Device and method for preparing hypochlorous acid water

Abstract

The present invention relates to a device and method for preparing hypochlorous acid water, and belongs to the technical field of water electrolysis. The device comprises a container and a direct current power supply, wherein at least one pair of anode and cathode electrodes are arranged in the container, wherein the anode electrode is located above the cathode electrode when the container is placed in its normal state, and the DC power supply supplies power to the electrodes to form electrolysis of the solution, and the container is provided with a liquid inlet and a liquid inlet valve, a liquid discharge port and a liquid discharge valve; an opening connected to the atmosphere is arranged at the bottom of the container when it is placed in its normal state, the cathode electrode is close to the opening and a channel is left for the solution to pass through the opening, and a resistance member is arranged at the opening to form a resistance pressure for the solution to flow outward through the opening; during electrolysis, when the gas pressure in the container + the gravity pressure-resistance pressure of the solution > the atmospheric pressure, the solution is discharged outward through the resistance member. The device can be used to stably prepare slightly acidic hypochlorous acid water with a pH value of 5.5 to 6.5.

Description

Technical Field

[0001] The invention relates to a device for preparing hypochlorous acid water and a method for preparing hypochlorous acid water, belonging to the technical field of water electrolysis. Background Art

[0002] Hypochlorous acid water is a chlorine-containing disinfectant, and its effective bactericidal ingredient is hypochlorous acid (HClO). The pH of hypochlorous acid water has a great influence on the concentration of hypochlorous acid in the water. When the pH value is in the range of 5.5 to 6.5, the concentration of hypochlorous acid tends to be the maximum, and the bactericidal effect of hypochlorous acid water is greatly enhanced; the more alkaline the pH value is, the more hypochlorous acid in the hypochlorous acid water is converted into the state of hypochlorite ions (OCl-), and the bactericidal power decreases (according to relevant tests, the bactericidal power of hypochlorite ions is only about 1 / 80 of that of hypochlorous acid); if the pH value of hypochlorous acid water is more acidic, more chlorine gas is generated in the water, and the concentration of hypochlorous acid is also reduced. (The above relationship is shown in Figure 1 ).

[0003] There are many methods for producing hypochlorous acid water. The known standard method is to produce it by electrolyzing 2% to 6% dilute hydrochloric acid water (generally diluted with pure water) in a one-chamber type, i.e., non-diaphragm electrolytic cell at a DC voltage of about 2 V. Chlorine gas and H+ are generated at the anode. H+ dissolves in water to make the water acidic. Chlorine gas reacts with water to generate hydrochloric acid and hypochlorous acid (HClO), so that the effective chlorine concentration in the water reaches 10 to 30 mg / L; hydrogen gas is generated at the cathode.

[0004] Since hydrochloric acid is expensive and is a highly toxic and dangerous substance that is restricted for purchase and difficult to obtain, it cannot be widely used. Currently, table salt (sodium chloride) is commonly used to replace hydrochloric acid.

[0005] The typical method for producing hypochlorous acid water with sodium chloride as the electrolytic solution is to use two-chamber or three-chamber diaphragm electrolysis. Taking the two-chamber electrolytic cell as an example, the raw water (salt water) is sent to the anode chamber (or sent to the cathode chamber at the same time), the water output from the anode chamber is acidic electrolyzed water and the water output from the cathode chamber is alkaline electrolyzed water, the alkaline water produced by the cathode chamber is mixed with the acidic electrolyzed water produced by the anode chamber in a certain proportion, and the pH of the acidic electrolyzed water produced by the anode chamber is increased, and finally slightly acidic hypochlorous acid water with a pH value of 5.5-6.5 is obtained.

[0006] Another method for producing hypochlorous acid water is to first electrolyze sodium chloride aqueous solution without a diaphragm to obtain an alkaline sodium hypochlorite solution, and then add acid (typically dilute hydrochloric acid, but also weak acids such as acetic acid and carbonic acid) to the sodium hypochlorite solution in proportion to gradually reduce the alkalinity of the sodium hypochlorite solution until it becomes neutral or slightly acidic hypochlorous acid water.

[0007] The key point of the existing device for producing hypochlorous acid water by electrolyzing salt water is the online monitoring of pH value, and some are also equipped with online monitoring of redox potential or effective chlorine. However, there are many factors that affect the above parameters, so that the control system (usually single parameter or multi-parameter closed-loop regulation) has a very complex structure, difficult process control, difficult to maintain stable characteristic parameters, poor safety and many other problems. Summary of the invention

[0008] The technical problem to be solved by the present invention is to simplify the structure and process of the existing hypochlorous acid water preparation device to achieve the preparation of hypochlorous acid water with stable and reliable process, simple device structure and high safety, so as to be suitable for promotion and popularization to households.

[0009] The present invention proposes a first technical solution to solve the above technical problems: a device for preparing hypochlorous acid water, comprising a container for containing a salt solution and a DC power supply, at least one pair of anode and cathode electrodes are arranged in the container, the anode electrode is located above the cathode electrode when the container is placed in its normal state, the DC power supply supplies power to the anode and cathode electrodes to form electrolysis of the solution, and the container is provided with a liquid inlet and a liquid inlet valve, a liquid discharge port and a liquid discharge valve; characterized in that: the bottom of the container is provided with an opening connected to the atmosphere when it is placed in its normal state, the cathode electrode is close to the opening and has a channel for allowing the solution to pass through the opening, and a resistance member is provided at the opening to form a resistance pressure for the solution to flow outward through the opening; during electrolysis, when the gas pressure in the container + the gravity pressure of the solution - the resistance pressure > atmospheric pressure, the solution is discharged outward through the resistance member.

[0010] The technical solution of the first aspect is further that: the resistance pressure is a set constant. The top wall of the container is provided with an exhaust port and an exhaust valve; the top wall of the container is provided with a salt adding tank, the side wall of the salt adding tank located in the container is provided with a small hole, and the tank mouth of the salt adding tank is provided with a cap and a sealing member. The bottom of the container is also connected to a waste liquid tank, and the tank wall of the waste liquid tank is provided with a waste outlet and a waste valve that is normally open and connected to the atmosphere. The resistance member is a microporous plate, a microporous membrane or a pressure reducing valve.

[0011] A variation of the technical solution of the first aspect mentioned above is: the container is a bucket, a support seat is formed at the bottom of the bucket, the support seat is formed with a through hole to form the opening, a screw cover is provided between the support seat and the bottom of the bucket to form a threaded connection between the bottom of the bucket and the support seat, and the resistance member is arranged at the connection between the screw cover and the end face of the support seat; the cathode electrode is arranged at the bottom of the bucket close to the resistance member, one end of which is fixed to the support seat, and the other end of which is connected to the first wire hole on the screw cover; the anode electrode is arranged on the upper part of the bucket, one end of which is fixed to the support seat, and the other end of which is connected to the second wire hole on the upper part of the bucket.

[0012] The present invention proposes a second technical solution to solve the above technical problem: a method for preparing hypochlorous acid water, applying the above first technical solution and performing the following steps:

[0013] 1) setting a first volume of the container and a second volume of the saline solution such that the first volume is greater than the second volume;

[0014] 2) selecting a resistance member with resistance pressure and placing it at the opening of the container;

[0015] 3) placing the container in a normal state and filling the container with the second volume of saline solution;

[0016] 4) setting an electrolysis time according to the second volume, supplying power to the cathode electrode and the anode electrode, and electrolyzing the solution in the container;

[0017] 5) Gas is generated in the container during electrolysis, and when the gas pressure formed by the gas in the container + the gravity pressure of the solution - the resistance pressure > atmospheric pressure, the opening is observed to discharge the solution outward;

[0018] 6) When the electrolysis time is reached, turn off the DC power supply, open the drain valve, and discharge the electrolyzed solution.

[0019] The first change of the technical solution of the second aspect is that an exhaust port and an exhaust valve are provided on the top wall of the container; in the step 5), the exhaust valve is adjusted so that the air pressure formed by the gas in the container + the gravity pressure of the solution - the resistance pressure > atmospheric pressure.

[0020] A second variation of the technical solution of the second aspect is that a salt adding tank is provided on the top wall of the container, and a cap and a seal are provided at the mouth of the salt adding tank; the step 3) is to cover the salt adding tank with the cap after adding salt, and then fill the container with the second volume of pure water.

[0021] A third variation of the technical solution of the second aspect is that a waste liquid tank is connected to the bottom of the container, and a waste discharge port and a waste discharge valve normally open and connected to the atmosphere are provided on the tank wall of the waste liquid tank. In the step 6), the drain valve is opened to discharge the electrolyzed solution into the waste liquid tank.

[0022] The beneficial effects of the present invention are:

[0023] 1. Compared with the existing hypochlorous acid water preparation process and device, the device of the present invention has a simple structure, a stable and reliable method, low requirements on components, and a very high cost performance, and is suitable for promotion and popularization to thousands of households.

[0024] 2. Based on the arrangement of the positive and negative electrodes of the device of the present invention in the container, since the positive electrode is close to the discharge port on the side wall of the container, high-quality hypochlorous acid water can be obtained; at the same time, since the negative electrode is close to the opening at the bottom of the container, heavy metal ions and alkali solution (NaOH) etc. generated by the electrolysis of the solution near the negative electrode can be discharged from the container, thereby improving safety.

[0025] 3. The device of the present invention can be designed with a container of fixed size as required, so that a fixed amount of hypochlorous acid water can be produced and the electrolysis automatically stops after being discharged. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The device for preparing hypochlorous acid water of the present invention will be further described below in conjunction with the accompanying drawings.

[0027] Figure 1 A graph showing the relationship between the residual ratio of hypochlorous acid water and the pH value of hypochlorous acid water in the background art.

[0028] Figure 2 It is a structural schematic diagram of a device for preparing hypochlorous acid water in Example 1.

[0029] Figure 3 It is a structural schematic diagram of a device for preparing hypochlorous acid water in Example 2.

[0030] Figure 4 It is a structural schematic diagram of a device for preparing hypochlorous acid water in Example 3.

[0031] Figure 5 It is a structural schematic diagram of a device for preparing hypochlorous acid water in Example 4.

[0032] Figure 6 It is a structural schematic diagram of a household hypochlorous acid water preparation device according to Embodiment 5. DETAILED DESCRIPTION Example

[0033] This embodiment proposes a device for preparing hypochlorous acid water, such as Figure 2As shown, it includes a container 1 for holding a salt-containing solution (salt is selected in this embodiment) and a DC power supply 6. A pair of positive electrodes 5 and negative electrodes 2 arranged in upper and lower positions are arranged in the container 1 (that is, the positive electrode 5 is located above the negative electrode 2 when the container 1 is placed in its normal state). The negative electrode 2 and the positive electrode 5 can usually be made into a plate, a block or other shapes. The DC power supply 6 supplies power to the negative electrode 2 and the positive electrode 5 to form a diaphragm-free electrolysis of the solution in the container 1. The side wall of the container 1 is provided with a liquid inlet 7 and a liquid inlet valve 9, a liquid discharge port 8 and a liquid discharge valve 10. An opening 3 connected to the atmosphere is provided at the bottom of the container 1 when it is placed in its normal state, and the negative electrode 2 is close to the opening and has a channel for the solution in the container 1 to pass through the opening. A resistance member 4 is provided at the opening to form a resistance pressure for the solution in the container 1 to flow outward through the opening. In this embodiment, the resistance member 4 is a metal microporous plate (metal mesh plate) with micropores, and the pore size of the micropores is between 10-100 microns. The surface tension of the metal mesh plate to salt solutions such as water or brine can form a resistance pressure on the solution in the container. The resistance pressure is usually a constant based on the metal mesh plate and its micropores.

[0034] The specific process of producing hypochlorous acid water by the hypochlorous acid water production device of this embodiment is as follows:

[0035] 1) The volume of the container 1 is set as the first volume V1 and the volume of the salt solution is set as the second volume V2, so that the first volume V1 is larger than the second volume V2. In this embodiment, the height of the container 1 is set as h, the distance between the anode 5 and the top surface of the container 1 is set as h1, the distance between the anode 5 and the bottom surface of the container 1 is set as h2, h1+h2<h, and the cross-sectional area of ​​the container 1 is set as S, then the second volume V2 can be set as h1xS or (h1+h2)xS.

[0036] 2) Select a resistance member 4 with a constant resistance pressure and place it at the opening 7 of the container 1. The resistance pressure Presistance of the solution in the resistance member 4 can usually be obtained through experiments.

[0037] 3) The container 1 is placed in a normal state (i.e., the anode electrode 5 is located above the cathode electrode 2), and a second volume V2 of brine is added to the container 1. Before electrolysis, the gravity pressure Pweight of the brine in the container 1 minus the resistance pressure Presistance ≤ atmospheric pressure.

[0038] 4) Set the electrolysis time T according to the second volume. Usually, the electrolysis time is obtained through experiments on different volumes of saline solutions. Turn on the DC power supply 6 to supply power to the cathode electrode 2 and the anode electrode 5 to electrolyze the salt water. The following electrochemical reactions occur during the electrolysis:

[0039] 2NaCl+2H2O+e→2NaOH+H2+Cl2+O2 (1)

[0040] 2H2O+e→2H2+O2 (2)

[0041] H2O+Cl2→HClO+HCl (3)

[0042] 2NaOH+Cl2=2NaClO+H2 (4);

[0043] Cl is generated on the anode 5 side ２ ↑ and O2↑, generating H on the cathode 2 side ２ ↑, Cl is generated on the anode 5 side ２ Dissolved in salt water to react and generate hypochlorous acid HClO; some Cl ２ The oxygen and O2 rise and gather in the upper space of container 1 (the volume of this space = V1-V2) and gradually form a gas pressure Pgas on the brine and its electrolytic solution in container 1. When electrolysis begins, Pgas + Pweight - Presistance ≤ atmospheric pressure. At this time, the brine cannot be discharged through the micropores of the metal mesh due to the resistance pressure formed by the surface tension of the liquid and the atmospheric pressure.

[0044] 5) During electrolysis, when the pressure in container 1 is Pgas + Pweight - Presistance>atmospheric pressure, the solution generated after electrolysis of the salt water in container 1 is discharged outward through the micropores of the resistance member 4 (metal mesh plate) at the opening 3. The solution contains NaOH, the product on the cathode side, that is, NaOH on the cathode side is discharged from the micropores. At this time, it can be observed that the solution is discharged outward from the opening 3, thereby reducing the alkalinity of the solution in the container and making the pH value as low as possible.

[0045] 6) When the electrolysis time T is reached, the DC power supply 6 is turned off, and the drain valve 10 is opened to discharge the solution generated after the electrolysis of the salt water, which contains hypochlorous acid HClO and sodium hypochlorite NaClO produced on the anode side, thereby obtaining the desired solution containing hypochlorous acid HClO.

[0046] In this embodiment, the second volume V2 is the total amount of liquid that can be discharged. When the amount of liquid discharged exceeds the second volume V2, the distance between the liquid level of container 1 and the top surface of container 1 will be greater than h, that is, the anode 5 is exposed from the liquid surface. At this time, the electrolysis current drops to zero, and the electrolysis stops automatically to provide safety protection. Example

[0047] This embodiment is a variation of the first embodiment. Figure 3 As shown, the embodiment 1 is the same as the embodiment 1 except that: (1) an exhaust port and an exhaust valve 11 are added to the top of the container 1; (2) a salt adding tank 12 is added to the top wall of the container, a small hole is provided on the side wall of the salt adding tank located inside the container 1, and a cap and a sealing member are provided at the tank opening of the salt adding tank.

[0048] The method for preparing hypochlorous acid water in the hypochlorous acid preparation device of this embodiment is basically the same as that in the first embodiment, except that:

[0049] (1) In step 3), salt is added to the salt adding tank, the cap is put on, and then the second volume of pure water is filled into the container.

[0050] (2) In step 5), an adjustable exhaust valve is added to make the relationship between Pgas + Pweight - Presistance in container 1 and the atmospheric pressure controllable, so as to achieve the controllable discharge of the NaOH-containing solution from the micropores of the metal mesh. Example

[0051] This embodiment is a variation of the second embodiment. Figure 4 As shown, in addition to being the same as Example 2, the differences are: (1) the cathode 2 is directly attached to the bottom inner wall of the container 1, and the opening 3 extends to the cathode 2, that is, the cathode 2 is also opened and connected with the opening 3 at the bottom of the container 1; (2) the resistance member 4 is replaced by a metal microporous plate with micropores and a microporous membrane with micropores and is arranged on the opening 3. Example

[0052] This embodiment is a variation of the third embodiment. Figure 5 As shown, in addition to being the same as Example 2, the differences are: (1) the resistance member 4 is replaced by a microporous membrane and a pressure reducing valve 16; (2) a waste liquid tank 12 is also connected to the bottom of the container 1, and a waste discharge port and a waste discharge valve 15 that is normally open and connected to the atmosphere are provided on the tank wall of the waste liquid tank 12; (3) in step 6), the drain valve is opened to discharge the electrolyzed solution into the waste liquid tank. Example

[0053] This embodiment is a household device for preparing hypochlorous acid water, which is a specific product of the above embodiment. Figure 6 As shown, specifically: (1) the container 1 is a bucket that can be seen on the market and is compatible with various household water dispensers; (2) a support seat 14 (similar to the support seat that is compatible with the water drop sleeve of various household water dispensers) is made at the bottom of the bucket. The support seat 14 is made of an electrically insulating material and is provided with a through hole to form an outlet at the bottom of the bucket (i.e., an opening 3 at the bottom of the container 1); (3) a screw cap 13 is also provided between the support seat 14 and the bottom of the bucket to form a threaded connection between the bottom of the bucket and the support seat 14, and a microporous membrane is provided at the connection between the screw cap 13 and the end face of the support seat 14 to form a resistance member 4; 4) the cathode electrode 2 is provided at the bottom of the bucket near the microporous membrane, one end of which is fixed to the support seat 14, and the other end of which is connected to the first wire hole (not marked in the figure) on the screw cap 13; the anode electrode 5 is provided at the upper part of the bucket, one end of which is fixed to the support seat 14, and the other end of which is connected to the second wire hole (not marked in the figure) on the upper part of the bucket.

[0054] The above description is only a preferred embodiment of the present invention, but the present invention is not limited to this. For example, the number of electrodes is not limited to a pair of positive and negative electrodes, etc. All equivalent replacements or equivalent changes based on the concepts and technical solutions of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A device for preparing hypochlorous acid water, comprising a container for containing a saline solution and a DC power supply, wherein at least one pair of anode and cathode electrodes are arranged in the container, wherein the anode electrode is located above the cathode electrode when the container is placed normally, and the DC power supply supplies power to the anode electrode and the cathode electrode to form electrolysis of the solution, wherein the container is provided with a liquid inlet and a liquid inlet valve, a liquid discharge port and a liquid discharge valve; characterized in that : The bottom of the container is provided with an opening connected to the atmosphere when it is normally placed, the cathode electrode is close to the opening and has a channel for the solution to pass through the opening, and a resistance member is provided at the opening to form a resistance pressure for the solution to flow outward through the opening; during electrolysis, when the gas pressure in the container + the gravity pressure of the solution - the resistance pressure > atmospheric pressure, the solution is discharged outward through the resistance member; the resistance pressure is a set constant; the top wall of the container is provided with an exhaust port and an exhaust valve; the resistance member is a microporous plate or a microporous membrane.

2. The device for producing hypochlorous acid water according to claim 1, characterized in that: The top wall of the container is provided with a salt adding tank, a side wall of the salt adding tank located in the container is provided with a small hole, and the tank mouth of the salt adding tank is provided with a cover cap and a sealing member.

3. The device for preparing hypochlorous acid water according to claim 1, characterized in that: The bottom of the container is also connected to a waste liquid tank, and the tank wall of the waste liquid tank is provided with a waste discharge port and a waste discharge valve which is normally open and connected to the atmosphere.

4. The device for producing hypochlorous acid water according to claim 1, characterized in that: The container is a bucket, and a support seat is formed at the bottom of the bucket. The support seat is formed with a through hole to form the opening. A screw cap for threadedly connecting the bottom of the bucket with the support seat is provided between the support seat and the bottom of the bucket, and the resistance member is arranged at the connection between the screw cap and the end face of the support seat; the cathode electrode is arranged at the bottom of the bucket near the resistance member, one end of which is fixed to the support seat, and the other end of which is connected to the first wire hole on the screw cap; the anode electrode is arranged on the upper part of the bucket, one end of which is fixed to the support seat, and the other end of which is connected to the second wire hole on the upper part of the bucket.

5. A method for producing hypochlorous acid water, using the hypochlorous acid water production device according to claim 1, characterized in that Perform the following steps: 1) setting a first volume of the container and a second volume of the saline solution such that the first volume is greater than the second volume; 2) selecting a resistance member with resistance pressure and placing it at the opening of the container; 3) placing the container in a normal state and filling the container with the second volume of saline solution; 4) setting an electrolysis time according to the second volume, supplying power to the cathode electrode and the anode electrode, and electrolyzing the solution in the container; 5) Gas is generated in the container during electrolysis, and when the gas pressure formed by the gas in the container + the gravity pressure of the solution - the resistance pressure > atmospheric pressure, the opening is observed to discharge the solution outward; 6) When the electrolysis time is reached, turn off the DC power supply, open the drain valve, and discharge the electrolyzed solution.

6. The method for producing hypochlorous acid water according to claim 5, characterized in that: An exhaust port and an exhaust valve are provided on the top wall of the container; in the step 5), the exhaust valve is adjusted so that the air pressure formed by the gas in the container + the gravity pressure of the solution - the resistance pressure > atmospheric pressure.

7. The method for producing hypochlorous acid water according to claim 5, characterized in that: A salt adding tank is arranged on the top wall of the container, and a cap and a sealing member are arranged on the tank mouth of the salt adding tank; the step 3) is to cover the cap after adding salt to the salt adding tank, and then fill the second volume of pure water into the container.

8. The method for producing hypochlorous acid water according to claim 5, characterized in that: A waste liquid tank is connected to the bottom of the container, and a waste discharge port and a waste discharge valve normally open to the atmosphere are provided on the tank wall of the waste liquid tank. In the step 6), the drain valve is opened to discharge the electrolyzed solution into the waste liquid tank.

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