Composite electrode unit, and electrochemical water treatment system and electrochemical water treatment method

Abstract

A composite electrode unit, and an electrochemical water treatment system and an electrochemical water treatment method. The composite electrode unit comprises: an electrolytic-water cathode (2), a porous insulating filler layer (4) and an electrolytic-water anode (3), wherein the porous insulating filler layer (4) is located between the electrolytic-water cathode (2) and the electrolytic-water anode (3), and the material of the interior of the porous insulating filler layer does not contain exchangeable ions, and the interior refers to a non-surface portion. In the composite electrode unit, a cathode and an anode are respectively integrated on two sides of the porous insulating filler layer (4) to form a unique "filler-electrode" integrated structure; and under the driving of ultra-low direct-current operating voltages, the transport of water is controlled by means of filler micro-channels to realize migration blocking of hydroxyl radicals, and the hydroxyl radicals are diffused into an aqueous-phase body in a cathode chamber by means of a local gradient diffusion effect generated by an electrode-surface catalytic reaction and a forced diffusion effect of pumping, thereby facilitating the rapid crystallization and precipitation of scaling ions in a cathode region, and thus reducing the hardness of water.

Description

A composite electrode unit, an electrochemical water treatment system, and an electrochemical water treatment method. Technical Field

[0001] This invention relates to the field of water treatment technology, and mainly to a composite electrode unit, an electrochemical water treatment system, and an electrochemical water treatment method. Background Technology

[0002] In industrial water systems, circulating cooling water serves as the core medium for maintaining equipment operation, and its water quality management faces severe challenges: traditional processes relying on repeated concentration and circulation easily lead to mineral salt deposition, resulting in frequent scaling. Hard scale not only accelerates the electrochemical corrosion of metal pipes, creating a risk of localized perforation, but also significantly reduces the heat transfer efficiency of heat exchange equipment, directly impacting production efficiency. For a long time, the industry has generally adopted chemical intervention methods such as adjusting pH values ​​with acids and alkalis or adding scale inhibitors. While these methods can alleviate scaling problems in the short term, they have drawbacks such as high consumption of chemicals, potential secondary pollution, and high operation and maintenance costs. At the same time, the concentration of chloride ions (chloride ions) in the water gradually enhances the corrosion of metal equipment. With the deepening of the green manufacturing concept, new hardening and dechlorination technologies based on electrochemical principles have emerged.

[0003] Electrochemical hardening and dechlorination technology achieves a dual breakthrough in water quality control and resource recovery through electrolysis. Its basic principle is as follows: In the cathode chamber, the electrolysis reaction generates a large number of hydroxide ions, which promote the conversion of bicarbonate ions in the water to carbonate ions under alkaline conditions. This drives the directional migration of scale-forming ions such as calcium and magnesium ions, preferentially forming crystalline precipitates such as calcium carbonate and magnesium hydroxide, thus achieving targeted separation of hard scale. In the anode chamber, chloride ions are oxidized to generate HClO / ClO, which has bactericidal functions. - The technology incorporates trace amounts of chlorine gas, while the hydrogen ions generated from water electrolysis dynamically adjust the system's pH value, creating an adaptive scale-inhibiting environment. This technology not only eliminates the need for traditional external additions of scale inhibitors and acid / alkali agents, avoiding the risk of chemical residue pollution at the source, but also inhibits microbial growth through the simultaneously generated active chlorine, solving the industry problem of mutually reinforcing scaling and corrosion. The treated circulating water system exhibits a significantly increased concentration ratio, reducing makeup water and wastewater discharge while achieving synergistic optimization of water resource utilization efficiency and environmental benefits. This provides a clean and economical technical approach for industrial circulating water management.

[0004] The above-mentioned technical approach has several serious problems: First, the utilization efficiency of hydroxide ions generated by water electrolysis is low; second, the single-stage voltage of the electrolysis unit is high; and third, there is a problem of self-scaling of the electrodes. For example, Chinese patent "CN101585569A-Circulating Water Electrolysis Descaling Device and Descaling Method" discloses a circulating water electrolysis descaling device and method, belonging to the field of water treatment and environmental protection technology. The core of the device includes a metal reaction chamber (as the electrolysis cathode), an anode, a test electrode, an ultrasonic cleaner, and an automatic control system. Its working principle is divided into two stages: electrolysis scaling and cleaning descaling. During the electrolysis process, hydroxide ions are generated in the cathode chamber, causing calcium ions, magnesium ions, and carbonate ions in the water to combine and form loose soft scale deposited on the inner wall of the reaction chamber. At the same time, chloride ions are oxidized at the anode to generate bactericidal substances such as hypochlorous acid and chlorine. When the test electrode detects that the scale layer has thickened and the resistance exceeds the limit, the system automatically switches to the cleaning mode, closes the inlet and outlet water valves, and starts the ultrasonic cleaner to remove the scale, which is then discharged through the drain valve. This technology integrates electrolysis and ultrasonic physical cleaning, eliminating the need for chemical scale inhibitors. It achieves descaling, sterilization, and water softening in one integrated process by dynamically adjusting pH and active substances, significantly increasing the concentration ratio of circulating water (calcium hardness reduction of up to 44%). It also features automatic control and an epoxy resin anti-corrosion structure, effectively solving the problems of strong chemical dependence, frequent maintenance, and secondary pollution associated with traditional methods.

[0005] However, during the development of this invention, the applicant discovered that the electrolysis system in Chinese patent "CN101585569A - Electrolytic Descaling Device and Method for Circulating Water" uses an integrated tank design. During the electrolytic descaling process, the anode and cathode coexist in the same reaction chamber without ion isolation, resulting in a dynamically neutral environment and low utilization efficiency of the hydroxide ions generated during electrolysis. Simultaneously, the large distance between the anode and cathode leads to high cell voltage in the electrolysis unit, exacerbating energy loss. Experimental data shows that at the same current density, for every 1cm increase in the distance between the electrodes, the cell voltage rises by approximately 0.5-1.2V, and energy consumption increases by 15%-30%. This high energy consumption characteristic limits the economic viability of this technology in large-scale industrial circulating water systems.

[0006] To address the above problems, this invention is proposed. Summary of the Invention

[0007] This application provides a composite electrode unit, an electrochemical water treatment system, and an electrochemical water treatment method. Compared with the prior art, the breakthroughs of this application include: (1) using a porous insulating filler layer, combined with the cathode and anode, to form an integrated composite electrode unit; the porous characteristics of the porous insulating filler layer allow water molecules to pass through in a constrained manner; (2) forming a built-in electric field within the porous insulating filler layer to resist the applied voltage, reducing the high energy consumption caused by high tank voltage; (3) due to the hydrophobic effect of the porous insulating filler layer, the migration of hydroxide ions generated at the cathode is suppressed, and then forced diffusion to the aqueous phase of the cathode chamber is achieved through high flow rate, accelerating its combination with scale ions such as calcium and magnesium ions, and improving the utilization rate of hydroxide ions; (4) due to the hydrophobic effect of the porous insulating filler layer, the H generated at the anode... + The migration of chloride ions is suppressed, and then forced diffusion is carried out through high flow rate to form an acidic environment in the anode area, which promotes the oxidation of chloride ions into bactericidal substances such as hypochlorous acid and chlorine in the acidic environment; (5) the catalytic electrode of water electrolysis is used to further reduce the voltage of water electrolysis and reduce energy consumption; (6) in addition to directly using direct current, alternating current (such as square wave alternating current) is used to automatically switch between the anode and cathode to achieve automatic descaling. Through the above-mentioned invention, this application improves the defects of existing electro-descaling technology, greatly improves the efficiency of electro-descaling, and reduces power consumption.

[0008] A first aspect of this application provides a composite electrode unit, comprising: a water electrolysis cathode, a porous insulating filler layer, and a water electrolysis anode; wherein the porous insulating filler layer is located between the water electrolysis cathode and the water electrolysis anode.

[0009] The internal material of the porous insulating filler layer does not contain exchangeable ions; the internal part refers to the non-surface portion.

[0010] Preferably, the electrolytic water cathode, the porous insulating filler layer, and the electrolytic water anode are bonded together.

[0011] One of the key points of this invention is that the internal material of the porous insulating filler layer itself does not contain exchangeable ions. This invention distinguishes between "insulating" and "conductive" filler layer materials based on how ions in an aqueous solution containing ions pass through the porous filler layer. If the porous filler layer material itself contains exchangeable ions, for example, anion exchange resin materials contain anions that can be exchanged, or cation exchange resin materials contain cations that can be exchanged, then ions in the aqueous solution can migrate through the porous filler layer in two ways:

[0012] A. Migration occurs through ion exchange with the porous packing layer material itself. This migration is selective; for example, anion exchange resins only allow anions to migrate and not cations to migrate, while cation exchange resins only allow cations to migrate and not anions to migrate.

[0013] B. Migration occurs through the flow of the aqueous solution within the pores of the porous material. This migration is non-selective, and both anions and cations in the aqueous solution can migrate.

[0014] Therefore, when the porous filler layer material itself has exchangeable ions, since ion migration mode A is carried out through the porous filler layer material itself, the porous filler layer itself appears to be conductive ion-conducting, i.e., conductive. Hence, the porous filler layer with exchangeable ions is called a "porous conductive filler layer".

[0015] If the porous filler layer material itself does not contain exchangeable ions, that is, the material itself does not provide ion exchange, then when the porous filler layer is placed in an aqueous solution containing ions, the above-mentioned ion migration mode A does not exist, and ion migration only relies on the above-mentioned ion migration mode B. Therefore, it appears that the porous filler layer itself is non-conductive and only becomes conductive by the flow of aqueous solution in the pores. Hence, the porous filler layer that does not contain exchangeable ions is called a "porous insulating filler layer", which is the filler layer used in this application.

[0016] The aforementioned composite electrode unit is the smallest technical unit of this application and also the smallest commercially available patent implementation unit. The aforementioned composite electrode unit can be placed in an electrolytic cell and begins operation after a voltage is applied.

[0017] The internal material of the porous insulating filler layer does not contain exchangeable ions; "internal" refers to the non-surface portion. In other words, the internal material of the porous insulating filler layer does not contain exchangeable ions, and ion transfer cannot occur within the internal material through ion exchange. Therefore, ions in the external solution cannot pass through the porous insulating filler layer solely through ion exchange within the porous insulating filler layer itself.

[0018] Of course, the surface of the porous insulating filler layer may or may not contain ions, but this does not affect the fact that ions in the external solution of the porous insulating filler layer cannot pass through the porous insulating filler layer solely through ion exchange with the porous insulating filler layer material itself.

[0019] In this invention, there are no requirements regarding whether the porous insulating filler layer is hydrophobic or hydrophilic. However, preferably, the porous insulating filler layer is entirely made of a hydrophobic material. This is because a hydrophobic material can inhibit the flow of aqueous solution within the pores of the porous insulating filler layer, thereby inhibiting the migration rate of the aforementioned ion migration mode B.

[0020] Alternatively, the internal material of the porous insulating filler layer may be hydrophobic, while the surface material may be hydrophilic; the "internal" refers to the non-surface portion. This configuration can also suppress the migration rate of the aforementioned ion migration mode B.

[0021] Of course, the porous insulating filler layer can also partially realize the solution of this application if it is a hydrophilic material. However, the accelerated ion migration mode B causes more hydroxide ions in the cathode chamber to migrate to the anode chamber through ion migration mode B before they can combine with calcium or magnesium ions to form precipitates. This results in the utilization efficiency of hydroxide ions being lower than that of the porous insulating filler layer with hydrophobic material. However, low efficiency does not mean infeasibility.

[0022] Preferably, the porous insulating filler layer has a porosity of 1% to 98%, a thickness of 0.05 to 5 mm, and a pore size of 0.1 to 500 micrometers.

[0023] More preferably, the porosity is 50%–98%. Even more preferably, the porosity is 52%–98%. Still more preferably, the porosity is 55%–98%. Even more preferably, the porosity is 60%–98%. Furthermore, the porosity range can be 60%–75%, 60%–73%, 52%–75%, 52%–73%, 52%–68%, 55%–75%, 55%–73%, or 55%–68%, etc.

[0024] More preferably, the thickness can be in the range of 0.05-5 mm, 0.1-5 mm, 0.18-5 mm, 0.2-5 mm, 0.5-5 mm, 1-5 mm, 1.2-5 mm, 1.5-5 mm, 2-5 mm, 2.2-5 mm, 2.5-5 mm, 0.2-2.5 mm, or 0.2-2.2 mm, etc.

[0025] The pore size can range from 0.1-0.5 micrometers, 0.2-0.8 micrometers, 0.3-500 micrometers, 0.5-500 micrometers, 0.1-0.3 micrometers, 0.3-1 micrometer, 0.1-0.4 micrometers, 1-500 micrometers, 0.2-0.6 micrometers, 10-200 micrometers, 0.2-0.6 micrometers, or 10-500 micrometers, etc.

[0026] Preferably, the porous insulating filler layer is made of one or more of the following materials: polyethylene, polystyrene, polyphenylene sulfide, polyvinyl chloride, polypropylene, polyurethane, polyamide, polyethersulfone, polypropylene hollow fiber, polytetrafluoroethylene, polyvinylidene fluoride, sulfonated polyether ether ketone, polybenzimidazole, polyimide, asbestos, alumina, silicon carbide, silicon nitride, zirconium oxide, boron nitride, mullite, cordierite, aluminum titanate, and silicon dioxide.

[0027] That is, the porous insulating filler layer can be made of a single material, a mixture of multiple materials, or a composite material composed of multiple single material layers.

[0028] In other words, the porous insulating filler layer is selected from one or more of the following: polyethylene layer, polystyrene layer, polyphenylene sulfide layer, polyvinyl chloride layer, polypropylene layer, polyurethane layer, polyamide layer, polyethersulfone layer, polypropylene hollow fiber layer, polytetrafluoroethylene composite layer, polyvinylidene fluoride layer, sulfonated polyether ether ketone layer, polybenzimidazole layer, polyimide layer, asbestos layer, alumina layer, silicon carbide layer, silicon nitride layer, zirconium oxide layer, boron nitride layer, mullite layer, cordierite layer, aluminum titanate layer, and silica layer.

[0029] In addition, the porous insulating filler layer can also be an organic layer doped with inorganic substances such as iron oxides.

[0030] Preferably, the surface of the porous insulating filler layer is modified. In other words, the surface of the porous insulating filler layer has a modified layer. The modified layer can be a hydrophilic layer. The hydrophilic modification of the surface of the porous insulating filler layer does not affect the fact that the interior of the porous insulating filler layer remains hydrophobic, thus still restricting the passage of water.

[0031] Furthermore, the surface grafting modification of the porous insulating filler layer does not affect the fact that the internal material of the porous insulating filler layer (i.e., the bulk phase) is free of anions and cations, and the interior (i.e., the bulk phase) of the porous insulating filler layer still does not contain ions.

[0032] In this application, due to the hydrophobic material of the porous insulating filler layer, the rate at which water and ions pass through its pores is extremely slow. Therefore, the aforementioned ion migration mode B also proceeds extremely slowly. Consequently, the hydroxide ions generated by water electrolysis in the cathode chamber are almost completely consumed by the calcium and magnesium ions in the cathode chamber before they pass through the porous insulating filler layer and enter the anode chamber.

[0033] Of course, regardless of whether voltage is applied to the anode and cathode, protons and hydroxide ions can slowly pass through the porous insulating filler layer and mix (the passage rate of protons and hydroxide ions when voltage is applied is greater than that when no voltage is applied). However, before they mix, the protons and hydroxide ions are discharged separately from the anode and cathode chambers, thus yielding acidic and alkaline water respectively.

[0034] A second aspect of this application provides an electrochemical water treatment system, the system comprising: a reaction chamber;

[0035] The reaction chamber is equipped with the composite electrode unit described in the first aspect;

[0036] Within the reaction chamber, the chamber on the cathode side of the composite electrode unit is the cathode chamber, and the chamber on the anode side of the composite electrode unit is the anode chamber.

[0037] Preferably, the reaction chamber further includes a power source that provides direct current or alternating current to the water electrolysis cathode and the water electrolysis anode.

[0038] Preferably, the top plate of the reaction chamber is attached to the top of the composite electrode unit, and the bottom plate of the reaction chamber is attached to the bottom of the composite electrode unit, so as to achieve physical isolation between the cathode chamber and the anode chamber by the composite electrode unit and prevent the water on both sides from mixing directly.

[0039] Preferably, the system further includes: a raw water tank and a reclaimed water tank;

[0040] The raw water tank is connected to the anode chamber via the anode chamber inlet pipe;

[0041] The raw water tank is connected to the cathode chamber via the cathode chamber inlet pipe;

[0042] The reclaimed water tank is connected to the anode chamber via the anode chamber outlet pipe;

[0043] The regenerated water tank is connected to the cathode chamber via the cathode chamber outlet pipe.

[0044] Preferably, the system further includes a filter device installed on the cathode chamber outlet pipe for filtering solid substances in the liquid of the cathode chamber outlet pipe.

[0045] Preferably, the raw water tank and the reclaimed water tank are connected by a circulation pipeline. This allows the reclaimed water in the reclaimed water tank to re-enter the reaction chamber through the raw water tank for electrochemical treatment. The entire process can be repeated multiple times until the quality of the reclaimed water meets the standards.

[0046] Preferably, the water electrolysis cathode of this application is a mesh electrode, and its material is any catalyst capable of catalyzing the water electrolysis cathode reaction. The water electrolysis anode of this application is a mesh electrode, and its material is a catalyst capable of catalyzing the water electrolysis anode reaction under acidic conditions.

[0047] A third aspect of this application provides an electrochemical water treatment method, wherein the method is performed using the electrochemical water treatment system described in any one of the second aspects, and the method includes the following steps:

[0048] Raw water containing calcium ions and / or magnesium ions is injected into the cathode chamber and the anode chamber respectively. The power is turned on, and direct current or alternating current is applied between the electrolytic water cathode and the electrolytic water anode to carry out electrolysis. The electrolysis reaction of water occurs in the composite electrode unit.

[0049] When direct current is supplied: during water electrolysis, hydrogen gas is generated in the cathode chamber, creating an alkaline environment that causes calcium and / or magnesium ions to precipitate as solids, reducing water hardness; during water electrolysis, oxygen is generated in the anode chamber, creating an acidic environment; ultimately, alkaline water containing solids is obtained in the cathode chamber, and acidic water is obtained in the anode chamber.

[0050] When AC power is supplied:

[0051] Before the current direction changes in each alternating current cycle: during water electrolysis, hydrogen gas is generated in the cathode chamber, creating an alkaline environment that causes calcium and / or magnesium ions to precipitate as solids, with some of the solid precipitates crystallizing on the original cathode surface; during water electrolysis, oxygen gas is generated in the anode chamber, creating an acidic environment.

[0052] After the current direction changes in each alternating current cycle: the electrolytic water cathode and the electrolytic water anode are reversed, so that the original electrolytic water anode becomes a temporary cathode and begins to generate hydroxide ions, and the original electrolytic water cathode becomes a temporary anode and begins to generate hydrogen ions. The hydrogen ions cause the solid material crystallized on the surface of the original electrolytic water cathode to dissolve from the surface of the original electrolytic water cathode, thus realizing the in-situ self-cleaning of the electrolytic water cathode.

[0053] During the next alternating current cycle, calcium and / or magnesium ions in the water continuously precipitate out in the cathode chamber, thereby reducing water hardness.

[0054] Finally, alkaline water containing solids is obtained in the cathode chamber, and acidic water is obtained in the anode chamber.

[0055] Preferably, when the raw water also contains chloride ions, the chloride ions in the anode chamber are oxidized to chlorine gas and removed. The anode chamber then produces acidic water containing dissolved chlorine, which has a self-antibacterial effect.

[0056] Preferably, when the method is performed using the electrochemical water treatment system described above:

[0057] The raw water tank contains raw water containing calcium ions and / or magnesium ions;

[0058] The resulting alkaline water and acidic water containing solids are discharged into the regenerated water tank through the cathode chamber outlet pipe and the anode chamber outlet pipe, respectively, and mixed to obtain neutral water.

[0059] Preferably, the solids in the alkaline water containing solids are filtered by the filtration device. Alternatively, a filtration device may not be necessary; solids can be removed by sedimentation, pressure filtration, or other solid-liquid separation methods in the reclaimed water tank.

[0060] Preferably, the chlorine in the acidic water containing chlorine can be aerated before being discharged into the reclaimed water tank. For example, an acid tank is installed and aerated on the outlet pipe of the anode chamber. The chlorine discharge pipe of the acid tank is connected to the absorption tower. Sodium hydroxide solution is sprayed into the absorption tower, where sodium hydroxide reacts with chlorine to form sodium hypochlorite, a valuable chemical product.

[0061] Preferably, the voltage of the DC or AC power is 1.5V to 30V.

[0062] Preferably, when the direct current or alternating current is applied, the current density on the electrolytic water cathode or the electrolytic water anode is 1 to 1000 A / m. 2 .

[0063] Furthermore, the electrochemical water treatment system of this application is essentially an electrolytic descaling device, which is fundamentally different from conventional water electrolysis devices:

[0064] 1. First, regarding the objective:

[0065] Conventional water electrolysis devices achieve electrochemical reactions through the migration of hydroxide ions or hydrogen ions. Their main products are hydrogen and oxygen. The hydroxide ions or hydrogen ions need to rapidly pass through the membrane to reach the anode or cathode. For example, in CN116334647A, the water electrolysis device achieves electrochemical reactions through the migration of hydroxide ions. Its main products are hydrogen and oxygen. The hydroxide ions need to rapidly pass through the membrane to reach the anode to participate in the electrolysis reaction to produce oxygen.

[0066] The composite electrode unit in the electrochemical water treatment system of this application is characterized by a porous insulating filler layer that "blocks the migration of hydroxide ions" so that hydroxide ions are retained in the cathode chamber and combine with calcium and magnesium ions as much as possible.

[0067] 2. From the perspective of device structure:

[0068] The characteristics of conventional water electrolysis devices (such as CN116334647A) are as follows:

[0069] In a conventional water electrolysis device, the cathode, anode, and membrane are spaced apart and not attached to each other. The cathode and anode are located on opposite sides of the electrolysis cell, while the membrane is located in the middle. The cathode chamber, containing the electrolyte, is located between the cathode and the membrane. The anode chamber, containing the electrolyte, is located between the anode and the membrane. Therefore, when a voltage is applied between the cathode and anode, the electrolyte in both the entire cathode chamber and the entire anode chamber is in the current loop and participates in the water electrolysis reaction.

[0070] Simultaneously, hydrogen ions or hydroxide ions cross the membrane and participate in the water electrolysis reaction. The electrolyte in both the entire cathode chamber and the entire anode chamber undergoes the water electrolysis reaction to produce hydrogen and oxygen.

[0071] The primary purpose of the electrochemical water treatment system in this application is not to produce hydrogen and oxygen, but to remove scale electrochemically. Its characteristics are as follows:

[0072] The electrolytic water cathode, electrolytic water anode, and porous insulating packing layer are bonded together to form a gapless composite electrode unit. This gapless composite electrode unit is located in the middle of the reaction chamber. Between the electrolytic water cathode and the side wall of the reaction chamber is a cathode chamber containing raw water containing calcium and / or magnesium ions. Between the electrolytic water anode and the other side wall of the reaction chamber is an anode chamber containing raw water containing calcium and / or magnesium ions. Therefore, when a voltage is applied between the electrolytic water cathode and the electrolytic water anode, only the raw water in the gapless composite electrode unit is in the current loop and participates in the water electrolysis reaction. The raw water in the cathode and anode chambers outside the gapless composite electrode unit is not in the current loop and does not participate in the water electrolysis reaction; it only receives electrolysis products from the gapless composite electrode unit through forced diffusion to carry out conventional chemical reactions (e.g., water in the cathode chamber receives hydroxide ions generated on the cathode surface to produce calcium and magnesium precipitates, and water in the anode chamber receives H+ ions generated on the anode surface). + (e.g., using Cl2 or hypochlorous acid for chemical disinfection).

[0073] Therefore, only the portion of the raw water located in the gapless composite electrode unit (which may be one percent or one-thousandth the volume of the raw water in the cathode and anode chambers outside the entire gapless composite electrode unit) participates in the water electrolysis reaction.

[0074] Hydroxide ions are generated at the cathode during water electrolysis, and then forced to diffuse into the aqueous phase of the cathode chamber through high flow rate. This accelerates the combination of hydroxyl ions with scale ions such as calcium and magnesium ions, resulting in rapid crystallization and precipitation, thus improving the utilization rate of hydroxyl ions.

[0075] The H2 produced at the anode during water electrolysis + Chlorine or hypochlorous acid is forced to diffuse into the aqueous phase of the anode chamber through a high flow rate, creating an acidic environment rich in bactericidal substances such as hypochlorous acid and chlorine.

[0076] 3. The differences between the membrane of a conventional water electrolysis device and the porous insulating packing layer of the electrolytic descaling device of this application are as follows:

[0077] The membrane requirements for conventional water electrolysis devices are: low resistivity, high conductivity, and the ability to allow anions and / or cations in the electrolyte to rapidly pass through the membrane to participate in the electrolysis reaction. Generally, the membrane material of conventional water electrolysis devices contains exchangeable ions to exchange with the electrolyte, allowing anions and / or cations in the electrolyte to rapidly pass through the membrane to participate in the electrolysis reaction.

[0078] The purpose of the porous insulating filler layer in this application is to minimize the penetration of water and ions through the porous insulating filler layer, thereby preventing hydroxyl ions generated at the cathode from penetrating the porous insulating filler layer and combining with hydrogen ions at the anode, and also preventing hydrogen ions generated at the anode from penetrating the porous insulating filler layer and combining with hydroxyl ions generated at the cathode. Both of these factors would reduce the utilization rate of hydroxyl descaling.

[0079] Therefore, the porous insulating filler layer material of this application does not contain exchangeable ions, so as to prevent hydroxide ions and hydrogen ions in water from passing through the porous insulating filler layer through ion exchange (i.e., ion migration mode A proposed on page 3 of this application specification).

[0080] Furthermore, the porous insulating filler layer of this application has a porous nature, is relatively thick (preferably 1-5 mm), and is preferably made of a hydrophobic material. These characteristics can slow down the passage of water and ions through the porous insulating filler layer, i.e., suppress the migration rate of ion migration mode B proposed on page 3 of this application specification.

[0081] 4. In terms of usage:

[0082] The higher the current in the water electrolysis device, the better, in order to accelerate the water electrolysis rate.

[0083] In the electrostatic descaling device of this application, the lower the current, the better, because only a small amount of water needs to be electrolyzed to generate enough hydroxide ions to precipitate and remove calcium and magnesium ions. There is no need to electrolyze a large amount of water to generate hydrogen and oxygen. Therefore, it is desirable to have a low current to reduce the energy consumption of descaling.

[0084] Compared with the prior art, this application has the following advantages:

[0085] 1. This device uses a porous insulating packing layer as a functional partition, with the cathode and anode integrated on both sides respectively, forming a unique composite electrode unit with an integrated "packing-electrode" structure. Driven by an ultra-low DC operating voltage, the migration and blockage of hydroxide ions are achieved by controlling water transport through the micropores of the packing. At the same time, the local gradient diffusion effect generated by the catalytic reaction on the electrode surface and the forced diffusion effect of pumping diffuse hydroxide ions into the aqueous phase of the cathode chamber, promoting the rapid crystallization and precipitation of scale-forming ions in the cathode region, thereby reducing the hardness of the water.

[0086] 2. Furthermore, the apparatus of this application can also treat water containing chloride ions. During the removal of chloride ions by electrolysis at the anode, an acidic microenvironment (pH < 7) is formed in the anode chamber due to the oxygen / chlorine evolution reaction. Moreover, the alkaline water obtained at the cathode and the acidic water obtained at the anode are neutralized outside the reaction chamber. This ensures that the chlorine gas generated by anode electrolysis is in an acidic water environment within the anode chamber, allowing for efficient chlorine removal via air stripping without additional acidification treatment. Furthermore, the acidic water obtained in the anode chamber contains dissolved chlorine, which has a self-antibacterial effect.

[0087] 3. In the preferred embodiment, this application adopts an alternating current mode, which can achieve in-situ cleaning of scale after periodic reversal of the anode and cathode to achieve self-cleaning of the electrolytic water cathode, without the need to set up an ultrasonic cleaner to remove scale.

[0088] 4. The solution proposed in this application not only eliminates the need for external addition of traditional scale inhibitors and acid-base agents, thus avoiding the risk of chemical residue pollution from the source, but also inhibits the growth of microorganisms by simultaneously generating active chlorine substances, thereby solving the industry problem of scale and corrosion reinforcing each other.

[0089] 5. In the preferred embodiment, the composite electrode unit of this application comprises an electrolytic water cathode, a porous insulating filler layer, and an electrolytic water anode that are bonded together. This minimizes the direct distance between the anode and cathode, thereby reducing the electrolyte resistance between them and lowering the energy consumption of the system. Attached Figure Description

[0090] Figure 1 is a schematic diagram of the electrochemical water treatment system of this application.

[0091] Figure 2 is a schematic diagram of a conventional water electrolysis device.

[0092] List of reference numerals in the attached diagram: 1-Power supply; 2-Cathode for water electrolysis; 3-Anode for water electrolysis; 4-Porous insulating packing layer; 5-Reaction chamber; 6-Raw water tank; 7-Regenerated water tank; 8-Anode chamber inlet pipe; 9-Cathode chamber inlet pipe; 10-Anode chamber outlet pipe; 11-Cathode chamber outlet pipe; 12-Filtration device; 01-Membrane; 02-Cathode chamber of conventional water electrolysis device; 03-Anode chamber of conventional water electrolysis device. Detailed Implementation

[0093] The present invention will be described below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. Experimental methods not specifically described in the embodiments generally use conventional conditions and conditions described in the manual, or conditions recommended by the manufacturer. The general equipment, materials, reagents, etc., used are all commercially available unless otherwise specified. The raw materials used in the following embodiments and comparative examples are all commercially available.

[0094] This application proposes a low-energy electrochemical water treatment method based on the synergistic effect of ion blocking and forced diffusion. The core of this method lies in the innovative design of a gapless electrolysis unit composed of a porous insulating packing layer 4 and a catalytic electrode. The device uses the hydrophobic porous insulating packing layer 4 as a functional separator, with a highly catalytically active mesh cathode and anode integrated on both sides, forming a unique integrated "packing-electrode" structure. Driven by an ultra-low DC voltage of 1.5V to 30V, the controlled transport of hydroxide ions through the micropores of the packing layer achieves directional migration blocking, causing them to precipitate with calcium and magnesium ions. Simultaneously, the rapid flow of water entering the cathode chamber at the cathode of the electrolyzed water generates a local forced diffusion effect, promoting the rapid crystallization and precipitation of scale-forming ions in the water. During electrolysis, the acidic microenvironment (pH < 7) formed in the anode chamber due to the oxygen / chlorine evolution reaction allows the generated chlorine gas to be efficiently removed by air stripping without additional acidification treatment. This dual-action mechanism enables the system to efficiently remove hardness ions from circulating water while maintaining a low energy consumption level, and significantly improve the cooling water concentration capacity, thereby significantly reducing the amount of make-up water and sewage discharge, ultimately achieving high efficiency, energy saving and near-zero discharge in the industrial water treatment process.

[0095] The preferred technical solution is as follows:

[0096] The porous insulating filler layer 4 can be made of a hydrophobic resin material. The porous insulating filler layer 4 can be an open-cell foam plastic layer or an open-cell foam plastic layer, including but not limited to a polyethylene polymer layer, such as a polyethylene layer, polystyrene layer, polyvinyl chloride layer, polypropylene layer, polyurethane layer, etc. The porosity of the porous insulating filler layer 4 is 1%–98% (preferably 30%–60%), the thickness is 0.05–5 mm (preferably 0.1–2 mm), and the COD (chemical oxygen demand) tolerance range is 0–10000 mg / L. The pore size distribution of the porous insulating filler layer 4 is 0.1–500 micrometers. Similar effects are achieved when the porous insulating filler layer 4 is made of foam plastic doped with inorganic substances such as iron oxides.

[0097] The porous insulating filler layer 4 may also use other organic materials, including but not limited to polyamide layer, polyethersulfone layer, polypropylene hollow fiber layer, polytetrafluoroethylene composite layer, sulfonated polyether ether ketone layer, polybenzimidazole layer, and polyimide layer.

[0098] The electrolytic water cathode 2 is selected from one or a combination of the following materials: nickel wire mesh (50-200 mesh), stainless steel mesh (304 / 316L), nickel foam (porosity 85%-95%), nickel wire mesh supported on Raney nickel catalyst (loading 5%-20%), platinum, and titanium.

[0099] The anode 3 for water electrolysis is a titanium-based composite coating electrode or a platinum, graphene, etc., wherein the titanium-based composite coating electrode is selected from one or more of the following: titanium-plated iridium oxide (IrO2-Ti), titanium-plated ruthenium oxide (RuO2-Ti), and iridium-tantalum mixed oxide coating (IrO2-Ta2O5-Ti).

[0100] The device integrates a self-cleaning function as follows: The electrode polarity is periodically switched via a square wave AC control system. The square wave AC switching frequency is 0.00001–0.1 Hz. Preferably, the square wave AC switching frequency is 0.0001–0.05 Hz. The peak-to-valley ratio of the square wave AC is (100:1)–(1:100). Preferably, the peak-to-valley ratio is 10:1–1:10. Of course, other forms of AC can also be used.

[0101] The water flow velocity in the cathode and anode chambers is 0.1–1.0 m / s, preferably 0.3–0.5 m / s, to ensure an ion mass transfer rate ≥ 5 × 10⁻⁶ m / s. -5 mol / (m 2 ·s).

[0102] The flow channels of the cathode chamber and anode chamber are designed as serpentine or baffle structures to extend the hydraulic residence time to 10–30 seconds.

[0103] Electrochemical water treatment methods are suitable for circulating water treatment with calcium and magnesium ion concentrations of 10–20,000 mg / L.

[0104] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0105] The circulating water electrochemical water treatment device proposed in this invention achieves low-energy consumption, high-efficiency removal of hardness ions and self-cleaning functions in circulating water through innovative structural design and reaction mechanism coupling. The following is a systematic description from three dimensions: device structure, treatment process, and reaction mechanism.

[0106] First, as shown in Figure 1, the device consists of the following core components:

[0107] Reaction chamber 5: Constructed of carbon steel or stainless steel substrate, with an epoxy resin anti-corrosion coating on the outer surface, providing both electrical insulation and corrosion resistance. The interior of reaction chamber 5 is divided into an anode chamber and a cathode chamber by a composite electrode unit. The anode chamber and cathode chamber are respectively equipped with an anode chamber inlet pipe 8, a cathode chamber inlet pipe 9, an anode chamber outlet pipe 10, a cathode chamber outlet pipe 11, and a filter device 12, forming independent fluid channels. The filter device 12 is used to intercept suspended crystals.

[0108] Figure 1 only shows the two side plates of reaction chamber 5. The bottom plate, top plate, front plate, and rear plate of reaction chamber 5 are not shown.

[0109] The system also includes: a raw water tank 6 and a reclaimed water tank 7. The raw water tank 6 is connected to the anode chamber via an anode chamber inlet pipe 8, and the raw water tank 6 is connected to the cathode chamber via a cathode chamber inlet pipe 9. The reclaimed water tank 7 is connected to the anode chamber via an anode chamber outlet pipe 10, and the reclaimed water tank 7 is connected to the cathode chamber via a cathode chamber outlet pipe 11.

[0110] Composite electrode unit: It is integrally formed by water electrolysis cathode 2, water electrolysis anode 3 and porous insulating filler layer 4.

[0111] Electrolytic water cathode 2: It adopts one or more of nickel-based high specific surface area materials (such as nickel wire mesh, nickel foam or metal skeleton supported on Raney nickel catalyst) or platinum, titanium, and stainless steel mesh, whose three-dimensional channel structure can enhance hydroxide diffusion and crystal adhesion.

[0112] Electrolytic water anode 3: Select one or more of the following: titanium-based coated electrodes (such as titanium-plated iridium oxide, titanium-plated ruthenium oxide or iridium-tantalum composite coating) or platinum, graphene-doped electrodes, etc., which have low chlorine evolution and oxygen evolution overpotential and acid corrosion resistance.

[0113] Porous insulating filler layer 4: prepared from hydrophobic resin. The hydrophobic resin has a porosity of 3% to 98% and a thickness of 0.05 to 5 mm, allowing water molecules to permeate in a controlled manner and ensuring a stable ion concentration gradient in the anode and cathode chambers.

[0114] The composite electrode unit has the same length and height as the side plate of the reaction chamber 5. This matching design with equal height and length ensures a seamless physical fit between the composite electrode unit and the reaction chamber 5, preventing direct mixing of alkaline and acidic water within the anode and cathode chambers. The design of the composite electrode unit also reduces the distance between the anode and cathode, effectively eliminating the inter-electrode resistance loss common in traditional reaction chambers.

[0115] Power supply 1 is a square wave AC power control system, specifically using an integrated low-frequency square wave generator with a frequency of 0.00001 to 0.1 Hz and an adjustable peak-to-valley ratio of 100:1 to 1:100. The purpose of the square wave AC power control system is to generate a dynamic acid-base environment through periodic polarity reversal, triggering the self-stripping of scale on the electrode surface.

[0116] Second, circulating water treatment process

[0117] Raw material supply stage: Circulating water containing high concentrations of calcium and magnesium ions (calcium / magnesium ion concentration 10~20000mg / L) is stored in raw water tank 6 and pumped into the anode chamber and cathode chamber of reaction chamber 5 respectively through anode chamber inlet pipe 8 and cathode chamber inlet pipe 9 at a flow rate ≥0.1m / s.

[0118] Preferably, one end of the anode chamber inlet pipe 8 and the cathode chamber inlet pipe 9 are respectively located at the bottom of the electrodes in the anode chamber and the cathode chamber, and the pipe openings face the electrode surface, so as to utilize fluid inertia to form a swirling flow that covers the entire electrode surface.

[0119] Preferably, one end of the anode chamber outlet pipe 10 and the cathode chamber outlet pipe 11 are respectively located at the top of the anode chamber and the cathode chamber to facilitate the rapid escape of gases generated during electrolysis and prevent bubbles from adhering to the electrode surface and reducing reaction efficiency. Preferably, the outlet pipe and the inlet pipe are designed diagonally. For example, the outlet pipe opening is at the top on the side away from the electrode, or the pipe opening is at the top on the electrode side. This allows the water flow to continuously flush the electrode surface in the flow path from inlet to outlet. Simultaneously, it prolongs the residence time of the water flow within the chamber. Furthermore, by controlling the water flow velocity, forced convection is formed within the anode and cathode chambers. This forced convection design can suppress boundary layer thickening and enhance ion mass transfer efficiency.

[0120] Third, electrochemical treatment stage

[0121] Typically, under an ultra-low DC voltage of 1.5V, differential electrochemical reactions occur in the anode and cathode chambers.

[0122] Cathode chamber: Electrolysis of water generates hydroxide ions (2H₂O + 2e⁻) - →H₂↑+2OH - An alkaline environment promotes the conversion of bicarbonate ions into carbonate ions (HCO3-). - +OH - →CO3 2- +H2O), which then combines with calcium / magnesium ions to form calcium carbonate, magnesium hydroxide, and magnesium carbonate crystals.

[0123] Anode chamber: Chloride ions are oxidized to produce active chlorine (2Cl₂). - →Cl2↑+2e - Simultaneously, water electrolysis generates hydrogen ions (H2O→1 / 2O2↑+2H+). + +2e - The acidic environment inhibits secondary scaling and simultaneously kills bacteria and inhibits algae.

[0124] The meaning of secondary scaling is as follows:

[0125] Cathode reaction: Water electrolysis produces hydroxide ions (2H₂O + 2e⁻) - →H₂↑+2OH - The pH in the cathode area increases (becomes alkaline), which promotes the precipitation of calcium / magnesium ions (conventional scaling).

[0126] If the micron-sized precipitates generated in the cathode area diffuse to the anode area with the water flow, they may redissolve in a neutral or weakly acidic environment. However, if the anode environment is not properly controlled (such as the pH not being low enough), these particles may be re-deposited on the anode electrode surface due to electrostatic adsorption or turbulent disturbance, forming "secondary scaling".

[0127] Reclaimed water recovery stage: The treated anode reclaimed water (pH 2-4, enriched with hydrogen ions) and cathode reclaimed water (pH 10-12, containing suspended crystals) are pumped into the reclaimed water tank 7 through the anode chamber outlet pipe 10 and the cathode chamber outlet pipe 11, respectively (wherein the suspended crystals flowing out of the cathode chamber are intercepted and filtered into device 12 and no longer come into contact with the anode reclaimed water), and neutralized through a neutralization reaction (H+). + +OH - →H2O) restores electroneutrality, and the precipitate is utilized as a resource after solid-liquid separation.

[0128] Fourth, self-cleaning and energy efficiency optimization mechanisms

[0129] Dynamic scale removal: The square wave AC power system of power supply 1 periodically switches the electrode polarity, utilizing the local strong acid (hydrogen ions in the anode chamber) or strong alkaline (hydroxyl ions in the cathode chamber) environment at the moment of polarity reversal to dissolve the microcrystalline scale layer on the electrode surface, achieving in-situ self-cleaning (scale removal efficiency ≥95%).

[0130] Energy consumption control strategy: The gapless electrode design combined with the square wave power supply mode reduces concentration polarization loss, and the overall energy consumption is reduced by 20% to 70% compared with the existing technology, with a power consumption of 2 to 5 kWh per kilogram of hardness (calculated as calcium carbonate).

[0131] The general formula for calculating energy consumption based on hydroxide ion formation and calcium ion precipitation is as follows:

[0132] When the reaction generates hydroxide ions through water electrolysis, which then combine with calcium ions to precipitate (e.g., to form calcium hydroxide or calcium carbonate), the theoretical energy consumption steps for removing one kilogram of hardness (based on calcium carbonate) are calculated as follows:

[0133] 1. Relationship between reaction pathway and electron transfer

[0134] Cathode reaction (formation of hydroxide ions): 2H₂O + 2e⁻ - →H₂↑+2OH -

[0135] Precipitation reaction (removal of calcium ions): Ca 2+ +2OH - →Ca(OH)2↓ or Ca 2+ +CO3 2- →CaCO3↓

[0136] Electron transfer relationship: 2 mol of electrons are required to remove 1 mol of calcium ions.

[0137] 2. Calculation steps:

[0138] Number of moles of calcium carbonate removed: Number of moles = m × 1000 / M (calcium carbonate) = 1000m / 100.08 ≈ 10m (mol)

[0139] Where m represents the hardness mass of the treatment, expressed as calcium carbonate, in kg.

[0140] Theoretical power requirement: Q 理论 = n × number of moles × F = 2 × 10m × 96485 (C)

[0141] Where n is the number of electrons transferred, and F is the Faraday constant.

[0142] Theoretical energy consumption (electrical energy = quantity × voltage): E 理论 =Q 理论 ×V / (3.6×10 6 (kWh)

[0143] Taking Example 1 as an example: Hardness (calculated as calcium carbonate) removal amount m = 1000L × 1000mg / L × 95% = 0.95kg;

[0144] The applied single-stage voltage V = 4.4V; the single-stage voltage is the voltage applied between the anode and cathode of the same composite electrode unit. Each reaction chamber 5 contains one composite electrode unit. Multiple reaction chambers 5 can be connected in series, also called multi-stage series connection. The embodiments in this application all use only one stage of reaction chamber 5. Theoretical energy consumption = 2 × 10 × 0.95 × 96485 × 4.4 / (3.6 × 10⁻⁶) 6 )≈2.24kWh;

[0145] For the calculation of hardness (calculated as calcium carbonate) removed per kilogram in comparative patent CN101585569A:

[0146] Since the voltage is not explicitly given in the embodiments of the comparative patent, we consulted relevant materials and found that the typical voltage range of the device proposed in comparative patent CN101585569A is 12-24V. Taking the lowest voltage of 12V as an example (for processing 1 kg of calcium carbonate): Theoretical energy consumption = 2 × 10 × 1 × 96485 × 12 / 3.6 × 10 6 ≈6.43kWh.

[0147] The following examples illustrate the effects of this application. The experimental materials used in this application, such as electrodes and the materials used in the porous insulating filler layer 4, can be obtained by purchasing or by self-preparation using existing methods. The preparation method of the porous insulating filler layer 4 in this application is a conventional process. When the porous insulating filler layer 4 is a polymer material, a solution casting method is used. When the porous insulating filler layer 4 is a material containing both polymer and inorganic materials, the two types of particles are mixed and then a solution casting method is used. When the porous insulating filler layer 4 is an inorganic material, an adhesive pressing method is used.

[0148] The water hardness or calcium and magnesium ions in this application are expressed as calcium carbonate.

[0149] Example 1

[0150] 1. Target of treatment: 1 ton (1000L) of concentrated circulating water stored in raw water tank 6, with an initial calcium and magnesium ion concentration (calculated as calcium carbonate) of 1000mg / L.

[0151] 2. Equipment configuration:

[0152] Electrode system: The anode 3 for water electrolysis uses a titanium-based iridium oxide coated electrode (IrO2 loading 2.5 mg / cm³). 2 The cathode 2 for water electrolysis uses a foamed nickel electrode (porosity 85%).

[0153] Porous insulating filler layer 4: Polyethylene-polyamide composite layer (porosity 60%, thickness 2 mm, pore size 0.1-0.5 micrometers), with a sulfonated modified layer on the surface.

[0154] The preparation method of the polyethylene-polyamide composite layer is as follows:

[0155] (1) Add 12.0g of polyamide (PA6) to 108.0mL of o-dichlorobenzene, heat in an oil bath at 160 degrees Celsius, and stir mechanically (300rpm) for 2 hours until completely dissolved to form a clear solution with a solid content of 10.0wt%.

[0156] (2) Cool the PA6 solution to 100 degrees Celsius, add 6.0g of high-density polyethylene (HDPE) particles in batches, heat to 140 degrees Celsius at a rate of 1 degree Celsius per minute, and disperse at 800 rpm at 140 degrees Celsius for 1.5 hours.

[0157] (3) Add 2.52g of n-octanol at 140 degrees Celsius and stir at 500 rpm for 30 minutes until completely dispersed.

[0158] (4) Pour the uniform high-temperature solution into a Teflon mold preheated to 100 degrees Celsius (mold depth: 2.5 mm).

[0159] (5) Control the cooling rate (first cool slowly to 80 degrees Celsius at a rate of 0.1 degrees Celsius per minute, then cool naturally to room temperature) to induce phase separation and solvent evaporation to form pores.

[0160] (6) Cool to below 30 degrees Celsius and demold.

[0161] (7) Soak in 98% concentrated sulfuric acid for 40 min for sulfonation modification, and then dry in a vacuum oven at 60 degrees Celsius for 12 h.

[0162] 3. Operating Procedures:

[0163] (1) Feeding stage: The concentrated circulating water is injected into the two polar chambers at a flow rate of 0.5m / s by a booster pump.

[0164] (2) Electrochemical treatment: Apply square wave alternating current (single-stage voltage 4.4V) with a current density of 200A / m. 2 The frequency is 0.0033Hz (cycle 300s / 5 minutes), peak-to-valley ratio is 10:1, and it runs for 4 cycles (total duration 1200s).

[0165] (3) Discharge of reclaimed water: Open the outlet pipe 10 of the anode chamber and the outlet pipe 11 of the cathode chamber, and pump the reclaimed water into the reclaimed water tank 7 at a flow rate of 1.0 m / s.

[0166] (4) Cyclic processing: Repeat the feeding-processing-draining steps 5 times, for a total of 20 cycles, with a total processing time of 6000s (100 minutes).

[0167] 4. Treatment effect:

[0168] Raw water tank 6: 1000L of concentrated circulating water has been completely treated;

[0169] Effluent quality: When 1000L of reclaimed water is collected, the concentration of calcium and magnesium ions is reduced to 50mg / L, with a removal rate of 95%.

[0170] Actual energy consumption data: The initial cell voltage is 4.5V, and the cell voltage rises to 4.7V at the end of the processing cycle (an increase of 0.2V). The power consumption to remove each kilogram of hardness (calculated as calcium carbonate) is 2.5kWh, which is 61.1% lower than the comparison patent CN101585569A (6.43kWh).

[0171] Example 2

[0172] High-temperature and corrosion-resistant scenarios:

[0173] 1. Target of treatment: 1.2 tons (1200L) of high-temperature concentrated circulating water (temperature 80 degrees Celsius), with an initial hardness (calculated as calcium carbonate) of 1200mg / L.

[0174] 2. Equipment configuration:

[0175] Electrode system: The anode 3 for water electrolysis uses a titanium-plated ruthenium oxide electrode with a ruthenium loading of 1.8 mg / cm³. 2 The cathode 2 for water electrolysis uses a porous nickel wire mesh electrode.

[0176] Porous insulating filler layer 4: Polyphenylene sulfide-alumina composite layer (porosity 70%, thickness 1.5 mm, pore size 0.2-0.8 micrometers).

[0177] The preparation method of polyphenylene sulfide-alumina composite layer is as follows:

[0178] (1) Under nitrogen protection, add 20.0g of polyphenylene sulfide (PPS) particles to 180mL of N-methylpyrrolidone (NMP), heat to 216 degrees Celsius, and stir vigorously (800rpm) until completely dissolved;

[0179] (2) Cool down to 180 degrees Celsius, add 30.0g of alumina (Al2O3) powder, and sonicate for 30 minutes to ensure good dispersion;

[0180] (3) Add 3.0g of polyethylene glycol 400 and ultrasonically disperse until uniform;

[0181] (4) Quickly pour the uniform high-temperature slurry into a stainless steel mold preheated to 150 degrees Celsius (mold depth: 1.65 mm);

[0182] (5) Place it in an oven and keep it at 180 degrees Celsius for 1.5 hours (to prevent crystallization from cooling too quickly). Then, cool it down to 100 degrees Celsius at a rate of 0.8 degrees Celsius per minute. Finally, evaporate the residual solvent to room temperature under ventilation conditions.

[0183] (6) Demolding.

[0184] 3. Operating Procedures:

[0185] (1) Feeding stage: Concentrated circulating water is injected at a flow rate of 0.6 m / s;

[0186] (2) Electrochemical treatment: Apply square wave alternating current (single-stage voltage 4.8V, frequency 0.0017Hz (cycle 600s / 10 minutes), peak-to-valley ratio 8:1), run for 6 cycles (total duration 3600s), current density 150A / m 2 ;

[0187] (3) Reclaimed water discharge: Reclaimed water is discharged at a flow rate of 0.8 m / s.

[0188] (4) Cyclic processing: Repeat 6 times, run a total of 36 cycles, and the total processing time is 21,600s (6 hours).

[0189] 4. Treatment effect:

[0190] Raw water tank 6: 1200L concentrated circulating water treatment completed;

[0191] Effluent water quality: 1200L of reclaimed water was collected, with hardness reduced to 72mg / L and a retention rate of 94%.

[0192] Actual energy consumption data: The initial cell pressure is 4.9V, and the cell pressure rises to 5.2V at the end of the processing cycle (an increase of 0.3V). The power consumption to remove one kilogram of hardness (calculated as calcium carbonate) is 3.8kWh, which is 40.9% lower than the comparison patent CN101585569A (6.43kWh).

[0193] Example 3

[0194] Low-cost and environmentally friendly solutions:

[0195] 1. Target water to be treated: 800L of low-concentration circulating water with a hardness (calculated as calcium carbonate) of 300mg / L.

[0196] 2. Equipment configuration:

[0197] Electrode system: The anode 3 for water electrolysis uses an iridium-tantalum mixed oxide, and the cathode 2 for water electrolysis uses a nickel wire mesh loaded with a Raney nickel electrode;

[0198] Porous insulating filler layer 4: Polypropylene hollow fiber-silica composite layer (porosity 1%, thickness 0.05 mm, pore size 0.3-500 micrometers), with a quaternary ammonium group modified layer on the surface.

[0199] The preparation method of the polypropylene hollow fiber-silica composite layer is as follows:

[0200] (1) Dissolve 15.0g of polypropylene (PP) granules in 135mL of decahydronaphthalene at 140°C to form a solution;

[0201] (2) Cool down to 100 degrees Celsius, add 4.5g of silica nanoparticles, stir vigorously and disperse evenly by ultrasonication;

[0202] (3) Add 1.5g of cyclohexane;

[0203] (4) Lay the polypropylene hollow fiber (PPHF) woven fabric flat at the bottom of the mold (mold depth: 1 mm);

[0204] (5) Pour the mixed slurry onto the PPHF layer while it is still hot (100 degrees Celsius) to ensure full impregnation;

[0205] (6) Allow to cool naturally to room temperature to evaporate the solvent;

[0206] (7) Demolding;

[0207] (8) Immerse in an ethanol solution of 5wt% quaternized silane for 60 minutes and cure at 80 degrees Celsius for 1 hour.

[0208] 3. Operating Procedures:

[0209] (1) Feeding stage: Concentrated circulating water is injected at a flow rate of 0.3 m / s;

[0210] (2) Electrochemical treatment: Apply square wave alternating current (single-stage voltage 30V, frequency 0.0011Hz (cycle 900s / 15 minutes), peak-to-valley ratio 12:1), run for 3 cycles (total duration 2700s), current density 1000A / m 2 ;

[0211] (3) Reclaimed water discharge: Reclaimed water is discharged at a flow rate of 0.8 m / s;

[0212] (4) Cyclic processing: Repeat 13 times, run a total of 40 cycles, and the total processing time is 108,000s (30 hours).

[0213] 4. Treatment effect:

[0214] Raw water tank 6: 800L of circulating water has been treated;

[0215] Effluent water quality: 800L of reclaimed water is collected, with hardness reduced to 15mg / L and a retention rate of 95%.

[0216] Actual energy consumption data: The initial cell pressure is 30.1V, and the cell pressure rises to 30.4V at the end of the processing cycle (an increase of 0.3V). The power consumption to remove each kilogram of hardness (calculated as calcium carbonate) is 4.0kWh, which is 37.7% lower than the comparison patent CN101585569A (6.43kWh).

[0217] Example 4

[0218] High-salinity seawater pretreatment:

[0219] 1. Subject of treatment: 2000L of seawater desalination pretreatment solution with a hardness (calculated as calcium carbonate) of 800mg / L.

[0220] 2. Equipment configuration:

[0221] Electrode system: The anode 3 for water electrolysis uses a platinum-carbon electrode, and the cathode 2 for water electrolysis uses a nickel foam electrode;

[0222] Porous insulating filler layer 4: Polytetrafluoroethylene-silicon carbide composite layer (porosity 65%, thickness 2.2 mm, pore size 0.5-500 micrometers);

[0223] The preparation method of the polytetrafluoroethylene-silicon carbide composite layer is as follows:

[0224] (1) Dilute 100 mL of polytetrafluoroethylene dispersion with a solid content of 60 wt% (solvent is water) with deionized water to a solid content of 24 wt%;

[0225] (2) Add 45g of silicon carbide (SiC) powder, stir vigorously and disperse evenly by ultrasonication;

[0226] (3) Add a dual pore-forming agent: Add 30.0g of NaCl particles with a particle size of 200 micrometers and 15.0g of sucrose powder with a particle size of 5 micrometers;

[0227] (4) Pour the mixed slurry into the mold (mold depth: 2.5 mm);

[0228] (5) First, dry slowly at room temperature (to prevent cracking), and then sinter in an oven by gradually increasing the temperature. The temperature and holding time are as follows: 60 degrees Celsius for 12 hours, 100 degrees Celsius for 12 hours, 200 degrees Celsius for 2 hours, and 327 degrees Celsius for 1 hour.

[0229] (6) Demold after cooling to room temperature.

[0230] 3. Operating Procedures:

[0231] (1) Feeding stage: Concentrated circulating water is injected at a flow rate of 0.7 m / s;

[0232] (2) Electrochemical treatment: Apply square wave alternating current (single-stage voltage 4.2V, frequency 0.00083Hz (cycle 1200s / 20 minutes), peak-to-valley ratio 5:1), run for 5 cycles (total duration 6000s), current density 300A / m 2 ;

[0233] (3) Reclaimed water discharge: Reclaimed water is discharged at a flow rate of 1.0 m / s.

[0234] (4) Cyclic processing: Repeat 12 times, run a total of 60 cycles, and the total processing time is 72,000s (20 hours).

[0235] 4. Treatment effect:

[0236] Raw water tank 6: 2000L of pretreatment solution has been processed;

[0237] Effluent water quality: 2000L of reclaimed water was collected, with hardness reduced to 64mg / L and a retention rate of 92%.

[0238] Actual energy consumption data: The initial cell pressure is 4.4V, and the cell pressure rises to 4.6V at the end of the processing cycle (an increase of 0.2V). The power consumption to remove each kilogram of hardness (calculated as calcium carbonate) is 3.7kWh, which is 42.4% lower than the comparison patent CN101585569A (6.43kWh).

[0239] Example 5

[0240] 1. Subject of treatment: 2 tons (2000L) of concentrated circulating water from the cooling tower circulating water system, with an initial hardness (calculated as calcium carbonate) of 800mg / L.

[0241] 2. Equipment configuration:

[0242] Electrode system: The anode 3 for water electrolysis uses a platinum sheet electrode (0.5 mm thick, 0.2 m² surface area). 2 The electrolytic water cathode 2 uses a platinum mesh electrode (75% porosity, 1.0 mm pore size);

[0243] Porous insulating filler layer 4: Polyvinylidene fluoride-zirconia composite layer (porosity 55%, thickness 1.5 mm, pore size 0.2-0.8 micrometers).

[0244] The preparation method of the polyvinylidene fluoride-zirconia composite layer is as follows:

[0245] (1) Dissolve 20.0g of polyvinylidene fluoride (PVDF) particles in 180mL of dimethylformamide (DMF) and heat and stir at 50 degrees Celsius until a clear solution is obtained;

[0246] (2) Add 6.0g of zirconium oxide (ZrO2) powder, stir vigorously and disperse evenly by ultrasonication;

[0247] (3) Add 4.0g of polyethylene glycol 1000;

[0248] (4) Pour the mixed slurry into the mold (mold depth: 1.6 mm);

[0249] (5) Keep the mold at 50 degrees Celsius for 24 hours;

[0250] (6) After the solvent has basically evaporated, raise the temperature to 90 degrees Celsius to further remove the residual solvent;

[0251] (7) Cool to room temperature and demold.

[0252] 3. Operating Procedures:

[0253] (1) Feeding stage: Concentrated circulating water is injected into the two-electrode chamber at a flow rate of 0.6 m / s.

[0254] (2) Electrochemical treatment: Apply square wave alternating current (single-stage voltage 5.0V, frequency 0.00067Hz (cycle 1500s / 25 minutes), peak-to-valley ratio 10:1), run for 3 cycles (total duration 4500s), current density 400A / m 2 ;

[0255] (3) Discharge of reclaimed water: Open the outlet pipe 10 of the anode chamber and the outlet pipe 11 of the cathode chamber, and pump the reclaimed water into the reclaimed water tank 7 at a flow rate of 1.0 m / s.

[0256] (4) Cyclic processing: Repeat 15 times, run a total of 45 cycles, and the total processing time is 67,500s (18.75 hours).

[0257] 4. Treatment effect:

[0258] Raw water tank: 2000L of concentrated circulating water has been completely treated;

[0259] Effluent quality: 2000L of reclaimed water was collected, and the concentration of calcium and magnesium ions was reduced to 32mg / L, with a removal rate of 96%.

[0260] Actual energy consumption data: The initial cell voltage is 5.5V, and the cell voltage rises to 5.7V at the end of the processing cycle (an increase of 0.2V). The power consumption to remove one kilogram of hardness (calculated as calcium carbonate) is 4.4kWh, which is 31.5% lower than the comparison patent CN101585569A (6.43kWh).

[0261] Example 6

[0262] 1. Target of treatment: 1.5 tons (1500L) of industrial boiler return water, with an initial calcium and magnesium ion concentration (calculated as calcium carbonate) of 1200mg / L.

[0263] 2. Equipment configuration:

[0264] Electrode system: The anode 3 for water electrolysis uses a platinum-plated titanium electrode (platinum layer thickness 50 micrometers, surface area 0.15 m²). 2 The cathode 2 for water electrolysis uses a porous platinum electrode (porosity 80%, pore size 0.5 mm);

[0265] Porous insulating filler layer 4: Sulfonated polyether ether ketone-polybenzimidazole composite layer (porosity 98%, thickness 5 mm, pore size 0.1-0.3 μm).

[0266] The preparation method of the sulfonated polyether ether ketone-polybenzimidazole composite layer is as follows:

[0267] (1) Dissolve 5.0 g of sulfonated polyether ether ketone (SPEEK) and 5.0 g of polybenzimidazole (PBI) in 45 mL of dimethyl sulfoxide (DMSO) to obtain their respective clear solutions;

[0268] (2) Mix the two solutions together and stir vigorously to ensure uniformity;

[0269] (3) Add biporation agents: ethylene glycol: 1.0g, 1-propanol: 0.5g;

[0270] (4) Pour the mixed solution into the mold (mold depth: 5.5 mm);

[0271] (5) Place in a constant temperature (70 degrees Celsius) and well-ventilated oven to slowly evaporate the solvent (3 days);

[0272] (6) After the solvent has completely evaporated, the temperature is raised to 110 degrees Celsius for further drying and curing;

[0273] (7) Cool to room temperature and demold.

[0274] 3. Operating Procedures:

[0275] (1) Feeding stage: The concentrated circulating water is injected into the two-stage chamber at a flow rate of 0.4 m / s by a booster pump;

[0276] (2) Electrochemical treatment: Apply square wave alternating current (single-stage voltage 3.8V, frequency 0.0021Hz (cycle 480s / 8 minutes), peak-to-valley ratio 10:1), run for 5 cycles (total duration 2400s), current density 250A / m 2 ;

[0277] (3) Discharge of reclaimed water: Open the outlet pipe 10 of the anode chamber and the outlet pipe 11 of the cathode chamber, and pump the reclaimed water into the reclaimed water tank 7 at a flow rate of 0.8 m / s.

[0278] (4) Cyclic processing: Repeat 9 times, run a total of 48 cycles, and the total processing time is 115,200s (32 hours).

[0279] 4. Treatment effect:

[0280] Raw water tank: 1500L of concentrated circulating water has been completely treated;

[0281] Effluent quality: 1500L of reclaimed water was collected, and the concentration of calcium and magnesium ions was reduced to 24mg / L, with a removal rate of 98%.

[0282] Actual energy consumption data: The initial cell voltage is 3.9V, and the cell voltage rises to 4.1V at the end of the processing cycle (an increase of 0.2V). The power consumption to remove one kilogram of hardness (calculated as calcium carbonate) is 3.8kWh, which is 40.9% lower than the comparison patent CN101585569A (6.43kWh).

[0283] Example 7:

[0284] 1. Target of treatment: 3 tons (3000L) of central air conditioning circulating water, with an initial calcium and magnesium ion concentration (calculated as calcium carbonate) of 600mg / L.

[0285] 2. Equipment configuration:

[0286] Electrode system: The anode 3 for water electrolysis uses a platinum-ruthenium oxide composite electrode (RuO2 loading 3.0 mg / cm³). 2 The electrolytic water cathode 2 uses a platinum-coated stainless steel mesh electrode (porosity 90%).

[0287] Porous insulating filler layer 4: Polyimide-mullite composite layer (porosity 65%, thickness 2.2 mm, pore size 0.3-1.0 micrometers).

[0288] The preparation method of the polyimide-mullite composite layer is as follows:

[0289] (1) Dissolve 20.0g of polyimide precursor polyamic acid (PAA) in 180mL of N-methylpyrrolidone (NMP);

[0290] (2) Add 30.0g of mullite powder, stir vigorously and disperse evenly by ultrasonication;

[0291] (3) Add 10.0g of polyethylene glycol 2000;

[0292] (4) Pour the mixed slurry into the mold (mold depth: 2.35 mm);

[0293] (5) Place the mold in a ventilated oven and perform programmed temperature imidization: 80 degrees Celsius for 1 hour, 135 degrees Celsius for 1 hour, 200 degrees Celsius for 1 hour, 250 degrees Celsius for 1 hour, and 300 degrees Celsius for 1 hour.

[0294] (6) Cool naturally to room temperature and then demold.

[0295] 3. Operating Procedures:

[0296] (1) Feeding stage: The concentrated circulating water is injected into the two-stage chamber at a flow rate of 0.7 m / s by a booster pump;

[0297] (2) Electrochemical treatment: Apply square wave alternating current (single-stage voltage 4.2V, frequency 0.0014Hz (cycle 720s / 12 minutes), peak-to-valley ratio 10:1), run for 4 cycles (total duration 2880s), current density 350A / m 2 ;

[0298] (3) Discharge of reclaimed water: Open the outlet pipe 10 of the anode chamber and the outlet pipe 11 of the cathode chamber, and pump the reclaimed water into the reclaimed water tank 7 at a flow rate of 0.9 m / s.

[0299] (4) Cyclic processing: Repeat 4 times, run a total of 16 cycles, and the total processing time is 46,080s (12.8 hours).

[0300] 4. Treatment effect:

[0301] Raw water tank: All 3000L of concentrated circulating water has been treated;

[0302] Effluent quality: 3000L of reclaimed water was collected, and the concentration of calcium and magnesium ions was reduced to 30mg / L, with a removal rate of 95%.

[0303] Actual energy consumption data: The initial cell voltage is 4.5V, and the cell voltage rises to 4.7V at the end of the processing cycle (an increase of 0.2V). The power consumption to remove one kilogram of hardness (calculated as calcium carbonate) is 4.1kWh, which is 36.2% lower than that of the comparative patent CN101585569A (6.43kWh).

[0304] Example 8:

[0305] 1. Subject of treatment: 0.8 tons (800L) of geothermal reinjection water, with an initial calcium and magnesium ion concentration (calculated as calcium carbonate) of 1500mg / L.

[0306] 2. Equipment configuration:

[0307] Electrode system: The anode 3 for water electrolysis uses a nano-platinum black electrode (specific surface area 120m²). 2 / g), the electrolytic water cathode 2 uses a platinum-coated carbon fiber electrode (porosity 85%);

[0308] Porous insulating filler layer 4: Polyimide-silicon nitride composite layer (porosity 50%, thickness 1.2 mm, pore size 0.1-0.4 μm), with an amino-modified layer on the surface.

[0309] The method for preparing the porous insulating filler layer 4 is as follows:

[0310] (1) Dissolve 20.0g of polyimide precursor polyamic acid (PAA) in 180mL of NMP;

[0311] (2) Add 40.0g of silicon nitride powder, stir vigorously and disperse evenly by ultrasonication;

[0312] (3) Add 8.0g of polyethylene glycol 2000;

[0313] (4) Pour the mixed slurry into the mold (mold depth: 1.5 mm);

[0314] (5) Place the mold in a ventilated oven and perform programmed temperature imidization: 80 degrees Celsius for 1 hour, 135 degrees Celsius for 1 hour, 200 degrees Celsius for 1 hour, 250 degrees Celsius for 1 hour, and 300 degrees Celsius for 1 hour.

[0315] (6) Allow to cool naturally to room temperature before demolding;

[0316] (7) The composite layer is placed in the plasma reaction chamber, ammonia is introduced, and it is treated at 100W power for 5 minutes to introduce amino groups onto the surface of the polyimide-silicon nitride composite layer.

[0317] 3. Operating Procedures:

[0318] (1) Feeding stage: The concentrated circulating water is injected into the two-stage chamber at a flow rate of 0.3 m / s by a booster pump;

[0319] (2) Electrochemical treatment: Apply square wave alternating current (single-stage voltage 4.5V, frequency 0.00056Hz (cycle 1800s / 30 minutes), peak-to-valley ratio 10:1), run for 6 cycles (total duration 10,800s), current density 100A / m 2 ;

[0320] (3) Discharge of reclaimed water: Open the outlet pipe 10 of the anode chamber and the outlet pipe 11 of the cathode chamber, and pump the reclaimed water into the reclaimed water tank 7 at a flow rate of 0.6 m / s.

[0321] (4) Cyclic processing: Repeat 16 times, run a total of 100 cycles, and the total processing time is 180,000s (50 hours).

[0322] 4. Treatment effect:

[0323] Raw water tank: 800L of concentrated circulating water has been completely treated;

[0324] Effluent quality: 800L of reclaimed water was collected, and the concentration of calcium and magnesium ions was reduced to 45mg / L, with a removal rate of 97%.

[0325] Actual energy consumption data: The initial cell pressure is 4.7V, and the cell pressure rises to 4.9V at the end of the processing cycle (an increase of 0.2V). The power consumption to remove each kilogram of hardness (calculated as calcium carbonate) is 3.0kWh, which is 53.3% lower than the comparison patent CN101585569A (6.43kWh).

[0326] Example 9

[0327] 1. Target of treatment: 2.5 tons (2500L) of pretreated seawater desalination water, with an initial calcium and magnesium ion concentration (calculated as calcium carbonate) of 2000mg / L.

[0328] 2. Equipment configuration:

[0329] Electrode system: The anode 3 for water electrolysis uses an iridium oxide electrode, and the cathode 2 for water electrolysis uses a titanium mesh electrode (porosity 95%).

[0330] Porous insulating filler layer 4: Asbestos layer (porosity 75%, thickness 0.18 mm, pore size 1-500 micrometers).

[0331] The asbestos layer is prepared as follows:

[0332] (1) Protective preparation: Operate in a negative pressure glove box or a dedicated fume hood. Wear full protective clothing, goggles, N100 mask, and gloves.

[0333] (2) Pretreatment: Gently break the asbestos fibers into shorter fibers (1-2 mm in length) (avoid excessive crushing to prevent dust generation), and sieve to remove large impurities.

[0334] (3) Mixing:

[0335] Weigh 30.0g of asbestos fiber, add 7.5g of silica sol, add 9.0g of pore-forming agent - ammonium bicarbonate powder, add 18mL of deionized water, adjust to a suitable consistency (similar to wet mortar), and gently stir with a low-speed mixer to mix evenly (avoid fiber breakage and dust generation).

[0336] (4) Molding and pre-compression: Fill the mold with the mixed slurry coated with release agent (silicone grease) (mold depth: 0.3 mm), and apply slight pre-compression (0.5 MPa) to remove large air bubbles and make the fibers initially oriented.

[0337] (5) Pressing: Apply pressure (1.5 MPa, hold for 2 minutes). The pressure should not be too high to avoid excessive damage to the pore structure.

[0338] (6) Drying: Carefully demold (low wet strength), place in a well-ventilated area and dry at a low temperature (40 degrees Celsius for 48 hours) until constant weight. The silica sol will initially gel. Heat treatment and samples may have a small amount of residual carbon. If a completely white color is required, it can be calcined in air at 500 degrees Celsius for 1.5 hours.

[0339] (7) Cooling and sealing: Cool to room temperature. The sample must be sealed and stored (in a double plastic bag).

[0340] 3. Operating Procedures:

[0341] (1) Feeding stage: The concentrated circulating water is injected into the two-stage chamber at a flow rate of 0.9 m / s by a booster pump;

[0342] (2) Electrochemical treatment: A square wave alternating current was applied (single-stage voltage 1.5V, frequency 0.0024Hz (cycle 420s / 7 minutes), peak-to-valley ratio 10:1), running for 150 cycles (total duration 63,000s / 17.5 hours), current density 1A / m 2 ;

[0343] (3) Discharge of reclaimed water: Open the outlet pipe 10 of the anode chamber and the outlet pipe 11 of the cathode chamber, and pump the reclaimed water into the reclaimed water tank 7 at a flow rate of 1.0 m / s.

[0344] (4) Cyclic processing: Repeat once, run a total of 150 cycles, with a total processing time of 63,000s (17.5 hours).

[0345] 4. Treatment effect

[0346] Raw water tank: 2500L of concentrated circulating water has been completely treated;

[0347] Effluent quality: 2500L of reclaimed water was collected, and the concentration of calcium and magnesium ions was reduced to 80mg / L, with a removal rate of 96%.

[0348] Actual energy consumption data: The initial cell pressure is 1.7V, and the cell pressure rises to 2.2V at the end of the processing cycle (an increase of 0.5V). The power consumption to remove one kilogram of hardness (calculated as calcium carbonate) is 4.2kWh, which is 34.6% lower than the comparison patent CN101585569A (6.43kWh).

[0349] Example 10

[0350] 1. Subject of treatment: 4 tons (4000L) of circulating cooling water from a petrochemical plant, with an initial calcium and magnesium ion concentration (calculated as calcium carbonate) of 450mg / L.

[0351] 2. Equipment configuration:

[0352] Electrode system: The anode 3 for water electrolysis uses a platinum sheet electrode, and the cathode 2 for water electrolysis uses a platinum-coated graphite electrode (porosity 88%).

[0353] Porous insulating filler layer 4: Silicon carbide layer (porosity 68%, thickness 2.5 mm, pore size 0.2-0.6 micrometers).

[0354] The method for preparing the silicon carbide layer is as follows:

[0355] (1) Mixing: Weigh 560.0g of coarse silicon carbide (SiC) powder and 240.0g of fine silicon carbide (SiC) powder. Add 52g of Y2O3 sintering aid, 1005g of 8wt% polyvinyl alcohol solution, 148g of nano-graphite powder, and 5.0g of ammonium polyacrylate dispersant.

[0356] (2) Aging: After mixing evenly, seal the billet and age it for 24 hours.

[0357] (3) Molding: Dry pressing (mold depth: 3.0 mm).

[0358] (4) Drying: Dry slowly in a low-temperature oven (40 degrees Celsius) until constant weight to prevent cracking.

[0359] (5) Degreasing: Keep in a muffle furnace at 600 degrees Celsius for 2 hours (heating rate 0.5 degrees Celsius per minute).

[0360] (6) High-temperature sintering under argon atmosphere (heating from 25 degrees Celsius to 1000 degrees Celsius at a rate of 5 degrees Celsius per minute, and then holding at 1000 degrees Celsius for 45 minutes).

[0361] (7) Cooling: Cool to room temperature at a rate of 2 degrees Celsius per minute.

[0362] (8) The sintered sample was calcined in air at 700 degrees Celsius (heating rate: 1 degree Celsius per minute) for 3 hours to oxidize and remove the residual graphite pore-forming agent, thus forming the final pores.

[0363] 3. Operating Procedures:

[0364] (1) Feeding stage: The concentrated circulating water is injected into the two-stage chamber at a flow rate of 0.5 m / s by a booster pump;

[0365] (2) Electrochemical treatment: Apply square wave alternating current (single-stage voltage 4.8V, frequency 0.00093Hz (cycle 1080s / 18 minutes), peak-to-valley ratio 10:1), run for 4 cycles (total duration 4320s), current density 600A / m 2 ;

[0366] (3) Discharge of reclaimed water: Open the outlet pipe 10 of the anode chamber and the outlet pipe 11 of the cathode chamber, and pump the reclaimed water into the reclaimed water tank 7 at a flow rate of 0.8 m / s.

[0367] (4) Cyclic processing: Repeat 10 times, run a total of 40 cycles, and the total processing time is 43,200s (12 hours).

[0368] 4. Treatment effect:

[0369] Raw water tank: 4000L of concentrated circulating water has been completely treated;

[0370] Effluent quality: 4000L of reclaimed water was collected, and the concentration of calcium and magnesium ions was reduced to 18mg / L, with a removal rate of 96%.

[0371] Actual energy consumption data: The initial cell pressure is 5.1V, and the cell pressure rises to 5.3V at the end of the processing cycle (an increase of 0.2V). The power consumption to remove each kilogram of hardness (calculated as calcium carbonate) is 4.7kWh, which is 26.9% lower than the comparison patent CN101585569A (6.43kWh).

[0372] Example 11

[0373] Continuous method:

[0374] 1. Subject of treatment: 10,000L of circulating cooling water in a petrochemical plant, with a calcium and magnesium ion concentration (calculated as calcium carbonate) of 400mg / L.

[0375] 2. Equipment configuration:

[0376] Electrode system: Both the anode 3 and the cathode 2 of the water electrolysis system are titanium mesh electrodes coated with iridium tantalum oxide;

[0377] Porous insulating filler layer 4: Polypropylene-PTFE composite layer (porosity 68%, thickness 0.2 mm, pore size 10-200 micrometers).

[0378] The preparation method of the polypropylene-polytetrafluoroethylene composite layer is as follows:

[0379] (1) Dissolve 15.0g of polypropylene (PP) granules in 135mL of decahydronaphthalene at 145°C.

[0380] (2) Cool down to 100 degrees Celsius, add 30.0g of polytetrafluoroethylene aqueous dispersion, and stir vigorously to emulsify and disperse.

[0381] (3) Quickly pour the hot emulsion into a preheated (80 degrees Celsius) mold (0.25 mm deep).

[0382] (4) Gradually increase the temperature in the oven (80 degrees Celsius for 6 hours, 120 degrees Celsius for 6 hours, and 140 degrees Celsius for 3 hours) to remove the solvent and water.

[0383] (5) Cool to below 40 degrees Celsius and demold.

[0384] 3. Operating Procedures:

[0385] (1) Feeding stage: Cooling water is pumped into the two-stage chamber at a flow rate of 0.5 m / s by a booster pump;

[0386] (2) Electrochemical treatment: Apply square wave AC current (single-stage voltage 2.0V), with the frequency set to 0.001Hz for positive bias and 50s for negative bias, peak-to-valley ratio of 100:1, and simultaneously set the switching current to 1A / m. 2 If the current is less than the flip current, a negative bias is applied to perform electrode self-cleaning.

[0387] (3) Continuous processing.

[0388] 4. Treatment effect:

[0389] The calcium and magnesium ion concentration was reduced to 112 mg / L, the removal rate was 72%, the tank pressure was maintained at 2.3V, and the power consumption was 4.5 kWh per kilogram of hardness (calculated as calcium carbonate).

[0390] Example 12

[0391] Continuous method:

[0392] 1. Target of treatment: 20-ton (20000L) cooling tower of a thermal power plant, with an initial calcium and magnesium ion concentration (calculated as calcium carbonate) of 200mg / L.

[0393] 2. Equipment configuration:

[0394] Electrode system: The anode 3 for water electrolysis adopts a platinum-coated mesh electrode, and the cathode 2 for water electrolysis adopts a 316L mesh electrode;

[0395] Porous insulating filler layer 4: Polypropylene layer (porosity 61%, thickness 0.5 mm, pore size 10-200 micrometers).

[0396] The preparation method of the polypropylene layer is as follows:

[0397] (1) Dissolve 20.0g of polypropylene granules in 160mL of decahydronaphthalene at 140°C.

[0398] (2) Add 6.0g of liquid paraffin.

[0399] (3) Pour the solution into a preheated mold (100 degrees Celsius, 0.65 mm deep).

[0400] (4) Control the cooling rate, cool down from 140 degrees Celsius to 100 degrees Celsius at a rate of 0.5 degrees Celsius per minute, and then cool naturally from 100 degrees Celsius to 25 degrees Celsius.

[0401] (5) Demolding.

[0402] 3. Operating Procedures:

[0403] (1) Feeding stage: Water in the cooling tower is pumped into the two-stage chamber at a flow rate of 1m / s by a booster pump;

[0404] (2) Electrochemical treatment: Apply square wave alternating current (single-stage voltage 1.5V), with the frequency set to 4900s for positive bias and 100s for negative bias, a frequency of 0.0002Hz, a peak-to-valley ratio of 100:1, and simultaneously set the switching current to 1A / m. 2 If the current is less than the flip current, a negative bias is applied to perform electrode self-cleaning.

[0405] (3) Continuous processing.

[0406] 4. Treatment effect:

[0407] The calcium and magnesium ion concentration was reduced to 20 mg / L, with a removal rate of 90%. The tank voltage was maintained at 2.0V. The power consumption was 3.4 kWh per kilogram of hardness (calculated as calcium carbonate) removed.

[0408] Example 13

[0409] Continuous dechlorination:

[0410] 1. Target of treatment: 1 ton (1000L) of circulating water in a data center, with an initial chloride ion concentration of 800mg / L.

[0411] 2. Equipment configuration:

[0412] Electrode system: The anode 3 for water electrolysis adopts a ruthenium-iridium-graphene coated mesh electrode, and the cathode 2 for water electrolysis adopts a titanium mesh electrode;

[0413] Porous insulating filler layer 4: Polyamide layer (porosity 52%, thickness 0.8 mm, pore size 10-200 micrometers).

[0414] The polyamide layer is prepared as follows:

[0415] (1) 20.0g of polyamide (PA) particles were dissolved in 180mL of formic acid to form a solution.

[0416] (2) Add 3.6g NaCl.

[0417] (3) Pour the solution into the mold (mold depth: 1.0 mm).

[0418] (4) Place it in a fume hood (formic acid has an irritating odor and is corrosive) and let the solvent evaporate slowly at 35 degrees Celsius.

[0419] (5) After the solvent has basically evaporated, rinse the surface with water to remove residual formic acid, and then place it in an oven to dry under vacuum at 60 degrees Celsius.

[0420] (6) Demold after cooling to room temperature.

[0421] 3. Operating Procedures:

[0422] (1) Feeding stage: Data center circulating water is injected into the two-stage chamber at a flow rate of 1m / s by a booster pump;

[0423] (2) Electrochemical treatment: Apply square wave AC current (single-stage voltage 7.2V), with the frequency set to positive bias for 95s and negative bias for 5s, frequency 0.01Hz, peak-to-valley ratio 50:1, and simultaneously set the switching current to 1A / m. 2 If the current is less than the flip current, a negative bias is applied to perform electrode self-cleaning.

[0424] (3) Continuous processing.

[0425] 4. Treatment effect:

[0426] The chloride ion concentration was reduced to 160 mg / L, with a removal rate of 80%. The tank voltage was maintained at 7.4V.

[0427] Example 14

[0428] Continuous dechlorination:

[0429] 1. Target of treatment: 5 tons (5000L) of circulating water from a chemical plant, with an initial chloride ion concentration of 1000mg / L.

[0430] 2. Equipment configuration:

[0431] Electrode system: The anode 3 for water electrolysis adopts a ruthenium-iridium coated mesh electrode, and the cathode 2 for water electrolysis adopts a titanium-coated ruthenium-iridium coated mesh electrode;

[0432] Porous insulating filler layer 4: Polyimide-polypropylene composite layer (porosity 73%, thickness 1 mm, pore size 10-200 micrometers).

[0433] The preparation method of the polyimide-polypropylene composite layer is as follows:

[0434] (1) Add 20.0 g of polyamic acid (PAA) to 180.0 mL of N-methylpyrrolidone (NMP) solvent. In a constant temperature water bath at 25 degrees Celsius, mechanically stir at 400 rpm for 6 hours to obtain a homogeneous and transparent PAA / NMP solution with a solid content of 10.0 wt%.

[0435] (2) Add 6.0g of polypropylene powder (PP) with an average particle size of 20 micrometers to the above PAA / NMP solution, and disperse it at 25 degrees Celsius for 30 minutes using a high-speed shear emulsifier (speed 8000 rpm) until there are no visible PP agglomerates in the slurry.

[0436] (3) Add 10.0g of polyethylene glycol 2000 to the slurry and mechanically stir at 500rpm for 60 minutes at 25 degrees Celsius to ensure that the polyethylene glycol 2000 is completely dissolved.

[0437] (4) Pour into the mold (mold depth: 2 mm).

[0438] (5) Perform programmed temperature drying and imidization: 80 degrees Celsius for 1 hour, 120 degrees Celsius for 1 hour, 200 degrees Celsius for 1 hour, 250 degrees Celsius for 1 hour, and 300 degrees Celsius for 1 hour.

[0439] (6) Cool to below 50 degrees Celsius and demold.

[0440] 3. Operating Procedures:

[0441] (1) Feeding stage: The chemical plant's circulating water is injected into the two-stage chamber at a flow rate of 0.5 m / s by a booster pump;

[0442] (2) Electrochemical treatment: Apply square wave alternating current (single-stage voltage 5.2V), with the frequency set to 1800s for positive bias and 300s for negative bias, a frequency of 0.00047Hz, a peak-to-valley ratio of 20:1, and simultaneously set the switching current to 1A / m. 2If the current is less than the flip current, a negative bias is applied to perform electrode self-cleaning.

[0443] (3) Continuous processing.

[0444] 4. Treatment effect:

[0445] The chloride ion concentration dropped to 280 mg / L, with a removal rate of 72%. The tank pressure was maintained at 5.3V.

[0446] Example 15

[0447] 1. Target of treatment: 10 tons (10000L) of circulating cooling water from a waste-to-energy plant, with an initial chloride ion concentration of 1100mg / L.

[0448] 2. Equipment configuration:

[0449] Electrode system: The anode 3 for water electrolysis adopts a ruthenium oxide-graphene mesh electrode, and the cathode 2 for water electrolysis adopts a platinum-coated graphene mesh electrode;

[0450] Porous insulating filler layer 4: Polypropylene hollow fiber layer (porosity 68%, thickness 1 mm, pore size 0.2-0.6 micrometers).

[0451] The preparation method of polypropylene hollow fiber layer is as follows (forming a self-supporting layer):

[0452] (1) The polypropylene hollow fibers (PPHF) are laid out tightly in parallel and fixed in the mold frame (mold depth: 2 mm).

[0453] (2) Spray hot melt adhesive at the fiber contact point, and then lightly heat press at 50 degrees Celsius to bond the fibers together.

[0454] (3) After cooling to room temperature, demolding yields a porous layer composed of the pores of PPHF itself.

[0455] 3. Operating Procedures:

[0456] (1) Feeding stage: Circulating cooling water is injected into the two-stage chamber at a flow rate of 0.5 m / s by a booster pump.

[0457] (2) Electrochemical treatment: Apply square wave AC current (single-stage voltage 4.5V, frequency 0.00093Hz (cycle 1080s / 18 minutes), peak-to-valley ratio 10:1), run for 4 cycles (total duration 4320s).

[0458] (3) Discharge of reclaimed water: Open the outlet pipe 10 of the anode chamber and the outlet pipe 11 of the cathode chamber, and pump the reclaimed water into the reclaimed water tank 7 at a flow rate of 0.5 m / s.

[0459] (4) Cyclic processing: Repeat 10 times, run a total of 40 cycles, and the total processing time is 43,200s (12 hours).

[0460] 4. Treatment effect:

[0461] Raw water tank: 10,000L waste-to-energy plant circulating water has been completely treated.

[0462] Effluent quality: 10,000L of reclaimed water was collected, and the chloride ion concentration was reduced to 44mg / L, with a removal rate of 96%.

[0463] Actual energy consumption data: Initial cell voltage 4.7V, cell voltage rises to 4.8V at the end of the processing cycle (up 0.1V).

[0464] Example 16

[0465] 1. Target of treatment: 5 tons (5000L) of landfill leachate, with an initial chloride ion concentration of 2800mg / L.

[0466] 2. Equipment configuration:

[0467] Electrode system: The anode 3 for water electrolysis adopts an iridium oxide-graphene mesh electrode, and the cathode 2 for water electrolysis adopts an iridium oxide-graphene mesh electrode.

[0468] Porous insulating filler layer 4: Polytetrafluoroethylene composite layer (porosity 56%, thickness 0.5 mm, pore size 10-500 micrometers).

[0469] The preparation method of the polytetrafluoroethylene composite layer is as follows:

[0470] (1) Add 50 mL of deionized water to 100 mL of polytetrafluoroethylene dispersion (solid content 60 wt%, solvent is water), stir and mix thoroughly to obtain a diluted polytetrafluoroethylene dispersion with a solid content of 30 wt%.

[0471] (2) Add 45g of sodium chloride particles with a particle size range of 100 to 150 micrometers as a pore-forming agent. Stir continuously at 500 rpm for 60 minutes in a constant temperature water bath at 25 degrees Celsius to ensure that the pore-forming agent particles are uniformly dispersed and do not agglomerate.

[0472] (3) Pour into the mold (mold depth: 1 mm).

[0473] (4) Dry at room temperature, then program the temperature to rise: dry at 80 degrees Celsius for 1 hour, remove organic matter at 250 degrees Celsius for 1 hour, and sinter at 365 degrees Celsius for 1 hour.

[0474] (5) Cool to below 50 degrees Celsius and demold.

[0475] 3. Operating Procedures:

[0476] (1) Feeding stage: The concentrated circulating water is injected into the two-stage chamber at a flow rate of 1.0 m / s by a booster pump.

[0477] (2) Electrochemical treatment: Apply square wave AC current (single-stage voltage 4.8V, frequency 0.0017Hz (cycle 600s / 10 minutes), peak-to-valley ratio 10:1), run for 5 cycles (total duration 3000s).

[0478] (3) Discharge of reclaimed water: Open the outlet pipe 10 of the anode chamber and the outlet pipe 11 of the cathode chamber, and pump the reclaimed water into the reclaimed water tank 7 at a flow rate of 1.0 m / s.

[0479] (4) Cyclic processing: Repeat 10 times, run a total of 50 cycles, and the total processing time is 30,000s (500min).

[0480] 4. Treatment effect:

[0481] Raw water tank: 5000L of landfill leachate has been completely treated.

[0482] Effluent water quality: 5000L of reclaimed water was collected, and the chloride ion concentration was reduced to 84mg / L, with a removal rate of 97%.

[0483] Actual energy consumption data: Initial cell voltage 4.9V, cell voltage rises to 5.0V at the end of the processing cycle (up 0.1V).

[0484] The above embodiments are summarized in Table 1 below.

[0485] Table 1

[0486] Table 2 Comparison of chloride ion removal rates in different embodiments

Claims

1. A composite electrode unit, characterized by, It includes: electrolyzed water The cathode (2), the porous insulating filler layer (4), and the water electrolysis anode (3) are located between the water electrolysis cathode (2) and the water electrolysis anode (3). The internal material of the porous insulating filler layer (4) itself does not contain exchangeable ions, and the internal part refers to the non-surface part; The electrolytic water cathode (2), the porous insulating filler layer (4), and the electrolytic water anode (3) are bonded together.

2. The composite electrode unit of claim 1, wherein The porous insulating filler layer (4) is made of hydrophobic material. Alternatively, the internal material of the porous insulating filler layer (4) is hydrophobic, while the surface is hydrophilic, and the internal part refers to the non-surface part.

3. The composite electrode unit of claim 1, wherein, The porous insulating filler layer (4) has a porosity of 1% to 98%, a thickness of 1 to 5 mm, and a pore size of 10 to 500 micrometers.

4. The composite electrode unit of claim 1, wherein, The porous insulating filler layer (4) is made of one or more of the following materials: polyethylene, polystyrene, polyphenylene sulfide, polyvinyl chloride, polypropylene, polyurethane, polyamide, polyethersulfone, polypropylene hollow fiber, polytetrafluoroethylene, polyvinylidene fluoride, sulfonated polyether ether ketone, polybenzimidazole, polyimide, asbestos, alumina, silicon carbide, silicon nitride, zirconium oxide, boron nitride, mullite, cordierite, aluminum titanate, and silicon dioxide.

5. The composite electrode unit of claim 3, wherein The surface of the porous insulating filler layer (4) has been modified.

6. An electrochemical water treatment system characterized by, The system includes: a reaction chamber (5); The reaction chamber (5) is provided with a composite electrode unit as described in any one of claims 1 to 5; Inside the reaction chamber (5), the chamber on the side of the water electrolysis cathode (2) of the composite electrode unit is the cathode chamber, and the chamber on the side of the water electrolysis anode (3) of the composite electrode unit is the anode chamber.

7. The electro-chemical water treatment system of claim 6, wherein, The reaction chamber (5) further includes a power source (1) that provides direct current or alternating current to the electrolytic water cathode (2) and the electrolytic water anode (3).

8. The electro-chemical water treatment system of claim 6, wherein, The top plate of the reaction chamber (5) is attached to the top of the composite electrode unit, and the bottom plate of the reaction chamber (5) is attached to the bottom of the composite electrode unit to achieve physical isolation between the cathode chamber and the anode chamber by the composite electrode unit.

9. The electro-chemical water treatment system of claim 6, wherein, The system also includes: a raw water tank (6) and a reclaimed water tank (7); The raw water tank (6) is connected to the anode chamber through the anode chamber inlet pipe (8); The raw water tank (6) is connected to the cathode chamber through the cathode chamber inlet pipe (9); The reclaimed water tank (7) is connected to the anode chamber via the anode chamber outlet pipe (10); The regenerated water tank (7) is connected to the cathode chamber through the cathode chamber outlet pipe (11).

10. The electro-chemical water treatment system of claim 9, wherein, The system further includes a filter device (12) installed on the cathode chamber outlet pipe (11) for filtering solid substances in the liquid of the cathode chamber outlet pipe (11).

11. The electro-chemical water treatment system of claim 9, wherein, The raw water tank (6) and the reclaimed water tank (7) are connected by a circulation pipeline.

12. An electrochemical water treatment method, characterized by, The method is performed using the electrochemical water treatment system according to any one of claims 6-11, and the method includes the following steps: Raw water containing calcium ions and / or magnesium ions is injected into the cathode chamber and the anode chamber respectively. The power supply (1) is turned on, and direct current or alternating current is applied between the electrolytic water cathode (2) and the electrolytic water anode (3) to carry out electrolysis. The electrolysis reaction of water occurs in the composite electrode unit. When direct current is supplied: during water electrolysis, hydrogen gas is generated in the cathode chamber, creating an alkaline environment that causes calcium and / or magnesium ions to precipitate as solids, reducing water hardness; during water electrolysis, oxygen is generated in the anode chamber, creating an acidic environment; ultimately, alkaline water containing solids is obtained in the cathode chamber, and acidic water is obtained in the anode chamber. When AC power is supplied: Before the current direction changes in each alternating current cycle: during water electrolysis, hydrogen gas is generated in the cathode chamber and an alkaline environment is formed, causing calcium ions and / or magnesium ions to form solid precipitates, and some of the solid precipitates crystallize on the surface of the original water electrolysis cathode (2); during water electrolysis, oxygen gas is generated in the anode chamber and an acidic environment is formed. After the current direction changes in each alternating current cycle: the electrolytic water cathode (2) and the electrolytic water anode (3) are reversed, so that the original electrolytic water anode (3) becomes a temporary cathode and begins to generate hydroxide ions, and the original electrolytic water cathode (2) becomes a temporary anode and begins to generate hydrogen ions. The hydrogen ions cause the solid material crystallized on the surface of the original electrolytic water cathode (2) to dissolve from the surface of the original electrolytic water cathode (2), thus realizing the in-situ self-cleaning of the electrolytic water cathode (2). During the next alternating current cycle, calcium and / or magnesium ions in the water continuously precipitate out in the cathode chamber, thereby reducing water hardness. Finally, alkaline water containing solids is obtained in the cathode chamber, and acidic water is obtained in the anode chamber.

13. The electrochemical water treatment method of claim 12, wherein, When the raw water still contains chloride ions, the chloride ions in the anode chamber are oxidized into chlorine gas and removed.

14. The electrochemical water treatment method of claim 12, wherein, When the method is performed using the electrochemical water treatment system of claim 9: The raw water tank (6) contains raw water containing calcium ions and / or magnesium ions; The alkaline water and acidic water containing solid matter obtained according to claim 12 are discharged into the regenerated water tank (7) through the cathode chamber outlet pipe (11) and the anode chamber outlet pipe (10) respectively, and mixed to obtain neutral water.

15. The electrochemical water treatment method of claim 12, wherein, When the method is performed using the electrochemical water treatment system of claim 10: The solids in the alkaline water containing solids are filtered by the filtration device (12).

16. The electrochemical water treatment method of claim 12, wherein, The voltage of the DC or AC power is 1.5V to 30V.

17. The electrochemical water treatment method of claim 12, wherein, The current density on the electrolytic water cathode (2) or the electrolytic water anode (3) when the direct current or alternating current is applied is 1 to 1000 A / m 2 .

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