An electrochemical reduction indigo dye solution device and method

Abstract

The present invention provides an electrochemical reduction indigo dye solution device and method. The electrochemical reduction indigo dye solution device of the present invention includes a cathode plate, a cathode functional plate, a diaphragm, an anode functional plate, an anode plate, etc.; the electrochemical reduction indigo dye solution device of the present invention can electrochemically reduce a high-concentration indigo dye solution, and the highest reduction concentration can reach 300 g / L. Moreover, no sulfur-containing compounds are generated during the reduction process, no other heavy metal ions are added, and the process is greener and cleaner. The electrochemical reduction indigo dye solution method of the present invention has the optimal process parameters as follows: the electrolysis temperature is 50 °C, the electrolysis voltage is 11 V, the electrolyte flow rate is 15 ml / min, and the ultrasonic time is 2 h. When electrolyzing through these process parameters, the indigo reduction time is the shortest and the electrolysis efficiency is the highest.

Description

Technical Field

[0001] The present invention belongs to the technical field of textile dyeing, and particularly relates to an electrochemical reduction indigo dye solution device and method. Background Art

[0002] As a fabric dye, indigo is widely used in the entire dyeing and finishing industry, especially commonly used in the denim dyeing process. However, indigo is insoluble in water and cannot directly dye fabrics. Therefore, a reducing agent is needed to reduce indigo into a leuco body, which has a better "affinity" with cotton fibers and can thus better dye cotton fabrics.

[0003] The reaction between indigo and the leuco body is as follows:

[0004]

[0005] In the process, it is more commonly used to use sodium dithionite (commonly known as sodium hydrosulfite) as a reducing agent to reduce indigo. However, its products contain sulfur compounds such as sulfites, which cause serious environmental pollution. Therefore, it is necessary to find a substitute for the indigo reduction dyeing process of sodium hydrosulfite, and the electrochemical reduction technology has well solved the current problem.

[0006] The prior art discloses a single-solute indirect electrochemical reduction indigo dye solution and dyeing method, which uses indirect electrochemical technology to reduce the dye. Its disadvantage is that this method introduces metals such as iron ions, and the reduction liquid dyeing will have a certain impact on the fabric, and the generated wastewater will also pollute the environment. Currently, when artificially reducing indigo powder, the concentration of the leuco body is generally about 80g / L - 120g / L. In China, the direct electrochemical reduction technology has rarely been studied due to its low electron transfer efficiency and low reduction efficiency. Based on this, it is necessary to improve the existing indigo reduction methods. Summary of the Invention

[0007] In view of this, the present invention provides an electrochemical reduction indigo dye solution device and method to solve the technical problems existing in the prior art.

[0008] In a first aspect, the present invention provides an electrochemical reduction indigo dye solution device, including:

[0009] A cathode plate;

[0010] A cathode functional plate, one side of which is attached to the cathode plate. The cathode functional plate is provided with a first through hole, and the cathode functional plate is provided with a cathode liquid inlet hole, and the cathode liquid inlet hole is communicated with the first through hole;

[0011] A diaphragm, one side of which is attached to the other side of the cathode functional plate;

[0012] The anode functional plate, one side of which is attached to the other side of the diaphragm, is provided with a second through hole, and an anode liquid inlet hole is provided on the anode functional plate, and the anode liquid inlet hole communicates with the second through hole;

[0013] The anode plate, which is attached to the other side of the anode functional plate;

[0014] Wherein, a cathode chamber is formed by enclosing between the cathode plate, the first through hole, and the diaphragm, and an anode chamber is formed by enclosing between the anode plate, the second through hole, and the diaphragm.

[0015] Preferably, in the electrochemical reduction indigo dye solution device, first gaskets are provided between the cathode plate and the cathode functional plate, and between the cathode functional plate and the diaphragm, and the first gaskets are provided with third through holes corresponding to the first through holes.

[0016] Preferably, in the electrochemical reduction indigo dye solution device, second gaskets are provided between the anode plate and the anode functional plate, and between the anode functional plate and the diaphragm, and the second gaskets are provided with fourth through holes corresponding to the second through holes.

[0017] Preferably, in the electrochemical reduction indigo dye solution device, a cathode insulating backing plate, a cathode insulating plate, and a cathode cover plate are sequentially attached to the side of the cathode plate away from the diaphragm;

[0018] An anode insulating backing plate, an anode insulating plate, and an anode cover plate are sequentially attached to the side of the anode plate away from the diaphragm.

[0019] Preferably, in the electrochemical reduction indigo dye solution device, a cathode liquid outlet hole is further provided on the cathode functional plate, and the cathode liquid outlet hole communicates with the first through hole;

[0020] An anode liquid outlet hole is provided on the anode functional plate, and the anode liquid outlet hole communicates with the second through hole.

[0021] In a second aspect, the present invention also provides an electrochemical reduction indigo dye solution method, including the following steps:

[0022] Provide the electrochemical reduction indigo dye solution device;

[0023] Prepare an anode electrolyte solution;

[0024] Prepare a cathode electrolyte solution, and the cathode electrolyte solution includes an alkali solution containing indigo;

[0025] Introduce the cathode electrolyte solution into the cathode chamber through the cathode liquid inlet hole, and introduce the anode electrolyte solution into the anode chamber through the anode liquid inlet hole;

[0026] Connect the cathode plate to the negative pole of the power supply and the anode plate to the positive pole of the power supply, and perform electrolysis.

[0027] Preferably, in the method for electrochemically reducing an indigo dye solution, the anolyte is a sodium hydroxide solution with a concentration of 0.5 - 2 M;

[0028] The catholyte is a sodium hydroxide solution containing indigo, and the concentration of sodium hydroxide in the catholyte is 0.5 - 2 M, and the concentration of indigo is 80 - 300 g / L.

[0029] Preferably, in the method for electrochemically reducing an indigo dye solution, the catholyte is ultrasonically treated before electrolysis, the ultrasonic frequency is 35 - 45 KHz, the ultrasonic power is 350 - 450 W, and the ultrasonic time is 0.5 - 3 h;

[0030] The electrolysis process parameters are: the temperatures of the anolyte and the catholyte are 30 - 70 °C, and the electrolysis voltage is 7 - 15 V.

[0031] Preferably, the method for electrochemically reducing an indigo dye solution further includes an anolyte storage tank and a catholyte storage tank;

[0032] The anolyte storage tank is respectively connected to the anodic inlet hole and the anodic outlet hole, and the anolyte storage tank is used for storing the anolyte;

[0033] The catholyte storage tank is respectively connected to the cathodic inlet hole and the cathodic outlet hole, and the catholyte storage tank is used for storing the catholyte;

[0034] During electrolysis, the catholyte flows into the cathode chamber through the cathodic inlet hole at a rate of 5 - 25 ml / min, is electrolyzed, and then flows back to the catholyte storage tank through the cathodic outlet hole, and then flows into the cathode chamber again for electrolysis and circulation;

[0035] The anolyte flows into the anode chamber through the anodic inlet hole at a rate of 5 - 25 ml / min, is electrolyzed, and then flows back to the anolyte storage tank through the anodic outlet hole, and then flows into the anode chamber again for electrolysis and circulation.

[0036] Preferably, in the method for electrochemically reducing an indigo dye solution, the ultrasonic time is 2 h;

[0037] The electrolysis process parameters are: the temperatures of the anolyte and the catholyte are 50 °C, and the electrolysis voltage is 11 V;

[0038] The catholyte flows into the cathode chamber through the cathodic inlet hole at a rate of 15 ml / min;

[0039] The anolyte flows into the anode chamber through the anodic inlet hole at a rate of 15 ml / min.

[0040] An electrochemical reduction indigo dye solution device and method of the present invention have the following beneficial effects compared with the prior art:

[0041] 1. The electrochemical reduction indigo dye solution device of the present invention can electrochemically reduce high-concentration indigo dye solution, and the highest reduction concentration can reach 300 g / L. Moreover, no sulfur-containing compounds are produced during the reduction process, and no other heavy metal ions are added, making the process greener and cleaner.

[0042] 2. The electrochemical reduction indigo dye solution method of the present invention has the following optimal process parameters: the electrolysis temperature is 50 °C, the electrolysis voltage is 11 V, the electrolyte flow rate is 15 ml / min, and the ultrasonic time is 2 h. When electrolyzing according to these process parameters, the indigo reduction time is the shortest and the electrolysis efficiency is the highest. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0044] Figure 1 It is an exploded view of the electrochemical reduction indigo dye solution device in one of the embodiments of the present invention;

[0045] Figure 2 It is a schematic structural diagram of the cathode functional plate in one of the embodiments of the present invention;

[0046] Figure 3 It is a schematic structural diagram of the anode functional plate in one of the embodiments of the present invention;

[0047] Figure 4 It is an assembly diagram of the electrochemical reduction indigo dye solution device in one of the embodiments of the present invention;

[0048] Figure 5 It is a schematic structural diagram of the electrochemical reduction indigo dye solution device in one of the embodiments of the present invention;

[0049] Figure 6 It is a test result diagram in Embodiment 1 of the present invention;

[0050] Figure 7 It is a test result diagram in Embodiment 2 of the present invention;

[0051] Figure 8 It is a test result diagram in Embodiment 3 of the present invention;

[0052] Figure 9 It is a test result diagram in Embodiment 4 of the present invention;

[0053] Figure 10This is the test result diagram in Embodiment 5 of the present invention. Detailed implementation manners

[0054] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0055] Therefore, the detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0056] It should be noted that: like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0057] In the description of the present invention, it should be understood that the relationships indicating orientations or positions such as "upper" are based on the orientations or positions shown in the drawings, or the orientations or positions in which the products of the invention are usually placed during use, or the orientations or positions commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0058] In addition, the terms "first", "second", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0059] For a better understanding of the present invention rather than limiting its scope, all numbers representing amounts, percentages, and other numerical values used in this application should be understood to be modified by the word "about" in all cases. Therefore, unless otherwise specified, the numerical parameters listed in the specification and the appended claims are approximate values, which may vary depending on the desired properties to be obtained. Each numerical parameter should at least be regarded as obtained according to the reported significant figures and by the conventional rounding method.

[0060] It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments. Additionally, in the description of the present application, the term "including" means "including but not limited to". The various embodiments of the present invention may exist in a range form; it should be understood that the description in a range form is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, which applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited numbers (fractions or integers) within the indicated range.

[0061] The present invention provides an electrochemical reduction indigo dye solution device 1, as Figures 1 to 4 shown, including:

[0062] a cathode plate 10;

[0063] a cathode functional plate 11, one side of which is attached to the cathode plate 10. A first through hole 110 is provided on the cathode functional plate 11, and a cathode liquid inlet hole 111 is provided on the cathode functional plate 11. The cathode liquid inlet hole 111 is communicated with the first through hole 110;

[0064] a diaphragm 12, one side of which is attached to the other side of the cathode functional plate 11;

[0065] an anode functional plate 13, one side of which is attached to the other side of the diaphragm 12. A second through hole 130 is provided on the anode functional plate 13, and an anode liquid inlet hole 131 is provided on the anode functional plate 13. The anode liquid inlet hole 131 is communicated with the second through hole 130;

[0066] an anode plate 14, which is attached to the other side of the anode functional plate 13;

[0067] wherein, a cathode chamber is enclosed among the cathode plate 10, the first through hole 110, and the diaphragm 12, and an anode chamber is enclosed among the anode plate 14, the second through hole 130, and the diaphragm 12.

[0068] It should be noted that the electrochemical reduction indigo dye solution device 1 of the present invention includes a cathode plate 10, a cathode functional plate 11, a diaphragm 12, an anode functional plate 13, and an anode plate 14 that are sequentially attached; a cathode chamber is formed by enclosing between the cathode plate 10, the cathode functional plate 11, the diaphragm 12, and the first through hole 110 on the cathode functional plate 11; an anode chamber is formed by enclosing between the anode plate 14, the anode functional plate 13, the diaphragm 12, and the second through hole 130 on the anode functional plate 13; during application, a cathode electrolyte is introduced into the cathode chamber through a cathode liquid inlet hole 111, an anode electrolyte is introduced into the anode chamber through an anode liquid inlet hole 131, then the cathode plate 10 is connected to the negative electrode of the power supply, and the anode plate 14 is connected to the positive electrode of the power supply for electrolysis reaction; by using the electrochemical reduction indigo dye solution device of the present invention, high-concentration indigo dye solution can be electrochemically reduced, the reduction concentration can reach up to 300 g / L at most, and no sulfur-containing compounds are generated during the reduction process, and no other heavy metal ions are added, and the process is greener and cleaner.

[0069] In some embodiments, first gaskets 15 are provided between the cathode plate 10 and the cathode functional plate 11, and between the cathode functional plate 11 and the diaphragm 12. The first gaskets 15 are provided with third through holes corresponding to the first through holes 110.

[0070] In the above embodiments, the first gaskets 15 are insulating gaskets, and the materials used are soft insulating plastics, such as the materials of the first gaskets 15 are silicone, polyethylene, polypropylene, etc.

[0071] In some embodiments, the diaphragm 12 is an ion exchange membrane, specifically a cation membrane, and the cation membrane allows cations to pass through during electrolysis to form a current loop.

[0072] In some embodiments, second gaskets 16 are provided between the anode plate 14 and the anode functional plate 13, and between the anode functional plate 13 and the diaphragm 12. The second gaskets 16 are provided with fourth through holes corresponding to the second through holes 130.

[0073] In the above embodiments, the second gaskets 16 are insulating gaskets, and the materials used are soft insulating plastics, such as the materials of the second gaskets 16 are silicone, polyethylene, polypropylene, etc.

[0074] In some embodiments, a cathode insulating backing plate 17, a cathode insulating plate 18, and a cathode cover plate 19 are sequentially attached to the side of the cathode plate 10 away from the diaphragm 12.

[0075] In some embodiments, an anode insulating backing plate 20, an anode insulating plate 21, and an anode cover plate 22 are sequentially attached to the side of the anode plate 14 away from the diaphragm 12.

[0076] Specifically, the cathode cover plate 19 and the anode cover plate 22 are both provided with screw holes. After screwing bolts through the screw holes, the components between the cathode cover plate 19 and the anode cover plate 22 can be closely fitted, and then the entire electrochemical reduction indigo dye solution device is assembled.

[0077] In some embodiments, the cathode plate 10 and the anode plate 14 are both made of conductive materials. For example, the materials of the cathode plate 10 and the anode plate 14 can be graphite, platinum, titanium, nickel, ruthenium, iridium, and some metal alloys, etc.

[0078] The materials used for the cathode functional plate 11 and the anode functional plate 13 can be polyether ether ketone, polyethylene, polypropylene, etc.

[0079] In some embodiments, the cathode functional plate 11 is further provided with a cathode liquid outlet hole 112, and the cathode liquid outlet hole 112 communicates with the first through hole 110; the cathode electrolyte in the cathode chamber can be discharged through the cathode liquid outlet hole 112.

[0080] In some embodiments, the anode functional plate 13 is provided with an anode liquid outlet hole 132, and the anode liquid outlet hole 132 communicates with the second through hole 130; the anode electrolyte in the anode chamber can be discharged through the anode liquid outlet hole 132.

[0081] Based on the same inventive concept, the present invention also provides an electrochemical reduction indigo dye solution method, including the following steps:

[0082] S1. Provide the above-mentioned electrochemical reduction indigo dye solution device;

[0083] S2. Prepare the anode electrolyte;

[0084] S3. Prepare the cathode electrolyte, and the cathode electrolyte includes an alkali solution containing indigo;

[0085] S4. Pass the cathode electrolyte into the cathode chamber through the cathode liquid inlet hole, and pass the anode electrolyte into the anode chamber through the anode liquid inlet hole;

[0086] S5. Connect the cathode plate to the negative pole of the power supply and the anode plate to the positive pole of the power supply, and perform electrolysis.

[0087] In the electrochemical reduction indigo dye solution method of the present invention, by passing the cathode electrolyte into the cathode chamber, passing the anode electrolyte into the anode chamber, connecting the cathode plate to the negative pole of the power supply, and connecting the anode plate to the positive pole of the power supply, and by controlling the voltage, the indigo in the cathode electrolyte can be reduced.

[0088] In some embodiments, the anode electrolyte is an alkali solution, specifically a sodium hydroxide solution, preferably a sodium hydroxide solution with a concentration of 0.5 - 2M. Specifically, the preparation method of the anode electrolyte is: adding sodium hydroxide to water to obtain the anode electrolyte.

[0089] In some embodiments, the catholyte is an alkaline solution containing indigo, specifically a sodium hydroxide solution containing indigo. Specifically, after adding sodium hydroxide to water, indigo is added to obtain a sodium hydroxide solution containing indigo. Preferably, the concentration of sodium hydroxide in the catholyte is 0.5 - 2 M, and the concentration of indigo is 80 - 300 g / L.

[0090] In some embodiments, before electrolysis, the catholyte is ultrasonically treated. The ultrasonic frequency is 35 - 45 KHz, the ultrasonic power is 350 - 450 W, and the ultrasonic time is 0.5 - 3 h.

[0091] In some embodiments, the electrolysis process parameters are as follows: the temperatures of the anolyte and catholyte are 30 - 70 °C, and the electrolysis voltage is 7 - 15 V.

[0092] Specifically, the power supply used in the present invention is a DC regulated power supply.

[0093] In some embodiments, as Figure 4 shown, it further includes an anolyte storage tank 2 and a catholyte storage tank 3.

[0094] The anolyte storage tank 2 is respectively connected to the anolyte inlet hole 131 and the anolyte outlet hole 132. The anolyte storage tank 2 is used to store the anolyte.

[0095] The catholyte storage tank 3 is respectively connected to the catholyte inlet hole 111 and the catholyte outlet hole 112. The catholyte storage tank 3 is used to store the catholyte.

[0096] During electrolysis, the catholyte flows into the cathode chamber through the catholyte inlet hole 111 at a rate of 5 - 25 ml / min, is electrolyzed, and then flows back to the catholyte storage tank 3 through the catholyte outlet hole 112, and then flows into the cathode chamber again for electrolysis and circulation.

[0097] The anolyte flows into the anode chamber through the anolyte inlet hole 131 at a rate of 5 - 25 ml / min, is electrolyzed, and then flows back to the anolyte storage tank 2 through the anolyte outlet hole 132, and then flows into the anode chamber again for electrolysis and circulation.

[0098] Specifically, in the above embodiments, the anolyte inlet hole 131 and the anolyte outlet hole 132 are connected to the anolyte storage tank 2 through the first circulation pipeline 4; the catholyte inlet hole 111 and the catholyte outlet hole 112 are connected to the catholyte storage tank 3 through the second circulation pipeline 5. Specifically, a first peristaltic pump 6 is provided on the first circulation pipeline 4 to control the flow rate of the anolyte; a second peristaltic pump 7 is provided on the second circulation pipeline 5 to control the flow rate of the catholyte. During electrolysis, the catholyte / anolyte circulates and is continuously electrolyzed until the indigo contained in the catholyte in the catholyte storage tank 3 is reduced. When the reduction current approaches zero, the indigo is completely reduced.

[0099] Specifically, in some embodiments, before electrolysis, the catholyte storage tank 3 is placed in the ultrasonic generator 8 for ultrasonic treatment, thereby performing ultrasonic treatment on the catholyte.

[0100] In some embodiments, the ultrasonic frequency is 40 KHz, the ultrasonic power is 400 W, and the ultrasonic time is 2 h;

[0101] The electrolysis process parameters are as follows: the temperatures of the anolyte and the catholyte are 50 °C, and the electrolysis voltage is 11 V;

[0102] The catholyte flows into the cathode chamber through the cathode liquid inlet hole at a rate of 15 ml / min;

[0103] The anolyte flows into the anode chamber through the anode liquid inlet hole at a rate of 15 ml / min.

[0104] By setting the electrolysis process parameters, the efficiency of electrochemical indigo can be greatly improved in the present invention.

[0105] The following further illustrates the electrochemical reduction indigo dye solution method of the present application with specific examples. This part further illustrates the content of the present invention in combination with specific examples, but should not be construed as a limitation to the present invention. Unless otherwise specified, the technical means adopted in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0106] Example 1

[0107] The embodiment of the present application provides an electrochemical reduction indigo dye solution method, including the following steps:

[0108] S1. Provide an electrochemical reduction indigo dye solution device as shown in Figure 5 ;

[0109] S2. Prepare the anolyte, and the anolyte is a sodium hydroxide solution with a concentration of 1 M;

[0110] S3. Prepare the catholyte, and the catholyte is a sodium hydroxide solution containing indigo. The concentration of sodium hydroxide in the catholyte is 1 M, and the concentration of indigo is 200 g / L;

[0111] S4. Place the anolyte in the anolyte storage tank, place the catholyte in the catholyte storage tank, and perform ultrasonic treatment on the catholyte before electrolysis. The ultrasonic frequency is 40 KHz, the ultrasonic power is 400 W, and the ultrasonic time is 2 h;

[0112] During electrolysis, the cathode plate is connected to the negative pole of the power supply, and the anode plate is connected to the positive pole of the power supply. The cathode electrolyte flows into the cathode chamber at a rate of 15 ml / min, undergoes electrolysis, and then returns to the cathode electrolyte storage tank through the cathode liquid outlet hole, and then flows into the cathode chamber again for electrolysis and circulation;

[0113] The anode electrolyte flows into the anode chamber at a rate of 15 ml / min, undergoes electrolysis, and then returns to the anode electrolyte storage tank through the anode liquid outlet hole, and then flows into the anode chamber again for electrolysis and circulation;

[0114] The electrolysis process parameters are as follows: the temperatures of the anode electrolyte and the cathode electrolyte are 60 °C, and the electrolysis voltages are 7V, 9V, 11V, 13V, and 15V respectively.

[0115] According to the method in Example 1, control different electrolysis voltages, record the current changes per hour until the current value is basically zero, and the test results are as Figure 6 shown. When the reduction potential is measured to be -810 mV, it is considered to be completely reduced.

[0116] Example 2

[0117] An embodiment of the present application provides a method for electrochemically reducing indigo dye solution, including the following steps:

[0118] S1. Provide an electrochemically reducing indigo dye solution device as Figure 5 shown;

[0119] S2. Prepare the anode electrolyte, and the anode electrolyte is a sodium hydroxide solution with a concentration of 1M;

[0120] S3. Prepare the cathode electrolyte, and the cathode electrolyte is a sodium hydroxide solution containing indigo. The concentration of sodium hydroxide in the cathode electrolyte is 1M, and the concentration of indigo is 200 g / L;

[0121] S4. Place the anode electrolyte in the anode electrolyte storage tank, and place the cathode electrolyte in the cathode electrolyte storage tank. Before electrolysis, ultrasonicate the cathode electrolyte. The ultrasonic frequency is 40 KHz, the ultrasonic power is 400 W, and the ultrasonic times are 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, and 3 h respectively;

[0122] During electrolysis, the cathode plate is connected to the negative pole of the power supply, and the anode plate is connected to the positive pole of the power supply. The cathode electrolyte flows into the cathode chamber at a rate of 15 ml / min, undergoes electrolysis, and then returns to the cathode electrolyte storage tank through the cathode liquid outlet hole, and then flows into the cathode chamber again for electrolysis and circulation;

[0123] The anode electrolyte flows into the anode chamber at a rate of 15 ml / min, undergoes electrolysis, and then returns to the anode electrolyte storage tank through the anode liquid outlet hole, and then flows into the anode chamber again for electrolysis and circulation;

[0124] The electrolysis process parameters are as follows: the temperatures of the anolyte and the catholyte are 50°C, and the electrolysis voltage is 11V.

[0125] According to the method in Example 2, after different ultrasonic times, electrolytic reduction is carried out, and the current change per hour is recorded until the current value is basically zero. The test results are as Figure 7 shown. When the reduction potential is measured to be -790 mV, it is regarded as complete reduction.

[0126] Example 3

[0127] An embodiment of the present application provides a method for electrochemically reducing indigo dye solution, including the following steps:

[0128] S1. Provide an electrochemically reducing indigo dye solution device as Figure 5 shown;

[0129] S2. Prepare an anolyte, and the anolyte is a sodium hydroxide solution with a concentration of 1M;

[0130] S3. Prepare a catholyte, and the catholyte is a sodium hydroxide solution containing indigo. The concentration of sodium hydroxide in the catholyte is 1M, and the concentration of indigo is 200 g / L;

[0131] S4. Place the anolyte in the anolyte storage tank, and place the catholyte in the catholyte storage tank. Before electrolysis, ultrasonicate the catholyte. The ultrasonic frequency is 40 kHz, the ultrasonic power is 400 W, and the ultrasonic time is 2 h;

[0132] During electrolysis, connect the cathode plate to the negative pole of the power supply and the anode plate to the positive pole of the power supply. The catholyte flows into the cathode chamber at a rate of 15 ml / min for electrolysis and then returns to the catholyte storage tank through the cathode liquid outlet hole and then flows into the cathode chamber for electrolysis and circulation;

[0133] The anolyte flows into the anode chamber at a rate of 15 ml / min for electrolysis and then returns to the anolyte storage tank through the anode liquid outlet hole and then flows into the anode chamber for electrolysis and circulation;

[0134] The electrolysis process parameters are as follows: the temperatures of the anolyte and the catholyte are 30°C, 40°C, 50°C, 60°C, and 70°C respectively, and the electrolysis voltage is 11V.

[0135] According to the method in Example 3, electrolytic reduction is carried out at different electrolysis temperatures, and the current change per hour is recorded until the current value is basically zero. The test results are as Figure 8 shown. When the reduction potential is measured to be -805 mV, it is regarded as complete reduction.

[0136] Example 4

[0137] An embodiment of the present application provides a method for electrochemically reducing indigo dye solution, including the following steps:

[0138] S1. Provide an electrochemically reducing indigo dye solution device as Figure 5 shown;

[0139] S2. Prepare an anolyte, and the anolyte is a sodium hydroxide solution with a concentration of 1M;

[0140] S3. Prepare a catholyte, and the catholyte is a sodium hydroxide solution containing indigo. The concentration of sodium hydroxide in the catholyte is 1M, and the concentration of indigo is 200 g / L;

[0141] S4. Place the anolyte in the anolyte storage tank, and place the catholyte in the catholyte storage tank. Before electrolysis, ultrasonicate the catholyte. The ultrasonic frequency is 40 KHz, the ultrasonic power is 400 W, and the ultrasonic time is 2 h;

[0142] During electrolysis, connect the cathode plate to the negative pole of the power supply, and connect the anode plate to the positive pole of the power supply. The catholyte flows into the cathode chamber at 5 ml / min, 10 ml / min, 15 ml / min, 20 ml / min, and 25 ml / min respectively for electrolysis, and then flows back to the catholyte storage tank through the cathode liquid outlet hole and then flows into the cathode chamber for electrolysis and circulation;

[0143] The anolyte flows into the anode chamber at 5 ml / min, 10 ml / min, 15 ml / min, 20 ml / min, and 25 ml / min respectively for electrolysis, and then flows back to the anolyte storage tank through the anode liquid outlet hole and then flows into the anode chamber for electrolysis and circulation;

[0144] The electrolysis process parameters are: the temperatures of the anolyte and the catholyte are 50 °C, and the electrolysis voltage is 11 V.

[0145] According to the method in Example 4, perform electrolytic reduction at different electrolyte flow rates, record the current change per hour until the current value is basically zero, and the test results are as Figure 9 shown. Measure its reduction potential to be -809 mV, which is regarded as complete reduction.

[0146] Test results

[0147] The test results in Examples 1 to 4 are as Figures 6 to 9 shown, Figures 6 to 9 The unit of the abscissa in which is h (hour). It can be seen from Figure 6 that the optimal reduction voltage is 11 V; it can be seen from Figure 7 that the ultrasonic treatment time to achieve the best reduction effect is 2 h; it can be seen from Figure 8It can be seen that the optimal reduction temperature for achieving the best reduction effect is 50°C; from Figure 9 it can be seen that the optimal electrolyte flow rate for achieving the best reduction effect is 15 ml / min.

[0148] Furthermore, electrolysis is carried out at different electrolysis voltages in Example 1, electrolysis is carried out after different ultrasonic treatment times in Example 2, electrolysis is carried out at different electrolysis temperatures in Example 3, and electrolysis is carried out at different electrolyte flow rates in Example 4. The final reduction times are shown in Table 1 below.

[0149] Table 1 - Influence of Different Electrolysis Process Parameters on Reduction Time

[0150]

[0151] It can be seen from Table 1 that when the electrolysis voltage is 11 V, the reduction time required for complete reduction of indigo is 6 h, the reduction time is the least, and the reduction efficiency is the highest. Therefore, the optimal reduction voltage is 11 V; when the electrolysis temperature is 50°C, the reduction time required for complete reduction of indigo is 6 h, the reduction time is the least, and the reduction efficiency is the highest. Therefore, the optimal electrolysis temperature is 50°C; when the ultrasonic time is 2 h, the reduction time required for complete reduction of indigo is 6 h, the reduction time is the least, and the reduction efficiency is the highest. Therefore, the optimal ultrasonic time is 2 h; when the electrolyte flow rate is 15 ml / min, the reduction time required for complete reduction of indigo is 6 h, the reduction time is the least, and the reduction efficiency is the highest. Therefore, the optimal electrolyte flow rate is 15 ml / min.

[0152] Example 5

[0153] Further research on the electrochemical reduction of indigo is carried out with the optimal electrolysis process, specifically as follows:

[0154] The embodiment of the present application provides a method for electrochemically reducing indigo dye solution, including the following steps:

[0155] S1. Provide an electrochemical reduction indigo dye solution device as Figure 5 shown;

[0156] S2. Prepare an anodic electrolyte, and the anodic electrolyte is a sodium hydroxide solution with a concentration of 1 M;

[0157] S3. Prepare a cathodic electrolyte, and the cathodic electrolyte is a sodium hydroxide solution containing indigo. The concentration of sodium hydroxide in the cathodic electrolyte is 1 M, and the concentrations of indigo are 120 g / L, 150, 200 g / L, 250 g / L, and 300 g / L respectively;

[0158] S4. Place the anolyte in the anolyte storage tank and the catholyte in the catholyte storage tank. Before electrolysis, ultrasonicate the catholyte at an ultrasonic frequency of 40 KHz, an ultrasonic power of 400 W, and an ultrasonic time of 2 h.

[0159] During electrolysis, connect the cathode plate to the negative pole of the power supply and the anode plate to the positive pole of the power supply. The catholyte flows into the cathode chamber at a rate of 15 ml / min for electrolysis and then returns to the catholyte storage tank through the cathode liquid outlet hole and then flows into the cathode chamber for electrolysis and circulation.

[0160] The anolyte flows into the anode chamber at a rate of 15 ml / min for electrolysis and then returns to the anolyte storage tank through the anode liquid outlet hole and then flows into the anode chamber for electrolysis and circulation.

[0161] The electrolysis process parameters are as follows: the temperatures of the anolyte and catholyte are 50 °C, and the electrolysis voltage is 11 V.

[0162] According to the method in Example 5, electrolytic reduction is carried out with catholytes of different indigo concentrations, and the reduction time required for complete reduction of indigo finally is recorded. The results are as Figure 10 shown.

[0163] From Figure 10 it can be seen that as the indigo concentration increases, the required reduction time increases, and there is a roughly linear correlation between the indigo concentration and the reduction time.

[0164] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for electrochemically reducing indigo dye solution, characterized in that, It includes the following steps: Provide an electrochemical reduction indigo dye solution device; The electrochemical reduction indigo dye solution device includes: A cathode plate; A cathode functional plate, one side of which is attached to the cathode plate. The cathode functional plate is provided with a first through hole, and the cathode functional plate is provided with a cathode liquid inlet hole, and the cathode liquid inlet hole is communicated with the first through hole; A diaphragm, one side of which is attached to the other side of the cathode functional plate; An anode functional plate, one side of which is attached to the other side of the diaphragm. The anode functional plate is provided with a second through hole, and the anode functional plate is provided with an anode liquid inlet hole, and the anode liquid inlet hole is communicated with the second through hole; An anode plate, which is attached to the other side of the anode functional plate; Wherein, a cathode chamber is enclosed among the cathode plate, the first through hole and the diaphragm, and an anode chamber is enclosed among the anode plate, the second through hole and the diaphragm; Prepare an anode electrolyte solution; Prepare a cathode electrolyte solution, and the cathode electrolyte solution includes an alkali solution containing indigo; Pass the cathode electrolyte solution into the cathode chamber through the cathode liquid inlet hole, and pass the anode electrolyte solution into the anode chamber through the anode liquid inlet hole; Connect the cathode plate to the negative pole of the power supply and the anode plate to the positive pole of the power supply for electrolysis; The anode electrolyte solution is a sodium hydroxide solution with a concentration of 1M; The cathode electrolyte solution is a sodium hydroxide solution containing indigo, and the concentration of sodium hydroxide in the cathode electrolyte solution is 1M, and the concentration of indigo is 120 - 300g / L; Before electrolysis, ultrasonically treat the cathode electrolyte solution. Among them, the ultrasonic frequency is 40KHz, the ultrasonic power is 400W, and the ultrasonic time is 2h; The electrolysis process parameters are: the temperatures of the anode electrolyte solution and the cathode electrolyte solution are 50°C, and the electrolysis voltage is 11V; It also includes an anode electrolyte storage tank and a cathode electrolyte storage tank; The anode electrolyte storage tank is respectively communicated with the anode liquid inlet hole and the anode liquid outlet hole, and the anode electrolyte storage tank is used for storing the anode electrolyte solution; The cathode electrolyte storage tank is respectively communicated with the cathode liquid inlet hole and the cathode liquid outlet hole, and the cathode electrolyte storage tank is used for storing the cathode electrolyte solution; During electrolysis, the cathode electrolyte solution flows into the cathode chamber at a rate of 15ml / min through the cathode liquid inlet hole, is electrolyzed and then flows back to the cathode electrolyte storage tank through the cathode liquid outlet hole, and then flows into the cathode chamber for electrolysis and circulates; The anode electrolyte solution flows into the anode chamber at a rate of 15ml / min through the anode liquid inlet hole, is electrolyzed and then flows back to the anode electrolyte storage tank through the anode liquid outlet hole, and then flows into the anode chamber for electrolysis and circulates.

2. The method for electrochemically reducing an indigo dye solution according to claim 1, wherein First gaskets are provided between the cathode plate and the cathode functional plate, and between the cathode functional plate and the diaphragm. The first gasket is provided with a third through hole corresponding to the first through hole.

3. The method for electrochemically reducing indigo dye solution according to claim 1, wherein Second gaskets are provided between the anode plate and the anode functional plate, and between the anode functional plate and the diaphragm. The second gasket is provided with a fourth through hole corresponding to the second through hole.

4. The method for electrochemically reducing indigo dye solution according to claim 1, characterized in that, On the side of the cathode plate away from the diaphragm, a cathode insulating backing plate, a cathode insulating plate, and a cathode cover plate are sequentially attached; On the side of the anode plate away from the diaphragm, an anode insulating backing plate, an anode insulating plate, and an anode cover plate are sequentially attached.

5. The method for electrochemically reducing indigo dye solution according to claim 1, wherein The cathode functional plate is also provided with a cathode liquid outlet hole, and the cathode liquid outlet hole is communicated with the first through hole; An anodic liquid outlet hole is formed in the anodic functional plate, and the anodic liquid outlet hole communicates with the second through hole.

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