Alkaline electrolyzed water diaphragm as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of water electrolysis hydrogen production, and particularly relates to an alkaline electrolyzed water diaphragm as well as a preparation method and application thereof. The preparation method comprises the following steps: repeatedly dipping a fiber plane material in a mixed solution of ZrO2 nanoparticles and hydrated zirconia sol, and drying to obtain a composite membrane; the composite membrane is subjected to hot pressing, and the alkaline electrolyzed water diaphragm is obtained; the preparation method of the hydrated zirconium oxide sol comprises the following steps: carrying out anion exchange treatment on an aqueous solution of zirconium oxychloride, and mixing the obtained exchange liquid with a mixed liquid of citric acid and acetic acid to obtain the hydrated zirconium oxide sol. The alkaline electrolyzed water diaphragm prepared by the method has excellent comprehensive performance, shows good ionic conductivity, wear resistance, hydrophilicity and alkali corrosion resistance (the diaphragm cannot fall off after alkali treatment), can remarkably reduce the operation energy consumption of an alkaline electrolytic bath, improves the water electrolysis efficiency, prolongs the service life of the diaphragm, and has wide application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen production by water electrolysis, and particularly relates to an alkaline water electrolysis diaphragm, a preparation method thereof, and an application thereof. Background Art

[0002] The advantages of hydrogen energy as an energy carrier lie not only in its high energy density, but also in its ability to convert electricity into hydrogen through water electrolysis hydrogen production technology, that is, using the electric energy produced by renewable energy to electrolyze water to produce hydrogen, so as to obtain hydrogen energy on a large scale. Among the water electrolysis hydrogen production technologies, the commercially applied ones are alkaline water electrolysis technology and proton exchange membrane water electrolysis technology. Considering factors such as equipment manufacturing cost, investment cost, equipment service life, equipment operation and maintenance cost, etc., alkaline water electrolysis technology is the hydrogen production method with the most mature technology, the widest global commercial application, and the greatest potential for large-scale application.

[0003] The main component of an alkaline water electrolysis hydrogen production device is an alkaline electrolyzer, which is assembled from components such as end plates, gaskets, electrode plates, electrodes, diaphragms, etc. Among them, the diaphragm is located between the cathode and the anode, separating the cathode and the anode to form a cathode chamber and an anode chamber to prevent short circuits. In addition, the diaphragm also has the characteristics of hydrophilic and hydrophobic gas, which can not only allow hydroxide ions in the alkali solution to freely pass through the diaphragm, but also separate hydrogen and oxygen gases at the same time, avoiding the mixing of gas products at both poles, and ensuring the safety of the electrolysis process and the purity of hydrogen and oxygen gases.

[0004] The quality of the diaphragm is the key factor determining the service life of the alkaline electrolyzer. Looking at the development of alkaline electrolyzer diaphragms, they have gone through three generations. The first-generation alkaline electrolyzer diaphragm was asbestos, which was gradually phased out because it is a carcinogen. In the 1970s, researchers began to search for new polymer materials to replace asbestos diaphragms. The polymer materials used for alkaline electrolyzers should have the characteristics of low resistance, high gas barrier property, high mechanical strength, and high chemical stability. The most commonly used polymer materials include polyphenylene sulfide (PPS), polysulfone (PSF), polyether ether ketone (PEEK), etc. And PPS is of great significance to alkaline electrolyzers because of its excellent heat resistance, good mechanical properties, corrosion resistance, and good dimensional stability. However, PPS diaphragms have weaknesses such as low bubble point, poor hydrophilicity, and poor gas barrier property, resulting in higher energy consumption of the electrolyzers composed of them. The composite diaphragm mainly includes three parts: a binder, nano-inorganic oxide particles, and a support layer. Among them, the binders currently used in technology are mostly high-temperature resistant and corrosion-resistant organic polymer polymers. The composite diaphragm combines the advantages of multiple materials, having both good high-temperature resistance and alkali corrosion resistance, and a low surface resistance. However, in actual applications, the composite diaphragm has the problem that its wear resistance decreases and it is damaged under high temperature and long-term erosion of the electrolyte, thus shortening its service life. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an alkaline electrolyzed water diaphragm, a preparation method and an application thereof. The alkaline electrolyzed water diaphragm has excellent wear resistance and hydrophilicity without affecting alkali corrosion resistance.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a preparation method of an alkaline electrolyzed water diaphragm, comprising the following steps:

[0008] The fibrous planar material is repeatedly impregnated in a mixed solution of ZrO2 nanoparticles and hydrated zirconia sol and then dried to obtain a composite film;

[0009] The composite film is hot-pressed to obtain an alkaline electrolyzed water diaphragm;

[0010] The preparation method of the hydrated zirconia sol comprises the following steps: an aqueous solution of zirconium oxychloride is subjected to anion exchange treatment, and the obtained exchange solution is mixed with a mixed solution of citric acid and acetic acid to obtain a hydrated zirconia sol.

[0011] Preferably, the material of the fibrous planar material includes one or more of polyphenylene sulfide, polysulfone resin, polyethylene, polypropylene, fluororesin, poly(p-phenylene benzobisoxazole), polyketone, polyether ether ketone, polyimide and polyetherimide.

[0012] Preferably, the average particle size of the ZrO2 nanoparticles is 20-50 nm.

[0013] Preferably, the mass percentage content of hydrated zirconia in the hydrated zirconia sol is 5-25%.

[0014] Preferably, the mass ratio of the ZrO2 nanoparticles to the hydrated zirconia sol is 1:5-1.

[0015] Preferably, the mass of the composite film is 1.5-1.8 times the mass of the fibrous planar material.

[0016] Preferably, the temperature of the hot pressing is 120-150 °C; the time of the hot pressing is 20-30 min.

[0017] Preferably, the molar ratio of zirconium oxychloride, citric acid and acetic acid is 0.1-0.2:1:1.

[0018] The present invention also provides an alkaline electrolyzed water diaphragm prepared by the preparation method described in the above technical solution, comprising a fibrous planar material and a superhydrophilic shell layer coated on the surface and inside of the fibrous planar material; the superhydrophilic shell layer comprises hydrated zirconia gel and ZrO2 nanoparticles dispersed in the hydrated zirconia gel.

[0019] The present invention also provides an application of the above-described alkaline electrolyzed water diaphragm in an alkaline electrolytic cell.

[0020] The present invention provides a method for preparing an alkaline electrolyzed water diaphragm, comprising the following steps: repeatedly impregnating a fibrous planar material in a mixed solution of ZrO2 nanoparticles and hydrated zirconia sol and then drying to obtain a composite membrane; hot pressing the composite membrane to obtain an alkaline electrolyzed water diaphragm; the method for preparing the hydrated zirconia sol comprises the following steps: subjecting an aqueous solution of zirconyl chloride to anion exchange treatment, and mixing the obtained exchange solution with a mixed solution of citric acid and acetic acid to obtain a hydrated zirconia sol.

[0021] The present invention impregnates a fibrous planar material in a mixed solution of ZrO2 nanoparticles and hydrated zirconia sol. As the impregnation process proceeds, the hydrated zirconia sol undergoes self-condensation to form a cross-linked gel protective layer on the fiber surface, which tightly wraps around the outer surface of the fiber, making the fiber surface gradually rough and providing many active sites for the ZrO2 nanoparticles (mainly oxygen vacancies on the zirconia surface). Since the zirconia surface is polar, it can adsorb water molecules in the environment. These adsorbed water molecules dissociate at the surface active sites (such as oxygen vacancies or exposed metal atoms) to generate hydrophilic hydroxyl groups. These active sites can also enhance the adhesion between the zirconia nanoparticles and the fiber. In addition, the ZrO2 nanoparticles themselves have high hardness and high toughness, and their small size effect enables them to be uniformly dispersed in the hydrated zirconia sol with high compatibility with them to form a dense protective layer, further improving the wear resistance, chemical stability (alkali corrosion resistance) and bubble point pressure of the diaphragm, and avoiding safety hazards such as gas crossover, efficiency reduction and electrical short circuit caused by erosion damage (as Figure 1 shown) during the actual application of the alkaline electrolytic cell diaphragm. Finally, a uniformly distributed super-hydrophilic shell layer is formed on the surface and inside of the fiber. Through subsequent hot pressing treatment, the fibrous planar material and the super-hydrophilic shell layer can be more tightly combined to form a more uniform and dense pore structure, thereby obtaining an alkaline electrolyzed water diaphragm with excellent wear resistance and hydrophilicity. The test results of the examples show that the alkaline electrolyzed water diaphragm prepared by the present invention has excellent comprehensive properties: the mass wear rate at 500 cycles is 2.31 - 6.29 mg / cm 2 , the surface resistance is 0.16 - 0.23 Ω·cm 2 , the bubble point pressure is 8.62 - 19.72 KPa, the contact angle is 0 - 10.2°, the alkali loss is 0.88 - 1.98%, showing good ion conductivity, wear resistance, alkali corrosion resistance and hydrophilicity, which can significantly reduce the operating energy consumption of the alkaline electrolytic cell, improve the electrolyzed water efficiency, extend the service life of the diaphragm, and have broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1It is a physical picture of the diaphragm breakage during the actual application of the alkaline electrolyzer in industry;

[0023] Figure 2 It is the contact angle diagram of the pretreated PPS woven fabric (a) in Comparative Example 1 and the alkaline electrolyzed water diaphragm (b) prepared in Example 4. Detailed implementation manners

[0024] The present invention provides a method for preparing an alkaline electrolyzed water diaphragm, which includes the following steps:

[0025] Repeatedly impregnate the fibrous planar material in a mixed solution of ZrO2 nanoparticles and zirconium hydrous oxide sol and then dry it to obtain a composite membrane;

[0026] Hot press the composite membrane to obtain an alkaline electrolyzed water diaphragm;

[0027] The preparation method of the zirconium hydrous oxide sol includes the following steps: subject an aqueous solution of zirconium oxychloride to anion exchange treatment, and mix the obtained exchange solution with a mixed solution of citric acid and acetic acid to obtain a zirconium hydrous oxide sol.

[0028] Unless otherwise specified, the present invention has no special requirements for the sources of the raw materials used, and commercially available products well-known to those skilled in the art can be used.

[0029] The present invention repeatedly impregnates the fibrous planar material in a mixed solution of ZrO2 nanoparticles and zirconium hydrous oxide sol and then dries it to obtain a composite membrane.

[0030] As an implementation manner, the usage mode of the fibrous planar material includes a mesh, a porous membrane, a non-woven fabric, a woven fabric or a composite fabric, and it is a woven fabric in specific embodiments; the material of the fibrous planar material includes one or more of polyphenylene sulfide (PPS), polysulfone resin, polyethylene, polypropylene, fluororesin, poly(p-phenylene benzobisoxazole), polyketone, polyether ether ketone, polyimide and polyetherimide, and it is polyphenylene sulfide or polysulfone resin in specific embodiments.

[0031] As an implementation manner, before the impregnation, it further includes: pretreating the fibrous planar material; the pretreatment is to soak the fibrous planar material in absolute ethanol, perform ultrasonic cleaning and then dry it; the power of the ultrasonic cleaning is 120-480W, specifically 480W in specific embodiments, the time is 5min-2h, specifically 5-30min in specific embodiments; the drying temperature is 80-250°C, specifically 80-100°C in specific embodiments, the time is 1-6h, specifically 1-2h in specific embodiments; the drying is drying by baking. The present invention removes surface impurities (grease and dust) of the fibrous planar material through the pretreatment.

[0032] As an embodiment, the average particle size of the ZrO2 nanoparticles is 20 - 50 nm, and in a specific embodiment, it is 30 nm.

[0033] As an embodiment, the mass percentage of zirconium oxide hydrate in the zirconium oxide hydrate sol is 5 - 25%, and in specific embodiments, it is 5%, 10%, 15%, 20% or 25%.

[0034] As an embodiment, the method for preparing the zirconium oxide hydrate sol comprises the following steps: performing anion exchange treatment on an aqueous solution of zirconyl chloride, mixing the obtained exchange solution with a mixed solution of citric acid and acetic acid to obtain a zirconium oxide hydrate sol; the zirconyl chloride is zirconyl chloride octahydrate; the concentration of zirconyl chloride in the aqueous solution of zirconyl chloride is 0.3 - 1 mol / L, and in a specific embodiment, it is 0.5 mol / L; the anion exchange treatment is carried out with an anion exchange resin; the pH value of the exchange solution is 3 - 3.5, and in a specific embodiment, it is 3 - 3.2; the molar ratio of zirconyl chloride, citric acid and acetic acid is 0.1 - 0.2:1:1, and in a specific embodiment, it is 0.2:1:1.

[0035] When zirconyl chloride (ZrOCl2) is dissolved in water, colloidal Zr(OH)4 and HCl are formed. Zr - O - Zr bonds are formed between Zr(OH)4 molecules through dehydration reactions to gradually form larger polymers. As the condensation reaction continues, the solution becomes increasingly viscous and finally forms a gel.

[0036] As an embodiment, the mass ratio of ZrO2 nanoparticles to the zirconium oxide hydrate sol is 1:5 - 1, and in specific embodiments, it is 1:5, 1:4, 1:3, 1:2 or 1:1; the method for preparing the mixed solution of ZrO2 nanoparticles and the zirconium oxide hydrate sol is: mixing ZrO2 nanoparticles and the zirconium oxide hydrate sol, and alternately performing magnetic stirring and ultrasonic dispersion treatment; the stirring is magnetic stirring; the stirring speed is 80 - 120 rpm, and in a specific embodiment, it is 100 rpm; the power of the ultrasonic dispersion treatment is 100 - 1000 W, and in a specific embodiment, it is 480 W; the time for each stirring is 10 - 30 min, and in a specific embodiment, it is 15 min; the time for each ultrasonic dispersion treatment is 3 - 10 min, and in a specific embodiment, it is 5 min; the total time for alternately performing stirring and ultrasonic dispersion treatment is 1 - 3 h, and in a specific embodiment, it is 2 h. The present invention ensures the uniform dispersion of zirconium oxide nanoparticles in the zirconium oxide hydrate sol through stirring and ultrasonic dispersion treatment.

[0037] As an implementation manner, the impregnation is to completely immerse the fibrous planar material in a mixed solution of ZrO₂ nanoparticles and hydrated zirconia sol; the temperature of the impregnation is 20 to 60 °C, specifically 40 °C in a specific embodiment; the time for each impregnation is 1 to 4 h, specifically 2 h in a specific embodiment; the temperature of the drying is 60 to 120 °C, specifically 60 to 80 °C in a specific embodiment; the time for each drying is 0.5 to 2 h, specifically 0.5 to 1 h in a specific embodiment.

[0038] As an implementation manner, the mass of the composite membrane is 1.5 to 1.8 times the mass of the fibrous planar material, specifically 1.6 to 1.7 times in a specific embodiment. The present invention has no special limitation on the number of repetitions, and it is sufficient to make the mass of the composite membrane reach 1.5 to 1.8 times the mass of the fibrous planar material.

[0039] After obtaining the composite membrane, the present invention hot-presses the composite membrane to obtain an alkaline electrolyzed water diaphragm. Through the hot-pressing treatment, the fibrous planar material and the superhydrophilic shell layer can be more tightly combined, forming a more uniform and dense pore structure, further improving the wear resistance, chemical stability (alkali corrosion resistance), and bubble point pressure of the alkaline electrolyzed water diaphragm.

[0040] As an implementation manner, the temperature of the hot pressing is 120 to 150 °C, specifically 130 to 140 °C in a specific embodiment; the time of the hot pressing is 20 to 30 min, specifically 25 min in a specific embodiment; the equipment used for the hot pressing is a splint.

[0041] The present invention mixes ZrO₂ nanoparticles and hydrated zirconia sol and coats them on the surface and inside of the fibrous planar material by impregnation. Compared with the traditional immersion method, due to the high compatibility of the hydrated zirconia sol with the ZrO₂ nanoparticles, it not only overcomes the charge repulsion between the loaded substance and the fibrous planar material, but also has a higher raw material utilization rate, and the ZrO₂ nanoparticles and the hydrated zirconia sol enter the pore channels of the fibrous planar material more efficiently and are more evenly distributed. The present invention uses an inorganic binder (hydrated zirconia sol), which improves the overall wear resistance of the alkaline electrolyzed water diaphragm and at the same time improves the hydrophilicity of the surface of the alkaline electrolyzed water diaphragm. The raw materials for synthesizing the hydrated zirconia sol in the present invention are cheap and easily available, and the cost is low. The method provided by the present invention has the characteristics of simple operation, mild conditions, excellent functional group compatibility, and high yield.

[0042] The present invention also provides an alkaline electrolyzed water diaphragm prepared by the preparation method described in the above technical solution, including a fibrous planar material and a superhydrophilic shell layer coated on the surface and inside of the fibrous planar material; the superhydrophilic shell layer includes hydrated zirconia gel and ZrO₂ nanoparticles dispersed in the hydrated zirconia gel.

[0043] As an implementation manner, the thickness of the alkaline electrolyzed water diaphragm is <800 μm. Another implementation manner is 700 ± 20 μm, and in a specific embodiment, it is 700 μm.

[0044] The present invention also provides an application of the above-mentioned alkaline electrolyzed water diaphragm in an alkaline electrolytic cell.

[0045] The present invention has no special limitation on the application method of the alkaline electrolyzed water diaphragm in the alkaline electrolytic cell, and the well-known application methods in the art can be adopted.

[0046] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention, but they cannot be understood as a limitation to the protection scope of the present invention.

[0047] Example 1

[0048] (1) Pretreatment: Immerse the fibrous planar material (PPS woven fabric) in absolute ethanol, ultrasonically clean it at 480 W for 5 min, and then dry it at 80 °C for 1 h to remove surface impurities;

[0049] (2) Preparation of zirconium hydrous oxide sol: Dissolve ZrOCl2·8H2O in deionized water to obtain a zirconium oxychloride solution with a concentration of 0.5 mol / L. Perform anion exchange treatment on this solution with an anion exchange resin, control the pH value of the obtained exchange solution to be 3.0, and add the exchange solution to a mixed solution of citric acid and acetic acid so that the molar ratio of ZrOCl2·8H2O, citric acid, and acetic acid is 0.2:1:1 to obtain a stable and transparent zirconium hydrous oxide sol, where the mass concentration of zirconium hydrous oxide is 25 wt%;

[0050] (3) Dispersion: Disperse 30-nm ZrO2 nanoparticles in a 25 wt% zirconium hydrous oxide sol, and then alternately perform magnetic stirring (100 rpm) and ultrasonic dispersion treatment (power of 480 W) for a total of 2 h. After each 15 min of magnetic stirring, perform ultrasonic dispersion treatment for 5 min to ensure that the zirconia particles are completely dispersed, obtaining a mixed solution of ZrO2 nanoparticles and zirconium hydrous oxide sol, where the mass ratio of ZrO2 nanoparticles to zirconium hydrous oxide sol is 1:5;

[0051] (4) Impregnation: Completely immerse the pretreated PPS woven fabric in the above-mentioned mixed solution of ZrO2 nanoparticles and zirconium hydrous oxide sol at 40 °C. After impregnation for 2 h, dry it at 60 °C for 0.5 h to form a uniformly distributed super-hydrophilic shell layer on the surface and inside of the PPS woven fabric. Repeat the impregnation and drying processes until the mass of the obtained composite membrane reaches 1.7 times the mass of the PPS woven fabric;

[0052] (5) Hot pressing: The above composite film was hot pressed with a splint at 130 °C for 25 min to obtain an alkaline electrolyzed water diaphragm (with a thickness of 700 μm).

[0053] Example 2

[0054] The difference from Example 1 is that the mass concentration of zirconium hydrous oxide in the zirconium hydrous oxide sol is 20 wt%, and the mass ratio of ZrO2 nanoparticles to zirconium hydrous oxide sol in the mixture of ZrO2 nanoparticles and zirconium hydrous oxide sol is 1:4, and the rest is the same as in Example 1.

[0055] Example 3

[0056] The difference from Example 1 is that the mass concentration of zirconium hydrous oxide in the zirconium hydrous oxide sol is 15 wt%, and the mass ratio of ZrO2 nanoparticles to zirconium hydrous oxide sol in the mixture of ZrO2 nanoparticles and zirconium hydrous oxide sol is 1:3, and the rest is the same as in Example 1.

[0057] Example 4

[0058] The difference from Example 1 is that the mass concentration of zirconium hydrous oxide in the zirconium hydrous oxide sol is 10 wt%, and the mass ratio of ZrO2 nanoparticles to zirconium hydrous oxide sol in the mixture of ZrO2 nanoparticles and zirconium hydrous oxide sol is 1:2, and the rest is the same as in Example 1.

[0059] Example 5

[0060] The difference from Example 1 is that the mass concentration of zirconium hydrous oxide in the zirconium hydrous oxide sol is 5 wt%, and the mass ratio of ZrO2 nanoparticles to zirconium hydrous oxide sol in the mixture of ZrO2 nanoparticles and zirconium hydrous oxide sol is 1:1, and the rest is the same as in Example 1.

[0061] Comparative Example 1

[0062] The commercial PPS fabric was soaked in deionized water, ultrasonically cleaned at 480 W for 30 min, and then dried at 105 °C for 2 h to obtain the pretreated PPS fabric.

[0063] Comparative Example 2

[0064] The difference from Example 1 is that the mass ratio of ZrO2 nanoparticles to zirconium hydrous oxide sol in the mixture of ZrO2 nanoparticles and zirconium hydrous oxide sol is 2:1, and the rest is the same as in Example 1.

[0065] Comparative Example 3

[0066] The difference from Example 1 is that the zirconium hydrous oxide sol is not added, and the ZrO2 nanoparticles are dispersed in water, and the mass ratio of ZrO2 nanoparticles to water is 1:5, and the rest is the same as in Example 1.

[0067] Comparative Example 4

[0068] It is different from Example 1 in that zirconium oxide hydrosol is not added, and ZrO2 nanoparticles are dispersed in a 5% polyvinyl alcohol solution, and the mass ratio of ZrO2 nanoparticles to polyvinyl alcohol is 3:2. The rest is the same as in Example 1.

[0069] Performance Test

[0070] (1) Figure 2 It is the contact angle diagram of the pretreated PPS woven fabric (a) in Comparative Example 1 and the alkaline electrolyzed water diaphragm (b) prepared in Example 4.

[0071] From Figure 2 in (a), it can be observed that the original PPS woven fabric is a hydrophobic membrane with a contact angle of 131.8°. From Figure 2 in (b), it can be observed that the alkaline electrolyzed water diaphragm prepared in Example 4 has become a hydrophilic membrane with a contact angle of 0°.

[0072] (2) The following performance tests were carried out on the alkaline electrolyzed water diaphragms prepared in Examples 1 to 5 and the pretreated PPS woven fabrics in Comparative Examples 1 to 4:

[0073] 1) Bubble point pressure: Refer to "GB / T32361-2015 Test Method for Pore Size of Separation Membranes - Bubble Point and Mean Flow Rate Method" to test the bubble point pressure;

[0074] 2) Surface resistance: After soaking overnight in a 30wt% KOH solution, it was tested and obtained through an electrochemical workstation;

[0075] 3) Alkali absorption rate: The alkali absorption rate was tested in a 30wt% KOH solution;

[0076] 4) Contact angle: The contact angle of 4 μL of deionized water at room temperature was tested using a DSA-30S dynamic contact angle measuring instrument;

[0077] 5) Mass wear rate: The mass change rate before and after wear was tested according to GB / T 3960-1983;

[0078] 6) Alkali loss: Soak in a 30wt% KOH aqueous solution at 150 °C for 12 h, and test the mass loss rate of the diaphragm after alkali boiling;

[0079] The above performance test results are shown in Table 1.

[0080] Table 1 Performance Test Results of the Alkaline Electrolyzed Water Diaphragms Prepared in Examples 1 to 5 and the Pretreated PPS Woven Fabrics in Comparative Examples 1 to 4

[0081]

[0082] As can be seen from the data in Table 1, the alkaline electrolyzed water diaphragm prepared by the present invention has excellent comprehensive properties: the mass wear rate at 500 cycles is 2.31 - 6.29 mg / cm 2 , the surface resistance is 0.16 - 0.23 Ω·cm 2 , the bubble point pressure is 8.62 - 19.72 KPa, the contact angle is 0 - 10.2°, and the alkali loss is 0.88 - 1.98%.

[0083] Compared with Comparative Example 1, the diaphragms prepared in the 5 examples have significant improvements in terms of abrasion resistance, surface resistance, bubble point pressure, alkali absorption rate, alkali corrosion resistance, and hydrophilicity. Specifically, after 500 frictions, the wear rates of the diaphragms in the 5 examples all decreased, while the diaphragm of Comparative Example 1 (PPS woven fabric after pretreatment) was damaged after only 300 frictions. In addition, the surface resistances of the diaphragms in the 5 examples all decreased, indicating improved electrical conductivity; the increase in bubble point pressure shows that the pore structure of the diaphragm is more dense and the airtightness is enhanced; the increase in alkali absorption rate reflects the enhanced adsorption ability of the diaphragm to alkaline substances; the alkali loss less than 2% proves that the diaphragm provided by the present invention has good alkali corrosion resistance; the hydrophilicity is also significantly better than that of Comparative Example 1, which will help improve the performance of the diaphragm in practical applications.

[0084] The alkaline electrolyzed water diaphragm prepared by the present invention exhibits good ionic conductivity, abrasion resistance, alkali corrosion resistance, and hydrophilicity, can significantly reduce the operating energy consumption of alkaline electrolyzers, improve the electrolyzed water efficiency, extend the service life of the diaphragm, and has broad application prospects.

[0085] Although the above embodiments have described the present invention in detail, they are only a part rather than all of the embodiments of the present invention. People can also obtain other embodiments without creative efforts based on these embodiments, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing an alkaline electrolyzed water diaphragm, characterized in that, It includes the following steps: The fibrous planar material is repeatedly impregnated in a mixed solution of ZrO2 nanoparticles and hydrated zirconia sol and then dried to obtain a composite membrane; The composite membrane is hot-pressed to obtain an alkaline electrolyzed water diaphragm; The preparation method of the hydrated zirconia sol includes the following steps: an aqueous solution of zirconium oxychloride is subjected to anion exchange treatment, and the obtained exchange solution is mixed with a mixed solution of citric acid and acetic acid to obtain a hydrated zirconia sol.

2. The preparation method according to claim 1, wherein The material of the fibrous planar material includes one or more of polyphenylene sulfide, polysulfone resin, polyethylene, polypropylene, fluorine-based resin, poly(p-phenylene benzobisoxazole), polyketone, polyether ether ketone, polyimide, and polyetherimide.

3. The preparation method according to claim 1, wherein The average particle size of the ZrO2 nanoparticles is 20 - 50 nm.

4. The preparation method according to claim 1, characterized in that, The mass percentage content of hydrated zirconia in the hydrated zirconia sol is 5 - 25%.

5. The preparation method according to claim 1 or 4, characterized in that, The mass ratio of the ZrO2 nanoparticles to the hydrated zirconia sol is 1:5 - 1.

6. The preparation method according to claim 1, wherein The mass of the composite membrane is 1.5 - 1.8 times the mass of the fibrous planar material.

7. The preparation method according to claim 1, characterized in that, The temperature of the hot pressing is 120 - 150 °C; the time of the hot pressing is 20 - 30 min.

8. The preparation method according to claim 1, characterized in that, The molar ratio of zirconium oxychloride, citric acid, and acetic acid is 0.1 - 0.2:1:

1.

9. The alkaline electrolyzed water diaphragm prepared by the preparation method according to any one of claims 1 to 8, characterized in that, It includes a fibrous planar material and a superhydrophilic shell layer coated on the surface and inside of the fibrous planar material; the superhydrophilic shell layer includes hydrated zirconia gel and ZrO2 nanoparticles dispersed in the hydrated zirconia gel.

10. Application of the alkaline electrolyzed water diaphragm according to claim 9 in an alkaline electrolytic cell.

Images