Production method for removing silicon impurities in ultrapure water

Abstract

The invention relates to the field of ultrapure water purification treatment, and discloses a production method for removing silicon impurities in ultrapure water, which comprises the following steps: pretreating ultrapure water to remove suspended silicon particles in water; carrying out adsorption treatment on the pretreated ultrapure water by adopting a functional adsorption material to remove soluble silicon compounds; and the ultrapure water subjected to adsorption treatment is deeply purified, so that the content of residual silicon is reduced. Through a step-by-step treatment mode of pretreatment, adsorption treatment and deep purification, suspended silicon particles, soluble silicon compounds and residual silicon in the ultrapure water are removed in a targeted manner, the core problem that silicon impurities in different forms are difficult to efficiently remove by an existing single treatment means is solved, the content of the silicon impurities in the ultrapure water is effectively reduced, and the quality of the ultrapure water is improved. The ultrapure water better meets the strict requirements of electronics, semiconductors and other high-tech fields on the purity of the ultrapure water, and a high-quality ultrapure water raw material is provided for high-precision product production.

Description

Technical Field

[0001] This invention relates to the field of ultrapure water purification technology, specifically a production method for removing silicon impurities from ultrapure water. Background Technology

[0002] Ultrapure water is widely used in high-tech fields such as electronics and semiconductors, requiring extremely high purity, especially in controlling the content of silicon impurities to a very low level to avoid adverse effects on the performance and quality of subsequent products. Currently, the industry commonly uses single filtration or adsorption methods to remove silicon impurities from ultrapure water. However, silicon impurities in ultrapure water exist in a wide variety of forms, including suspended silicon particles of varying sizes, which may be difficult to completely retain due to surface charge or adsorption characteristics, as well as various soluble silicon compounds, such as silicic acid and silicates. Furthermore, some soluble silicon compounds are chemically stable and difficult to remove under conventional treatment conditions.

[0003] For example, while conventional filtration can remove some larger suspended silicon particles, its removal effect is often very limited for tiny suspended silicon particles and the large amount of soluble silicon compounds present, making it difficult to meet the strict standards for silicon impurity content in ultrapure water. On the other hand, when relying solely on ordinary adsorption materials for adsorption treatment, the selectivity and adsorption capacity of the adsorption materials are limited, making it difficult to fully adsorb and remove tiny suspended silicon particles in the water. At the same time, it is also difficult to achieve efficient adsorption of some highly stable soluble silicon compounds.

[0004] The limitations of this single treatment method directly result in a still high level of residual silicon impurities in the treated ultrapure water, which cannot meet the stringent requirements of high-precision production processes for ultrapure water purity, posing potential quality risks to the production of high-tech products such as electronics and semiconductors. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a production method for removing silicon impurities from ultrapure water, thus solving the problems mentioned in the background section.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a production method for removing silicon impurities from ultrapure water, characterized by comprising the following steps:

[0007] Pre-treatment of ultrapure water removes suspended silicon particles.

[0008] Functional adsorption materials were used to adsorb soluble silicon compounds from pretreated ultrapure water.

[0009] The ultrapure water after adsorption treatment is further purified to reduce the residual silicon content.

[0010] Preferably, the pretreatment includes filtration, using a polypropylene microfiltration membrane with a pore size of 0.1-0.5 μm, with the filtration pressure controlled at 0.1-0.3 MPa and the filtration temperature at 20-30℃.

[0011] Preferably, the polypropylene microfiltration membrane is hydrophilically treated, and the treatment process includes:

[0012] Immerse the polypropylene microfiltration membrane in a 5-10% hydrogen peroxide solution at 40-60°C for 2-4 hours.

[0013] After removal, rinse with deionized water until neutral, then immerse in a 2-5% polyvinyl alcohol solution at 30-50°C for 1-2 hours.

[0014] The membrane was then removed and dried at 60-80℃ for 3-5 hours to obtain a hydrophilically treated polypropylene microfiltration membrane with a water contact angle ≤60° and a membrane flux ≥100 L / (m²) at 0.2 MPa pressure. 2 ·h).

[0015] Preferably, the functional adsorbent material is activated carbon loaded with iron ions, wherein the iron ion loading is 3-6% of the activated carbon mass, the activated carbon particle size is 0.5-2 mm, and the specific surface area is 800-1500 m². 2 / g.

[0016] Preferably, the iron-loaded activated carbon is prepared by the following steps:

[0017] Activated carbon was added to a ferric chloride solution, with a concentration of 0.1-0.3 mol / L.

[0018] Stir at 30-50℃ for 3-5 hours, then let stand for 8-12 hours;

[0019] After filtration, the solid is dried at 100-120℃ for 4-6 hours, and then calcined at 300-400℃ for 2-3 hours.

[0020] Preferably, during the adsorption treatment, the contact time between ultrapure water and activated carbon loaded with iron ions is 20-60 minutes, and the stirring rate during the treatment is 100-200 r / min.

[0021] Preferably, the deep purification includes ion exchange treatment, using macroporous strong basic anion exchange resin, resin type 201×7, particle size 0.4-1.2mm, and height-to-diameter ratio of the exchange column 6-12:1.

[0022] Preferably, the process parameters for the ion exchange treatment are: flow rate of 15-25 m / h, temperature of 25-35℃, and influent pH of 7-9.

[0023] Preferably, the ultrapure water is adjusted before adsorption treatment to control its pH value at 8-10. The reagent used for adjustment is sodium hydroxide solution with a concentration of 0.5-2 mol / L.

[0024] Preferably, after deep purification, terminal treatment is performed using a 0.02μm polyethersulfone ultrafiltration membrane for filtration, with an operating pressure of 0.1-0.2MPa and a temperature of 20-30℃.

[0025] This invention provides a production method for removing silicon impurities from ultrapure water. It has the following beneficial effects:

[0026] 1. This invention uses a step-by-step treatment method involving pretreatment, adsorption treatment, and deep purification to specifically remove suspended silicon particles, soluble silicon compounds, and residual silicon from ultrapure water. This solves the core problem that existing single treatment methods are unable to efficiently remove silicon impurities in different forms, effectively reducing the silicon impurity content in ultrapure water. This better meets the stringent purity requirements of ultrapure water in high-tech fields such as electronics and semiconductors, providing high-quality ultrapure water raw materials for the production of high-precision products.

[0027] 2. In this invention, the hydrophilic polypropylene microfiltration membrane improves the filtration efficiency for suspended silicon particles, the iron-loaded activated carbon enhances the adsorption capacity for soluble silicon compounds, and the macroporous strong base anion exchange resin combined with terminal ultrafiltration membrane filtration further reduces the residual silicon content. At the same time, the pH adjustment before adsorption optimizes the adsorption environment, improves the overall treatment effect, and makes the ultrapure water purification process more stable and efficient. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the method flow of the present invention. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] A production method for removing silicon impurities from ultrapure water includes the following steps:

[0032] Step 1, Pretreatment: Take 60L of ultrapure water and filter it using a hydrophilic polypropylene microfiltration membrane (pore size 0.1μm). The filtration pressure is strictly controlled at 0.1MPa and the filtration temperature is stably maintained at 20℃.

[0033] Hydrophilic treatment process: The polypropylene microfiltration membrane was completely immersed in a 5% hydrogen peroxide solution and continuously soaked in a constant temperature water bath at 40℃ for 2 hours, with gentle stirring every 30 minutes to ensure full contact between the membrane surface and the treatment solution. After removal, it was repeatedly rinsed with deionized water until the rinsing solution was neutral (pH 7.0), and then immersed in a 2% polyvinyl alcohol solution at 30℃ for 1 hour, again with stirring every 20 minutes. Subsequently, the membrane was removed, excess liquid was blotted off with filter paper, and dried in a 60℃ forced-air drying oven for 3 hours, finally yielding a membrane with a water contact angle of 55° and a membrane flux of 105 L / (m²) at 0.2 MPa pressure. 2 ·h) microfiltration membrane.

[0034] Step 2, pH adjustment: Slowly add 0.5 mol / L sodium hydroxide solution dropwise to the pretreated ultrapure water while stirring with a magnetic stirrer at a rate of 100 r / min for 10 min until the pH value of the solution is stabilized at 8.0.

[0035] Step 3, Adsorption Treatment: Accurately weigh 200g of activated carbon loaded with iron ions (iron ion loading of 3%, particle size of 0.5mm, specific surface area of ​​800m²). 2 Add / g) to the above-prepared pH-adjusted ultrapure water, control the contact time between activated carbon and ultrapure water to 20 min, and maintain the stirring speed at 100 r / min to ensure that the activated carbon is evenly dispersed in the water;

[0036] Activated carbon preparation: Selected activated carbon particles were added to a 0.1 mol / L ferric chloride solution, with the solution volume being 5 times the volume of the activated carbon. The mixture was stirred in a constant temperature water bath at 30°C for 3 hours, maintaining a uniform stirring rate. After stirring, the mixture was allowed to stand for 8 hours to allow the activated carbon to fully adsorb iron ions. The mixture was then filtered, and the resulting solid was placed in a drying oven at 100°C for 4 hours. The solid was turned over every hour during the drying process to ensure uniform drying. Finally, the dried solid was placed in a muffle furnace and calcined at 300°C for 2 hours, maintaining air circulation within the furnace during calcination. After calcination, the solid was allowed to cool naturally to room temperature to obtain the desired iron-loaded activated carbon.

[0037] Step 4, Deep purification: Ion exchange treatment is carried out using 201×7 type anion exchange resin (particle size 0.4mm). The height-to-diameter ratio of the exchange column is 6:1. The ultrapure water that has undergone adsorption treatment is introduced into the exchange column at a flow rate of 15m / h. The temperature inside the column is controlled at 25℃, and the pH value of the influent is adjusted to 7.0 to ensure that the water flow is evenly distributed inside the column and fully contacts the resin.

[0038] Step 5, Terminal Processing: The deeply purified ultrapure water is filtered through a 0.02μm polyethersulfone ultrafiltration membrane. The operating pressure is set to 0.1MPa, and the filtration temperature is maintained at 20℃. The pressure difference between the membrane inlet and outlet is monitored in real time during the filtration process to ensure that the filtration process is stable, and finally ultrapure water with silicon impurities removed is obtained.

[0039] Example 2

[0040] A production method for removing silicon impurities from ultrapure water includes the following steps:

[0041] Step 1, Pretreatment: 60L of ultrapure water is filtered through a hydrophilic polypropylene microfiltration membrane (pore size 0.2μm), with the filtration pressure controlled at 0.15MPa and the filtration temperature at 22℃.

[0042] Hydrophilic treatment: The polypropylene microfiltration membrane was immersed in a 6% (w / w) hydrogen peroxide solution at 45°C for 2.5 hours, with the solution stirred periodically during this time. After removal, it was rinsed with deionized water until neutral, and then immersed in a 3% (w / w) polyvinyl alcohol solution at 35°C for 1.2 hours. The membrane was then removed, the surface liquid was blotted dry, and it was dried in a 65°C forced-air drying oven for 3.5 hours, yielding a membrane flux of 10⁸ L / (m²) with a water contact angle of 52° and a pressure of 0.2 MPa. 2 ·h) microfiltration membrane.

[0043] Step 2, pH adjustment: Add 1 mol / L sodium hydroxide solution to the pretreated ultrapure water and stir at 120 r / min for 12 min to adjust the pH value of the solution to 8.5. During the stirring process, use a pH meter to monitor the pH value change in real time.

[0044] Step 3, Adsorption Treatment: Weigh 210g of activated carbon loaded with iron ions (loading 4%, particle size 1mm, specific surface area 1000m²). 2 Add / g) to ultrapure water, control the contact time to 30min, and the stirring rate to 130r / min, so that the activated carbon can fully exert its adsorption effect;

[0045] Preparation of activated carbon: Add activated carbon to a 0.15 mol / L ferric chloride solution, with the solution volume being 6 times the volume of activated carbon. Stir at 35℃ for 3.5 h, let stand for 9 h, and then filter. Dry the obtained solid at 105℃ for 4.5 h, turning it regularly during the process. Then calcine at 320℃ for 2.2 h and let it cool naturally before use.

[0046] Step 4, Deep purification: 201×7 type resin (particle size 0.6mm) is used, the height-to-diameter ratio of the exchange column is 8:1, the flow rate of ultrapure water is controlled at 18m / h, the internal temperature of the column is 28℃, and the pH value of the influent is 7.5 to ensure that the ion exchange reaction proceeds fully.

[0047] Step 5, Terminal treatment: Filter through a 0.02μm ultrafiltration membrane at an operating pressure of 0.12MPa and a temperature of 22℃. Record the filtration volume and time during the filtration process and calculate the filtration rate.

[0048] Example 3

[0049] A production method for removing silicon impurities from ultrapure water includes the following steps:

[0050] Step 1, Pretreatment: 60L of ultrapure water was filtered through a hydrophilic polypropylene microfiltration membrane (pore size 0.3μm) at a pressure of 0.2MPa and a temperature of 25℃.

[0051] Hydrophilic treatment: The membrane was immersed in an 8% hydrogen peroxide solution at 50°C for 3 hours, rinsed until neutral, then immersed in a 4% polyvinyl alcohol solution at 40°C for 1.5 hours, and finally dried at 70°C for 4 hours, resulting in a water contact angle of 50° and a membrane flux of 110 L / (m²). 2 The microfiltration membrane (·h) is used, and the temperature and time of each step in the process are strictly controlled.

[0052] Step 2, pH adjustment: Adjust the pH to 9 with 1.5 mol / L sodium hydroxide solution, stirring at 150 r / min for 15 min to ensure that the pH value of the solution is uniform and stable.

[0053] Step 3, Adsorption Treatment: Add 220g of iron-loaded activated carbon (5% loading, 1.5mm particle size, 1200m² specific surface area). 2 / g), contact time 40min, stirring rate 150r / min, to ensure that activated carbon and ultrapure water are fully mixed;

[0054] Activated carbon preparation: Activated carbon was added to 0.2 mol / L ferric chloride solution, stirred at 40℃ for 4 h, allowed to stand for 10 h and then filtered. The solid was dried at 110℃ for 5 h and calcined at 350℃ for 2.5 h. All parameters were strictly controlled during the preparation process.

[0055] Step 4, Deep purification: 201×7 type resin (particle size 0.8mm), exchange column height-to-diameter ratio 10:1, flow rate 20m / h, temperature 30℃, influent pH 8, ensuring sufficient contact time between ultrapure water and resin.

[0056] Step 5, Terminal treatment: Filtration with a 0.02μm ultrafiltration membrane at a pressure of 0.15MPa and a temperature of 25℃. After filtration, the ultrafiltration membrane is preliminarily cleaned for future use.

[0057] Example 4

[0058] A production method for removing silicon impurities from ultrapure water includes the following steps:

[0059] Step 1, Pretreatment: 60L of ultrapure water was filtered through a hydrophilic polypropylene microfiltration membrane (pore size 0.4μm) at a pressure of 0.25MPa and a temperature of 28℃.

[0060] Hydrophilic treatment: Soak in 9% hydrogen peroxide solution at 55℃ for 3.5 h, rinse until neutral, then immerse in 4.5% polyvinyl alcohol solution at 45℃ for 1.8 h, and dry at 75℃ for 4.5 h, yielding a membrane with a water contact angle of 48° and a membrane flux of 115 L / (m²). 2 The microfiltration membrane (·h) undergoes strict quality control at every step of the process.

[0061] Step 2, pH adjustment: Adjust the pH to 9.5 with 1.8 mol / L sodium hydroxide solution, stirring at 180 r / min for 18 min to ensure accurate pH adjustment.

[0062] Step 3, Adsorption Treatment: 240g of iron-loaded activated carbon (loading 5.5%, particle size 1.8mm, specific surface area 1400m²). 2 / g), contact time 50min, stirring rate 180r / min, to ensure that the adsorption reaction is fully carried out;

[0063] Activated carbon preparation: 0.25 mol / L ferric chloride solution, stirred at 45℃ for 4.5 h, allowed to stand for 11 h, filtered, the solid was dried at 115℃ for 5.5 h, and calcined at 380℃ for 2.8 h. All operations were carried out according to the standard procedure.

[0064] Step 4, Deep Purification: 201×7 type resin (particle size 1.0mm), height-to-diameter ratio 11:1, flow rate 23m / h, temperature 33℃, influent pH 8.5, to ensure deep purification effect.

[0065] Step 5, Terminal treatment: Filtration through a 0.02μm ultrafiltration membrane at a pressure of 0.18MPa and a temperature of 28℃. After filtration, the ultrapure water is sampled and tested.

[0066] Example 5

[0067] A production method for removing silicon impurities from ultrapure water includes the following steps:

[0068] Step 1, Pretreatment: 60L of ultrapure water is filtered through a hydrophilic polypropylene microfiltration membrane (pore size 0.5μm) at a pressure of 0.3MPa and a temperature of 30℃.

[0069] Hydrophilic treatment: Soak in 10% hydrogen peroxide solution at 60℃ for 4 hours, rinse with deionized water until neutral, then immerse in 5% polyvinyl alcohol solution at 50℃ for 2 hours, and dry at 80℃ for 5 hours to obtain a membrane with a water contact angle of 45° and a membrane flux of 120 L / (m²). 2 The microfiltration membrane (·h) was used, and all parameters were recorded in detail during the treatment process.

[0070] Step 2, pH adjustment: Adjust the pH to 10 with 2 mol / L sodium hydroxide solution, stir at 200 r / min for 20 min, and ensure that the pH value of the solution meets the set requirements.

[0071] Step 3, Adsorption Treatment: 250g of iron-loaded activated carbon (6% loading, 2mm particle size, 1500m² specific surface area). 2 / g), contact time 60min, stirring rate 200r / min, to ensure the adsorption efficiency of activated carbon;

[0072] Activated carbon preparation: 0.3 mol / L ferric chloride solution, stirred at 50℃ for 5 h, allowed to stand for 12 h, filtered, the solid was dried at 120℃ for 6 h, and calcined at 400℃ for 3 h. After preparation, the performance of the activated carbon was tested.

[0073] Step 4, Deep Purification: 201×7 type resin (particle size 1.2mm), height-to-diameter ratio 12:1, flow rate 25m / h, temperature 35℃, influent pH 9, to ensure that the ultrapure water is deeply purified.

[0074] Step 5, Terminal treatment: Filtration through a 0.02μm ultrafiltration membrane at a pressure of 0.2MPa and a temperature of 30℃ to finally obtain ultrapure water that meets the requirements.

[0075] Comparative Example 1

[0076] A production method for removing silicon impurities from ultrapure water includes the following steps:

[0077] Step 1, Pretreatment: 60L of ultrapure water was filtered through an untreated polypropylene microfiltration membrane (0.5μm pore size) at a filtration pressure of 0.3MPa and a filtration temperature of 30℃; the untreated microfiltration membrane had a water contact angle of 85° and a membrane flux of 80L / (m²). 2 ·h), directly used for filtration without any surface modification.

[0078] Step 2, pH adjustment: Add 2 mol / L sodium hydroxide solution to the pretreated ultrapure water to adjust the pH to 10, stir at 200 r / min for 20 min, and the operation process is the same as in Example 5.

[0079] Step 3, Adsorption Treatment: Add 250g of activated carbon loaded with iron ions (iron ion loading 6%, particle size 2mm, specific surface area 1500m²). 2 / g), contact time 60min, stirring rate 200r / min;

[0080] Preparation of activated carbon: Activated carbon was added to 0.3 mol / L ferric chloride solution, stirred at 50°C for 5 h, allowed to stand for 12 h, dried at 120°C for 6 h, and calcined at 400°C for 3 h. The preparation method was the same as in Example 5.

[0081] Step 4, Deep purification: 201×7 type anion exchange resin (particle size 1.2mm) was used, the height-to-diameter ratio of the exchange column was 12:1, the flow rate was 25m / h, the temperature was 35℃, and the influent pH was 9, which were the same as the deep purification parameters in Example 5.

[0082] Step 5, Terminal processing: Filter through a 0.02μm polyethersulfone ultrafiltration membrane at an operating pressure of 0.2MPa and a temperature of 30℃. The filtration method is the same as in Example 5.

[0083] Comparative Example 2

[0084] A production method for removing silicon impurities from ultrapure water includes the following steps:

[0085] Step 1, Pretreatment: 60L of ultrapure water is filtered through a hydrophilic polypropylene microfiltration membrane (pore size 0.5μm) at a pressure of 0.3MPa and a temperature of 30℃.

[0086] Hydrophilic treatment: Immersion in 10% hydrogen peroxide solution at 60℃ for 4 hours → rinsing with deionized water → immersion in 5% polyvinyl alcohol solution at 50℃ for 2 hours → drying at 80℃ for 5 hours, resulting in a water contact angle of 45° and a membrane flux of 120 L / (m²). 2 The microfiltration membrane (·h) undergoes the same pretreatment process as in Example 5.

[0087] Step 2, pH adjustment: Add 2 mol / L sodium hydroxide solution to the pretreated ultrapure water to adjust the pH to 10, stir at 200 r / min for 20 min, and the adjustment method and parameters are the same as in Example 5.

[0088] Step 3, Adsorption Treatment: Add 250g of unloaded iron-containing activated carbon (particle size 2mm, specific surface area 1500m²). 2 / g), without any iron ion loading treatment, contact time 60min, stirring rate 200r / min, adsorption operation parameters are the same as in Example 5.

[0089] Step 4, Deep purification: 201×7 type anion exchange resin (particle size 1.2mm) was used, the height-to-diameter ratio of the exchange column was 12:1, the flow rate was 25m / h, the temperature was 35℃, the influent pH was 9, and the deep purification parameters were the same as in Example 5.

[0090] Step 5, Terminal treatment: Filter through a 0.02μm polyethersulfone ultrafiltration membrane at an operating pressure of 0.2MPa and a temperature of 30℃. The terminal treatment method is the same as in Example 5.

[0091] Comparative Example 3

[0092] A production method for removing silicon impurities from ultrapure water includes the following steps:

[0093] 60L of ultrapure water was treated using conventional ion exchange resin (201×7 type, particle size 1.2mm). The height-to-diameter ratio of the exchange column was 12:1, the flow rate was 20m / h, and the temperature was 30℃. There were no pretreatment, adsorption, or terminal ultrafiltration steps. The ultrapure water was directly passed into the ion exchange column for treatment, and the effluent was collected directly after treatment.

[0094] Performance testing:

[0095] The silicon content of ultrapure water from Examples 1-5 and Comparative Examples 1-2 and 3 before and after treatment was determined according to the national standard GB / T11446.7-2013 "Determination of Silicon in Electronic Grade Water". Each sample was measured in triplicate, and the average value was taken. Simultaneously, the membrane flux decay rate (characterizing stability) after 100 hours of continuous operation was tested. The membrane flux decay rate was calculated as (initial membrane flux - membrane flux after 100 hours) / initial membrane flux × 100%. The test results are shown in the table below:

[0096]

[0097] in conclusion:

[0098] The silicon removal rates of Examples 1-5 all exceeded 99%, significantly higher than Comparative Examples 1-2 and Comparative Example 3, and the membrane flux decay rate was lower, indicating superior stability. The results of Comparative Example 1 show that the hydrophilic treatment step effectively reduces membrane fouling while improving the retention efficiency of suspended silicon particles. Comparative Example 2 demonstrates that iron-loaded activated carbon plays a crucial role in adsorbing soluble silicon compounds; the absence of this step leads to a significant decrease in silicon removal rate. The comparison between Comparative Example 3 and the Examples fully demonstrates the significant advantages of the production method of this invention compared to commercially available conventional processes in removing silicon impurities from ultrapure water. In summary, the production method of this invention, through the synergistic effect of pretreatment, pH adjustment, adsorption treatment, deep purification, and final treatment, can efficiently and stably remove silicon impurities from ultrapure water, making it suitable for fields requiring high-purity water, such as electronic and semiconductor grades.

[0099] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A production method for removing silicon impurities from ultrapure water, characterized in that, Includes the following steps: Pre-treatment of ultrapure water removes suspended silicon particles. Functional adsorption materials were used to adsorb soluble silicon compounds from pretreated ultrapure water. The ultrapure water after adsorption treatment is further purified to reduce the residual silicon content.

2. The production method for removing silicon impurities from ultrapure water according to claim 1, characterized in that, The pretreatment includes filtration, which is performed using a polypropylene microfiltration membrane with a pore size of 0.1-0.5 μm, with the filtration pressure controlled at 0.1-0.3 MPa and the filtration temperature at 20-30℃.

3. The production method for removing silicon impurities from ultrapure water according to claim 2, characterized in that, The polypropylene microfiltration membrane undergoes a hydrophilic treatment, the process of which includes: Immerse the polypropylene microfiltration membrane in a 5-10% hydrogen peroxide solution at 40-60°C for 2-4 hours. After removal, rinse with deionized water until neutral, then immerse in a 2-5% polyvinyl alcohol solution at 30-50°C for 1-2 hours. The membrane was then removed and dried at 60-80℃ for 3-5 hours to obtain a hydrophilically treated polypropylene microfiltration membrane with a water contact angle ≤60° and a membrane flux ≥100 L / (m²) at 0.2 MPa pressure. 2 ·h).

4. The production method for removing silicon impurities from ultrapure water according to claim 1, characterized in that, The functional adsorbent material is activated carbon loaded with iron ions, wherein the iron ion loading is 3-6% of the activated carbon mass, the activated carbon particle size is 0.5-2 mm, and the specific surface area is 800-1500 m². 2 / g.

5. The production method for removing silicon impurities from ultrapure water according to claim 4, characterized in that, The iron-loaded activated carbon is prepared by the following steps: Activated carbon was added to a ferric chloride solution, with a concentration of 0.1-0.3 mol / L. Stir at 30-50℃ for 3-5 hours, then let stand for 8-12 hours; After filtration, the solid is dried at 100-120℃ for 4-6 hours, and then calcined at 300-400℃ for 2-3 hours.

6. The production method for removing silicon impurities from ultrapure water according to claim 1, characterized in that, During the adsorption treatment, the contact time between ultrapure water and activated carbon loaded with iron ions is 20-60 minutes, and the stirring rate during the treatment is 100-200 r / min.

7. The production method for removing silicon impurities from ultrapure water according to claim 1, characterized in that, The deep purification includes ion exchange treatment, using macroporous strong basic anion exchange resin, resin type 201×7, particle size 0.4-1.2mm, and height-to-diameter ratio of the exchange column 6-12:

1.

8. The production method for removing silicon impurities from ultrapure water according to claim 7, characterized in that, The process parameters for the ion exchange treatment are: flow rate of 15-25 m / h, temperature of 25-35℃, and influent pH of 7-9.

9. The production method for removing silicon impurities from ultrapure water according to claim 1, characterized in that, Before adsorption treatment, the ultrapure water is adjusted to a pH value of 8-10 using sodium hydroxide solution with a concentration of 0.5-2 mol / L.

10. The production method for removing silicon impurities from ultrapure water according to claim 1, characterized in that, After deep purification, the final treatment is carried out using a 0.02μm polyethersulfone ultrafiltration membrane for filtration at an operating pressure of 0.1-0.2MPa and a temperature of 20-30℃.

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