A high-efficiency, low-corrosive electrochemical water softening reactor and treatment method

Abstract

The present invention relates to an electrochemical water softening reactor with high efficiency and low corrosion and a treatment method. The reactor comprises a cathode, an activated carbon separator, and an anode. The activated carbon separator comprises activated carbon, a nylon mesh, and a hollow-core separator. The activated carbon is filled in the separator, and the nylon mesh is sheathed outside the separator. The activated carbon separator blocks the H generated by the anode and cathode respectively. + and OH ‑ Neutralization under the action of water flow and bubbles inhibits H + With OH ‑ Neutralization reaction. Compared with the prior art, the activated carbon separator prepared in the present invention can be used in electrochemical reactors to effectively improve water softening efficiency. At the same time, it can effectively adsorb active substances such as hypochlorite ions generated by electrolysis, reducing the corrosiveness of the water body after electrolysis. In addition, the preparation process is simple, the reaction conditions are easy to control, the raw materials are readily available, the preparation cost is low, and it is suitable for large-scale industrial production applications.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, in particular to a high-efficiency, low-corrosive electrochemical water softening reactor and a treatment method. Background Art

[0002] In a circulating cooling water system, as the circulating water passes through the cooling pipes, scaling substances in the water will precipitate as inorganic salts such as calcium and magnesium due to the high surface temperature of the cooling pipes. This scale formation can easily clog pipes and equipment, seriously affecting heat transfer efficiency and the normal operation of the circulating cooling water. To address the scaling and corrosion problems caused by high salt water, appropriate measures must be taken to reduce the hardness and alkalinity of the circulating cooling water to ensure stable system operation.

[0003] There are many methods for softening water, including chemical softening, ion exchange softening, membrane separation softening, adsorption softening and electrochemical softening. Among them, electrochemical water softening can effectively remove hardness ions and alkalinity ions in water by electrolysis without adding additional chemical agents, thereby preventing the formation of scale, keeping the pipe surface clean, and further improving the concentration of water and reducing the discharge of circulating water wastewater. However, the OH produced by the cathode in the conventional electrochemical softening reactor during use - The H generated at the anode + The rapid neutralization results in a low efficiency of electrochemical water softening. Meanwhile, during the electrolysis process, the cathode surface is gradually covered with inorganic salt scale, which deactivates the cathode and reduces the hardness removal efficiency. Active substances such as hypochlorite ions are generated on the anode surface, which increases the water's corrosiveness to metals such as carbon steel.

[0004] Therefore, improving conventional electrochemical water softening reactors and resolving the above problems are of great significance for the industrial promotion of electrochemical water softening technology. Summary of the Invention

[0005] The purpose of the present invention is to provide an electrochemical water softening reactor and treatment method with high efficiency and low corrosion in order to overcome the defects of the above-mentioned prior art. By inserting an isolation membrane between the anode and cathode, the movement of water flow and bubbles is effectively slowed down, and the H generated at the anode and cathode can be effectively suppressed. + and OH - The neutralization reaction occurs, making most of the OH - In the cathode area, a high concentration is maintained, driving the hardness ions to undergo a homogeneous crystallization reaction in this area, thereby achieving efficient removal of hardness in water.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The present invention provides a reactor for improving the efficiency of electrochemical water softening and reducing the corrosion of electrolyzed water to metals, comprising a cathode and an anode, wherein the activated carbon separator comprises activated carbon, a nylon mesh and a separator with a hollow center, wherein the activated carbon is filled in the separator and the nylon mesh is sheathed outside the separator;

[0008] The activated carbon separator blocks the H generated by the anode and cathode respectively. + and OH - Neutralization under the action of water flow and bubbles inhibits H + With OH - neutralization reaction.

[0009] Furthermore, the cathode is a stainless steel plate electrode.

[0010] Furthermore, the anode is a titanium, iridium, and ruthenium mesh electrode.

[0011] Furthermore, a water inlet is provided at the bottom of the reaction tank, and the water inlet is connected to the peristaltic pump through a pipeline.

[0012] Furthermore, the input end of the peristaltic pump is connected to the water pool, and the peristaltic pump is used to pump water into the lower part of the reaction tank.

[0013] Furthermore, the activated carbon particles in the activated carbon separator adsorb hypochlorite generated by electrolysis, thereby inhibiting the corrosion of hypochlorite on metal materials and reducing the corrosiveness of water.

[0014] Furthermore, an anode overflow outlet and a cathode overflow outlet are respectively provided on both sides of the reactor. The cathode overflow outlet is connected to a crystallization chamber through a pipeline. The crystallization chamber is used to discharge cathode alkaline water to enhance the precipitation of CaCO3.

[0015] Furthermore, the volume of the reactor is 1-3L.

[0016] The present invention also provides a method for improving the electrochemical water softening efficiency and reducing the corrosion of electrolyzed water to metals, characterized in that the water to be softened is placed in the above-mentioned reactor for electrochemical water softening treatment.

[0017] Furthermore, a constant current mode is adopted with a current density of 10-150 A / m 2 .

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0019] 1. The present invention effectively slows down the movement of water flow and bubbles by building an activated carbon separator between the anode and cathode, which can effectively inhibit the H generated by the anode and cathode respectively. + and OH - The neutralization reaction occurs, making most of the OH- In the cathode area, a high concentration is maintained, driving the hardness ions to undergo a homogeneous crystallization reaction in this area, thereby achieving efficient removal of hardness in water.

[0020] 2. The activated carbon particles used in the present invention can act as crystal nuclei in water, promoting the precipitation and crystallization of inorganic salts on the surface of the activated carbon, thereby inhibiting scaling on the cathode surface and slowing down the occurrence of cathode surface deactivation.

[0021] 3. The present invention uses activated carbon particles in the activated carbon separator to adsorb active substances such as hypochlorite generated by electrolysis, which can effectively inhibit the corrosion of metal materials in water by these active substances and reduce the corrosiveness of water.

[0022] 4. The preparation process of the present invention is simple, the reaction conditions are easy to control, the raw materials are readily available, the preparation cost is low, and it is suitable for industrial large-scale production applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a comparison chart of the removal rates of hardness, calcium ions, and magnesium ions in water in Example 1;

[0024] Figure 2 This is a graph showing the effect of current density on the treatment performance of the electrochemical water softening reactor in Test Example 1;

[0025] Figure 3 The electrochemical impedance spectroscopy of carbon steel in test example 2 in aqueous solutions containing different concentrations of hypochlorite ions;

[0026] Figure 4 This is the electrochemical impedance spectroscopy of the carbon steel in Test Example 2 in the hypochlorite-containing aqueous solution after being immersed in the activated carbon plate for different times. DETAILED DESCRIPTION

[0027] The specific implementation methods of the present invention are described in detail below through examples. These examples are implemented under the premise of the scheme described in the present invention, and provide detailed implementation methods and specific operating processes, but the protection scope of the present invention is not limited to the following examples.

[0028] The present invention is further described below with reference to the accompanying drawings and specific embodiments. Any features, such as component models, material names, connection structures, preparation methods, materials, structures, or composition ratios, that are not explicitly described in this technical solution are considered to be common technical features disclosed in the prior art.

[0029] Example 1

[0030] The present embodiment provides a high-efficiency, low-corrosive electrochemical water softening reactor, comprising a cathode, an activated carbon separator, and an anode, wherein the activated carbon separator comprises activated carbon, a nylon mesh, and a separator with a hollow center, wherein the activated carbon is filled in the separator, and the nylon mesh is sleeved outside the separator. The cathode is a stainless steel plate electrode, and the anode is a titanium iridium ruthenium mesh electrode. A water inlet is provided at the bottom of the reaction tank, and the water inlet is connected to a peristaltic pump through a pipeline. The input end of the peristaltic pump is connected to a water pool, and the peristaltic pump is used to pump water into the lower part of the reaction tank. An anode overflow outlet and a cathode overflow outlet are provided on both sides of the reactor, respectively. The cathode overflow outlet is connected to a crystallization chamber through a pipeline, and the crystallization chamber is used to discharge cathode alkaline water to enhance the precipitation of CaCO3.

[0031] The activated carbon separator blocks the H generated by the anode and cathode respectively. + and OH - Neutralization under the action of water flow and bubbles inhibits H + With OH - The activated carbon particles in the activated carbon separator absorb the hypochlorite generated by electrolysis, inhibiting the corrosion of hypochlorite on metal materials and reducing the corrosiveness of water.

[0032] This embodiment also provides an efficient and low-corrosive electrochemical water softening treatment method, using Mg(OH)2, CaCl2 and NaHCO3 to simulate hardness and alkalinity. The hardness, alkalinity and conductivity of the prepared water sample are 800 mg CaCO3 / L, 250 mg CaCO3 / L and 11780 μS / cm, respectively. Electrochemical water softening experiments are carried out in the above-mentioned reactor.

[0033] The effective volume of the electrolytic cell is 2 L. The constant current mode is used and the electrolysis time is 60 min. Figure 1 As shown, when the electrochemical water softening reactor in this embodiment is used, the removal rates of total hardness, calcium ions and magnesium ions are 51.6%, 48.2% and 62.0%, respectively, while when a conventional electrochemical water softening reactor is used, that is, a reactor without an activated carbon partition, the removal rates of total hardness, calcium ions and magnesium ions are 5.7%, 7.2% and 1.5%, respectively. It can be seen that the electrochemical water softening reactor in this embodiment effectively improves the efficiency of electrochemical water softening.

[0034] Test Example 1

[0035] This test example determined the effect of current density on the treatment performance of an electrochemical water softening reactor. Mg(OH)2, CaCl2, and NaHCO3 were used to simulate hardness and alkalinity. The hardness, alkalinity, and conductivity of the prepared water sample were 800 mg CaCO3 / L, 250 mg CaCO3 / L, and 11780 μS / cm, respectively. The electrochemical water softening experiment was conducted in an electrolytic cell with an effective volume of 2 L. The constant current mode was used, and the current densities used were 3, 6, 8, 9, and 12 mA / cm, respectively. 2 .

[0036] The current density determines the OH - The production rate of OH in the electrolytic cell - The driving force behind the diffusion of a large alkaline region is the movement of H2 bubbles generated by water reduction. The current density determines the rate of H2 bubble generation, which in turn affects the movement of H2 bubbles. As the current increases, the efficiency of H2 release increases. When the current density increases, the pH value increases significantly. The results are shown in Figure 2. Figure 2 As shown in the figure, with the increase of current density, the hardness removal rate in water increases. When the current density is 9 mA / cm 2 When the current density increases, the hardness removal rate no longer increases, which may be because the solution has generated enough OH - , but due to the lack of more HCO3 in the solution - , CO3 cannot be generated 2- To make Ca 2+ precipitation.

[0037] Test Example 2

[0038] This test example determines whether hypochlorite causes the water to become more corrosive to carbon steel. Figure 3 As shown, 20, 50, and 100 mg / ClO were added to the raw water. - The electrochemical test of hypochlorite is carried out, such as Figure 3 As shown in the figure, as the concentration of added hypochlorite ions increases, the radius of the impedance spectrum of the carbon steel electrode shows a decreasing trend, and the impedance modulus also gradually decreases, indicating that hypochlorite ions accelerate the corrosion of carbon steel. The higher the concentration, the smaller the corrosion resistance of carbon steel. After adopting the electrochemical reactor of the present invention, since the activated carbon separator is introduced into the reactor, this separator not only improves the efficiency of the electrochemical treatment, but also the activated carbon can effectively adsorb hypochlorite ions in the water, thereby reducing the corrosiveness of electrolyzed water to carbon steel. Figure 4As shown in the figure, the activated carbon separator was immersed in hypochlorite-containing water for 0 hours, 12 hours, 24 hours, and 48 hours, respectively. As can be seen from the figure, as the activated carbon plate is immersed in hypochlorite-containing water for longer, the impedance value of the carbon steel electrode increases, and the water's corrosiveness to carbon steel decreases. This is due to the activated carbon plate's adsorption of hypochlorite ions. Testing found that the hypochlorite concentration in the water decreased from an initial 100 mg / L to 12 mg / L after 48 hours, effectively suppressing carbon steel corrosion.

[0039] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A high-efficiency, low-corrosive electrochemical water softening reactor, characterized in that: It includes a cathode, an activated carbon separator and an anode, wherein the activated carbon separator includes activated carbon, a nylon mesh and a separator with a hollow center, the activated carbon is filled in the separator, and the nylon mesh is sheathed outside the separator; The activated carbon separator blocks the H generated by the anode and cathode respectively. + and OH - Neutralization under the action of water flow and bubbles inhibits H + With OH - neutralization reaction.

2. The high-efficiency, low-corrosive electrochemical water softening reactor according to claim 1, characterized in that: The cathode is a stainless steel plate electrode.

3. The high-efficiency, low-corrosive electrochemical water softening reactor according to claim 1, characterized in that: The anode is a titanium, iridium, and ruthenium mesh electrode.

4. The high-efficiency, low-corrosive electrochemical water softening reactor according to claim 1, characterized in that: The activated carbon particles in the activated carbon separator adsorb hypochlorite generated by electrolysis, inhibit the corrosion of hypochlorite to metal materials, and reduce the corrosiveness of water.

5. The high-efficiency, low-corrosive electrochemical water softening reactor according to claim 1, characterized in that: An anode overflow outlet and a cathode overflow outlet are respectively provided on both sides of the reactor. The cathode overflow outlet is connected to a crystallization chamber through a pipeline. The crystallization chamber is used to discharge cathode alkaline water to enhance the precipitation of CaCO3.

6. The high-efficiency, low-corrosive electrochemical water softening reactor according to claim 1, characterized in that: The volume of the reactor is 1-3L.

7. A high-efficiency, low-corrosive electrochemical water softening treatment method, characterized in that: The water to be softened is placed in the reactor as described in any one of claims 1 to 6 for electrochemical water softening treatment.

8. The high-efficiency, low-corrosive electrochemical water softening treatment method according to claim 7, characterized in that: Use constant current mode with a current density of 10-150 A / m 2 .

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