Carbon fiber based on printing and dyeing white mud raw material and preparation method thereof

Abstract

The invention discloses a preparation method of carbon fibers based on a printing and dyeing white mud raw material, which comprises the following steps: adding printing and dyeing white mud taking terephthalic acid as a main component and calcium oxide into water, and carrying out ultrasonic dispersion to obtain a calcified product; mixing and stirring the calcified product and an organic solvent, and carrying out electrostatic spinning on the dissolved solution to obtain calcified white mud electrostatic spinning fibers; and heating the calcified white mud electrostatic spinning fiber in a tubular furnace in an inert atmosphere, cooling, pickling the carbon fiber, and drying to obtain the target product carbon fiber. The printing and dyeing white mud is recycled to finally prepare the flexible carbon fiber, the preparation method is simple, the input cost is low, the economic benefit is better, the method is environmentally friendly, the method can be applied to more fields, and the requirement for resource recycling is met.

Description

Technical Field

[0001] The present invention relates to a carbon fiber based on printing and dyeing white mud raw materials and a preparation method thereof, belonging to the technical field of material synthesis and preparation. Background Art

[0002] Since the alkali weight reduction process can improve the hand feeling and comfort of polyester fabrics, this process is widely used in the textile printing and dyeing industry. The alkali weight reduction wastewater contains a large amount of substances such as sodium terephthalate and ethylene glycol. Its common treatment method is to recover terephthalic acid (PTA) with a relatively high content in the wastewater through acid precipitation to obtain crude terephthalic acid (printing and dyeing white mud), which can not only greatly remove the COD in the sewage, but also obtain printing and dyeing white mud raw materials with a high carbon content. Developing high-tech products based on printing and dyeing white mud raw materials is an important measure to realize the efficient resource utilization of alkali weight reduction wastewater.

[0003] Due to its excellent structural and functional characteristics such as high specific strength, high specific modulus, high conductivity, and high thermal conductivity, carbon fiber has received extensive attention and favor in application fields such as aerospace, energy and transportation, high-end equipment, civil construction, and sports and leisure. Especially in recent years, the application proportion in wind turbine blades and the automotive industry is increasing significantly. However, at present, more than 90% of the carbon fibers on the market use polyacrylonitrile (PAN) as the carbon source. Compared with other composite material reinforcements such as glass fiber, the price of PAN-based carbon fiber is relatively high, which limits its application in the civilian market, especially in the industrial equipment field. Therefore, the low-cost preparation technology of carbon fiber has become the key to the development of the carbon fiber material industry.

[0004] Compared with the traditional wet spinning and dry-jet wet spinning technologies for preparing carbon fiber, the electrospinning technology can synthesize one-dimensional ultrafine carbon fibers with a diameter of dozens of nanometers and customized structures and compositions, and has the characteristics of high yield and strong scalability. More importantly, its equipment is simple, easy to operate, can quickly and efficiently prepare fiber materials during the working process and is pollution-free to the environment, which is the most effective method for preparing carbon nanofibers at present. However, the currently developed electrospinning technology for preparing carbon fiber still uses PAN, polyvinylpyrrolidone (PVP), and polyvinyl alcohol (PVA) as carbon sources. These organic carbon sources have relatively high costs, so it is difficult to be applied in actual production. It is urgent to develop low-cost carbon sources applicable to the electrospinning technology to reduce the cost of producing carbon fiber by electrospinning and promote the practical application of this technology.

[0005] Electrospinning with respect to traditional carbon sources, using crude terephthalic acid as a carbon source to prepare carbon fibers can greatly reduce the preparation cost. If a large amount of printed and dyed white mud (crude terephthalic acid) extracted from alkali-deweighted wastewater is used as a carbon source and carbon fibers are prepared by electrospinning technology, the current preparation cost of carbon fibers will be greatly reduced, which has more practical value. At the same time, this technology resourcefully utilizes a large amount of solid waste of printed and dyed white mud. However, there is currently no technical report on using terephthalic acid as a carbon source for electrospinning to produce carbon fibers. Summary of the Invention

[0006] The technical problem to be solved by the present invention is: to provide a method for preparing carbon fibers based on printed and dyed white mud raw materials, so as to effectively recycle and highly utilize printed and dyed white mud.

[0007] To solve the above problems, the present invention provides the following technical solutions:

[0008] A method for preparing carbon fibers based on printed and dyed white mud raw materials, comprising the following steps:

[0009] S1: Add printed and dyed white mud mainly composed of terephthalic acid and calcium oxide to water, and perform ultrasonic dispersion to obtain a calcified product;

[0010] S2: Mix and stir the calcified product obtained in S1 with an organic solvent, and perform electrospinning on the dissolved solution to obtain calcified white mud electrospun fibers;

[0011] S3: Heat the calcified white mud electrospun fibers obtained in S2 in a tubular furnace under an inert atmosphere, and after cooling, perform pickling and drying on the carbon fibers to obtain the carbon fibers of the target product.

[0012] Preferably, in step S1, the mass ratio of the printed and dyed white mud to calcium oxide is 1:0.5 - 10, preferably 1:2 - 3.

[0013] Preferably, in step S1, the mass of the water is 5 - 100% of the mass of the printed and dyed white mud.

[0014] Preferably, in step S1, after ultrasonic dispersion, the obtained mixed material is also dried and ground.

[0015] Preferably, in step S2, the mass ratio of the calcified product to the organic solvent is 1:0.5 - 3, preferably 1:1 - 2; the organic solvent is dimethylformamide.

[0016] Preferably, in step S2, the process parameters of the electrospinning are: the distance between the electrospinning needle head and the receiving device is 10 - 20 cm, preferably 17 cm, the advancing speed is 0.4 - 50 mL / h, preferably 5 mL / h, and the applied voltage is 10 - 20 kV, preferably 15 kV.

[0017] Preferably, in step S3, the heating rate of the tube furnace is 1-10 °C / min, preferably 5 °C / min, the heating temperature is 200-900 °C, preferably 700 °C, and the heat preservation time is 1-4 h, preferably 3 h; the inert gas is nitrogen, argon, helium or a hydrogen-argon mixture.

[0018] Preferably, in step S3, the chemicals used for pickling are one or more of hydrochloric acid, nitric acid, and sulfuric acid, preferably hydrochloric acid, and the acid concentration value is 0.1-3 mol / L, preferably 1 mol / L.

[0019] Preferably, in step S3, the drying temperature is 40-80 °C, the time is 2-24 h, preferably 8 h.

[0020] The present invention also provides a carbon fiber based on printing and dyeing white mud raw materials prepared by the above preparation method.

[0021] The present invention provides a simple, fast, and environmentally friendly preparation method for carbon fiber based on printing and dyeing white mud raw materials. The preparation method of the present invention does not require special equipment and harsh conditions, has a simple process, good environmental protection performance, is easy to realize large-scale production, and has practicability.

[0022] The present invention combines calcified white mud with electrospinning technology, has good environmental protection performance, and the obtained white mud carbon fiber has a larger specific surface area compared with traditional carbon fiber, which is conducive to realizing the resource recovery and reuse of printing and dyeing white mud.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention uses printing and dyeing white mud as a raw material and calcium oxide as a calcifying agent. The calcium oxide and terephthalic acid are fully contacted by the ultrasonic method, and then combined with the electrospinning technology. After carbonization and acidification, the reaction conditions are mild, the preparation method is simple, and finally the flexible porous white mud carbon fiber is prepared by recycling the printing and dyeing white mud.

[0025] (2) Compared with granular activated carbon, the present invention has a wider range of actual applications and lower input costs, can be applied to more fields, and can customize carbon fiber membranes of corresponding sizes according to different application scenarios.

[0026] (3) Compared with traditional carbon fiber, the present invention uses printing and dyeing white mud waste as a raw material, has low input costs, better economic benefits, is environmentally friendly, can be applied to more fields, and meets the requirements of resource recovery and utilization.

[0027] (4) The preparation method of printing and dyeing white mud carbon fiber does not require special equipment and harsh conditions, has a simple process, does not produce waste liquid, has good environmental protection performance, low cost, and can realize the sustainable recycling of waste printing and dyeing white mud. Description of the Drawings

[0028] Figure 1 SEM morphology diagram of carbon fiber based on printing and dyeing white mud raw material prepared in Example 1;

[0029] Figure 2 XRD of carbon fiber based on printing and dyeing white mud raw material prepared in Example 1;

[0030] Figure 3 Appearance diagram of the example samples: a Appearance diagram of the sample in Example 1; b Appearance diagram of the sample in Example 2; c Appearance diagram of the sample in Example 3; d Appearance diagram of the sample in Example 4. Detailed Description of the Invention

[0031] To make the present invention more obvious and understandable, preferred embodiments are given below in conjunction with the accompanying drawings for detailed description as follows.

[0032] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0033] Example 1

[0034] A preparation method of carbon fiber based on printing and dyeing white mud raw material:

[0035] (1) Take 5 g of crude terephthalic acid white mud, weigh 2 g of calcium oxide, add a small amount of deionized water and disperse evenly in ultrasonic to obtain a calcified product;

[0036] (2) Take 2 g of the calcified product prepared in step (1) and add 5 mL of N,N-dimethylformamide, and stir evenly at a rotation speed of 200 rpm at room temperature for 4 hours;

[0037] (3) After the calcified product is completely dissolved, draw 10 mL of spinning solution with a syringe, spray it out at a propulsion speed of 5 mL / h in a high-voltage electric field of 14 kV, and the distance between the syringe and the receiving device is 10 cm. After the electrospinning is completed, peel off the fiber membrane to obtain calcified white mud fiber.

[0038] (4) Put the white mud fiber membrane prepared in step (3) into a quartz boat, pass N2 atmosphere for 30 min, the gas flow rate is 100 mL / min, and then calcine it in a tube furnace at 600 °C for 1 h, with a heating rate of 5 °C / min. After natural cooling, take the black carbon fiber membrane in the quartz boat.

[0039] (5) Acidify the black carbon fiber membrane obtained in step (4) with hydrochloric acid under stirring conditions at a rotation speed of 100 rpm. The mass ratio of the black carbon fiber membrane to the hydrochloric acid solution is 1:15. The hydrochloric acid concentration is 2 mol / L, and the acidification time is 2 h. After acidification, wash the membrane with deionized water until neutral. Place the obtained product in an oven and dry it at 60 °C for 24 h to obtain a printed and dyed white mud carbon fiber membrane.

[0040] In this example, a scanning electron microscope was used to characterize the surface morphology of the prepared printed and dyed white mud carbon fiber membrane ( Figure 1 ), and X-ray diffraction (XRD) was used to characterize the crystallinity of carbon elements in the obtained carbon fiber ( Figure 2 ). This method can obtain an activated carbon fiber membrane with continuity, flexibility, and high strength ( Figure 3 a) in it.

[0041] Example 2

[0042] A preparation method of carbon fiber based on printed and dyed white mud raw materials:

[0043] (1) Take 10 g of crude terephthalic acid white mud, weigh 2 g of calcium oxide, add a small amount of deionized water, and disperse it evenly in an ultrasonic bath to obtain a calcified product;

[0044] (2) Put the calcified product obtained in step (1) into a quartz boat, pass N2 atmosphere for 30 min with a gas flow rate of 100 mL / min, and then calcine it in a tube furnace at 450 °C for 1 h with a heating rate of 5 °C / min. After natural cooling, grind the powder in the porcelain boat to obtain calcified white mud carbon.

[0045] (3) Acidify the calcified white mud carbon obtained in step (2) with hydrochloric acid under stirring conditions at a rotation speed of 1000 rpm. The mass ratio of the calcified white mud carbon to the hydrochloric acid solution is 1:15. The hydrochloric acid concentration is 2 mol / L, and the acidification time is 6 h. After acidification, wash it with deionized water until neutral. Place the obtained product in an oven and dry it at 60 °C for 24 h to obtain white mud carbon.

[0046] (4) Take 2 g of the product obtained in step (3), add 5 mL of N,N-dimethylformamide, and stir it evenly at a rotation speed of 200 rpm at room temperature for 4 hours;

[0047] (5) After the white mud carbon is completely dissolved, draw 10 mL of spinning solution with a syringe, spray it out at a propulsion speed of 5 mL / h in a high-voltage electric field of 14 kV, and the distance between the syringe and the receiving device is 10 cm. After the electrospinning is completed, peel off the fiber membrane to obtain a white mud fiber membrane.

[0048] (6) Place the white mud fiber membrane prepared in step (5) into a quartz boat, purge with N2 atmosphere for 30 min at a gas flow rate of 100 mL / min, then calcine in a tube furnace at 450 °C for 1 h with a heating rate of 5 °C / min. After natural cooling, a printed and dyed white mud carbon fiber membrane is obtained.

[0049] Compared with Example 1, the obtained carbon fiber membrane in this example has increased brittleness ( Figure 3 in b), indicating that the continuity, flexibility, and strength of the carbon fiber are inferior to those of the sample in Example 1.

[0050] Example 3

[0051] A preparation method of carbon fiber based on printed and dyed white mud raw materials:

[0052] (1) Take 10 g of terephthalic acid white mud, weigh 5 g of calcium oxide, add a small amount of deionized water, and disperse evenly in an ultrasonic bath to obtain a calcified product;

[0053] (2) Place the calcified product prepared in step (1) into a quartz boat, purge with N2 atmosphere for 30 min at a gas flow rate of 100 mL / min, then calcine in a tube furnace at 400 °C for 1 h with a heating rate of 5 °C / min. After natural cooling, grind the powder in the porcelain boat to obtain calcified white mud carbon.

[0054] (3) Acidify the calcified white mud carbon prepared in step (2) with hydrochloric acid under stirring at a rotation speed of 1000 rpm. The mass ratio of calcified white mud carbon to hydrochloric acid solution is 1:15. The hydrochloric acid concentration is 2 mol / L, and the acidification time is 6 h. After acidification, wash with deionized water until neutral. Place the obtained product in an oven and dry at 60 °C for 24 h to obtain white mud carbon.

[0055] (4) Take 2 g of the product prepared in step (3), add 5 mL of N,N-dimethylformamide, and stir evenly at a rotation speed of 200 rpm at room temperature for 4 hours;

[0056] (5) After the white mud carbon is completely dissolved, draw 10 mL of spinning solution with a syringe, spray it out at a propulsion speed of 5 mL / h in a 17 kV high-voltage electric field, and the distance between the syringe and the receiving device is 10 cm. After the electrospinning is completed, peel off the fiber membrane to obtain a white mud fiber membrane.

[0057] (6) Place the white mud fiber membrane prepared in step (5) into a quartz boat, purge with N2 atmosphere for 30 min at a gas flow rate of 100 mL / min, then calcine in a tube furnace at 600 °C for 1 h with a heating rate of 5 °C / min. After natural cooling, a printed and dyed white mud carbon fiber membrane is obtained.

[0058] In this example, the printing and dyeing white mud was first prepared into activated carbon, and then electrospun and calcined to obtain an activated carbon fiber membrane. It was found that the continuity, flexibility, and strength of this activated carbon fiber membrane were worse than those of the carbon fiber membrane obtained in Example 1. Figure 3 in c).

[0059] Example 4

[0060] A preparation method of carbon fiber based on printing and dyeing white mud raw materials:

[0061] (1) Take 10 g of terephthalic acid white mud and put it into a porcelain mortar for grinding; (2) Take 2 g of the white mud obtained in step (1) and add 5 mL of N,N-dimethylformamide, and stir evenly at a rotation speed of 200 rpm at room temperature for 4 hours;

[0062] (3) After the white mud is completely dissolved, draw 10 mL of spinning solution with a syringe and spray it out at a propulsion speed of 5 mL / h in a high-voltage electric field of 14 kV. The distance between the syringe and the receiving device is 10 cm. After the electrospinning is completed, peel off the fiber membrane to obtain a white mud fiber membrane;

[0063] (4) Put the white mud fiber membrane obtained in step (3) into a quartz boat, pass N2 atmosphere for 30 min, the gas flow rate is 100 mL / min, and then calcine it in a tube furnace at 500 °C for 1 h, and the heating rate is 5 °C / min. After natural cooling, take out the printing and dyeing white mud carbon fiber membrane in the quartz boat.

[0064] In this example, direct spinning of white mud calcification is not included. After calcination in a tube furnace, it was found that a carbon fiber membrane could not be formed ( Figure 3 in d), because terephthalic acid sublimes when heated before reaching the carbonization temperature. In summary, the present invention uses printing and dyeing white mud as a raw material and calcium oxide as a calcifying agent. The ultrasonic method is used to make calcium oxide and terephthalic acid fully contact, and then combined with the electrospinning technology. After carbonization and acidification, the reaction conditions are mild and the preparation method is simple. Finally, the printing and dyeing white mud is recycled to prepare flexible porous white mud carbon fiber, which has a larger specific surface area than traditional carbon fiber, realizing the resource recycling and reuse of printing and dyeing white mud.

Claims

1. A method for preparing carbon fiber based on printing and dyeing white mud raw material, characterized in that: The following steps are involved: S1: Add printing and dyeing white mud and calcium oxide into water, perform ultrasonic dispersion, and obtain a calcified product; S2: mixing the calcified product obtained in S1 with an organic solvent, and electrospinning the dissolved solution to obtain calcified white mud electrospun fibers; S3: The calcified white mud electrospun fibers obtained in S2 are heated in a tubular furnace under an inert atmosphere, and after cooling, the carbon fibers are acid-washed and dried to obtain the target carbon fibers.

2. The method for preparing carbon fiber based on printing and dyeing white mud raw material according to claim 1, characterized in that: In step S1, the mass ratio of the printing and dyeing white mud to calcium oxide is 1:0.5-10.

3. The method for preparing carbon fiber based on printing and dyeing white mud raw material according to claim 1, characterized in that: In step S1, the mass of the water is 5-100% of the mass of the printing and dyeing white mud.

4. The method for preparing carbon fiber based on printing and dyeing white mud raw material according to claim 1, characterized in that: In step S1, after the ultrasonic dispersion, the obtained mixed material is dry-ground.

5. The method for preparing carbon fiber based on printing and dyeing white mud raw material according to claim 1, characterized in that: In step S2, the mass ratio of the calcification product to the organic solvent is 1:0.5-3; and the organic solvent is dimethylformamide.

6. The method for preparing carbon fiber based on printing and dyeing white mud raw material according to claim 1, characterized in that: In step S2, the process parameters of the electrospinning are: the distance between the electrospinning needle and the receiving device is 10-20 cm, the propulsion speed is 0.4-50 mL / h, and the applied voltage is 10-20 kV.

7. The method for preparing carbon fiber based on printing and dyeing white mud raw material according to claim 1, characterized in that: In step S3, the heating rate of the tubular furnace is 1-10°C / min, the heating temperature is 200-900°C, and the insulation time is 1-4h; the inert gas is nitrogen, argon, helium or a hydrogen-argon mixture.

8. The method for preparing carbon fiber based on printing and dyeing white mud raw material according to claim 1, characterized in that: In step S3, the chemicals used for pickling are one or more of hydrochloric acid, nitric acid, and sulfuric acid, and the acid concentration is 0.1-3 mol / L.

9. The method for preparing carbon fiber based on printing and dyeing white mud raw material according to claim 1, characterized in that: In step S3, the drying temperature is 40-80°C and the drying time is 2-24 hours.

10. A carbon fiber based on printing and dyeing white mud raw material prepared by the preparation method according to any one of claims 1 to 9.

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