A method for combined degumming of hemp fibers based on photocatalysis and pectinase

Abstract

This invention discloses a method for combined degumming of hemp fibers based on photocatalysis and pectinase, comprising the following steps: (1) mixing a photocatalyst suspension and a pectinase solution to prepare a degumming mixed solution, and pouring it into a glass reactor; (2) placing hemp bast fibers into the degumming mixed solution and subjecting them to phototreatment, after which the hemp fibers are removed; (3) washing and drying the hemp fibers to obtain degummed hemp fibers. This invention utilizes photocatalysis and pectinase to remove pectin, lignin, and other non-cellulose components from hemp fibers. The degumming conditions are mild, causing minimal damage to the hemp fibers, consuming less energy, and no alkaline solution is used during the degumming process, resulting in less waste liquid and less environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of textile processing technology, specifically to a method for the combined degumming of hemp fibers based on photocatalysis and pectinase. Background Technology

[0002] Hemp is a natural bast fiber. As a high-quality natural cellulose resource, hemp fiber is multifunctional. End products made from hemp can be used in many fields, such as textiles, construction, papermaking, medicine, biofuels, food, and biocomposite materials. Hemp fiber has a bast fiber structure, consisting of individual cellulose protofibrils bound together by a gum substance, mainly composed of hemicellulose, pectin, waxes, water-soluble materials, and lignin. Because a large amount of gum substance increases the toughness and yellowing of hemp fiber, directly limiting its further utilization, it is essential to extract high-quality hemp fiber from hemp without sacrificing the physical properties or chemical structure of cellulose. Therefore, hemp should be degummed before spinning and textile production to obtain soft and fine spun hemp fibers.

[0003] Currently, the main methods for degumming hemp include physical degumming, traditional alkaline boiling degumming, biological degumming, and organic solvent degumming. Among these, physical degumming methods are often used as pretreatment because they are not thorough. Traditional alkaline boiling degumming is relatively stable and has a wide range of applications, but it is energy-intensive and causes significant pollution. Biological enzymatic degumming can significantly reduce pollution emissions, but the degumming enzymes have a limited function and require chemical reagents. Organic solvent degumming allows for the recovery of the degumming liquid, but the solvents are extremely expensive, and the wastewater requires further treatment. Therefore, there is an urgent need to develop a degumming method that is mild, produces minimal environmental pollution, and achieves good degumming results. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for the combined degumming of hemp fibers based on photocatalysis and pectinase. This method features mild reaction conditions, minimal environmental pollution, good degumming effect, and minimal damage to the hemp fibers.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for combined degumming of hemp fibers based on photocatalysis and pectinase includes the following steps:

[0007] (1) Mix the photocatalyst suspension and pectinase solution evenly to prepare a degumming mixture solution, and pour it into a glass reactor;

[0008] (2) Place the hemp bast fibers into the degumming mixture, add water to adjust the solid bath ratio, and perform light treatment. After the light treatment is completed, remove the hemp fibers.

[0009] (3) Wash and dry the hemp fibers to obtain degummed hemp fibers.

[0010] Furthermore, the photocatalyst in step (1) is a catalyst that can be excited in the visible light wavelength range, such as TiO2. 2- Composite photocatalysts containing carbon quantum dots, such as CQDs and ZnO-CQDs, as well as other types of photocatalysts, such as ZnIn2S4.

[0011] In the above technical solution, the photocatalyst is a catalyst that can be excited in the visible light wavelength range, such as TiO2-CQDs, ZnO-CQDs, ZnIn2S4 and other photocatalysts. This type of photocatalyst can be excited in the visible light wavelength range, and visible light accounts for 45% of the total solar energy, so its light utilization rate is high, thereby improving the degumming effect.

[0012] Furthermore, in step (1), the amount of photocatalyst used is 1-5 g / kg hemp fiber.

[0013] Furthermore, in step (1), the amount of pectinase used is 2000-10000 U / kg hemp fiber.

[0014] Furthermore, in step (2), the solid-bath ratio of the hemp bast fiber to the degummed mixed solution is 1:10 to 100.

[0015] Furthermore, the light treatment time in step (2) is 20 to 60 hours.

[0016] Furthermore, the light source used in the illumination process in step (2) is sunlight or simulated sunlight, and simulated sunlight is a light-emitting diode or a xenon lamp.

[0017] Furthermore, the hemp fiber is one of ramie, hemp, apocynum venetum, kenaf, or jute.

[0018] The beneficial effects of this invention are as follows:

[0019] This invention provides a method for degumming hemp fibers based on photocatalysis and pectinase. The method utilizes photocatalysis and pectinase to remove waxes, pectin, lignin, hemicellulose and other non-cellulose components from hemp bast fibers. The degumming conditions are mild, causing little damage to the hemp fibers and consuming less energy. Furthermore, no alkaline solution is used in the degumming process, resulting in less waste liquid and less environmental pollution. Attached Figure Description

[0020] To clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 SEM image of hemp bast fibers before degumming treatment;

[0022] Figure 2 SEM image of hemp fiber treated with TiO2-CQDs and pectinase in combination with light, as provided in Example 1;

[0023] Figure 3 SEM images of dark-treated hemp fibers with TiO2-CQDs only, provided for Comparative Example 1;

[0024] Figure 4 SEM images of hemp fibers treated with TiO2-CQDs only, provided for Comparative Example 2;

[0025] Figure 5 SEM image of hemp fibers treated with pectinase only in the dark, for Comparative Example 3;

[0026] Figure 6 SEM image of hemp fiber treated with pectinase only for Comparative Example 4;

[0027] Figure 7 SEM image of hemp fiber treated with TiO2-CQDs and pectinase in combination in the dark, as provided in Comparative Example 5. Detailed Implementation

[0028] This invention provides a method for the combined degumming of hemp fibers based on photocatalysis and pectinase. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0029] The present invention will now be described in detail with reference to the accompanying drawings.

[0030] Example 1

[0031] This embodiment provides a method for combined degumming of hemp fibers based on photocatalysis and pectinase, including the following steps:

[0032] (1) Mix 200ml of 5g / L TiO2-CQDs photocatalyst suspension and 2000U of pectinase solution evenly to prepare a degumming mixed solution, and pour it into a 30L glass reactor, wherein the pectinase activity content is 2U / mL;

[0033] (2) Place 1000g of undegummed hemp bast fiber into the degummed mixed solution prepared in step (1), add water to make the solid bath ratio of hemp bast fiber and solution 1:20, and then place it under sunlight for light treatment. Specifically, light treatment for 12 hours followed by dark treatment for 12 hours, repeat for 4 days, and then take out the hemp fiber.

[0034] (3) Wash and dry the hemp fiber to obtain degummed hemp fiber.

[0035] Example 2

[0036] This embodiment provides a method for combined degumming of hemp fibers based on photocatalysis and pectinase, including the following steps:

[0037] (1) Mix 500ml of 10g / L ZnO-CQDs photocatalyst suspension and 8000U pectinase solution evenly to prepare a degumming mixed solution, and pour it into a 30L glass reactor, wherein the pectinase activity content is 2U / mL;

[0038] (2) Place 1000g of undegummed hemp bast fiber into the degummed mixed solution prepared in step (1), add water to make the solid-bath ratio of hemp bast fiber to solution 1:50, and then place it under simulated sunlight for light treatment, specifically using LED lights, light treatment for 30h, and then take out the hemp fiber.

[0039] (3) Wash and dry the hemp fiber to obtain degummed hemp fiber.

[0040] Comparative Example 1

[0041] This comparative example provides a method for degumming hemp fibers using a photocatalyst, including the following steps:

[0042] (1) Pour 200 ml of 5 g / L TiO2-CQDs photocatalyst suspension into a 30 L glass reactor and stir evenly to prepare a degumming solution;

[0043] (2) Place 1000g of undegummed hemp bast fiber into the degumming solution prepared in step (1), add water to make the solid-bath ratio of hemp bast fiber to solution 1:20, and perform dark treatment for 4 days, and then take out the hemp fiber.

[0044] (3) Wash and dry the hemp fiber to obtain degummed hemp fiber.

[0045] Comparative Example 2

[0046] This comparative example provides a method for degumming hemp fibers using a photocatalyst, including the following steps:

[0047] (1) Pour 200 ml of 5 g / L TiO2-CQDs photocatalyst suspension into a 30 L glass reactor and stir evenly to prepare a degumming solution;

[0048] (2) Place 1000g of undegummed hemp bast fiber into the degumming solution prepared in step (1), add water to make the solid bath ratio of hemp bast fiber to solution 1:20, and then place it under sunlight for light treatment. Specifically, light treatment for 12 hours followed by dark treatment for 12 hours, repeat for 4 days, and then take out the hemp fiber.

[0049] (3) Wash and dry the hemp fiber to obtain degummed hemp fiber.

[0050] Comparative Example 3

[0051] This comparative example provides a method for degumming hemp fibers using pectinase, including the following steps:

[0052] (1) Add 2000U pectinase solution to a 30L glass reactor and stir evenly to prepare a degumming solution, wherein the pectinase activity content is 2U / mL;

[0053] (2) Place 1000g of undegummed hemp bast fiber into the degumming solution prepared in step (1), add water to make the solid-bath ratio of hemp bast fiber to solution 1:20, and perform dark treatment for 4 days, and then take out the hemp fiber.

[0054] (3) Wash and dry the hemp fiber to obtain degummed hemp fiber.

[0055] Comparative Example 4

[0056] This comparative example provides a method for degumming hemp fibers using pectinase, including the following steps:

[0057] (1) Add 2000U pectinase solution to a 30L glass reactor and stir evenly to prepare a degumming solution, wherein the pectinase activity content is 2U / mL;

[0058] (2) Place 1000g of undegummed hemp bast fiber into the degumming solution prepared in step (1), add water to make the solid bath ratio of hemp bast fiber to solution 1:20, and then place it under sunlight for light treatment. Specifically, light treatment for 12 hours followed by dark treatment for 12 hours, repeat for 4 days, and then take out the hemp fiber.

[0059] (3) Wash and dry the hemp fiber to obtain degummed hemp fiber.

[0060] Comparative Example 5

[0061] This comparative example provides a method for the combined degumming of hemp fibers based on photocatalysis and pectinase, including the following steps:

[0062] (1) Mix 200ml of 5g / L TiO2-CQDs photocatalyst suspension and 2000U of pectinase solution evenly to prepare a degumming mixed solution, and pour it into a 30L glass reactor, wherein the pectinase activity content is 2U / mL;

[0063] (2) Place 1000g of undegummed hemp bast fiber into the degummed mixed solution prepared in step (1), add water to make the solid bath ratio of hemp bast fiber to solution 1:20, and perform dark treatment for 4 days, and then take out the hemp fiber.

[0064] (3) Wash and dry the hemp fiber to obtain degummed hemp fiber.

[0065] Scanning electron microscopy was used to test the raw hemp before degumming treatment and the degummed hemp fibers prepared in Example 1 and Comparative Examples 1-5 above. Figure 1-7 As shown.

[0066] from Figure 1 It can be seen that the surface of hemp bast fibers before degumming is rough, covered with a thick layer of gum, and the fibers aggregate to form bundles.

[0067] from Figure 2 It can be seen that after being treated with TiO2-CQDs photocatalyst and pectinase by combined light irradiation, the hemp fiber is separated into individual fibers, and the fiber surface is relatively smooth with low pectin content.

[0068] from Figure 3 It can be seen that after TiO2-CQDs dark treatment, the fiber surface is still rough and not smooth, and the surface still contains a lot of gum components. Compared with the original hemp fiber before degumming treatment, there is basically no change, indicating that the TiO2-CQDs photocatalyst has no effect under dark treatment.

[0069] from Figure 4 It can be seen that after TiO2-CQDs light treatment, the amount of gum on the fiber surface is reduced, but the fiber bundle is not divided into several individual fibers. This is mainly because the fiber still contains a lot of gum, which causes the fibers to stick together.

[0070] from Figure 5-7 It can be seen that after treatment with pectinase, most of the hemp fiber bundles are separated into single fibers, but the surface of the single fibers still contains a relatively large amount of gum.

[0071] In addition, the degummed hemp fiber and hemp bast fiber prepared in Example 1 and Comparative Examples 1-5 were tested for chemical composition. The test results are shown in Table 1. The degummed hemp fiber prepared in Example 1 and Comparative Example 3 were tested for physical properties. The test results are shown in Table 2.

[0072] The methods for testing the above chemical composition and physical properties are as follows:

[0073] Test method for chemical composition: The residual gum rate of degummed hemp fiber was tested according to GB 5889–1986 "Quantitative Analysis Method for Chemical Composition of Ramie".

[0074] Fineness test method: Refer to GB / T 6100–2007 "Test method for linear density of cotton fiber - mid-section weighing method" to test the fineness of degummed hemp fiber.

[0075] Test method for bundle fiber strength: The strength of degummed hemp fiber is tested in accordance with GB / T 5882–1986 "Test method for breaking strength of ramie bundle fiber".

[0076] Table 1

[0077]

[0078] Table 2

[0079] Fineness (dtex) Fracture strength (cN / dtex) Comparative Example 3 8.52±0.09 4.11±0.99 Example 1 6.91±0.13 4.08±0.88

[0080] As can be seen from Table 1 above, the chemical composition of the degummed hemp fibers obtained in Example 1 and Comparative Examples 1-5 is similar to that of... Figure 2-7 The SEM results were basically consistent. The hemp fiber prepared in Example 1 showed the highest removal rates of waxes, pectin, lignin, and hemicellulose, indicating that the combined degumming effect of TiO2-CQDs and pectinase under light treatment was good. Compared to Example 1, Comparative Example 5, treated with TiO2-CQDs and pectinase under dark conditions, had higher contents of waxes, pectin, lignin, and hemicellulose than Example 1. Furthermore, Comparative Example 1, treated only with TiO2-CQDs under dark conditions, still had high contents of each gum; Comparative Example 2, treated only with TiO2-CQDs under light conditions, still had high contents of each gum, with only a slight decrease in lignin and hemicellulose; Comparative Example 3, treated with pectinase under dark conditions, removed some pectin, waxes, lignin, and hemicellulose; Compared to Comparative Example 3, Comparative Example 4, treated with pectinase under light, removed relatively more pectin, waxes, lignin, and hemicellulose.

[0081] As can be seen from Table 2 above, Example 1 uses TiO2-CQDs photocatalyst combined with pectinase for degumming. After degumming, the fiber fineness is 6.91 dtex and the breaking strength is 4.08 cN / dtex, indicating a good degumming effect. Compared with pectinase treatment alone, the breaking strength remains basically unchanged, indicating that photocatalysis has little impact on fiber properties. Moreover, the reaction conditions in Example 1 are mild, causing less damage to the hemp fiber and maintaining good breaking strength.

[0082] It should be noted that any parts not mentioned in this invention can be achieved by using or referencing existing technologies.

[0083] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for combined degumming of hemp fibers based on photocatalysis and pectinase, characterized in that, Including the following steps: (1) Mix the photocatalyst suspension and pectinase solution evenly to prepare a degumming mixture solution, and pour it into a glass reactor; (2) Place the bast fibers of hemp into the degumming mixture, add water to adjust the solid bath ratio, and perform light treatment. After the light treatment is completed, take out the hemp fibers. (3) Wash and dry the hemp fibers to obtain degummed hemp fibers; The photocatalyst in step (1) is TiO2-CQDs, ZnO-CQDs, or ZnIn2S4.

2. The method for combined degumming of hemp fibers based on photocatalysis and pectinase according to claim 1, characterized in that, In step (1), the photocatalyst is a catalyst that can be excited in the visible light wavelength range.

3. The method for combined degumming of hemp fibers based on photocatalysis and pectinase according to claim 1, characterized in that, In step (1), the amount of photocatalyst used is 1~5g / kg of hemp fiber.

4. The method for combined degumming of hemp fibers based on photocatalysis and pectinase according to claim 1, characterized in that, In step (1), the amount of pectinase used is 2000~10000 U / kg hemp fiber.

5. The method for combined degumming of hemp fibers based on photocatalysis and pectinase according to claim 1, characterized in that, In step (2), the solid-bath ratio of the hemp bast fiber to the degummed mixed solution is 1:10~100.

6. The method for combined degumming of hemp fibers based on photocatalysis and pectinase according to claim 1, characterized in that, The light treatment time in step (2) is 20~60h.

7. The method for combined degumming of hemp fibers based on photocatalysis and pectinase according to claim 1, characterized in that, The light source used in step (2) during the illumination process is sunlight or simulated sunlight, and simulated sunlight is a light-emitting diode or a xenon lamp.

8. A method for combined degumming of hemp fibers based on photocatalysis and pectinase according to any one of claims 1-7, characterized in that, The bast fiber of the bast fiber is one of ramie, hemp, apocynum venetum, kenaf, or jute.

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