the conductivity detector.

[0013] In the water treatment device based on capacitive deionization technology, the surfaces of the cathode electrode sheet and the anode electrode sheet are both covered with a hydrophilic diaphragm or an anion and cation exchange membrane.

[0014] In the water treatment device based on capacitive deionization technology, the size of the cathode electrode sheet and the anode electrode sheet is 20cm×40cm; the distance between the cathode electrode sheet and the anode electrode sheet is 0.5-3mm.

[0015] In the water treatment device based on capacitive deionization technology, electrode sheets with the same electrical properties are connected by internal conductive foil, cathode tabs are welded on the cathode electrode sheets, and anode tabs are welded on the anode electrode sheets.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0017] (1) The utility model device adopts a grid structure water flow channel, which is formed by gluing an outer frame support structure and an internal grid channel, and is made of polyethylene with a mesh size of 4-200. The internal grid structure channel allows the water flow to be evenly distributed in the water flow channel, and can also play a role in separating the electrode sheets to prevent the electrode contact during power-on operation and cause the device to short-circuit.

[0018] (2) The device of the utility model does not use metal materials such as platinum and titanium as the current collector, but uses a whole piece of graphite paper as the current collector, which not only reduces the assembly cost of the capacitive deionization device, but also reduces the internal resistance of the overall device and reduces energy loss.

[0019] (3) The main structure of ion adsorption of the utility model: positive and negative electrode sheets, hydrophilic diaphragms, water flow channels, etc. are in a layered overlapping structure, and the shells on both sides play a supporting role and are reinforced by bolts to ensure that the main structure is tightly compacted together, fully ensuring the contact between the various structures, and fully ensuring the close contact between the electrode material and the graphite current collector, so that the electrode material is not easy to fall off, extending the service life of the electrode, and after the device is powered on, ensuring that the contact resistance between the collector and the electrode active material is low (<0.1Ω).

[0020] (4) The silicone sheet, electrode sheet, hydrophilic diaphragm, water flow channel, etc. in the device are embedded in the rubber pad shell in an embedded structure. The thickness of the rubber pad shell can be adjusted according to the number of electrode pairs and is consistent with the total thickness of the entire stacking module (except the first shell and the second shell) to ensure that the entire device is sealed and leak-proof.

[0021] (5) The device of the utility model can arbitrarily expand the number of electrode pairs (single device <5000 pairs) according to the concentration of ions in the aqueous solution and the amount of water to be treated in the actual application scenario, and is suitable for various types of places in order to achieve the expected deionization effect.

[0022] (6) The capacitive deionization electrode is prepared by the coating method, which can freely adjust the activated carbon loading amount, achieve high loading of the capacitive deionization electrode, and improve the adsorption performance of the capacitive deionization device.

[0023] (7) The shell, silicone pad, and water flow channel body in the device structure of the utility model are formed by mold injection molding or 3D printing technology, with high molding precision, and can be standardized and mass-produced industrially. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the device structure of Example 1;

[0025] Figure 2 This is an anatomical diagram of the internal structure of the device of Example 1;

[0026] Figure 3 This is the actual desalination curve of Example 1. DETAILED DESCRIPTION

[0027] The present invention will be further explained below in conjunction with specific embodiments. The embodiments are implemented based on the technical solution of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0028] The preparation method of the electrode sheet used in the device of the utility model is as follows:

[0029] The activated carbon powder and conductive carbon black were placed in a 150°C constant temperature drying oven and dried for 3 hours. Polyvinylidene fluoride was dissolved in nitrogen-methylpyrrolidone. After being fully mixed with a magnetic stirrer, the activated carbon powder, conductive carbon black and polyvinylidene fluoride were added and mixed in a mass ratio of 8:1:1. After being fully mixed, the uniformly mixed activated carbon mixture was coated on the graphite paper current collector using a coating machine with a coating thickness of 500 μm. After drying in a vacuum drying oven at 80°C for 12 hours, the graphite paper was cut into 20 cm × 40 cm to obtain the working electrode of the capacitor deionization device. The activated carbon loading of the working electrode can be freely adjusted, which can achieve a high load of the capacitor deionization electrode and improve the adsorption performance of the capacitor deionization device.

[0030] Example 1

[0031] A water treatment device based on capacitive deionization technology, the structural diagram is as follows Figure 1-Figure 2 As shown, the device is provided with a first shell 3, a thick rubber pad 2, a silicone pad, a first current collector, a cathode electrode sheet 4, a first hydrophilic diaphragm, a water flow channel 5, a second hydrophilic diaphragm, a first anode electrode sheet 6, a second current collector, a second anode electrode sheet, a second shell 1, a cathode tab 7, an anode collector tab 8, and an internal conductive foil 9; the same electrical properties of the electrode sheets are connected by the internal conductive foil 9, the cathode electrode sheet 4 is welded with a cathode tab 7, and the first anode electrode sheet 6 is welded with an anode tab 8. The shell, silicone pad, and water flow channel body in the structure adopt mold injection molding or 3D printing technology, with high molding precision, and can be standardized batch industrialized production.

[0032] The size of the cathode electrode sheet and the anode electrode sheet is 20 cm×40 cm, and the surface is covered with a hydrophilic diaphragm; the distance between the cathode electrode sheet and the anode electrode sheet is 1.5 mm.

[0033] The water flow channel 5 is a grid-like structure, which plays a role in guiding flow; the water flow channel is formed by gluing the outer frame support structure and the internal grid-like channel, and is made of polyethylene. The mesh number can be set to 4-200 meshes, and the mesh number of this embodiment is 100 meshes. Setting the water flow channel 5 as a grid-like structure channel can realize uniform diversion of water flow in the water flow channel, and at the same time can also play a role in separating the electrode sheets to prevent the electrode contact during power-on operation from causing a short circuit in the device.

[0034] The first current collector and the second current collector are both made of a whole piece of graphite paper, and no metal materials such as platinum and titanium are used as the current collector; using a whole piece of graphite paper as the current collector not only reduces the assembly cost of the capacitive deionization device, but also reduces the internal resistance of the overall device and reduces energy loss.

[0035] The silica gel sheet, the first current collector, the cathode electrode sheet 4, the first hydrophilic diaphragm, the water flow channel 5, the second hydrophilic diaphragm, the first anode electrode sheet 6, the second current collector, and the second anode electrode sheet are arranged in a stacked structure; the first shell 3 and the second shell 1 are polypropylene partitions, which play the role of fixing and protecting the internal electrode part; threaded through holes are arranged around, and screws and bolts are used to reinforce the main structure to ensure that it is tightly compacted together, fully ensure the contact between the various structures, and fully ensure the close contact between the electrode material and the graphite current collector, so that the electrode material is not easy to fall off, and the service life of the electrode is extended. After the device is powered on, the contact resistance between the collector and the electrode active material is low (<0.1Ω).

[0036] The silicone sheet, electrode sheet, hydrophilic diaphragm, water flow channel, etc. in the device are embedded in the rubber pad shell in an embedded structure. The thickness of the rubber pad shell can be adjusted according to the number of electrode pairs and is consistent with the total thickness of the entire stacking module (except the first shell and the second shell) to ensure that the entire device is sealed and leak-proof.

[0037] A through hole is provided at the bottom of the first shell 3 as a water inlet, which is connected to the raw water tank through a silicone hose, and a peristaltic pump is used to transport the water source to be treated into the capacitor deionization device, and a water inlet control valve is provided between the water inlet and the water inlet pipe. A through hole is provided at the top of the first shell as a fresh water outlet, which is connected to the water outlet pipe, and a conductivity meter is provided at the fresh water outlet to monitor the conductivity of the outlet water in real time, and a water inlet control valve is provided between the water outlet and the water outlet pipe.

[0038] The operation process of the above device includes an adsorption process with a voltage of 1V and a desorption process with a short circuit. Specifically, the salty raw water enters the water flow channel 5 through the water inlet pipe, and a voltage is applied to the device. Under the action of the electric field force of the anode and cathode plates in the device, the positive and negative ions in the raw water in the water flow channel 5 move to the electrode plates of opposite electrical properties and are adsorbed on the electrode surface to form a double electric layer, so that the ion concentration of the raw water is reduced to form fresh water discharge. After the circuit is short-circuited, the electric field disappears, and the ions adsorbed on the electrode surface are released into the raw water to form concentrated water discharge, and the working electrode is regenerated.

[0039] like Figure 3 As shown, the device is used to treat slightly brackish water with a concentration of 1500 mg / L, and the effluent concentration is about 30 mg / L. The adsorption and desorption cycles can be repeated to achieve continuous preparation of fresh water.

[0040] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present invention should be included in the protection scope of the present invention.

Claims

1. A water treatment device based on capacitive deionization technology, characterized in that: It includes a shell and an electrode pair structure, wherein the shell is fixedly connected to the electrode pair structure; The electrode pair structure comprises a silica gel sheet, a first current collector, a cathode electrode sheet (4), a first hydrophilic diaphragm, a water flow channel (5), a second hydrophilic diaphragm, a first anode electrode sheet (6), a second current collector, and a second anode electrode sheet, and is arranged in a stacked structure; the water flow channel (5) is in a grid structure.

2. The water treatment device based on capacitive deionization technology according to claim 1, characterized in that: The water flow channel (5) is formed by gluing an outer frame support structure and an internal grid-shaped channel, and is made of polyethylene with a mesh size of 4-200 meshes; the first current collector and the second current collector are made of graphite paper.

3. The water treatment device based on capacitive deionization technology according to claim 1, characterized in that: The electrode pair structure is provided with n pairs, with n being less than 5000 for a single device, and connected in parallel; the plurality of electrode pair structures are arranged at intervals to form a first water flow channel, a second water flow channel, and an nth water flow channel; the outer shell comprises a first outer shell (3) and a second outer shell (1), which are polypropylene partitions.

4. The water treatment device based on capacitive deionization technology according to claim 3 is characterized in that: A thick rubber pad (2) is provided between the first shell (3) and the second shell (1) and the electrode pair structure, and the n pairs of electrode pair structures are embedded in the thick silicone pad in an embedded structure.

5. The water treatment device based on capacitive deionization technology according to claim 3, characterized in that: A water inlet is provided at the bottom of the first shell (3), and the water inlet is connected to a water inlet pipe. A fresh water outlet is provided at the top of the first shell, and the fresh water outlet is connected to a water outlet pipe. Threaded through holes are provided around the first shell (3) and the second shell (1), and are fixedly connected by screws and bolts. The water outlet pipe is connected to a conductivity detector.

6. The water treatment device based on capacitive deionization technology according to claim 1, characterized in that: The surfaces of the cathode electrode sheet and the anode electrode sheet are both covered with a hydrophilic diaphragm.

7. The water treatment device based on capacitive deionization technology according to claim 1, characterized in that: The size of the cathode electrode sheet and the anode electrode sheet is 20 cm×40 cm; the distance between the cathode electrode sheet and the anode electrode sheet is 0.5-3 mm.

8. The water treatment device based on capacitive deionization technology according to claim 1, characterized in that: The electrode sheets with the same electrical properties are connected via an internal conductive foil (9), a cathode electrode sheet is welded with a cathode tab, and an anode electrode sheet is welded with an anode tab.

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