High-flux silicon removal nanofiltration membrane and preparation process thereof

Abstract

The invention discloses a high-flux silicon removal nanofiltration membrane and a preparation process, and relates to the technical field of water treatment. The invention discloses a preparation process of a high-flux silicon removal nanofiltration membrane, which comprises the following steps: mixing sulfonic acid electrolyte and a manganese chloride solution to obtain a sulfonic acid-manganese chloride solution; soaking the bottom membrane in a sulfonic acid-manganese chloride solution for multiple times, baking and curing, and generating a hydrophilic silicon removal material layer on the surface of the bottom membrane, so as to obtain the high-flux silicon removal nanofiltration membrane. The bottom membrane is obtained by coating the surface of the polypropylene non-woven fabric with the polysulfone porous material, the hydrophilic silicon removal material layer is attached to the surface of the bottom membrane, and the good silicon pollution resisting effect is achieved by means of repulsion of surface charges of the hydrophilic silicon removal material layer and silicate.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a high-throughput silicon removal nanofiltration membrane and a preparation process thereof. Background Art

[0002] Solar energy is a clean energy source. Photovoltaic power generation converts inexhaustible solar energy into electrical energy, which not only replaces some conventional energy sources, but also will become the main body of the world's energy supply. However, with the rapid development of the photovoltaic industry in recent years, its raw material production and solar cell module processing are considered to be "high pollution and high energy consumption", and its pollution control has received widespread attention. Alloy silicon is extracted from silicon ore, purified to make semiconductor materials that can be used for photoelectric conversion, and then processed into standard-sized silicon wafers encapsulated into solar cell modules, and finally formed into a photovoltaic power generation system. The main links that produce pollutants are the preparation of single crystal / polycrystalline silicon, single crystal / polycrystalline silicon cutting, single crystal / polycrystalline silicon cell assembly and photovoltaic system operation. As one of the raw materials, the silicon-containing wastewater generated by silicon materials has complex components and a high silicon content. Usually, a series of pre-treatments are carried out on the wastewater to recover most of the crystalline silicon in the wastewater, and then deep treatment is carried out through reverse osmosis. Traditional pre-treatment methods include flocculation sedimentation and ultrafiltration, but both have shortcomings. The use of flocculation sedimentation equipment occupies a large area, the silicon in the wastewater cannot be completely collected, and the wastewater is difficult to reuse due to the presence of chemicals. Direct ultrafiltration treatment is susceptible to clogging and contamination of fine silicon powder particles by the membrane, the filtration pressure increases quickly, the flux decreases, the filtration cycle is short, and the treatment cost is high.

[0003] Nanofiltration membrane is a pressure-driven separation membrane with performance between reverse osmosis membrane and ultrafiltration membrane. It has the advantages of low operating pressure, low operating cost and high removal rate for multivalent ions and organic matter with relative molecular weight above 200Da. It is widely used in water softening, brackish water recovery, dye salt separation, photovoltaic wastewater recovery and other fields. Such applications do not require the high pressure and high NaCl retention rate required in reverse osmosis membranes, so the energy consumption required is also less. At present, the use of nanofiltration is growing rapidly. In the photovoltaic field, the silicon-containing wastewater produced by silicon materials as one of the raw materials has complex components and high silicon content, so there is an urgent need to develop a stable and silicon-resistant selective high-flux membrane. Summary of the invention

[0004] The purpose of the present invention is to provide a high-throughput desiliconization nanofiltration membrane and a preparation process to solve the following technical problems: Existing nanofiltration membranes have limited resistance to silica fouling and low selectivity flux.

[0005] The purpose of the present invention can be achieved by the following technical solutions: A preparation process for a high-flux desiliconization nanofiltration membrane comprises the following steps: soaking an ultrafiltration bottom membrane in a sulfonic acid-manganese chloride solution, taking it out and drying it, and repeating the above steps several times to obtain a high-flux desiliconization nanofiltration membrane; The ultrafiltration bottom membrane comprises a support layer and a polysulfone porous material layer attached to the surface of the support layer; The polysulfone porous material layer is obtained by coating the casting liquid on the surface of the support layer; The casting solution includes the following raw materials in weight percentage: 17-19% polysulfone, 1-4% polyvinyl pyrrolidone, 45-50% N,N-dimethylacetamide, 20-25% N-methyl-2-pyrrolidone, and 5-10% modified silicon dioxide; The modified silica is obtained by treating porous silica with γ-glycidoxypropyltrimethylsilane.

[0006] As a further scheme of the present invention: the preparation method of the casting liquid comprises the following steps: according to the raw material ratio, polysulfone, polyvinyl pyrrolidone, N,N-dimethylacetamide, N-methyl-2-pyrrolidone and modified silicon dioxide are added into the reaction kettle and dispersed evenly, the temperature is raised to 60°C, stirred and dissolved, and degassed to obtain the casting liquid.

[0007] As a further scheme of the present invention: the preparation method of the polysulfone porous material layer comprises the following steps: scraping the casting liquid onto a non-woven fabric with a scraper to obtain a primary membrane, placing the primary membrane in an oven to evaporate the solvent, and finally placing the primary membrane in a coagulation liquid (5% ethanol aqueous solution) to immerse and coagulate into a membrane, thereby obtaining an ultrafiltration bottom membrane with a polysulfone porous material layer on the surface.

[0008] As a further scheme of the present invention: the preparation method of porous silica comprises the following steps: adding anhydrous ethanol and ammonia water into a reaction kettle and dispersing them evenly, adding hexadecyltrimethylammonium bromide and stirring to dissolve, adding ethyl orthosilicate, stirring at room temperature, filtering, washing with water, drying, and calcining to obtain porous silica.

[0009] As a further scheme of the present invention: the preparation method of modified silica comprises the following steps: adding anhydrous ethanol, deionized water, and γ-glycidoxypropyltrimethylsilane into a reaction kettle and dispersing them evenly, adding porous silica, controlling the temperature at 60-70°C, keeping the reaction warm for 0.5-4h, washing with ethanol, and drying to obtain modified silica.

[0010] As a further solution of the present invention: the addition ratio of anhydrous ethanol, deionized water, γ-glycidoxypropyltrimethylsilane and porous silica is 6-12 mL: 3-6 mL: 0.4-1 mL: 1 g.

[0011] As a further solution of the present invention: the support layer is a polypropylene non-woven fabric, which has a better alkali resistance advantage (pH>12) compared with the traditional polyethylene terephthalate non-woven fabric.

[0012] As a further solution of the present invention: the specific steps of drying are: baking temperature 40-90° C., baking 0.5-10 min.

[0013] As a further solution of the present invention: the ultrafiltration bottom membrane is immersed in the sulfonic acid-manganese chloride solution and the drying step is repeated 2-6 times.

[0014] As a further solution of the present invention: the preparation method of the sulfonic acid-manganese chloride solution comprises the following steps: mixing the sulfonic acid electrolyte and the manganese chloride solution, adjusting the pH to 3-6, and standing to make the sulfonic acid electrolyte further dispersed evenly to obtain the sulfonic acid-manganese chloride solution.

[0015] As a further solution of the present invention: the manganese chloride solution is obtained by mixing manganese chloride as a solute and ultrapure water as a solute; the sulfonic acid-manganese chloride solution includes the following raw materials in weight percentage: 0.5-4% sulfonic acid electrolyte, 15-45% manganese chloride, and the balance is water, and the sum of the weight percentages is 100%.

[0016] As a further embodiment of the present invention: the sulfonic acid electrolyte is any one of benzidine disulfonic acid and diaminobenzenesulfonic acid.

[0017] A high-throughput silicon removal nanofiltration membrane sheet is made by any of the preparation processes described above.

[0018] Beneficial effects of the present invention: (1) The present invention uses sulfonic acid electrolyte as a carrier, adds manganese chloride, and prepares a sulfonic acid-manganese chloride solution; uses the sulfonic acid-manganese chloride solution as a treatment liquid to treat the ultrafiltration bottom membrane, so that the ultrafiltration surface has a negative charge, and prepares a high-flux silicon removal nanofiltration membrane. The high-flux silicon removal nanofiltration membrane prepared in this application has a good anti-silicon pollution effect because of its negative charge, which repels silicate ions, and has excellent stability, acid and alkali resistance, and heat resistance under complex water conditions.

[0019] (2) The present application utilizes sulfonic acid-manganese chloride solution to treat the ultrafiltration bottom membrane and prepares paramagnetic material on the surface of the ultrafiltration bottom membrane; the magnetization effect enhances the activity of water molecules, making it easier for water molecules to pass through the nanofiltration membrane under pressure, thereby increasing the water permeability of the membrane; the ion activity is weakened, thereby reducing the permeability of salt ions during membrane separation, resulting in an increase in the retention rate; the ultrafiltration bottom membrane treated with sulfonic acid-manganese chloride solution has anti-scaling and descaling effects, slows down the rate of membrane fouling, and extends the service life of the membrane.

[0020] (3) The present application uses porous silica as a basis, and uses epoxy silane coupling agent to organically modify the porous silica to obtain modified silica, and the modified silica is added to a polysulfone-based casting solution. Polysulfone is a hydrophilic polymer material rich in sulfone groups. The oxygen-containing double bonds on the sulfone groups form hydrogen bonds with groups such as hydroxyl groups on the surface of silica, so that the modified silica is evenly dispersed in the casting solution. The casting solution is coated on the surface of a polypropylene non-woven fabric to obtain an ultrafiltration base membrane with a polysulfone porous material layer; on this ultrafiltration base membrane, it is further immersed in a sulfonic acid-manganese chloride solution containing a sulfonic acid electrolyte, and interacts with the modified silica contained in the ultrafiltration base membrane. The epoxy groups on the surface of the modified silica and the amino groups of the sulfonic acid electrolyte in the sulfonic acid-manganese chloride solution are combined through intermolecular bonding, which effectively improves the composite strength of the sulfonic acid electrolyte and the base membrane, prolongs the service life of the membrane, and provides a basis for subsequent high-throughput nanofiltration membranes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below in conjunction with the accompanying drawings.

[0022] Figure 1 This is a microstructure diagram of the diaphragm prepared in this application. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1 A process for preparing a casting solution comprises the following steps: S1: Preparation of porous silica: 125 mL of anhydrous ethanol and 150 mL of 25 wt% ammonia water were added to a reaction kettle and dispersed evenly, 11 g of hexadecyltrimethylammonium bromide was added and stirred to dissolve, 20 g of tetraethyl orthosilicate was added, stirred at room temperature for 3 h, filtered, washed with water, dried, and calcined at 550 ° C for 6 h to obtain porous silica; S2: Preparation of modified silica: 60 mL of anhydrous ethanol, 30 mL of deionized water, and 4 mL of γ-glycidoxypropyltrimethylsilane were added to a reaction kettle and dispersed evenly, 10 g of porous silica was added, the temperature was controlled at 60°C, the reaction was kept warm for 3 h, and the modified silica was obtained after washing with ethanol and drying; S3: Preparation of casting solution: 19 g polysulfone, 4.4 g polyvinyl pyrrolidone, 47.7 g N,N-dimethylacetamide, 23.9 g N-methyl-2-pyrrolidone, and 5 g modified silicon dioxide were added into a reaction kettle and dispersed evenly, heated to 60° C., stirred and dissolved, and degassed to obtain a casting solution.

[0025] Example 2 A process for preparing a casting solution comprises the following steps: S1: Preparation of porous silica: 125 mL of anhydrous ethanol and 150 mL of 25 wt% ammonia water were added to a reaction kettle and dispersed evenly, 11 g of hexadecyltrimethylammonium bromide was added and stirred to dissolve, 20 g of tetraethyl orthosilicate was added, stirred at room temperature for 3 h, filtered, washed with water, dried, and calcined at 550 ° C for 6 h to obtain porous silica; S2: Preparation of modified silica: 100 mL of anhydrous ethanol, 50 mL of deionized water, and 6 mL of γ-glycidoxypropyltrimethylsilane were added to a reaction kettle and dispersed evenly, 10 g of porous silica was added, the temperature was controlled at 65°C, the reaction was kept warm for 3 h, and the modified silica was obtained after washing with ethanol and drying; S3: Preparation of casting solution: 19 g polysulfone, 4.4 g polyvinyl pyrrolidone, 47.7 g N,N-dimethylacetamide, 23.9 g N-methyl-2-pyrrolidone, and 5 g modified silicon dioxide were added into a reaction kettle and dispersed evenly, heated to 60° C., stirred and dissolved, and degassed to obtain a casting solution.

[0026] Example 3 The preparation process of the casting solution comprises the following steps: S1: Preparation of porous silica: 125 mL of anhydrous ethanol and 150 mL of 25 wt% ammonia water were added to a reaction kettle and dispersed evenly, 11 g of hexadecyltrimethylammonium bromide was added and stirred to dissolve, 20 g of tetraethyl orthosilicate was added, stirred at room temperature for 3 h, filtered, washed with water, dried, and calcined at 550 ° C for 6 h to obtain porous silica; S2: Preparation of modified silica: 120 mL of anhydrous ethanol, 60 mL of deionized water, and 10 mL of γ-glycidoxypropyltrimethylsilane were added to a reaction kettle and dispersed evenly, 10 g of porous silica was added, the temperature was controlled at 70°C, the reaction was kept warm for 3 h, and the modified silica was obtained after washing with ethanol and drying; S3: Preparation of casting solution: 19 g polysulfone, 4.4 g polyvinyl pyrrolidone, 47.7 g N,N-dimethylacetamide, 23.9 g N-methyl-2-pyrrolidone, and 5 g modified silicon dioxide were added into a reaction kettle and dispersed evenly, heated to 60° C., stirred and dissolved, and degassed to obtain a casting solution.

[0027] Example 4 Please refer to Figure 1 , a preparation process of a high-throughput desiliconization nanofiltration membrane comprises the following steps: A1: Preparation of ultrafiltration bottom membrane: The casting solution prepared in Example 1 is scraped onto a polypropylene non-woven fabric by a scraper to obtain a primary membrane, the primary membrane is placed in an oven to evaporate the solvent, and finally immersed in a coagulation solution of 5% ethanol aqueous solution for 12 hours to coagulate into a membrane, thereby obtaining an ultrafiltration bottom membrane; A2: Prepare sulfonic acid-manganese chloride solution: mix 30g manganese chloride and 67.8mL ultrapure water, add 2g diaminobenzenesulfonic acid and mix well, add sulfuric acid / sodium hydroxide to adjust the solution to pH 4, and let stand overnight to obtain sulfonic acid-manganese chloride solution; A3: Preparation of membrane: soak the ultrafiltration bottom membrane in sulfonic acid-manganese chloride solution, take it out, bake it at 55°C for 0.5 min, repeat the above steps 3 times to obtain a high-throughput silicon removal nanofiltration membrane.

[0028] Example 5 Please refer to Figure 1 , a preparation process of a high-throughput desiliconization nanofiltration membrane comprises the following steps: A1: Preparation of ultrafiltration bottom membrane: The casting solution prepared in Example 2 is scraped onto a polypropylene non-woven fabric by a scraper to obtain a primary membrane, the primary membrane is placed in an oven to evaporate the solvent, and finally, the primary membrane is immersed in a coagulation solution of 5% ethanol aqueous solution for 12 hours to coagulate into a membrane, thereby obtaining an ultrafiltration bottom membrane; A2: Prepare sulfonic acid-manganese chloride solution: mix 30g manganese chloride and 67.8mL ultrapure water, add 2g diaminobenzenesulfonic acid and mix well, add sulfuric acid / sodium hydroxide to adjust the solution to pH 4, and let stand overnight to obtain sulfonic acid-manganese chloride solution; A3: Preparation of membrane: soak the ultrafiltration bottom membrane in sulfonic acid-manganese chloride solution, take it out, bake it at 55°C for 0.5 min, repeat the above steps 3 times to obtain a high-throughput silicon removal nanofiltration membrane.

[0029] Example 6 Please refer to Figure 1 , a preparation process of a high-throughput desiliconization nanofiltration membrane comprises the following steps: A1: Preparation of ultrafiltration bottom membrane: The casting solution prepared in Example 3 is scraped onto a polypropylene non-woven fabric by a scraper to obtain a primary membrane, the primary membrane is placed in an oven to evaporate the solvent, and finally immersed in a coagulation solution of 5% ethanol aqueous solution for 12 hours to coagulate into a membrane, thereby obtaining an ultrafiltration bottom membrane; A2: Prepare sulfonic acid-manganese chloride solution: mix 30g manganese chloride and 67.8mL ultrapure water, add 2g diaminobenzenesulfonic acid and mix well, add sulfuric acid / sodium hydroxide to adjust the solution to pH 4, and let stand overnight to obtain sulfonic acid-manganese chloride solution; A3: Preparation of membrane: soak the ultrafiltration bottom membrane in sulfonic acid-manganese chloride solution, take it out, bake it at 55°C for 0.5 min, repeat the above steps 3 times to obtain a high-throughput silicon removal nanofiltration membrane.

[0030] Comparative Example 1 The preparation process of the casting solution comprises the following steps: S1: Preparation of modified silica: 100 mL of anhydrous ethanol, 50 mL of deionized water, and 6 mL of γ-glycidoxypropyltrimethylsilane were added to a reaction kettle and dispersed evenly, 10 g of nano-silica was added, the temperature was controlled at 65°C, the reaction was kept warm for 3 h, and the modified silica was obtained after washing with ethanol and drying; S2: Preparation of casting solution: 19 g polysulfone, 4.4 g polyvinyl pyrrolidone, 47.7 g N,N-dimethylacetamide, 23.9 g N-methyl-2-pyrrolidone, and 5 g modified silicon dioxide were added into a reaction kettle and dispersed evenly. The mixture was heated to 60° C., stirred and dissolved, and degassed to obtain a casting solution.

[0031] Comparative Example 2 The preparation process of the casting solution comprises the following steps: S1: Preparation of porous silica: 125 mL of anhydrous ethanol and 150 mL of 25 wt% ammonia water were added to a reaction kettle and dispersed evenly, 11 g of hexadecyltrimethylammonium bromide was added and stirred to dissolve, 20 g of tetraethyl orthosilicate was added, stirred at room temperature for 3 h, filtered, washed with water, dried, and calcined at 550 ° C for 6 h to obtain porous silica; S2: 19 g polysulfone, 4.4 g polyvinyl pyrrolidone, 47.7 g N,N-dimethylacetamide, 23.9 g N-methyl-2-pyrrolidone, and 5 g porous silica were added into a reaction kettle and dispersed evenly. The mixture was heated to 60° C. and stirred to dissolve. The mixture was degassed to obtain a casting solution.

[0032] Comparative Example 3 Compared with Example 5, Comparative Example 3 only replaces the casting solution prepared in Example 2 used in Example 5 with the casting solution prepared in Comparative Example 1. The remaining components and preparation method of Comparative Example 3 are completely consistent with those of Example 5.

[0033] Comparative Example 4 Compared with Example 5, Comparative Example 4 is only that the casting solution prepared in Example 2 used in Example 5 is replaced by the casting solution prepared in Comparative Example 2. The other components and preparation method of Comparative Example 4 are completely consistent with those of Example 5.

[0034] Comparative Example 5 A preparation process of a high-throughput silicon removal nanofiltration membrane comprises the following steps: A1: Preparation of ultrafiltration bottom membrane: The casting solution prepared in Example 2 is scraped onto a polypropylene non-woven fabric by a scraper to obtain a primary membrane, the primary membrane is placed in an oven to evaporate the solvent, and finally, the primary membrane is immersed in a coagulation solution of 5% ethanol aqueous solution for 12 hours to coagulate into a membrane, thereby obtaining an ultrafiltration bottom membrane; A2: Prepare sulfonic acid solution: mix 67.8 mL ultrapure water and 2 g diaminobenzenesulfonic acid evenly, add sulfuric acid / sodium hydroxide to adjust the solution to pH 4, and let stand overnight to obtain sulfonic acid solution; A3: Preparation of membrane: soak the ultrafiltration bottom membrane in sulfonic acid solution, take it out, bake it at 55°C for 0.5 min, repeat the above steps 3 times to obtain a high-throughput silicon removal nanofiltration membrane.

[0035] Comparative Example 6 A preparation process for a high-throughput desiliconizing nanofiltration membrane comprises the following steps: A1: Preparation of ultrafiltration bottom membrane: The casting solution prepared in Example 2 is scraped onto a polypropylene non-woven fabric by a scraper to obtain a primary membrane, the primary membrane is placed in an oven to evaporate the solvent, and finally, the primary membrane is immersed in a coagulation solution of 5% ethanol aqueous solution for 12 hours to coagulate into a membrane, thereby obtaining an ultrafiltration bottom membrane; A2: Prepare manganese chloride solution: Mix 30g manganese chloride and 67.8mL ultrapure water, add sulfuric acid / sodium hydroxide to adjust the solution to pH 4, and let it stand overnight to obtain a manganese chloride solution; A3: Preparation of membrane: soak the ultrafiltration bottom membrane in manganese chloride solution, take it out, bake it at 55°C for 0.5 min, repeat the above steps 3 times to obtain a high-throughput silicon removal nanofiltration membrane.

[0036] Comparative Example 7 A process for preparing a high-throughput silicon removal nanofiltration membrane comprises the following steps: The casting solution prepared in Example 2 was scraped onto a polypropylene non-woven fabric with a scraper to obtain a primary membrane. The primary membrane was placed in an oven to evaporate the solvent, and finally immersed in a coagulation solution of 5% ethanol aqueous solution for 12 hours to coagulate into a membrane, thereby obtaining a desiliconizing nanofiltration membrane sheet.

[0037] Performance Testing (1) Removal rate and water production 1. Prepare waste liquid: prepare a sodium silicate solution with a concentration of 6000ppm and adjust the pH value of the solution to 13 with sodium hydroxide; 2. Experimental materials: membranes prepared in Examples 4-6 and Comparative Examples 3-7; 3. Testing step: Under a test pressure of 1.0 MPa, the aqueous solution was treated with the membranes prepared in Examples 4-6 and Comparative Examples 3-7; and the removal rate of silicon dioxide and the water production of the membranes were tested; the test results are shown in Table 1; 4. Test results Table 1: Statistical table of water treatment results of Examples 4-6 and Comparative Examples 3-7

[0038] 5. Test conclusion The membrane prepared in the present application has good filtering effect on silica in wastewater and has high water production.

[0039] (2) Alkali resistance 1. Prepare waste liquid: prepare a sodium silicate solution with a concentration of 6000ppm and adjust the pH value of the solution to 13 with sodium hydroxide; 2. Experimental materials: Prepare a 10% sodium hydroxide solution, soak the membranes prepared in Examples 4-6 and Comparative Examples 3-7 in the 10wt% sodium hydroxide solution for 10 days, rinse with pure water and set aside; 3. Testing step: Under a test pressure of 1.0 MPa, the aqueous solution was treated with the membranes prepared in Examples 4-6 and Comparative Examples 3-7 after being treated with the above-mentioned sodium hydroxide aqueous solution; and the silicon dioxide removal rate and water production of the membranes were tested; the test results are shown in Table 2; 4. Test results Table 2: Statistical table of water treatment results of membrane after alkali treatment

[0040] 5. Test conclusion The membrane prepared in the present application still maintains a high silica filtration effect in an alkaline environment and has a high water production.

[0041] (3) Long-term effect 1. Wastewater: Take high silicon-containing wastewater from a photovoltaic plant as raw water, and test its pH to be 13.12 and the silicon dioxide content to be 7215ppm; 2. Experimental materials: the membranes prepared in Examples 4-6 and Comparative Examples 3-7; 3. Testing step: Under a test pressure of 1.0 MPa, the raw water was treated with the membranes prepared in the above Examples 4-6 and Comparative Examples 3-7. After 20 days of long-term testing, the removal rate of silicon dioxide by the membranes was tested. The test results are shown in Table 3. 4. Test results Table 3: Diaphragm long-term performance test data statistics

[0042] 5. Test conclusion The membrane prepared in the present application still maintains a relatively high silicon dioxide removal rate after long-term water treatment, and the resulting produced water can be reused as an alkaline material.

[0043] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A process for preparing a high-throughput desiliconizing nanofiltration membrane, characterized in that: The method comprises the following steps: soaking the ultrafiltration bottom membrane in a sulfonic acid-manganese chloride solution, taking it out and drying it, and repeating the above steps several times to obtain a high-flux silicon removal nanofiltration membrane; The ultrafiltration bottom membrane comprises a support layer and a polysulfone porous material layer attached to the surface of the support layer; The polysulfone porous material layer is obtained by coating the casting liquid on the surface of the support layer; The casting solution comprises the following raw materials in weight percentage: 17-19% polysulfone, 1-4% polyvinyl pyrrolidone, 45-50% N,N-dimethylacetamide, 20-25% N-methyl-2-pyrrolidone, and 5-10% modified silicon dioxide; The modified silica is obtained by treating porous silica with γ-glycidoxypropyltrimethylsilane.

2. The process for preparing a high-throughput silicon removal nanofiltration membrane according to claim 1, characterized in that: The preparation method of the modified silicon dioxide comprises the following steps: Anhydrous ethanol, deionized water and γ-glycidoxypropyltrimethylsilane are added into a reaction kettle and dispersed evenly, porous silica is added, the temperature is controlled at 60-70°C, the reaction is kept warm for 0.5-4h, washed with ethanol and dried to obtain modified silica.

3. The process for preparing a high-throughput desiliconizing nanofiltration membrane according to claim 2, characterized in that: The addition ratio of anhydrous ethanol, deionized water, γ-glycidoxypropyltrimethylsilane, and porous silica is 6-12 mL: 3-6 mL: 0.4-1 mL: 1 g.

4. The process for preparing a high-throughput desiliconizing nanofiltration membrane according to claim 1, characterized in that: The supporting layer is a polypropylene non-woven fabric.

5. The process for preparing a high-throughput silicon removal nanofiltration membrane according to claim 1, characterized in that: The specific steps of the drying are: baking at a temperature of 40-90° C. and baking for 0.5-10 minutes.

6. The process for preparing a high-throughput desiliconizing nanofiltration membrane according to claim 1, characterized in that: The ultrafiltration bottom membrane is immersed in the sulfonic acid-manganese chloride solution and dried for 2-6 times.

7. The process for preparing a high-throughput silicon removal nanofiltration membrane according to claim 1, characterized in that: The preparation method of the sulfonic acid-manganese chloride solution comprises the following steps: mixing a sulfonic acid electrolyte and a manganese chloride solution, adjusting the pH to 3-6, and standing to obtain the sulfonic acid-manganese chloride solution.

8. The process for preparing a high-throughput desiliconizing nanofiltration membrane according to claim 7, characterized in that: The manganese chloride solution is obtained by mixing manganese chloride as a solute and ultrapure water as a solute; the sulfonic acid-manganese chloride solution includes the following raw materials in weight percentage: 0.5-4% sulfonic acid electrolyte, 15-45% manganese chloride, and the balance is water, and the sum of the weight percentages is 100%.

9. The process for preparing a high-throughput desiliconizing nanofiltration membrane according to claim 7, characterized in that: The sulfonic acid electrolyte is any one of benzidine disulfonic acid and diaminobenzenesulfonic acid.

10. A high-throughput silicon removal nanofiltration membrane, characterized in that: The invention is prepared by the preparation process described in any one of claims 1 to 9.

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