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

Abstract

The present invention relates to the field of water treatment technology, and mainly relates to a composite electrode unit, an electrochemical water treatment system and an electrochemical water treatment method. The composite electrode unit includes: a water electrolysis cathode, a porous insulating filler layer and a water electrolysis anode; the porous insulating filler layer is located between the water electrolysis cathode and the water electrolysis anode; the internal material of the porous insulating filler layer itself does not contain exchangeable ions, and the internal refers to the non-surface part. The present device integrates the cathode and the anode on both sides of the porous insulating filler layer to form a composite electrode unit with a unique "filler-electrode" integrated structure. Driven by an ultra-low DC working voltage, the transmission of water is controlled by the filler micropores to achieve the blocking of the migration of hydroxide ions. 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 are used to diffuse hydroxide ions into the main body of the water phase in the cathode chamber, prompting the rapid crystallization and precipitation of scale ions in the cathode area, thereby reducing the hardness of the water.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and mainly relates to a composite electrode unit, an electrochemical water treatment system and an electrochemical water treatment method. Background Art

[0002] In industrial water systems, circulating cooling water, the core medium for maintaining equipment operation, faces significant challenges in water quality management: traditional processes rely on repeated concentration cycles, which can easily lead to mineral salt deposition and frequent scaling. Hard scale not only accelerates electrochemical corrosion of metal pipes, creating the 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 interventions such as adjusting pH with acids and alkalis or adding scale inhibitors. While these can alleviate scaling problems in the short term, they carry drawbacks such as high chemical consumption, the potential for secondary pollution, and high operational and maintenance costs. Furthermore, the concentration of chloride ions (chloride radicals) in water gradually increases the corrosion of metal equipment. With the deepening of the concept of green manufacturing, new hard and chlorine removal technologies based on electrochemical principles have emerged.

[0003] Electrochemical hardness and chlorine removal technology achieves dual breakthroughs in water quality control and resource recovery through the electrolysis process. Its basic principle is: in the cathode chamber, the electrolysis reaction generates a large amount of hydroxide, which promotes the conversion of bicarbonate in the water into carbonate in an alkaline environment, driving the directional migration of scale-forming ions such as calcium ions and magnesium ions and preferentially forming crystalline precipitates such as calcium carbonate and magnesium hydroxide, achieving targeted separation of hard scale; in the anode chamber, chloride ions are oxidized to produce HClO / ClO with bactericidal function. - The electrolysis of water produces trace amounts of chlorine, while the hydrogen ions generated by electrolysis can dynamically adjust the system's pH value, creating an adaptive anti-scaling environment. This technology not only eliminates the need for the exogenous addition of traditional scale inhibitors and acid-base agents, thus avoiding the risk of chemical residual contamination at the source, but also inhibits microbial growth through the simultaneous generation of active chlorine substances, solving the industry's difficult problem of the mutual reinforcement of scaling and corrosion. The treated circulating water system significantly increases its concentration factor, reducing both water replenishment and wastewater discharge while achieving synergistic optimization of water resource utilization efficiency and environmental benefits, providing a technical path for industrial circulating water management that combines cleanliness and economy.

[0004] The above-mentioned technical approach has several serious problems: first, the utilization efficiency of hydroxide generated by water electrolysis is low; second, the single-stage voltage of the electrolysis unit is high; and third, there is the problem of electrode self-scaling. For example, Chinese patent "CN101585569A - Circulating Water Electrolytic Descaling Device and Descaling Method" discloses a circulating water electrolytic descaling device and method, belonging to the field of water treatment and environmental protection technology. The core of the device consists of a metal reaction chamber (serving as the electrolysis cathode), an anode, a test electrode, an ultrasonic cleaner, and an automatic control system. Its operating principle is divided into two stages: electrolytic scaling and cleaning and descaling. During the electrolysis process, hydroxide is generated in the cathode chamber, which combines calcium and magnesium ions in the water with carbonate ions to form loose, soft scale that is deposited on the reaction chamber walls. Simultaneously, the anode oxidizes chloride ions to produce hypochlorous acid, chlorine gas, and other bactericidal substances. When the test electrode detects that the scale layer is thickening and the resistance exceeds the limit, the system automatically switches to cleaning mode, closing the inlet and outlet valves and activating the ultrasonic cleaner to remove the scale, which is then discharged through the drain valve. This technology combines electrolysis and ultrasonic physical cleaning, does not require chemical scale inhibitors, and achieves integrated descaling, sterilization, and water softening through dynamic adjustment of pH and active substances. The concentration ratio of circulating water is significantly improved (calcium hardness is reduced by 44%), and it has automatic control and epoxy resin anti-corrosion structure, effectively solving the problems of traditional methods such as strong dependence on chemicals, frequent maintenance, and secondary pollution.

[0005] However, in the process of realizing the present invention, the applicant discovered that the electrolysis system in the Chinese patent "CN101585569A-Circulating Water Electrolytic Descaling Device and Descaling Method" adopts an integrated tank design. During the electrolytic descaling process, the anode and cathode coexist in the same reaction chamber and no ion isolation is set, resulting in the overall system being in a dynamic neutral environment and low utilization efficiency of the hydroxide generated by electrolysis. At the same time, the distance between the anode and cathode is large, and the high cell pressure of the electrolysis unit leads to increased power loss. Experimental data show that under the same current density, for every 1 cm increase in the distance between the two electrodes, the cell voltage increases by about 0.5-1.2V, and the energy consumption increase can reach 15%-30%. This high energy consumption characteristic limits the economic application of this technology in large-scale industrial circulating water systems.

[0006] In order to solve the above problems, the present invention is proposed. Summary of the Invention

[0007] The present 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 the present application include: (1) a porous insulating filler layer is used, combined with a 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) a built-in electric field is formed in the porous insulating filler layer to resist the external voltage, reducing the high energy consumption caused by the high cell pressure; (3) due to the hydrophobic effect of the porous insulating filler layer, the migration of the hydroxide generated at the cathode is suppressed, and then forced to diffuse into the main body of the aqueous phase in the cathode chamber at a high flow rate, accelerating its combination with scaling ions such as calcium and magnesium ions, thereby improving the utilization rate of hydroxide; (4) due to the hydrophobic effect of the porous insulating filler layer, the H generated at the anode is + The migration of chloride ions is suppressed, and then forced diffusion is carried out through high flow rate, so that an acidic environment is formed in the anode area, which promotes the oxidation of chloride ions into hypochlorous acid, chlorine gas and other bactericidal substances in the acidic environment; (5) a catalytic electrode for electrolysis of water is used to further reduce the voltage of electrolysis of water 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 the anode and cathode to achieve automatic descaling. Through the above technical invention, this application improves the defects of existing electro-descaling technology, greatly improves the efficiency of electro-descaling, and reduces power consumption.

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

[0009] The inner material of the porous insulating filler layer itself does not contain exchangeable ions, and the inner part refers to the non-surface part.

[0010] Preferably, the water electrolysis cathode, the porous insulating filler layer and the water electrolysis anode are bonded to each other.

[0011] One of the key points of the present invention is that the internal material of the porous insulating filler layer itself does not contain exchangeable ions. In the present invention, the filler layer material itself is distinguished as "insulating" or "conductive" based on the way in which ions in the aqueous solution pass through the porous filler layer when the porous filler layer is placed in an aqueous solution containing ions. If the porous filler layer material itself has exchangeable ions, for example, the anion exchange resin material itself has anions that can be exchanged, and the cation exchange resin material itself has cations that can be exchanged, then the ions in the aqueous solution can migrate through the porous filler layer in two ways:

[0012] A. Migration through ion exchange with the porous filler material itself. This migration is selective. For example, anion exchange resin only allows anion migration but not cation migration, while cation exchange resin only allows cation migration but not anion migration.

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

[0014] Therefore, when the material of the porous filler layer itself has exchangeable ions, since the ion migration mode A is carried out through the porous filler layer material itself, it appears that the porous filler layer itself is conductive and ion-conducting, that is, conductive, so the porous filler layer whose material itself has exchangeable ions is called a "porous conductive filler layer".

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

[0016] The composite electrode unit is the smallest technical unit of this application and also the smallest salable patent implementation unit. The composite electrode unit can be placed in an electrolytic cell and start working after voltage is applied.

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

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

[0019] The present invention does not require the porous insulating filler layer to be hydrophobic or hydrophilic. However, preferably, the porous insulating filler layer is entirely hydrophobic. This is because a hydrophobic material can inhibit the flow of aqueous solutions within the pores of the porous insulating filler layer, thereby suppressing the migration rate of the aforementioned ion migration mode B.

[0020] Alternatively, the inner material of the porous insulating filler layer is a hydrophobic material, and the surface is a hydrophilic material, where the inner part refers to the non-surface part. This arrangement can also suppress the migration rate of the aforementioned ion migration mode B.

[0021] Of course, the porous insulating filler layer made of hydrophilic material can also partially realize the solution of the present application. However, the ion migration method B is accelerated, resulting in more hydroxides in the cathode chamber that do not have time to combine with calcium ions or magnesium ions to form precipitates and migrate to the anode chamber through ion migration method B, resulting in the utilization efficiency of hydroxides being lower than that of the porous insulating filler layer made of hydrophobic material. However, low efficiency does not mean that it is not feasible.

[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 μm.

[0023] More preferably, the porosity is 50% to 98%. More preferably, the porosity is 52% to 98%. More preferably, the porosity is 55% to 98%. Even more preferably, the porosity is 60% to 98%. Furthermore, the porosity may range from 60% to 75%, 60% to 73%, 52% to 75%, 52% to 73%, 52% to 68%, 55% to 75%, 55% to 73%, or 55% to 68%.

[0024] More preferably, the thickness range can be 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 range can be 0.1-0.5 microns, 0.2-0.8 microns, 0.3-500 microns, 0.5-500 microns, 0.1-0.3 microns, 0.3-1 microns, 0.1-0.4 microns, 1-500 microns, 0.2-0.6 microns, 10-200 microns, 0.2-0.6 microns or 10-500 microns, etc.

[0026] Preferably, the material of the porous insulating filler layer is selected from: polyethylene, polystyrene, polyphenylene sulfide, polyvinyl chloride, polypropylene, polyurethane, polyamide, polyethersulfone, polypropylene hollow fiber, polytetrafluoroethylene, polyvinylidene fluoride, sulfonated polyetheretherketone, polybenzimidazole, polyimide, asbestos, aluminum oxide, silicon carbide, silicon nitride, zirconium oxide, boron nitride, mullite, cordierite, aluminum titanate, and silica, or a combination of several thereof.

[0027] That is, the material of the porous insulating filler layer can be a single material, a mixed material 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: a polyethylene layer, a polystyrene layer, a polyphenylene sulfide layer, a polyvinyl chloride layer, a polypropylene layer, a polyurethane layer, a polyamide layer, a polyethersulfone layer, a polypropylene hollow fiber layer, a polytetrafluoroethylene composite layer, a polyvinylidene fluoride layer, a sulfonated polyetheretherketone layer, a polybenzimidazole layer, a polyimide layer, an asbestos layer, an aluminum oxide layer, a silicon carbide layer, a silicon nitride layer, a zirconium oxide layer, a boron nitride layer, a mullite layer, a cordierite layer, an aluminum titanate layer, and a silicon dioxide layer, or a combination of the foregoing.

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

[0030] Preferably, the surface of the porous insulating filler layer is modified. In other words, the surface of the porous insulating filler layer comprises a modified layer. The modified layer may be a hydrophilic layer. The hydrophilic modification of the surface of the porous insulating filler layer does not affect the hydrophobic nature of the interior of the porous insulating filler layer, thereby still restricting the passage of water.

[0031] In addition, the surface grafting modification of the porous insulating filler layer does not affect the nature of the internal material of the porous insulating filler layer (ie, the bulk phase) being free of anions and cations, and the interior of the porous insulating filler layer (ie, the bulk phase) 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, and therefore the above-mentioned ion migration method B also proceeds extremely slowly. Therefore, the hydroxide generated by the electrolysis of water in the cathode chamber is almost completely consumed by the calcium and magnesium ions in the cathode chamber before passing through the porous insulating filler layer and entering the anode chamber.

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

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

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

[0036] In the reaction chamber, the chamber on the cathode side of the composite electrode unit for water electrolysis is the cathode chamber, and the chamber on the anode side of the composite electrode unit for water electrolysis is the anode chamber.

[0037] Preferably, the reaction chamber further comprises: a power source for providing 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 that the composite electrode unit can physically separate the cathode chamber and the anode chamber to prevent direct mixing of water on both sides.

[0039] Preferably, the system further comprises: a raw water tank, a recycled water tank;

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

[0041] The raw water tank is connected to the cathode chamber through a cathode chamber inlet pipeline;

[0042] The regenerated water tank is connected to the anode chamber through the anode chamber outlet pipe;

[0043] The regenerated water tank is communicated with the cathode chamber through a cathode chamber outlet pipeline.

[0044] Preferably, the system further comprises: a filtering device provided on the cathode chamber outlet pipeline, for filtering solid matter in the liquid in the cathode chamber outlet pipeline.

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

[0046] Preferably, the cathode of the electrolysis water of the present application is a mesh electrode, and its material is any catalyst that can catalyze the cathode reaction of electrolysis water. The anode of the electrolysis water of the present application is a mesh electrode, and its material is any catalyst that can catalyze the anode reaction of electrolysis water under acidic conditions.

[0047] A third aspect of the present application provides an electrochemical water treatment method, which is performed using the electrochemical water treatment system according to any one of the second aspects, and comprises the following steps:

[0048] Injecting raw water containing calcium ions and / or magnesium ions into the cathode chamber and the anode chamber respectively, turning on the power supply, applying direct current or alternating current between the electrolytic water cathode and the electrolytic water anode to perform electrolysis, and causing a water electrolysis reaction to occur in the composite electrode unit;

[0049] When direct current is supplied: during water electrolysis, hydrogen is generated in the cathode chamber and an alkaline environment is formed, causing calcium ions and / or magnesium ions to form solid matter precipitation to reduce the hardness of the water; during water electrolysis, oxygen is generated in the anode chamber and an acidic environment is formed; ultimately, alkaline water containing solid matter 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: when electrolyzing water, hydrogen is generated in the cathode chamber and an alkaline environment is formed, so that calcium ions and / or magnesium ions form solid matter precipitation, and part of the solid matter precipitation crystallizes on the surface of the original electrolyzed water cathode; when electrolyzing water, oxygen is generated in the anode chamber and an acidic environment is formed;

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

[0053] During the next AC cycle, calcium ions and / or magnesium ions in the water are continuously precipitated in the cathode chamber, thereby reducing the water hardness.

[0054] Finally, alkaline water containing solid matter 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 into chlorine gas and removed. The anode chamber produces acidic water containing dissolved chlorine, which has a self-inhibitory 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 obtained alkaline water and acidic water containing solid matter are discharged into the regenerated water tank through the cathode chamber outlet pipeline and the anode chamber outlet pipeline respectively and mixed to obtain neutral water.

[0059] Preferably, the solid matter in the alkaline water containing solid matter is filtered by the filtering device. Of course, the filtering device can also be omitted, and the solid matter can be removed by sedimentation, filter press or other solid-liquid separation methods of the water in the regenerated water tank.

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

[0061] Preferably, the voltage of the direct current or alternating current is 1.5V~30V.

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

[0063] In addition, the electrochemical water treatment system of the present application is essentially an electrolytic descaling device, which is essentially different from conventional electrolytic water devices:

[0064] 1. First of all, let’s talk about the goal:

[0065] Conventional water electrolysis devices "achieve electrochemical reactions through the migration of hydroxide or hydrogen ions," with hydrogen and oxygen as the primary products. Hydroxides or hydrogen ions must quickly cross the membrane to reach the anode or cathode. For example, in CN116334647A, the water electrolysis device "achieves electrochemical reactions through the migration of hydroxide," with hydrogen and oxygen as the primary products. Hydroxides must quickly cross the membrane to reach the anode to participate in the electrolysis reaction and produce oxygen.

[0066] The composite electrode unit in the electrochemical water treatment system of the present application is characterized in that the porous insulating filler layer is required to "block the migration of hydroxide" so that the hydroxide is retained in the cathode chamber as much as possible and combined with calcium and magnesium ions.

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

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

[0069] In conventional water electrolysis devices, the cathode, anode, and membrane are spaced apart and not attached. The cathode and anode are located on either side of the electrolytic cell, with the membrane located in the center. Between the cathode and membrane is the cathode chamber, which holds the electrolyte. Between the anode and membrane is the anode chamber, which also holds the electrolyte. Therefore, when a voltage is applied between the cathode and anode, the electrolyte in both the cathode and anode chambers is in the current loop and participates in the water electrolysis reaction.

[0070] At the same time, hydrogen ions or hydroxide radicals pass through the membrane to participate in the water electrolysis reaction. The electrolyte in the entire cathode chamber and the entire anode chamber undergoes water electrolysis reaction to produce hydrogen and oxygen.

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

[0072] The water electrolysis cathode, water electrolysis anode, and porous insulating filler layer are bonded to each other to form a gapless composite electrode unit. The gapless composite electrode unit is located in the middle of the reaction chamber. Between the water electrolysis cathode of the gapless composite electrode and the side wall of the reaction chamber is a cathode chamber for accommodating raw water containing calcium ions and / or magnesium ions. Between the water electrolysis anode of the gapless composite electrode and the other side wall of the reaction chamber is an anode chamber for accommodating raw water containing calcium ions and / or magnesium ions. Therefore, when a voltage is applied between the water electrolysis cathode and the water electrolysis 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 chamber and the anode chamber outside the gapless composite electrode unit is not in the current loop and does not participate in the water electrolysis reaction. It only receives the electrolysis products from the gapless composite electrode unit transferred by forced diffusion to carry out conventional chemical reactions (for example, the water in the cathode chamber receives the hydroxide generated on the cathode surface to produce calcium and magnesium precipitation, and the water in the anode chamber receives the H generated on the anode surface). + and Cl2 or hypochlorous acid for chemical disinfection, etc.).

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

[0074] Electrolyzed water generates hydroxide at the cathode, which is then forced to diffuse into the main water phase in the cathode chamber at a high flow rate, accelerating its combination with scaling ions such as calcium and magnesium ions, causing rapid crystallization and precipitation, thereby improving the utilization rate of hydroxide.

[0075] H generated at the anode by electrolysis of water + Or chlorine or hypochlorous acid is forced to diffuse into the main body of the anode chamber water phase at a high flow rate, so that the main body of the anode chamber water phase forms an acidic environment and is 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 filler layer of the electrolytic descaling device of this application are as follows:

[0077] Conventional water electrolysis membranes require low resistivity, high conductivity, and the ability to quickly allow anions and / or cations in the electrolyte to pass through the membrane to participate in the electrolysis reaction. Typically, the membrane material of conventional water electrolysis devices contains exchangeable ions, which exchange ions with the electrolyte, allowing anions and / or cations in the electrolyte to quickly 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 passage of water and ions through the porous insulating filler layer, thereby preventing the hydroxide generated at the cathode from passing through the porous insulating filler layer and combining with the hydrogen ions at the anode, and also preventing the hydrogen ions generated at the anode from passing through the porous insulating filler layer and combining with the hydroxide generated at the cathode, as both of these will reduce the utilization rate of the hydroxide in descaling.

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

[0080] Furthermore, the porous insulating filler layer of the present application is porous, relatively thick (preferably 1-5 mm), and preferably made of a hydrophobic material. This can slow down the passage of water and ions through the porous insulating filler layer, thereby inhibiting the migration rate of ion migration method B proposed on page 3 of this specification.

[0081] 4. In terms of usage:

[0082] The larger the current of the water electrolysis device, the better, in order to speed up the water electrolysis rate.

[0083] In the electric descaling device of the present application, the smaller the current, the better, because only a small amount of water needs to be electrolyzed to produce hydroxide ions sufficient to precipitate and remove calcium ions and magnesium ions, and a large amount of water does not need to be electrolyzed to produce hydrogen and oxygen. Therefore, it is hoped that the current is small to reduce the energy consumption of descaling.

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

[0085] 1. This device uses a porous insulating filler layer as a functional barrier, with cathodes and anodes integrated on either side, forming a unique "filler-electrode" integrated composite electrode unit. Driven by an ultra-low DC operating voltage, the micropores of the filler control water transport, thereby blocking the migration of hydroxide ions. Simultaneously, 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 main aqueous phase of the cathode chamber, prompting the rapid crystallization and precipitation of scaling ions in the cathode region, thereby reducing water hardness.

[0086] 2. Furthermore, the device of this application can also treat water containing chloride ions. During the removal process of chloride ions by electrolysis at the anode to chlorine gas, the oxygen / chlorine evolution reaction forms an acidic microenvironment (pH <7) in the anode chamber. Furthermore, the alkaline water obtained at the cathode and the acidic water obtained at the anode in this application are neutralized outside the reaction chamber. This allows the chlorine gas generated by anode electrolysis to be efficiently purged and removed via gas stripping without the need for additional acidification treatment. Furthermore, the acidic water obtained in the anode chamber contains dissolved chlorine, which has a self-inhibiting effect.

[0087] 3. In the preferred solution, the present 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 electrolyzed water cathode, without the need to set up an ultrasonic cleaner for scale removal.

[0088] 4. The solution of this application not only abandons the exogenous addition of traditional scale inhibitors and acid and alkali agents, avoiding the risk of chemical residual pollution from the source, but also inhibits the growth of microorganisms through the simultaneous generation of active chlorine substances, solving the industry problem of mutual reinforcement of scaling and corrosion.

[0089] 5. In a preferred embodiment, in the composite electrode unit of the present application, the electrolytic water cathode, the porous insulating filler layer, and the electrolytic water anode are bonded to each other. This minimizes the distance between the anode and cathode, thereby reducing the electrolyte resistance between the anode and cathode and lowering the energy consumption of the system. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0091] Figure 2 Schematic diagram of the structure of a conventional water electrolysis device.

[0092] List of reference numerals:

[0093] 1-power supply; 2-electrolysis water cathode; 3-electrolysis water anode; 4-porous insulating filler layer; 5-reaction chamber; 6-raw water tank; 7-recycled 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 DESCRIPTION

[0094] The present invention is described below with reference to specific examples, but the embodiments of the present invention are not limited thereto. Experimental methods in the examples where specific conditions are not specified generally followed conventional conditions, those described in manuals, or those recommended by the manufacturer. The general equipment, materials, and reagents used are commercially available unless otherwise specified. The raw materials required in the following examples and comparative examples are all commercially available.

[0095] This application proposes a low-energy electrochemical water treatment method based on the synergistic effects of ion blocking and forced diffusion. Its core lies in the innovative design of a gapless electrolysis unit consisting of a porous insulating filler layer 4 and a catalytic electrode. The device utilizes a hydrophobic porous insulating filler layer 4 as a functional barrier, with highly catalytically active mesh cathode and anode integrated on either side, forming a unique "filler-electrode" integrated structure. Driven by an ultra-low DC voltage of 1.5V to 30V, controlled transport through the filler micropores blocks the directional migration of hydroxide ions, causing them to precipitate with calcium and magnesium ions. Simultaneously, the rapid flow of influent water at the cathode of the electrolyzed water chamber creates a localized forced diffusion effect, promoting the rapid crystallization and precipitation of scale-forming ions in the water. During the electrolysis process, the acidic microenvironment (pH <7) created by the oxygen / chlorine evolution reaction in the anode chamber allows the electrolytically generated chlorine to be efficiently purged and removed by gas stripping without additional acidification. This dual action mechanism enables the system to maintain a low energy consumption level while still efficiently removing hardness ions from the circulating water and significantly improving the cooling water concentration capacity, thereby significantly reducing the amount of water replenishment and sewage discharge, ultimately achieving efficient energy saving and zero emissions in the industrial water treatment process.

[0096] The preferred technical solutions are as follows:

[0097] 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, and other substrates. The porous insulating filler layer 4 has a porosity of 1% to 98% (preferably 30% to 60%), a thickness of 0.05 to 5 mm (preferably 0.1 to 2 mm), and a COD (chemical oxygen demand) tolerance range of 0 to 10,000 mg / L. The porous insulating filler layer 4 has a pore size distribution of 0.1 to 500 microns. Similar effects can be achieved when the porous insulating filler layer 4 is made of a foam plastic layer doped with an inorganic substance such as iron oxide.

[0098] The porous insulating filler layer 4 may also be made of other organic materials, including but not limited to a polyamide layer, a polyethersulfone layer, a polypropylene hollow fiber layer, a polytetrafluoroethylene composite layer, a sulfonated polyetheretherketone layer, a polybenzimidazole layer, and a polyimide layer.

[0099] The electrolytic water cathode 2 is selected from one or a combination of the following materials: nickel wire mesh (mesh size 50-200), stainless steel mesh (304 / 316L), foam nickel (porosity 85%-95%), nickel wire mesh loaded Raney nickel catalyst (loading amount 5%-20%), platinum, and titanium.

[0100] The electrolytic water anode 3 is a titanium-based composite coating electrode or platinum, graphene, etc., wherein the titanium-based composite coating electrode is selected from one or more of titanium-plated iridium oxide (IrO2-Ti), titanium-plated ruthenium oxide (RuO2-Ti), and iridium-tantalum mixed oxide coating (IrO2-Ta2O5-Ti).

[0101] The device's integrated self-cleaning function is as follows: The electrode polarity is periodically switched via a square-wave AC control system. The switching frequency of the square-wave AC is 0.00001 to 0.1 Hz. Preferably, the switching frequency is 0.0001 to 0.05 Hz. The peak-to-valley ratio of the square-wave AC is 100:1 to 1:100. Preferably, the peak-to-valley ratio is 10:1 to 1:10. Of course, other forms of AC are also possible.

[0102] The water flow rate in the cathode chamber and the anode chamber is 0.1~1.0m / s, preferably 0.3~0.5m / s, ensuring that the ion mass transfer rate is ≥5×10 -5 mol / (m 2 ·s).

[0103] The flow channels of the cathode chamber and the anode chamber are designed as serpentine or baffle structures to extend the hydraulic retention time to 10 to 30 seconds.

[0104] The electrochemical water treatment method is suitable for the treatment of circulating water with a calcium and magnesium ion concentration of 10~20000 mg / L.

[0105] The present invention will be further described below with reference to the accompanying drawings and examples.

[0106] The circulating water electrochemical water treatment device proposed in this invention achieves low-energy, high-efficiency hardness ion removal and self-cleaning capabilities in circulating water through innovative structural design coupled with a reaction mechanism. The following systematically explains the device from three perspectives: the device structure, the treatment process, and the reaction mechanism.

[0107] First, as Figure 1 , the device consists of the following core components:

[0108] Reaction chamber 5: Made of carbon steel or stainless steel, the exterior is coated with an epoxy resin anti-corrosion layer, 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 each equipped with an anode chamber inlet line 8, a cathode chamber inlet line 9, an anode chamber outlet line 10, a cathode chamber outlet line 11, and a filter device 12, forming independent fluid channels. Filter device 12 is used to intercept suspended crystals.

[0109] Figure 1 Only two side plates of the reaction chamber 5 are shown. The bottom plate, top plate, front plate and rear plate of the reaction chamber 5 are not shown.

[0110] The system also includes a raw water tank 6 and a regenerated water tank 7. The raw water tank 6 is connected to the anode chamber via an anode chamber inlet pipe 8, the raw water tank 6 is connected to the cathode chamber via a cathode chamber inlet pipe 9, the regenerated water tank 7 is connected to the anode chamber via an anode chamber outlet pipe 10, and the regenerated water tank 7 is connected to the cathode chamber via a cathode chamber outlet pipe 11.

[0111] Composite electrode unit: It is formed by integrating the water electrolysis cathode 2, the water electrolysis anode 3 and the porous insulating filler layer 4.

[0112] Electrolytic water cathode 2: uses nickel-based high specific surface area materials (such as nickel wire mesh, nickel foam or metal skeleton loaded with Raney nickel catalyst) or one or more of platinum, titanium, and stainless steel mesh, whose three-dimensional pore structure can enhance hydroxide diffusion and crystal adhesion.

[0113] Electrolytic water anode 3: Use one or more of titanium-based coating electrodes (such as titanium-plated iridium oxide, titanium-plated ruthenium oxide or iridium-tantalum composite coating) or platinum, graphene-doped electrodes, etc., with low chlorine and oxygen evolution overpotential and acid corrosion resistance.

[0114] Porous insulating filler layer 4: Made of a hydrophobic resin with a porosity of 3% to 98% and a thickness of 0.05 to 5 mm, it allows controlled penetration of water molecules and ensures a stable ion concentration gradient in the anode and cathode chambers.

[0115] The composite electrode unit and the side panels of reaction chamber 5 are of the same length and height. This matching design of equal height and length ensures a seamless physical fit between the composite electrode unit and reaction chamber 5, preventing direct mixing of the alkaline and acidic water in the cathode and anode chambers within reaction chamber 5. The composite electrode unit design reduces the distance between the cathode and anode, effectively eliminating the inter-electrode resistance losses common in traditional reaction chambers.

[0116] 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 from 100:1 to 1:100. The purpose of this square-wave AC power control system is to generate a dynamic acid-base environment through periodic polarity reversals, triggering the self-stripping of scale deposits on the electrode surface.

[0117] Second, circulating water treatment process

[0118] Raw solution supply stage: Circulating water containing high concentrations of calcium and magnesium ions (calcium ion / magnesium ion concentration 10~20000 mg / L) is stored in the raw water tank 6 and pumped into the anode chamber and cathode chamber of the reaction chamber 5 through the anode chamber inlet pipe 8 and the cathode chamber inlet pipe 9 at a flow rate of ≥0.1m / s.

[0119] Preferably, one end of the anode chamber inlet pipe 8 and the cathode chamber inlet pipe 9 are respectively arranged 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 the fluid inertia to form a vortex to cover the entire electrode surface.

[0120] Preferably, one end of the anode chamber outlet pipe 10 and the cathode chamber outlet pipe 11 are respectively arranged at the top of the anode chamber and the cathode chamber, so as to facilitate the rapid escape of the gas generated by electrolysis and avoid bubbles adhering to the electrode surface to reduce the reaction efficiency. Preferably, the outlet pipe and the inlet pipe are designed to be diagonal. For example: the outlet pipe opens at the top of the side away from the electrode or the pipe opens at the top of one side of the electrode. This allows the water flow to continuously flush the electrode surface in the flow path from the inlet to the outlet. At the same time, the residence time of the water flow in the chamber is extended. At the same time, by controlling the water flow velocity, forced convection is formed in the anode chamber and the cathode chamber. The forced convection design can suppress the thickening of the boundary layer and enhance the ion mass transfer efficiency.

[0121] Third, electrochemical treatment stage

[0122] Typically, driven by an ultra-low DC voltage of 1.5V, differentiated electrochemical reactions occur in the anode and cathode chambers.

[0123] Cathode chamber: electrolyzes water to generate hydroxide (2H2O+2e - →H2↑+2OH - ), the alkaline environment promotes the conversion of bicarbonate into carbonate (HCO3 - +OH - →CO3 2- +H2O), and then combine with calcium ions / magnesium ions to form calcium carbonate, magnesium hydroxide and magnesium carbonate crystals.

[0124] Anode chamber: Chloride ions are oxidized to produce active chlorine (2Cl - →Cl2↑+2e - ), while water electrolysis generates hydrogen ions (H2O→½O2↑+2H + +2e - ), the acidic environment inhibits secondary scaling and achieves simultaneous sterilization and algae inhibition.

[0125] The meaning of secondary scaling is as follows:

[0126] Cathode reaction: Water electrolysis generates hydroxide (2H2O+2e - →H2↑+2OH - ), the pH in the cathode area increases (alkaline), prompting the formation of calcium ions and magnesium ions (conventional scaling).

[0127] 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 is not low enough), these particles may be deposited again on the anode electrode surface due to electrostatic adsorption or turbulent disturbance, forming "secondary scaling".

[0128] Recycled water recovery stage: The treated anode recycle water (pH 2-4, enriched with hydrogen ions) and cathode recycle water (pH 10-12, containing suspended crystals) are pumped into the recycle 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 will be intercepted and filtered into the device 12 and no longer come into contact with the anode recycle water). + +OH - →H2O) to restore electrical neutrality, and the precipitate is recycled after solid-liquid separation.

[0129] Fourth, self-cleaning and energy efficiency optimization mechanism

[0130] Dynamic scaling removal: The square wave AC system of power supply 1 periodically switches the electrode polarity and utilizes the local strong acidity (hydrogen ions in the anode chamber) or strong alkalinity (hydroxyl radicals in the cathode chamber) environment at the moment of polarity reversal to dissolve the microcrystalline scaling layer on the electrode surface, achieving in-situ self-cleaning (scaling efficiency ≥ 95%).

[0131] Energy consumption control strategy: The gapless electrode design combined with the square wave power supply mode reduces concentration polarization loss, reducing overall energy consumption by 20% to 70% compared to existing technologies, and consuming 2 to 5 kWh of electricity for each kilogram of hardness removed (calculated as calcium carbonate).

[0132] The general formula for calculating energy consumption based on hydroxide generation and calcium ion precipitation is as follows:

[0133] When the reaction produces hydroxide (OH) through the electrolysis of water, which then combines with calcium ions to precipitate (such as to form calcium hydroxide or calcium carbonate), the theoretical energy consumption for removing each kilogram of hardness (calculated as calcium carbonate) is calculated as follows:

[0134] 1. Reaction pathway and electron transfer relationship

[0135] Cathode reaction (generating hydroxide):

[0136] 2H2O+2e - →H2↑+2OH -

[0137] Precipitation reaction (removal of calcium ions):

[0138] Ca 2+ +2OH - →Ca(OH)2↓ or Ca 2+ +CO3 2-→CaCO3↓

[0139] Electron transfer relationship: 2 mol of electrons are required to remove 1 mol of calcium ions.

[0140] 2. Calculation steps:

[0141] Moles of calcium carbonate removed:

[0142] Number of moles = m × 1000 / M (calcium carbonate) = 1000m / 100.08≈10m (mol)

[0143] Where m is the hardness mass treated, measured in calcium carbonate, in kg.

[0144] Theoretical power required:

[0145] Q 理论 =n×number of moles×F=2×10m×96485 (C)

[0146] Where n is the number of transferred electrons and F is the Faraday constant.

[0147] Theoretical energy consumption (electric energy = electricity × voltage):

[0148] E 理论 =Q 理论 ×V / (3.6×10 6 )(kWh)

[0149] Taking Example 1 as an example: the amount of hardness (calculated as calcium carbonate) removed is m = 1000L × 1000mg / L × 95% = 0.95kg;

[0150] The applied single-stage voltage V = 4.4V; a single-stage voltage is the voltage applied between the cathode and anode of a single composite electrode unit. Each reaction chamber 5 contains a composite electrode unit. Multiple reaction chambers 5 can be connected in series, also known as multi-stage series connection. The embodiments of this application all depict a single-stage reaction chamber 5.

[0151] Theoretical energy consumption = 2×10×0.95×96485×4.4 / (3.6×10 6 )≈2.24 kWh;

[0152] For the calculation of the hardness (calculated as calcium carbonate) removed per kilogram in the comparative patent CN101585569A:

[0153] Since the voltage is not clearly given in the embodiment of the comparative patent, we consulted the data for the device proposed in the comparative patent CN101585569A and learned that its typical voltage range is 12-24V. Taking the lowest voltage of 12V as an example (for processing 1 kg of calcium carbonate):

[0154] Theoretical energy consumption = 2 × 10 × 1 × 96485 × 12 / 3.6 × 10 6 ≈6.43 kWh.

[0155] The following examples are provided to illustrate the effects of the present application. The test materials of the present application, such as the materials used for the electrodes and the porous insulating filler layer 4, can be purchased or made by existing methods. The preparation method of the porous insulating filler layer 4 of the present application is a conventional process. When the porous insulating filler layer 4 is a polymer material, a solution casting method is adopted. When the porous insulating filler layer 4 is a material containing a polymer and an inorganic substance, the solution casting method is adopted after the two particles are mixed. When the porous insulating filler layer 4 is an inorganic material, a bonding pressing method is adopted.

[0156] The hardness of water or calcium and magnesium ions in this application is calculated as calcium carbonate. Example 1

[0157] 1. Treatment object: 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.

[0158] 2. Device configuration:

[0159] Electrode system: The electrolytic water anode 3 uses a titanium-based iridium oxide coating electrode (IrO2 loading 2.5 mg / cm²), and the electrolytic water cathode 2 uses a foam nickel electrode (porosity 85%);

[0160] Porous insulating filler layer 4: a polyethylene-polyamide composite layer (porosity 60%, thickness 2 mm, pore size 0.1-0.5 μm), with a sulfonated modified layer on the surface.

[0161] The preparation method of the polyethylene-polyamide composite layer is as follows:

[0162] (1) Add 12.0 g of polyamide (PA6) to 108.0 mL of o-dichlorobenzene, heat in an oil bath at 160 °C, and mechanically stir (300 rpm) for 2 h until completely dissolved to form a clear solution with a solid content of 10.0 wt%.

[0163] (2) The PA6 solution was cooled to 100 °C, 6.0 g of high-density polyethylene (HDPE) particles were added in batches, and the temperature was raised to 140 °C at a rate of 1 °C per minute. The mixture was dispersed at a high shear speed of 800 rpm at 140 °C for 1.5 hours.

[0164] (3) Add 2.52 g of n-octanol at 140 °C and stir at 500 rpm for 30 minutes until completely dispersed.

[0165] (4) Pour the uniform high-temperature solution into a Teflon mold preheated to 100 degrees Celsius (mold depth: 2.5 mm).

[0166] (5) Control the cooling rate (first slowly cool to 80 degrees Celsius at a rate of 0.1 degrees Celsius per minute, and then naturally cool to room temperature) to induce phase separation and solvent evaporation to form pores.

[0167] (6) Cool to below 30 degrees Celsius and demould.

[0168] (7) Soak in 98% concentrated sulfuric acid for 40 minutes for sulfonation modification, and then dry in a vacuum oven at 60 degrees Celsius for 12 hours.

[0169] 3. Operation process:

[0170] (1) Feeding stage: The concentrated circulating water is injected into the two electrode chambers at a flow rate of 0.5 m / s through a booster pump.

[0171] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 4.4 V), current density 200 A / m², frequency 0.0033 Hz (cycle 300 s / 5 min), peak-to-valley ratio 10:1), was applied for 4 cycles (total duration 1200 s);

[0172] (3) Discharge of regenerated water: Open the anode chamber outlet pipe 10 and the cathode chamber outlet pipe 11, and pump the regenerated water into the regenerated water tank 7 at a flow rate of 1.0 m / s.

[0173] (4) Circular treatment: Repeat the feeding-treatment-drainage steps 5 times, running a total of 20 cycles, with a total treatment time of 6000s (100 minutes).

[0174] 4. Treatment effect:

[0175] Raw water tank 6: 1000L concentrated circulating water has been completely processed;

[0176] Outlet water quality: 1000L of recycled water was collected, the concentration of calcium and magnesium ions dropped to 50mg / L, and the removal rate was 95%.

[0177] Actual energy consumption data: The initial cell voltage is 4.5V, and the cell voltage rises to 4.7V at the end of the treatment cycle (an increase of 0.2V). The power consumption for removing each kilogram of hardness (calculated as calcium carbonate) is 2.5kWh, which is 61.1% lower than the reference patent CN101585569A (6.43 kWh). Example 2

[0178] High temperature corrosion resistant scenarios:

[0179] 1. Treatment object: 1.2 tons (1200L) of high-temperature concentrated circulating water (temperature 80 degrees Celsius), initial hardness (calculated as calcium carbonate) 1200mg / L.

[0180] 2. Device configuration:

[0181] Electrode system: The electrolytic water anode 3 uses a titanium-plated ruthenium oxide electrode with a ruthenium loading of 1.8 mg / cm²; the electrolytic water cathode 2 uses a nickel wire mesh porous electrode;

[0182] Porous insulating filler layer 4: polyphenylene sulfide-alumina composite layer (porosity 70%, thickness 1.5 mm, pore diameter 0.2-0.8 μm).

[0183] The preparation method of the polyphenylene sulfide-aluminum oxide composite layer is as follows:

[0184] (1) Under nitrogen protection, add 20.0 g of polyphenylene sulfide (PPS) particles into 180 mL of N-methylpyrrolidone (NMP), heat to 216 °C, and stir vigorously (800 rpm) until completely dissolved;

[0185] (2) Cool to 180°C, add 30.0 g of aluminum oxide (Al2O3) powder, and ultrasonicate for 30 min to ensure good dispersion;

[0186] (3) Add 3.0 g of polyethylene glycol 400 and disperse evenly through ultrasonication;

[0187] (4) Quickly pour the uniform high-temperature slurry into a stainless steel mold preheated to 150 degrees Celsius (mold depth: 1.65 mm);

[0188] (5) Place in an oven, first keep at 180 degrees Celsius for 1.5 hours (to prevent crystallization by cooling too quickly), then cool to 100 degrees Celsius at a rate of 0.8 degrees Celsius per minute, and finally evaporate the residual solvent to room temperature under ventilation conditions;

[0189] (6) Demolding.

[0190] 3. Operation process:

[0191] (1) Feeding stage: concentrated circulating water is injected at a flow rate of 0.6 m / s;

[0192] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 4.8 V, frequency 0.0017 Hz (cycle 600 s / 10 min), peak-to-valley ratio 8:1) was applied for 6 cycles (total duration 3600 s), current density 150 A / m²;

[0193] (3) Recycled water discharge: Recycled water is discharged at a flow rate of 0.8 m / s.

[0194] (4) Loop processing: repeated 6 times, accumulating 36 cycles, with a total processing time of 21,600 seconds (6 hours).

[0195] 4. Treatment effect:

[0196] Raw water tank 6: 1200L concentrated circulating water treatment completed;

[0197] Outlet water quality: 1200L recycled water was collected, the hardness was reduced to 72mg / L, and the retention rate was 94%.

[0198] Actual energy consumption data: The initial cell voltage was 4.9V, and at the end of the treatment cycle the cell voltage rose to 5.2V (an increase of 0.3V). The power consumption for removing each kilogram of hardness (calculated as calcium carbonate) was 3.8kWh, which was 40.9% lower than that of the reference patent CN101585569A (6.43 kWh). Example 3

[0199] Low-cost environmentally friendly solution:

[0200] 1. Treatment object: 800L low-concentration concentrated circulating water, hardness (calculated as calcium carbonate) 300mg / L.

[0201] 2. Device configuration:

[0202] Electrode system: The anode 3 for electrolysis of water adopts iridium-tantalum mixed oxide, and the cathode 2 for electrolysis of water adopts nickel wire mesh loaded Raney nickel electrode;

[0203] Porous insulating filler layer 4: polypropylene hollow fiber-silica composite layer (porosity 1%, thickness 0.05 mm, pore size 0.3-500 μm), with a quaternary ammonium group modified layer on the surface.

[0204] The preparation method of polypropylene hollow fiber-silica composite layer is as follows:

[0205] (1) Dissolve 15.0 g of polypropylene (PP) pellets in 135 mL of decahydronaphthalene at 140 °C to form a solution;

[0206] (2) Cool to 100°C, add 4.5 g of silica nanoparticles, and disperse vigorously by stirring and ultrasonication;

[0207] (3) Add 1.5 g of cyclohexane;

[0208] (4) Lay the polypropylene hollow fiber (PPHF) braid flatly on the bottom of the mold (mold depth: 1 mm);

[0209] (5) Pour the mixed slurry onto the PPHF layer while it is hot (100 degrees Celsius) to ensure sufficient infiltration;

[0210] (6) Cool naturally to room temperature to evaporate the solvent;

[0211] (7) Demolding;

[0212] (8) Immerse in 5 wt% quaternary ammonium silane ethanol solution for 60 minutes and cure at 80 degrees Celsius for 1 hour.

[0213] 3. Operation process:

[0214] (1) Feeding stage: concentrated circulating water is injected at a flow rate of 0.3 m / s;

[0215] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 30 V, frequency 0.0011 Hz (cycle 900 s / 15 min), peak-to-valley ratio 12:1) was applied for 3 cycles (total duration 2700 s), current density 1000 A / m²;

[0216] (3) Recycled water discharge: Recycled water is discharged at a flow rate of 0.8 m / s;

[0217] (4) Loop processing: repeated 13 times, accumulating 40 cycles, with a total processing time of 108,000 seconds (30 hours).

[0218] 4. Treatment effect:

[0219] Raw water tank 6: 800L circulating water treatment completed;

[0220] Outlet water quality: 800L recycled water was collected, the hardness was reduced to 15mg / L, and the retention rate was 95%.

[0221] Actual energy consumption data: The initial cell voltage was 30.1V, and at the end of the treatment cycle the cell voltage rose to 30.4V (an increase of 0.3V). The power consumption for removing each kilogram of hardness (calculated as calcium carbonate) was 4.0kWh, which was 37.7% lower than that of the comparative patent CN101585569A (6.43 kWh). Example 4

[0222] High-salinity seawater pretreatment:

[0223] 1. Treatment object: 2000L seawater desalination pretreatment liquid, hardness (calculated as calcium carbonate) 800mg / L.

[0224] 2. Device configuration:

[0225] Electrode system: The electrolytic water anode 3 uses a platinum carbon electrode, and the electrolytic water cathode 2 uses a foam nickel electrode;

[0226] Porous insulating filler layer 4: polytetrafluoroethylene-silicon carbide composite layer (porosity 65%, thickness 2.2 mm, pore size 0.5-500 μm);

[0227] The preparation method of the polytetrafluoroethylene-silicon carbide composite layer is as follows:

[0228] (1) Dilute 100 mL of 60 wt% solid content polytetrafluoroethylene dispersion (solvent: water) with deionized water to 24 wt% solid content;

[0229] (2) Add 45g of silicon carbide (SiC) powder and disperse it evenly by vigorous stirring and ultrasonication;

[0230] (3) Adding dual pore formers: 30.0 g of 200 μm NaCl particles and 15.0 g of 5 μm sucrose powder;

[0231] (4) Pour the mixed slurry into the mold (mold depth: 2.5 mm);

[0232] (5) First, slowly dry at room temperature (to prevent cracking), then gradually increase the temperature in an oven and sinter. 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;

[0233] (6) De-mould after cooling to room temperature.

[0234] 3. Operation process:

[0235] (1) Feeding stage: concentrated circulating water is injected at a flow rate of 0.7 m / s;

[0236] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 4.2 V, frequency 0.00083 Hz (cycle 1200 s / 20 min), peak-to-valley ratio 5:1) was applied for 5 cycles (total duration 6000 s), current density 300 A / m²;

[0237] (3) Recycled water discharge: Recycled water is discharged at a flow rate of 1.0 m / s.

[0238] (4) Loop processing: Repeat 12 times, run 60 cycles in total, and the total processing time is 72,000 seconds (20 hours).

[0239] 4. Treatment effect:

[0240] Raw water tank 6: 2000L pre-treatment liquid processed;

[0241] Outlet water quality: 2000L recycled water was collected, the hardness was reduced to 64mg / L, and the retention rate was 92%.

[0242] Actual energy consumption data: The initial cell voltage was 4.4V, and at the end of the treatment cycle the cell voltage rose to 4.6V (an increase of 0.2V). The power consumption for removing each kilogram of hardness (calculated as calcium carbonate) was 3.7kWh, which was 42.4% lower than that of the reference patent CN101585569A (6.43 kWh). Example 5

[0243] 1. Treatment object: 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.

[0244] 2. Device configuration:

[0245] Electrode system: The electrolytic water anode 3 uses a platinum sheet electrode (thickness 0.5 mm, surface area 0.2 m²), and the electrolytic water cathode 2 uses a platinum mesh electrode (porosity 75%, pore size 1.0 mm);

[0246] Porous insulating filler layer 4: polyvinylidene fluoride-zirconium oxide composite layer (porosity 55%, thickness 1.5 mm, pore size 0.2-0.8 μm).

[0247] The preparation method of the polyvinylidene fluoride-zirconium oxide composite layer is as follows:

[0248] (1) Dissolve 20.0 g of polyvinylidene fluoride (PVDF) particles in 180 mL of dimethylformamide (DMF) and heat and stir at 50 °C until a clear solution is obtained;

[0249] (2) Add 6.0 g of zirconium oxide (ZrO2) powder and disperse it evenly by vigorous stirring and ultrasonication;

[0250] (3) Add 4.0 g of polyethylene glycol 1000;

[0251] (4) Pour the mixed slurry into the mold (mold depth: 1.6 mm);

[0252] (5) Keep the mold at a constant temperature of 50 degrees Celsius for 24 hours;

[0253] (6) After the solvent is basically evaporated, the temperature is raised to 90 degrees Celsius to further remove the residual solvent;

[0254] (7) Cool to room temperature and demould.

[0255] 3. Operation process:

[0256] (1) Feeding stage: Concentrated circulating water is injected into the bipolar chamber at a flow rate of 0.6 m / s.

[0257] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 5.0 V, frequency 0.00067 Hz (cycle 1500 s / 25 min), peak-to-valley ratio 10:1) was applied for 3 cycles (total duration 4500 s), current density 400 A / m²;

[0258] (3) Regenerated water discharge: Open the anode chamber outlet pipe 10 and the cathode chamber outlet pipe 11, and pump the regenerated water into the regenerated water tank 7 at a flow rate of 1.0 m / s;

[0259] (4) Loop processing: repeated 15 times, running a total of 45 cycles, with a total processing time of 67,500 seconds (18.75 hours).

[0260] 4. Treatment effect:

[0261] Raw water tank: 2000L concentrated circulating water has been completely processed;

[0262] Outlet water quality: 2000L recycled water was collected, the concentration of calcium and magnesium ions dropped to 32mg / L, and the removal rate was 96%.

[0263] Actual energy consumption data: The initial cell voltage is 5.5V, and the cell voltage rises to 5.7V at the end of the treatment cycle (an increase of 0.2V). The power consumption for removing each kilogram of hardness (calculated as calcium carbonate) is 4.4kWh, which is 31.5% lower than the reference patent CN101585569A (6.43 kWh). Example 6

[0264] 1. Treatment object: 1.5 tons (1500L) of industrial boiler return water, with an initial calcium and magnesium ion concentration (calculated as calcium carbonate) of 1200mg / L.

[0265] 2. Device configuration:

[0266] Electrode system: The electrolytic water anode 3 uses a platinum-plated titanium electrode (platinum layer thickness 50 microns, surface area 0.15m²), and the electrolytic water cathode 2 uses a porous platinum electrode (porosity 80%, pore diameter 0.5mm);

[0267] Porous insulating filler layer 4: sulfonated polyetheretherketone-polybenzimidazole composite layer (porosity 98%, thickness 5 mm, pore size 0.1-0.3 μm).

[0268] The preparation method of the sulfonated polyetheretherketone-polybenzimidazole composite layer is as follows:

[0269] (1) Dissolve 5.0 g of sulfonated polyetheretherketone (SPEEK) and 5.0 g of polybenzimidazole (PBI) in 45 mL of dimethyl sulfoxide (DMSO) to obtain clear solutions.

[0270] (2) Mix the above two solutions and stir vigorously to ensure uniformity;

[0271] (3) Add dual pore-forming agents: ethylene glycol: 1.0 g, 1-propanol: 0.5 g;

[0272] (4) Pour the mixed solution into the mold (mold depth: 5.5 mm);

[0273] (5) Place in a constant temperature (70 degrees Celsius) and well-ventilated oven to slowly evaporate the solvent (3 days);

[0274] (6) After the solvent evaporates completely, the temperature is raised to 110 degrees Celsius for further drying and solidification;

[0275] (7) Cool to room temperature and demould.

[0276] 3. Operation process:

[0277] (1) Feeding stage: Concentrated circulating water is injected into the bipolar chamber at a flow rate of 0.4 m / s through a booster pump;

[0278] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 3.8 V, frequency 0.0021 Hz (cycle 480 s / 8 min), peak-to-valley ratio 10:1) was applied for 5 cycles (total duration 2400 s), current density 250 A / m²;

[0279] (3) Discharge of regenerated water: Open the anode chamber outlet pipe 10 and the cathode chamber outlet pipe 11, and pump the regenerated water into the regenerated water tank 7 at a flow rate of 0.8 m / s;

[0280] (4) Loop processing: repeated 9 times, accumulating 48 cycles, with a total processing time of 115,200 seconds (32 hours).

[0281] 4. Treatment effect:

[0282] Raw water tank: 1500L concentrated circulating water is fully processed;

[0283] Outlet water quality: 1500L of recycled water was collected, the concentration of calcium and magnesium ions dropped to 24mg / L, and the removal rate was 98%.

[0284] Actual energy consumption data: The initial cell voltage was 3.9V, and at the end of the treatment cycle the cell voltage rose to 4.1V (an increase of 0.2V). The power consumption for removing each kilogram of hardness (calculated as calcium carbonate) was 3.8kWh, which was 40.9% lower than that of the reference patent CN101585569A (6.43 kWh). Example 7

[0285] 1. Treatment object: 3 tons (3000L) of central air-conditioning circulating water, with an initial calcium and magnesium ion concentration (calculated as calcium carbonate) of 600mg / L.

[0286] 2. Device configuration:

[0287] Electrode system: The electrolytic water anode 3 uses a platinum-ruthenium oxide composite electrode (RuO2 loading 3.0 mg / cm²), and the electrolytic water cathode 2 uses a platinum-coated stainless steel mesh electrode (porosity 90%);

[0288] Porous insulating filler layer 4: polyimide-mullite composite layer (porosity 65%, thickness 2.2 mm, pore diameter 0.3-1.0 μm).

[0289] The preparation method of the polyimide-mullite composite layer is as follows:

[0290] (1) Dissolve 20.0 g of polyimide precursor polyamic acid (PAA) in 180 mL of N-methylpyrrolidone (NMP);

[0291] (2) Add 30.0 g of mullite powder and disperse evenly by vigorous stirring and ultrasonication;

[0292] (3) Add 10.0 g of polyethylene glycol 2000;

[0293] (4) Pour the mixed slurry into the mold (mold depth: 2.35 mm);

[0294] (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.

[0295] (6) Cool naturally to room temperature and demould.

[0296] 3. Operation process:

[0297] (1) Feeding stage: The concentrated circulating water is injected into the bipolar chamber at a flow rate of 0.7 m / s through a booster pump;

[0298] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 4.2 V, frequency 0.0014 Hz (cycle 720 s / 12 min), peak-to-valley ratio 10:1) was applied for 4 cycles (total duration 2880 s), current density 350 A / m²;

[0299] (3) Regenerated water discharge: Open the anode chamber outlet pipe 10 and the cathode chamber outlet pipe 11, and pump the regenerated water into the regenerated water tank 7 at a flow rate of 0.9 m / s;

[0300] (4) Loop processing: Repeated 4 times, running a total of 16 cycles, with a total processing time of 46,080 seconds (12.8 hours).

[0301] 4. Treatment effect:

[0302] Raw water tank: 3000L concentrated circulating water has been completely processed;

[0303] Outlet water quality: 3000L recycled water was collected, the concentration of calcium and magnesium ions dropped to 30mg / L, and the removal rate was 95%.

[0304] Actual energy consumption data: The initial cell voltage is 4.5V, and at the end of the treatment cycle the cell voltage rises to 4.7V (an increase of 0.2V). The power consumption for removing each kilogram of hardness (calculated as calcium carbonate) is 4.1kWh, which is 36.2% lower than the reference patent CN101585569A (6.43 kWh). Example 8

[0305] 1. Treatment object: 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. Device configuration:

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

[0308] Porous insulating filler layer 4: a 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 preparation method of the porous insulating filler layer 4 is as follows:

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

[0311] (2) Add 40.0 g of silicon nitride powder and disperse it evenly by vigorous stirring and ultrasonication;

[0312] (3) Add 8.0 g 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) Cool naturally to room temperature and demould;

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

[0317] 3. Operation process:

[0318] (1) Feeding stage: Concentrated circulating water is injected into the bipolar chamber at a flow rate of 0.3 m / s through a booster pump;

[0319] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 4.5 V, frequency 0.00056 Hz (cycle 1800 s / 30 min), peak-to-valley ratio 10:1) was applied for 6 cycles (total duration 10,800 s), current density 100 A / m²;

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

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

[0322] 4. Treatment effect:

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

[0324] Outlet water quality: 800L of recycled water was collected, the concentration of calcium and magnesium ions dropped to 45mg / L, and the removal rate was 97%.

[0325] Actual energy consumption data: The initial cell voltage was 4.7V, and at the end of the treatment cycle the cell voltage rose to 4.9V (an increase of 0.2V). The power consumption for removing each kilogram of hardness (calculated as calcium carbonate) was 3.0kWh, which was 53.3% lower than that of the comparative patent CN101585569A (6.43 kWh). Example 9

[0326] 1. Treatment object: 2.5 tons (2500L) of seawater pre-treated water from desalination, with an initial calcium and magnesium ion concentration (calculated as calcium carbonate) of 2000mg / L.

[0327] 2. Device configuration:

[0328] Electrode system: The electrolytic water anode 3 uses an iridium oxide electrode, and the electrolytic water cathode 2 uses a titanium mesh electrode (porosity 95%);

[0329] Porous insulating filler layer 4: asbestos layer (porosity 75%, thickness 0.18 mm, pore size 1-500 μm).

[0330] The asbestos layer is prepared as follows:

[0331] (1) Protective preparation: Operate in a negative pressure glove box or a dedicated fume hood. Wear full-body protective clothing, goggles, N100 mask, and gloves.

[0332] (2) Pretreatment: Gently dissociate the asbestos fibers into shorter fibers (1-2 mm in length) (avoid excessive crushing to generate dust), and sieve to remove large impurities.

[0333] (3) Mixing:

[0334] Weigh 30.0 g of asbestos fiber, add 7.5 g of silica sol, add 9.0 g of pore-forming agent - ammonium bicarbonate powder, add 18 mL of deionized water, adjust to a suitable consistency (similar to wet mortar), and gently stir and mix with a low-speed stirrer (to avoid fiber breakage and dust generation).

[0335] (4) Molding and pre-pressing: Fill the mixed slurry into a mold coated with a release agent (silicone grease) (mold depth: 0.3 mm), and apply a slight pre-press (0.5 MPa) to eliminate large bubbles and allow the fibers to be initially oriented.

[0336] (5) Pressing: Apply pressure (1.5 MPa for 2 minutes). The pressure should not be too high to avoid excessive damage to the pore structure.

[0337] (6) Drying: Carefully demould (wet strength is low), place in a well-ventilated place and dry at low temperature (40 degrees Celsius for 48 hours) until constant weight. The silica sol will initially gel. After heat treatment and heat treatment, a small amount of carbon may remain in the sample. If a completely white color is required, it can be calcined in air at 500 degrees Celsius for 1.5 hours.

[0338] (7) Cooling and sealing: Cool to room temperature. The sample must be sealed (double plastic bag).

[0339] 3. Operation process:

[0340] (1) Feeding stage: The concentrated circulating water is injected into the bipolar chamber at a flow rate of 0.9 m / s through a booster pump;

[0341] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 1.5 V, frequency 0.0024 Hz (cycle 420 s / 7 min), peak-to-valley ratio 10:1) was applied for 150 cycles (total duration 63,000 s / 17.5 h), current density 1 A / m²;

[0342] (3) Regenerated water discharge: Open the anode chamber outlet pipe 10 and the cathode chamber outlet pipe 11, and pump the regenerated water into the regenerated water tank 7 at a flow rate of 1.0 m / s;

[0343] (4) Loop processing: Repeat once, run 150 cycles in total, and the total processing time is 63,000 seconds (17.5 hours).

[0344] 4. Treatment effect

[0345] Raw water tank: 2500L concentrated circulating water is fully processed;

[0346] Outlet water quality: 2500L recycled water was collected, the concentration of calcium and magnesium ions dropped to 80mg / L, and the removal rate was 96%.

[0347] Actual energy consumption data: The initial cell voltage is 1.7V, and the cell voltage rises to 2.2V at the end of the treatment cycle (an increase of 0.5V). The power consumption for removing each kilogram of hardness (calculated as calcium carbonate) is 4.2kWh, which is 34.6% lower than the comparative patent CN101585569A (6.43 kWh). Example 10

[0348] 1. Treatment object: 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.

[0349] 2. Device configuration:

[0350] Electrode system: The electrolytic water anode 3 uses a platinum sheet electrode, and the electrolytic water cathode 2 uses a platinum-coated graphite electrode (porosity 88%);

[0351] Porous insulating filler layer 4: silicon carbide layer (porosity 68%, thickness 2.5 mm, pore diameter 0.2-0.6 μm).

[0352] The preparation method of the silicon carbide layer is as follows:

[0353] (1) Mixing: Weigh 560.0 g of coarse silicon carbide (SiC) powder and 240.0 g of fine silicon carbide (SiC) powder. Add 52 g of Y2O3 sintering aid, 1005 g of 8 wt% polyvinyl alcohol solution, 148 g of nanographite powder, and 5.0 g of ammonium polyacrylate dispersant.

[0354] (2) Aging: After mixing evenly, seal the blank and age it for 24 hours.

[0355] (3) Molding: dry pressing (mold depth: 3.0 mm).

[0356] (4) Drying: Slowly dry in a low-temperature oven (40 degrees Celsius) to constant weight to prevent cracking.

[0357] (5) Debinding: Keep the temperature in a muffle furnace at 600°C for 2 hours (heating rate 0.5°C per minute).

[0358] (6) High temperature sintering in argon atmosphere (heating from 25°C to 1000°C at a heating rate of 5°C per minute, and then keeping at 1000°C for 45 minutes).

[0359] (7) Cooling: Cool down to room temperature at a cooling rate of 2 degrees Celsius per minute.

[0360] (8) The sintered sample was calcined at 700 °C (heating rate: 1 °C per minute) for 3 h in air atmosphere to oxidize and remove the residual graphite pore-forming agent to form the final pores.

[0361] 3. Operation process:

[0362] (1) Feeding stage: Concentrated circulating water is injected into the bipolar chamber at a flow rate of 0.5 m / s through a booster pump;

[0363] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 4.8 V, frequency 0.00093 Hz (cycle 1080 s / 18 min), peak-to-valley ratio 10:1) was applied for 4 cycles (total duration 4320 s), current density 600 A / m²;

[0364] (3) Discharge of regenerated water: Open the anode chamber outlet pipe 10 and the cathode chamber outlet pipe 11, and pump the regenerated water into the regenerated water tank 7 at a flow rate of 0.8 m / s;

[0365] (4) Loop processing: Repeat 10 times, run 40 cycles in total, and the total processing time is 43,200 seconds (12 hours).

[0366] 4. Treatment effect:

[0367] Raw water tank: 4000L concentrated circulating water has been completely processed;

[0368] Outlet water quality: 4000L recycled water was collected, the concentration of calcium and magnesium ions dropped to 18mg / L, and the removal rate was 96%.

[0369] Actual energy consumption data: The initial cell voltage was 5.1V, and at the end of the treatment cycle the cell voltage rose to 5.3V (an increase of 0.2V). The power consumption for removing each kilogram of hardness (calculated as calcium carbonate) was 4.7kWh, which was 26.9% lower than that of the reference patent CN101585569A (6.43 kWh). Example 11

[0370] Continuous method:

[0371] 1. Treatment object: 10,000L of circulating cooling water from a petrochemical plant, with a calcium and magnesium ion concentration (calculated as calcium carbonate) of 400mg / L.

[0372] 2. Device configuration:

[0373] Electrode system: Both the electrolytic water anode 3 and the electrolytic water cathode 2 use iridium tantalum oxide coated titanium mesh electrodes;

[0374] Porous insulating filler layer 4: polypropylene-polytetrafluoroethylene composite layer (porosity 68%, thickness 0.2 mm, pore size 10-200 μm).

[0375] The preparation method of the polypropylene-polytetrafluoroethylene composite layer is as follows:

[0376] (1) Dissolve 15.0 g of polypropylene (PP) pellets in 135 mL of decalin at 145 °C.

[0377] (2) Cool down to 100 degrees Celsius, add 30.0g of polytetrafluoroethylene aqueous dispersion, and stir vigorously to emulsify and disperse.

[0378] (3) The hot emulsion was quickly poured into a preheated (80°C) mold (depth 0.25 mm).

[0379] (4) Gradually increase the temperature in an 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.

[0380] (5) Cool to below 40 degrees Celsius and demould.

[0381] 3. Operation process:

[0382] (1) Feeding stage: Cooling water is pumped into the bipolar chamber at a flow rate of 0.5 m / s through a booster pump;

[0383] (2) Electrochemical treatment: Apply square wave alternating current (single-stage voltage 2.0 V), set the frequency to positive bias 950 s, negative bias 50 s, frequency 0.001 Hz, peak-to-valley ratio 100:1, and set the flip current 1 A / m 2 , when the current is less than the reversal current, negative voltage bias is applied to perform electrode self-cleaning.

[0384] (3) Continuous processing.

[0385] 4. Treatment effect:

[0386] The concentration of calcium and magnesium ions dropped to 112 mg / L, with a removal rate of 72%. The cell voltage was maintained at 2.3 V, and 4.5 kWh of electricity was consumed for each kilogram of hardness (calculated as calcium carbonate) removed. Example 12

[0387] Continuous method:

[0388] 1. Treatment object: 20 tons (20,000L) cooling tower of thermal power plant, initial calcium and magnesium ion concentration (calculated as calcium carbonate) is 200mg / L.

[0389] 2. Device configuration:

[0390] Electrode system: The electrolytic water anode 3 adopts a platinum-coated mesh electrode, and the electrolytic water cathode 2 adopts a 316L mesh electrode;

[0391] Porous insulating filler layer 4: polypropylene layer (porosity 61%, thickness 0.5 mm, pore size 10-200 μm).

[0392] The preparation method of the polypropylene layer is as follows:

[0393] (1) Dissolve 20.0 g of polypropylene pellets in 160 mL of decahydronaphthalene at 140 °C.

[0394] (2) Add 6.0 g of liquid paraffin.

[0395] (3) The solution was poured into a preheated mold (100 °C, depth 0.65 mm).

[0396] (4) Control the cooling rate, cool down from 140°C to 100°C at a cooling rate of 0.5°C per minute, and then cool naturally from 100°C to 25°C.

[0397] (5) Demolding.

[0398] 3. Operation process:

[0399] (1) Feeding stage: The water in the cooling tower is pumped into the two-electrode chamber at a flow rate of 1m / s through a booster pump;

[0400] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 1.5 V) was applied, with the frequency set to positive bias 4900 s, negative bias 100 s, frequency 0.0002 Hz, peak-to-valley ratio 100:1, and flip current 1 A / m 2 , when the current is less than the reversal current, negative voltage bias is applied to perform electrode self-cleaning.

[0401] (3) Continuous processing.

[0402] 4. Treatment effect:

[0403] The calcium and magnesium ion concentrations dropped to 20 mg / L, achieving a 90% removal rate. The cell voltage was maintained at 2.0 V. The power consumption for each kilogram of hardness (calculated as calcium carbonate) removed was 3.4 kWh. Example 13

[0404] Continuous dechlorination:

[0405] 1. Treatment object: 1 ton (1000L) of data center circulating water, initial chloride ion concentration 800mg / L.

[0406] 2. Device configuration:

[0407] Electrode system: The electrolytic water anode 3 adopts a ruthenium-iridium-graphene mesh electrode, and the electrolytic water cathode 2 adopts a titanium mesh electrode;

[0408] Porous insulating filler layer 4: polyamide layer (porosity 52%, thickness 0.8 mm, pore diameter 10-200 μm).

[0409] The preparation method of the polyamide layer is as follows:

[0410] (1) 20.0 g of polyamide (PA) particles were dissolved in 180 mL of formic acid to form a solution.

[0411] (2) Add 3.6g NaCl.

[0412] (3) Pour the solution into the mold (mold depth: 1.0 mm).

[0413] (4) Place in a fume hood (formic acid has a pungent odor and is corrosive) and slowly evaporate the solvent at 35 degrees Celsius.

[0414] (5) After the solvent has basically evaporated, rinse the residual formic acid on the surface with water, and then place it in an oven at 60 degrees Celsius for vacuum drying.

[0415] (6) De-mould after cooling to room temperature.

[0416] 3. Operation process:

[0417] (1) Feeding stage: The data center circulating water is injected into the bipolar chamber at a flow rate of 1 m / s through a booster pump;

[0418] (2) Electrochemical treatment: Apply square wave alternating current (single-stage voltage 7.2 V), set the frequency to positive bias 95 s, negative bias 5 s, frequency 0.01 Hz, peak-to-valley ratio 50:1, and set the flip current to 1 A / m 2 , when the current is less than the reversal current, negative voltage bias is applied to perform electrode self-cleaning.

[0419] (3) Continuous processing.

[0420] 4. Treatment effect:

[0421] The chloride ion concentration dropped to 160mg / L, with a removal rate of 80%. The cell voltage was maintained at 7.4V. Example 14

[0422] Continuous dechlorination:

[0423] 1. Treatment object: 5 tons (5000L) of circulating water from a chemical plant, with an initial chloride ion concentration of 1000mg / L.

[0424] 2. Device configuration:

[0425] Electrode system: The electrolytic water anode 3 adopts a ruthenium-iridium mesh electrode, and the electrolytic water cathode 2 adopts a titanium-coated ruthenium-iridium mesh electrode;

[0426] Porous insulating filler layer 4: polyimide-polypropylene composite layer (porosity 73%, thickness 1 mm, pore size 10-200 μm).

[0427] The preparation method of the polyimide-polypropylene composite layer is as follows:

[0428] (1) Add 20.0 g of polyamic acid (PAA) to 180.0 mL of N-methylpyrrolidone (NMP) solvent. Stir mechanically at 400 rpm in a constant temperature water bath at 25°C for 6 hours to obtain a homogeneous, transparent PAA / NMP solution with a solid content of 10.0 wt%.

[0429] (2) Add 6.0 g of polypropylene powder (PP) with an average particle size of 20 μm to the above PAA / NMP solution and disperse it at 25°C for 30 minutes using a high-speed shear emulsifier (speed 8000 rpm) until no PP agglomerated particles are visible in the slurry.

[0430] (3) Add 10.0 g of polyethylene glycol 2000 to the slurry and mechanically stir at 500 rpm for 60 minutes at 25 degrees Celsius to ensure that the polyethylene glycol 2000 is completely dissolved.

[0431] (4) Pour into the mold (mold depth: 2 mm).

[0432] (5) Perform programmed temperature drying and imidization: 80 °C for 1 h, 120 °C for 1 h, 200 °C for 1 h, 250 °C for 1 h, and 300 °C for 1 h.

[0433] (6) Cool to below 50 degrees Celsius and demould.

[0434] 3. Operation process:

[0435] (1) Feeding stage: The circulating water from the chemical plant is injected into the bipolar chamber at a flow rate of 0.5 m / s through a booster pump;

[0436] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 5.2 V) was applied, with the frequency set to positive bias 1800 s, negative bias 300 s, frequency 0.00047 Hz, peak-to-valley ratio 20:1, and flip current 1 A / m 2 , when the current is less than the reversal current, negative voltage bias is applied to perform electrode self-cleaning.

[0437] (3) Continuous processing.

[0438] 4. Treatment effect:

[0439] The chloride ion concentration dropped to 280 mg / L, with a removal rate of 72%. The cell voltage was maintained at 5.3 V. Example 15

[0440] 1. Treatment object: 10 tons (10,000 L) of circulating cooling water from a waste-to-energy plant, with an initial chloride ion concentration of 1,100 mg / L.

[0441] 2. Device configuration:

[0442] Electrode system: The electrolytic water anode 3 uses a ruthenium oxide-graphene mesh electrode, and the electrolytic water cathode 2 uses a platinum-coated graphene mesh electrode;

[0443] Porous insulating filler layer 4: polypropylene hollow fiber layer (porosity 68%, thickness 1 mm, pore size 0.2-0.6 μm).

[0444] The preparation method of the polypropylene hollow fiber layer is as follows (forming a self-supporting layer):

[0445] (1) Polypropylene hollow fibers (PPHF) are laid tightly and fixed in parallel in the mold frame (mold depth: 2 mm).

[0446] (2) Spray hot melt adhesive on the fiber contact points, and then gently heat press at 50 degrees Celsius to bond the fibers together.

[0447] (3) After cooling to room temperature, demolding is performed to obtain a porous layer composed of the pores of PPHF itself.

[0448] 3. Operation process:

[0449] (1) Feeding stage: Circulating cooling water is injected into the bipolar chamber at a flow rate of 0.5 m / s through a booster pump.

[0450] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 4.5 V, frequency 0.00093 Hz (cycle 1080 s / 18 min), peak-to-valley ratio 10:1) was applied for 4 cycles (total duration 4320 s).

[0451] (3) Discharge of regenerated water: Open the anode chamber outlet pipe 10 and the cathode chamber outlet pipe 11, and pump the regenerated water into the regenerated water tank 7 at a flow rate of 0.5 m / s.

[0452] (4) Loop processing: Repeat 10 times, run 40 cycles in total, and the total processing time is 43,200 seconds (12 hours).

[0453] 4. Treatment effect:

[0454] Raw water tank: 10,000L of recycled water from the waste-to-energy plant has been fully processed.

[0455] Outlet water quality: 10,000L of recycled water was collected, the chloride ion concentration dropped to 44mg / L, and the removal rate was 96%.

[0456] Actual energy consumption data: The initial slot voltage is 4.7V, and the slot voltage rises to 4.8V (increase value 0.1V) at the end of the treatment cycle. Example 16

[0457] 1. Treatment object: 5 tons (5000L) of landfill leachate, initial chloride ion concentration 2800mg / L.

[0458] 2. Device configuration:

[0459] Electrode system: The electrolytic water anode 3 adopts an iridium oxide-graphene mesh electrode, and the electrolytic water cathode 2 adopts an iridium oxide-graphene mesh electrode.

[0460] Porous insulating filler layer 4: polytetrafluoroethylene composite layer (porosity 56%, thickness 0.5 mm, pore size 10-500 μm).

[0461] The preparation method of the polytetrafluoroethylene composite layer is as follows:

[0462] (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%.

[0463] (2) Add 45 g of sodium chloride particles with a particle size range of 100 μm to 150 μm as a pore former and stir continuously at 500 rpm for 60 minutes in a constant temperature water bath at 25 degrees Celsius to ensure that the pore former particles are evenly dispersed and there is no agglomeration.

[0464] (3) Pour into the mold (mold depth: 1 mm).

[0465] (4) Dry at room temperature, then program the temperature increase: 80 degrees Celsius for drying for 1 hour, 250 degrees Celsius for removing organic matter for 1 hour, and 365 degrees Celsius for sintering for 1 hour.

[0466] (5) Cool to below 50 degrees Celsius and demould.

[0467] 3. Operation process:

[0468] (1) Feeding stage: The concentrated circulating water is injected into the bipolar chamber at a flow rate of 1.0 m / s through a booster pump.

[0469] (2) Electrochemical treatment: square wave alternating current (single-stage voltage 4.8 V, frequency 0.0017 Hz (cycle 600 s / 10 min), peak-to-valley ratio 10:1) was applied for 5 cycles (total duration 3000 s).

[0470] (3) Discharge of regenerated water: Open the anode chamber outlet pipe 10 and the cathode chamber outlet pipe 11, and pump the regenerated water into the regenerated water tank 7 at a flow rate of 1.0 m / s.

[0471] (4) Loop processing: Repeat 10 times, run 50 cycles in total, and the total processing time is 30,000 seconds (500 minutes).

[0472] 4. Treatment effect:

[0473] Raw water tank: 5000L of leachate has been processed.

[0474] Outlet water quality: 5000L of recycled water was collected, the chloride ion concentration dropped to 84mg / L, and the removal rate was 97%.

[0475] Actual energy consumption data: The initial slot voltage is 4.9V, and the slot voltage rises to 5.0V (increase value 0.1V) at the end of the treatment cycle.

[0476] The above examples are summarized in Table 1 below.

[0477]

[0478]

Claims

1. A composite electrode unit, characterized in that: It includes: A water electrolysis cathode (2), a porous insulating filler layer (4) and a water electrolysis anode (3); the porous insulating filler layer (4) is located between the water electrolysis cathode (2) and the water electrolysis anode (3); The inner material of the porous insulating filler layer (4) does not contain exchangeable ions, and the inner part refers to the non-surface part; The water electrolysis cathode (2), the porous insulating filler layer (4) and the water electrolysis anode (3) are bonded to each other; The porous insulating filler layer (4) is entirely made of a hydrophobic material; Alternatively, the inner material of the porous insulating filler layer (4) is a hydrophobic material, and the surface is a hydrophilic material, where the inner part refers to the non-surface part; 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 μm.

2. The composite electrode unit according to claim 1, characterized in that The material of the porous insulating filler layer (4) is selected from the group consisting of polyethylene, polystyrene, polyphenylene sulfide, polyvinyl chloride, polypropylene, polyurethane, polyamide, polyethersulfone, polypropylene hollow fiber, polytetrafluoroethylene, polyvinylidene fluoride, sulfonated polyetheretherketone, polybenzimidazole, polyimide, asbestos, aluminum oxide, silicon carbide, silicon nitride, zirconium oxide, boron nitride, mullite, cordierite, aluminum titanate, and silicon dioxide, or a combination thereof.

3. The composite electrode unit according to claim 1, characterized in that The surface of the porous insulating filler layer (4) is modified.

4. An electrochemical water treatment system, characterized in that: The system comprises: a reaction chamber (5); The reaction chamber (5) is provided with: the composite electrode unit according to any one of claims 1 to 3; In the reaction chamber (5), the chamber on the side of the water electrolysis cathode (2) of the composite electrode unit is a cathode chamber, and the chamber on the side of the water electrolysis anode (3) of the composite electrode unit is an anode chamber.

5. The electrochemical water treatment system according to claim 4, characterized in that: The reaction chamber (5) further comprises a power supply (1) for providing direct current or alternating current to the water electrolysis cathode (2) and the water electrolysis anode (3).

6. The electrochemical water treatment system according to claim 4, characterized in that: 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, so as to achieve physical isolation between the cathode chamber and the anode chamber by the composite electrode unit.

7. The electrochemical water treatment system according to claim 4, characterized in that: The system further comprises: a raw water tank (6), a recycled water tank (7); The raw water tank (6) is connected to the anode chamber via an anode chamber inlet pipe (8); The raw water tank (6) is connected to the cathode chamber via a cathode chamber inlet pipe (9); The regenerated water tank (7) is connected to the anode chamber via an anode chamber outlet pipe (10); The regenerated water tank (7) is in communication with the cathode chamber via a cathode chamber outlet pipe (11).

8. The electrochemical water treatment system according to claim 7, characterized in that: The system further comprises: a filtering device (12) provided on the cathode chamber outlet pipeline (11), for filtering solid matter in the liquid in the cathode chamber outlet pipeline (11).

9. The electrochemical water treatment system according to claim 7, characterized in that: The raw water tank (6) and the regenerated water tank (7) are connected via a circulation pipeline.

10. An electrochemical water treatment method, characterized in that: The method is performed using the electrochemical water treatment system according to any one of claims 4 to 9, and the method comprises the following steps: Raw water containing calcium ions and / or magnesium ions is injected into the cathode chamber and the anode chamber respectively, a 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 perform electrolysis, and a water electrolysis reaction occurs in the composite electrode unit; When direct current is supplied: during water electrolysis, hydrogen is generated in the cathode chamber and an alkaline environment is formed, causing calcium ions and / or magnesium ions to form solid matter precipitation to reduce the hardness of the water; during water electrolysis, oxygen is generated in the anode chamber and an acidic environment is formed; ultimately, alkaline water containing solid matter 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: when electrolyzing water, hydrogen is generated in the cathode chamber and an alkaline environment is formed, so that calcium ions and / or magnesium ions form solid matter precipitation, and part of the solid matter precipitation crystallizes on the surface of the original electrolytic water cathode (2); when electrolyzing water, oxygen is generated in the anode chamber and an acidic environment is formed; After the current direction changes in each alternating current cycle, the water electrolysis cathode (2) and the water electrolysis anode (3) are reversed, so that the original water electrolysis anode (3) becomes a temporary cathode and begins to generate hydroxide, and the original water electrolysis cathode (2) becomes a temporary anode and begins to generate hydrogen ions. The hydrogen ions dissolve solid matter crystallized on the surface of the original water electrolysis cathode (2) from the surface of the original water electrolysis cathode (2), thereby achieving in-situ self-cleaning of the water electrolysis cathode (2); During the next AC cycle, calcium ions and / or magnesium ions in the water are continuously precipitated in the cathode chamber, thereby reducing the water hardness. Finally, alkaline water containing solid matter is obtained in the cathode chamber, and acidic water is obtained in the anode chamber.

11. The electrochemical water treatment method according to claim 10, characterized in that: When the raw water also contains chloride ions, the chloride ions in the anode chamber are oxidized into chlorine gas and removed.

12. The electrochemical water treatment method according to claim 10, characterized in that: When the method is performed using the electrochemical water treatment system according to claim 7: 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 in claim 10 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.

13. The electrochemical water treatment method according to claim 10, characterized in that: When the method is performed using the electrochemical water treatment system according to claim 8: The solid matter in the alkaline water containing solid matter is filtered by the filtering device (12).

14. The electrochemical water treatment method according to claim 10, characterized in that: The voltage of the direct current or alternating current is: 1.5V~30V.

15. The electrochemical water treatment method according to claim 10, characterized in that: When the direct current or alternating current is applied, the current density on the water electrolysis cathode (2) or the water electrolysis anode (3) is 1-1000 A / m 2 .

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