A method for preparing polystyrene-loaded activated carbon fibers

Abstract

This invention discloses a method for preparing polystyrene-loaded activated carbon fibers. Using styrene and acrylic acid as raw materials, potassium persulfate (KPS) as an initiator, polyvinylpyrrolidone (PVP) as a binder, and activated carbon fibers (ACF) as the load, an in-situ loading method is employed. The specific steps are as follows: (1) The ACF is thoroughly rinsed with deionized water to remove surface impurities and then dried; (2) A measured amount of styrene and acrylic acid are slowly added dropwise to a bottom solution (PVP, sodium bicarbonate, and water) under a nitrogen atmosphere at room temperature, while a KPS aqueous solution is injected at a certain rate. After the addition is complete, the reaction is continued with stirring. After filtration, a polystyrene emulsion is obtained; (3) The obtained emulsion is used to impregnate the activated carbon fibers. After thorough impregnation, the fibers are dried to obtain polystyrene-loaded activated carbon fibers. The activated carbon fiber material prepared by this method is low in cost, simple in process, and has good adsorption effect, and can be used to improve the impurity removal effect of acesulfame potassium water.

Description

Technical Field

[0001] This invention relates to the field of activated carbon fibers supported on polystyrene, and more specifically to a method for preparing activated carbon fibers supported on polystyrene. Background Technology

[0002] Activated carbon fiber (ACF) has a well-developed microporous structure, resulting in a large adsorption capacity and high adsorption capacity for organic gases, inorganic substances in aqueous solutions, dyes, organic matter and heavy metal ions.

[0003] Compared with metallic and carbon-based materials, polymer materials such as polystyrene have many advantages, including a wide range of choices, excellent corrosion resistance, diverse modification methods, and controllable comprehensive properties, and can be flexibly applied in material synthesis.

[0004] CN106824160A discloses a method for preparing an ACF membrane-supported ZnO photocatalyst, illustrating the adsorption performance of the activated carbon fiber membrane for organic impurities.

[0005] CN103301884A discloses a preparation method and application of 8-hydroxyquinoline iron-modified ACF, which can efficiently treat dyeing and printing wastewater and avoid secondary pollution by iron ions. Summary of the Invention

[0006] The purpose of this invention is to provide an effective method for preparing activated carbon (ACF) for continuous impurity removal in the synthesis of acesulfame potassium. ACF with a controlled particle size range, due to its rapid adsorption-desorption characteristics, can be recycled. Using this type of ACF can effectively replace traditional activated carbon, achieving both efficient adsorption of organic impurities and improved sugar solution quality, while also reducing waste carbon generation and lowering production costs.

[0007] Traditional activated carbon decolorization processes in the workshop involve numerous steps, generate large amounts of waste carbon daily, and the waste carbon absorbs small amounts of acesulfame potassium, leading to reduced product yield. Using activated carbon fluoride (ACF) for impurity removal effectively avoids these drawbacks. Due to the manufacturing process, the pore size distribution within ACF is relatively wide, making precise control impossible to guide the adsorption of impurities of corresponding sizes. Therefore, to specifically improve the adsorption effect of impurities in acesulfame potassium syrup, polystyrene with a certain particle size range can be loaded onto ACF with a large porous structure. Since functionalized polystyrene microspheres also have excellent adsorption capacity for organic impurities in syrup, simultaneously expanding the internal pores of ACF and improving adsorption capacity effectively reduces the impurity content in the syrup. The circular sustainability of ACF contributes to the continuity, environmental friendliness, and economic benefits of the factory's production process.

[0008] In view of the above research, the present invention provides a method for preparing polystyrene-supported activated carbon fibers, which includes the following steps:

[0009] (1) Provide activated carbon fiber (ACF);

[0010] (2) Styrene and acrylic acid are added to a base solution containing polyvinylpyrrolidone (PVP), sodium bicarbonate and water, and then potassium persulfate (KPS) aqueous solution is added. After the reaction is complete, a polystyrene emulsion is obtained.

[0011] (3) Impregnate the ACF provided in step (1) with the polystyrene emulsion obtained in step (2) and then dry to obtain ACF loaded with polystyrene.

[0012] In one embodiment of the present invention, in step (1), the ACF is a polyacrylonitrile-based ACF or a viscose-based ACF. Further, the ACF is a polyacrylonitrile-based ACF. Further, the ACF is a viscose-based ACF.

[0013] In one embodiment of the invention, in step (1), the activated carbon fiber (ACF) is rinsed with a solvent to remove surface impurities, and then dried. Further, in step (1), the solvent used is water (e.g., deionized water), ethanol, and / or acetone. Further, the rinsing time with the solvent is 10-120 min.

[0014] In one embodiment of the present invention, in step (2), the temperature at which styrene and acrylic acid are added is 20-95°C, for example 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90°C.

[0015] In one embodiment of the invention, in step (2), styrene and acrylic acid are added under an inert atmosphere (e.g., under a nitrogen atmosphere).

[0016] In one embodiment of the present invention, in step (2), the mass ratio of styrene to acrylic acid is 10:1-100:1, for example 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1, 60:1, 65:1, 70:1, 75:1, 80:1, 85:1, 90:1, 95:1.

[0017] In one embodiment of the present invention, in step (2), the mass ratio of PVP to sodium bicarbonate is 1:1 to 1:10, for example 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, or 1:9.

[0018] In one embodiment of the present invention, in step (2), the mass ratio of water to PVP is 100:1-500:1, for example 150:1, 200:1, 250:1, 300:1, 350:1, 400:1, 450:1.

[0019] In one embodiment of the present invention, in step (2), the reaction time is 0.5-6h, for example 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5h.

[0020] In one embodiment of the present invention, in step (2), the content of the KPS aqueous solution is 0.1-1 wt%, for example 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9 wt%.

[0021] In one embodiment of the present invention, in step (2), the KPS aqueous solution is added over a period of 0.3-2 hours, for example, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, or 1.9 hours.

[0022] In one embodiment of the present invention, in step (2), the mass ratio of styrene to PVP is 1:1-10:1, for example 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1.

[0023] In one embodiment of the present invention, in step (2), the polystyrene content in the obtained polystyrene emulsion is 1-20 wt%, for example 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 wt%.

[0024] In one embodiment of the present invention, in step (2), the polystyrene particle size in the obtained polystyrene emulsion is 100-500 nm, for example 150, 200, 250, 300, 350, 400, 450 nm.

[0025] In one embodiment of the present invention, in step (3), the mass ratio of polystyrene emulsion to ACF is 5:1-50:1, for example 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1.

[0026] In one embodiment of the present invention, in step (3), the soaking time is 1-12 hours, for example 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11 hours.

[0027] The beneficial effects achieved by this invention include the following aspects.

[0028] Compared to existing industrial production processes using powder / granular activated carbon adsorption and ACF adsorption, the supported ACF prepared in this invention has several beneficial effects:

[0029] (1) The preparation method is relatively simple, the cost is low, and the raw materials are readily available;

[0030] (2) Due to the increased number of pores in a specific range, the functionalized polystyrene microspheres have a greater adsorption capacity and are more likely to adsorb organic impurities in acesulfame potassium water, thus improving adsorption efficiency.

[0031] (3) The loaded ACF prepared by the impregnation method has a higher porosity and specific surface area, so it has a better effect in the steam washing desorption process.

[0032] (4) This preparation method can achieve mass production and is conducive to the application of industrial continuous production. Detailed Implementation

[0033] The present invention will be further described below with reference to embodiments. Those skilled in the art should understand that the embodiments are for illustrative purposes only and do not constitute any limitation on the present invention.

[0034] Example 1

[0035] The preparation method of polystyrene-supported activated carbon fibers includes the following steps:

[0036] (1) The polyacrylonitrile-based ACF (Beijing Rixin Yuanwang Technology Development Co., Ltd., bjrxyw-05) was thoroughly rinsed with acetone, ethanol and water for 10 min each time to remove impurities on the surface of the ACF. Then it was placed in a vacuum oven at 120℃ for 2 h to dry.

[0037] (2) 4g of styrene (St) and 0.4g of acrylic acid (AA) were slowly added dropwise to the bottom liquid (1g PVP, 1g sodium bicarbonate, 200g water) at 85℃ under a nitrogen atmosphere. 15g of 0.1wt% KPS aqueous solution was injected at 15mL / h. After the addition was completed, the mixture was stirred at 300 rpm for 4h. After the reaction was completed, the polystyrene emulsion was obtained by filtration. The polystyrene content was 20% and the particle size was about 210-230nm.

[0038] (3) Take 200g of the emulsion prepared according to the proportion in step (2) and use it to impregnate 20g of ACF. After impregnation for 6 hours, dry it in a vacuum oven to obtain ACF loaded with polystyrene.

[0039] 20g of polystyrene-loaded ACF was cut into discs with a radius of 1.2cm and a thickness of 5mm and packed into an adsorption column for impurity removal from the sugar water (organic impurity content of 400ppm) produced by the preparation of 200g of acesulfame potassium. The sugar water feed rate was 2BV / h. After 4h, the organic impurity content in the sugar water was reduced by 82% and measured to be 72ppm.

[0040] Example 2

[0041] The preparation method of polystyrene-supported activated carbon fibers includes the following steps:

[0042] (1) The polyacrylonitrile-based ACF (Beijing Rixin Yuanwang Technology Development Co., Ltd., bjrxyw-05) was thoroughly rinsed with acetone, ethanol and water for 10 min each time to remove impurities on the surface of the ACF. Then it was placed in a vacuum oven at 120℃ for 2 h to dry.

[0043] (2) 8g styrene and 0.8g acrylic acid were slowly added dropwise to the bottom solution (2g PVP, 2g sodium bicarbonate, 200g water) at 95℃ under a nitrogen atmosphere. 2g 0.1wt% KPS aqueous solution was injected at 1mL / h. After the addition was complete, the mixture was stirred at 300 rpm for 0.5h. After the reaction was completed, the mixture was filtered to obtain a polystyrene emulsion with a polystyrene content of 5% and a particle size of about 100-150nm.

[0044] (3) Take 200g of the emulsion prepared according to the proportion in step (2) and use it to impregnate 20g of ACF. After impregnation for 1 hour, dry it in a vacuum oven to obtain ACF loaded with polystyrene.

[0045] The obtained 20g of polystyrene-loaded ACF was cut into circular pieces with a radius of 1.2cm and a thickness of 5mm and packed into an adsorption column for impurity removal from the sugar water (organic impurity content of 400ppm) produced by the preparation of 200g of acesulfame potassium. The sugar water feed rate was 2BV / h. After 4h, the organic impurity content in the sugar water was reduced by 65% ​​and measured to be 140ppm.

[0046] Example 3

[0047] The preparation method of polystyrene-supported activated carbon fibers includes the following steps:

[0048] (1) The viscose-based ACF (Anhui Xinju Carbon Fiber Co., Ltd., XJF-1400) was thoroughly rinsed with acetone, ethanol and water for 120 min each time to remove impurities from the ACF surface. Then it was placed in a vacuum oven at 120℃ for 2 h to dry.

[0049] (2) At 20℃, 10g of styrene and 0.1g of acrylic acid were slowly added dropwise to the bottom solution (1g PVP, 10g sodium bicarbonate, 500g water) under a nitrogen atmosphere. 30g of 1wt% KPS aqueous solution was injected at 50mL / h. After the addition was completed, the mixture was stirred at 300 rpm for 6h. After the reaction was completed, the polystyrene emulsion was obtained by filtration. The polystyrene content was 1% and the particle size was about 440-500nm.

[0050] (3) Take 500g of the emulsion prepared according to the proportion in step (2) and use it to impregnate 10g of ACF. After impregnation for 12h, dry it in a vacuum oven to obtain ACF loaded with polystyrene.

[0051] The obtained 20g of polystyrene-loaded ACF was cut into circular pieces with a radius of 1.2cm and a thickness of 5mm and packed into an adsorption column for impurity removal from the sugar water (organic impurity content of 400ppm) produced by the preparation of 200g of acesulfame potassium. The sugar water feed rate was 2BV / h. After 4h, the organic impurity content in the sugar water was reduced by 55% and measured to be 180ppm.

[0052] Example 4

[0053] The preparation method of polystyrene-supported activated carbon fibers includes the following steps:

[0054] (1) The viscose-based ACF (Anhui Xinju Carbon Fiber Co., Ltd., XJF-1400) was thoroughly rinsed with acetone, ethanol and water for 60 min each time to remove impurities on the surface of the ACF. Then it was placed in a vacuum oven at 120℃ for 2 h to dry.

[0055] (2) 6g styrene, 0.6g acrylic acid (0.6g PVP, 1g sodium bicarbonate, 200g water) were slowly added dropwise to the bottom solution at 70℃ under a nitrogen atmosphere. 15g 0.2wt% KPS aqueous solution was injected at 50mL / h. After the addition was completed, the mixture was stirred at 300 rpm for 4h. After the reaction was completed, the polystyrene emulsion was obtained by filtration. The solid polystyrene content was 10% and the particle size was about 260-310nm.

[0056] (3) Take 200g of the emulsion prepared according to the proportion in step (2) and use it to impregnate 40g of ACF. After impregnation for 6 hours, dry it in a vacuum oven to obtain ACF loaded with polystyrene.

[0057] The obtained 20g of polystyrene-loaded ACF was cut into circular pieces with a radius of 1.2cm and a thickness of 5mm and packed into an adsorption column for impurity removal from the sugar water (organic impurity content of 400ppm) produced by the preparation of 200g of acesulfame potassium. The sugar water feed rate was 2BV / h. After 4h, the organic impurity content in the sugar water was reduced by 76% and measured to be 96ppm.

[0058] Comparative Example 1

[0059] 20g of unmodified polyacrylonitrile-based ACF (Beijing Rixin Yuanwang Technology Development Co., Ltd., bjrxyw-05) was cut into circular pieces with a radius of 1.2cm and a thickness of 5mm and packed into an adsorption column for impurity removal from the sugar water (organic impurity content 400ppm) produced by the preparation of 200g of acesulfame potassium. The sugar water feed rate was 2BV / h. After 4h, the organic impurity content in the sugar water was reduced by 5%, and the measured value was 380ppm.

[0060] Comparative Example 2

[0061] 20g of unmodified viscose-based ACF (Anhui Xinju Carbon Fiber Co., Ltd., XJF-1400) was cut into circular pieces with a radius of 1.2cm and a thickness of 5mm and packed into an adsorption column for impurity removal from the sugar water (organic impurity content 400ppm) produced by the preparation of 200g of acesulfame potassium. The sugar water feed rate was 2BV / h. After 4h, the organic impurity content in the sugar water was reduced by 34%, and the measured value was 264ppm.

[0062] Table 1 lists the changes in conditions and results in Examples 1-4 and Comparative Examples 1-2. Except for the reaction conditions listed in Table 1, the reaction conditions for each example in other steps were kept consistent.

[0063] Table 1. Preparation Condition Data

[0064]

Claims

1. A method for preparing polystyrene-supported activated carbon fibers, comprising the following steps: (1) Provide activated carbon fiber (ACF); (2) Styrene and acrylic acid are added to a base solution containing polyvinylpyrrolidone (PVP), sodium bicarbonate and water, and then potassium persulfate (KPS) aqueous solution is added. After the reaction is complete, a polystyrene emulsion is obtained. (3) Impregnate the ACF provided in step (1) with the polystyrene emulsion obtained in step (2) and then dry to obtain ACF loaded with polystyrene.

2. The method of claim 1, wherein in step (1), the ACF is a polyacrylonitrile-based ACF or a viscose-based ACF.

3. The method of claim 1 or 2, wherein in step (1), the activated carbon fiber (ACF) is rinsed with a solvent to remove surface impurities and then dried.

4. The method of any one of claims 1-3, wherein in step (2), styrene and acrylic acid are added under an inert atmosphere.

5. The method of any one of claims 1-4, wherein in step (2), the mass ratio of styrene to acrylic acid is 10:1 to 100:

1.

6. The method of any one of claims 1-5, wherein in step (2), the mass ratio of PVP to sodium bicarbonate is 1:1 to 1:

10.

7. The method of any one of claims 1-6, wherein in step (2), the mass ratio of water to PVP is 100:1 to 500:

1.

8. The method of any one of claims 1-7, wherein in step (2), the mass ratio of styrene to PVP is 1:1 to 10:

1.

9. The method of any one of claims 1-8, wherein in step (2), the polystyrene particle size in the obtained polystyrene emulsion is 100-500 nm.

10. The method of any one of claims 1-9, wherein in step (3), the mass ratio of the polystyrene emulsion to ACF is 5-50:1.

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