A method for green degumming of ramie by acid-alkali synergistic biological enzyme

Abstract

The present application relates to ramie degumming process technical field, specifically is a kind of acid-base synergic biological enzyme assisted ramie green degumming method, the method uses NaOH-H2SO4 Synergic treatment system, by acid dipping-alkali dipping two-step method synergistic effect, acid dipping stage is treated with 1%-5% H2SO4 Solution adding surfactant etc., alkali boiling stage is treated with 2%-6% NaOH solution adding sodium silicate etc., combined with biological enzyme auxiliary treatment, realize efficient degumming, the present application acid-base synergic biological enzyme assisted ramie green degumming method, gum removal rate is >90%, reduce 20%-30% alkali dosage, fiber breaking strength is increased by 20%-25%, wettability is significantly improved, residual glue rate is as low as 2% or less, and reduce production cost and wastewater treatment cost, adapt to existing production line, can satisfy high-end textile demand.

Description

Technical Field

[0001] This invention relates to the field of ramie fiber degumming technology, specifically a green ramie degumming method using acid-base synergistic bio-enzyme assistance. Background Technology

[0002] In the current field of ramie degumming, traditional chemical degumming methods (such as sulfuric acid and sodium hydroxide treatment) are highly efficient, but they generate a large amount of wastewater containing high concentrations of chemical residues, causing serious environmental pollution. While biological degumming technology is relatively environmentally friendly, it suffers from low degumming efficiency and long processing time, making it difficult to meet the needs of large-scale industrial production.

[0003] Meanwhile, the fibers are easily damaged by chemical reagents during the degumming process, resulting in decreased fiber strength and poor color, which affects the quality of the final product. In addition, the quality of ramie raw materials varies greatly from region to region, making it difficult to standardize the degumming process, which further exacerbates the instability of fiber quality.

[0004] Furthermore, ramie degumming technology requires advanced equipment and skilled personnel. Many small and medium-sized enterprises lack the necessary technology and financial support, making it difficult to upgrade their technology. Farmers and growers have limited understanding of degumming technology, resulting in inconsistent initial processing levels of ramie raw materials, which affects the overall efficiency of the industrial chain. Moreover, the lack of effective coordination between ramie planting, degumming, and textile processes leads to resource waste and inefficiency. The shortcomings of degumming technology also limit the application of ramie in high-end textiles and environmentally friendly materials, reducing the added value of ramie products. Therefore, in light of the above situation, there is an urgent need to develop a green ramie degumming method that uses acid-base synergistic bio-enzyme assistance to overcome the current shortcomings in practical applications. Summary of the Invention

[0005] The purpose of this invention is to provide a green degumming method for ramie using an acid-base synergistic bio-enzyme-assisted approach, in order to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A green degumming method for ramie using an acid-base synergistic bio-enzyme-assisted process includes the following steps:

[0008] (1) Raw material preparation: Select ramie raw fibers with a moisture content of ≤12%, cut them to a length of 30-50cm, and mechanically loosen them to achieve a fiber separation degree of more than 85%;

[0009] (2) Acid soaking pretreatment: The raw ramie treated in step (1) is placed in an H2SO4 solution with a mass percentage of 1%-5%, wherein a surfactant is added to the H2SO4 solution for acid soaking treatment;

[0010] (3) Alkali boiling treatment: After washing the ramie fibers after acid soaking in step (2), place them in a NaOH solution with a mass percentage of 2%-6%, wherein the NaOH solution contains sodium silicate with a mass percentage of 2%-3%, and perform alkaline boiling treatment.

[0011] (4) Bio-enzyme-assisted treatment: After washing the ramie fiber after alkali boiling in step (3), place it in an enzyme treatment solution containing pectinase and xylanase for bio-enzyme treatment.

[0012] (5) Post-treatment: Wash the ramie fibers treated with bio-enzymes in step (4) until neutral, and then dry them until the moisture content is ≤8% to complete degumming.

[0013] As a further aspect of the present invention: in step (2), the surfactant is sodium dodecyl sulfonate or sodium dodecylbenzene sulfonate, and the mass percentage of the surfactant in the H2SO4 solution is 0.1%-0.5%;

[0014] The H2SO4 solution also contains malonic acid and / or oxalic acid, wherein the mass percentage of malonic acid is 1%-3% and the mass percentage of oxalic acid is 0.5%-2%.

[0015] As a further aspect of the present invention: in step (2), the process parameters for acid leaching are as follows:

[0016] The ratio of raw ramie to H2SO4 solution was 1:15, the treatment temperature was 85±2℃, and the treatment time was 30-45 min. Mechanical stirring was used with a stirring speed of 30-60 rpm. The stirring method was intermittent or continuous stirring. When intermittently stirring, stirring was performed for 1 min every 5 min.

[0017] As a further aspect of the present invention: in step (3), the NaOH solution is further supplemented with trisodium phosphate, hydrogen peroxide and / or EDTA, wherein the mass percentage of trisodium phosphate is 2%-5%, the mass percentage of hydrogen peroxide is 1%-3%, and the mass percentage of EDTA is 0.2%-1%.

[0018] As a further aspect of the present invention: in step (3), the process parameters for the alkali boiling treatment are as follows:

[0019] The ratio of ramie fiber to NaOH solution was 1:20, the treatment temperature was 100±2℃, the treatment time was 90-125 min, continuous mechanical stirring was used, the stirring speed was 60-80 rpm, and high-pressure steam was used during the alkaline boiling process, with a pressure of 0.15MPa-0.20MPa.

[0020] As a further aspect of the present invention: in step (4), laccase is also added to the enzyme treatment solution;

[0021] The pectinase activity is 2000-5000 U / g, the xylanase activity is 1000-3000 U / g, and the laccase activity is 500-1000 U / g.

[0022] The process parameters for bio-enzyme treatment are as follows: pH value of enzyme treatment solution is 6-8, treatment temperature is 50±2℃, treatment time is 60min, and treatment method is static soaking.

[0023] As a further aspect of the present invention: after acid immersion treatment in step (2), the ramie fibers are washed with water until the pH value is 6.5-7.0;

[0024] After the alkali boiling treatment in step (3), the ramie fiber is first boiled at 100℃ for 20-25 minutes, and then washed with water until the pH value is 7.0-7.5.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. This invention adopts a NaOH-H2SO4 synergistic treatment system, which achieves efficient degumming through a two-step acid-alkali immersion method, with a glue removal rate of >90%, while reducing the amount of alkali used by 20%-30%, resulting in higher fiber quality and significantly improved breaking resistance and wettability.

[0027] At the same time, since the alkali concentration used in this invention is very low, it is advantageous in terms of preventing fiber damage, controlling costs, and environmental protection.

[0028] 2. The multi-component synergistic system introduces organic acids and surfactants in the acid leaching stage and combines sodium silicate, oxidant and chelating agent in the alkaline boiling stage, which significantly improves degumming efficiency; the three-step process of bio-enzyme green treatment reduces the total amount of chemicals used by 40%, which is in line with the trend of environmental protection.

[0029] 3. Through data verification by electron microscopy, mechanical testing and other methods, the fiber performance meets the requirements of high-end textiles (such as medical bandages and high-end clothing); it has strong process compatibility and can be adapted to existing ramie production lines, requiring only the addition of enzyme treatment tanks, resulting in low modification costs;

[0030] 4. In contrast to the existing "alkali first, acid later" treatment method, the "acid first, alkali later" process of this invention opens up the fiber structure by acid first, so that the subsequent alkaline boiling under normal pressure can achieve the same degumming effect, avoiding fiber damage caused by high pressure.

[0031] 5. After optimizing the process flow, the amount of chemicals used was reduced, energy consumption was lowered, production costs were significantly reduced, and the economic benefits of enterprises were improved; the improved degumming technology reduced damage to fibers, improved fiber strength and quality, enabling ramie fibers to better meet the needs of high-end textiles and expand their application in clothing, home furnishings and other fields.

[0032] 6. Degumming treatment removes sticky substances around the fibers, improving their strength and flexibility, making them more suitable for spinning and weaving into textiles, or for use in other industrial production. Attached Figure Description

[0033] Figure 1 This is a comparison image of ramie before and after degumming in an embodiment of the present invention;

[0034] The left image shows a comparison before and after degumming; the right image is a photograph of the experimental sample.

[0035] Figure 2 This is an electron micrograph of ramie fibers after acid immersion pretreatment in an embodiment of the present invention.

[0036] Figure 3 This is a radar diagram of an orthogonal experiment on ramie degumming in an embodiment of the present invention.

[0037] Figure 4 This is a multi-index analysis chart of the ramie degumming process in an embodiment of the present invention.

[0038] Figure 5 These are electron microscope images comparing the microstructure of ramie fibers before and after degumming treatment in an embodiment of the present invention.

[0039] In this image, a is an electron microscope image of the microstructure of ramie fibers before degumming treatment; b is an electron microscope image of the microstructure of ramie fibers after degumming treatment. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0042] Please see Figures 1-5 This invention provides a green degumming method for ramie using an acid-base synergistic bio-enzyme-assisted process. It employs a NaOH-H2SO4 synergistic treatment system (replacing the traditional single strong alkali) and achieves highly efficient degumming through a two-step acid-alkali immersion process, achieving a gum removal rate >90%. Simultaneously, it reduces alkali usage by 20%-30%, resulting in higher fiber quality with significantly improved breaking resistance and wettability. The reaction mechanism is {ramie gum} → {H2SO4 acid immersion} → {water washing} → {NaOH alkali immersion} → {water washing}, detailed below:

[0043] 1. Raw material preparation: Select ramie raw fibers with a moisture content of ≤12%, cut them to a length of 30-50cm, and mechanically loosen them to achieve a fiber separation degree of over 85%.

[0044] 2. Acid leaching pretreatment: Acid leaching components: 1%-5% H2SO4 (industrial grade), with the addition of 0.1%-0.2% sodium dodecyl sulfate (surfactant), and may be supplemented with 1%-3% malonic acid (to assist in the degradation of lignin) and 0.5%-2% oxalic acid (to enhance pectin solubility).

[0045] Process parameters: liquid ratio 1:15, temperature 85±2℃, processing time 40-45min, using intermittent mechanical stirring (30rpm, stirring for 1min every 5min).

[0046] Subsequent treatment: After acid soaking, the fibers are washed with water to pH 6.5-7.0.

[0047] 3. Alkali boiling treatment: Alkali boiling components: 2%-6% NaOH (industrial grade), with the addition of 2%-3% sodium silicate, and may be supplemented with 2%-5% trisodium phosphate (buffer), 1%-3% hydrogen peroxide (oxidizing bleaching agent) and 0.2%-1% EDTA (metal ion chelating agent).

[0048] Process parameters: liquid ratio 1:20, temperature 100±2℃, processing time 120-125min, continuous mechanical stirring (60rpm), high-pressure steam assisted (0.15Mpa-0.20MPa).

[0049] 4. Bioenzyme-assisted treatment:

[0050] Enzyme preparations: pectinase (2000-5000U / g, pH 7-8, 50℃), xylanase (1000-3000U / g, pH 6-7), laccase (500-1000U / g).

[0051] 5. Post-treatment: Boil at high temperature (100℃, 20min-25min), wash with water until neutral (pH 7.0-7.5), and dry with hot air at 80℃ until the moisture content is below 8%.

[0052] The specific implementation method is as follows:

[0053] I. Preparation of raw materials and synergistic additives system;

[0054] Ramie raw hemp: Select ramie raw hemp with a moisture content ≤12%, a gum content of 25%-30%, and a fiber length ≥1.5m; cut the raw hemp to a length of 30-50cm, and mechanically loosen it to achieve a fiber separation degree of over 85% for later use.

[0055] Acid leaching components:

[0056] Sulfuric acid (H2SO4): 98% industrial grade (acid leaching concentration can be adjusted within the range of 1%-5% H2SO4);

[0057] Malonic acid: assists in the degradation of lignin, accounting for 1%-3% of the total mass of the acid solution;

[0058] Oxalic acid: enhances pectin solubility, accounting for 0.5%-2% of the total mass of the acid solution;

[0059] Sodium dodecylbenzenesulfonate (surfactant): promotes penetration, accounting for 0.1%-0.5% of the total mass of the acid solution.

[0060] Alkali-boiled components:

[0061] Sodium hydroxide (NaOH): 96% industrial grade (the concentration can be adjusted within the range of 2%-6% NaOH after alkaline boiling);

[0062] Trisodium phosphate (buffer): Reduces fiber damage, accounting for 2%-5% of the total mass of the alkali solution;

[0063] Hydrogen peroxide (oxidizing bleach): accounts for 1%-3% of the total mass of the alkaline solution;

[0064] Ethylenediaminetetraacetic acid (EDTA, a metal ion chelating agent): accounting for 0.2%-1% of the total mass of the alkaline solution;

[0065] Sodium silicate: accounts for 2%-3% of the total mass of the alkaline solution.

[0066] Biological enzyme preparation (for post-alkali boiling treatment):

[0067] Pectinase: 2000-5000 U / g, suitable pH 7-8, action temperature 50℃;

[0068] Xylanase: 1000-3000 U / g, suitable pH 6-7;

[0069] Laccase: Degrades residual lignin, 500-1000 U / g.

[0070] II. Acid leaching pretreatment (multi-component synergistic degradation);

[0071] Acid solution formulation (by mass percentage): 3% H2SO4 + 1% β-malonic acid + 0.5% oxalic acid + 0.3% sodium dodecylbenzenesulfonate.

[0072] Process parameters: liquid ratio (hemp: acid): 1:15; temperature: 85℃±2℃; processing time: 30min; stirring conditions: mechanical stirring, speed 60rpm.

[0073] Mechanism of action: Sulfuric acid primarily targets pectin and hemicellulose; citric acid and oxalic acid synergistically degrade lignin; surfactants enhance penetration efficiency.

[0074] Electron microscopy confirmed that after acid immersion, a porous structure (pore size 5-10 μm) is formed on the fiber surface, which facilitates the penetration of alkali solution.

[0075] Subsequent processing: After acid immersion, the fibers are washed with water to pH 6.5-7.0 and set aside for later use.

[0076] III. Dynamic alkaline boiling enhanced degumming (composite alkaline system);

[0077] Alkali solution formula (by mass percentage): 4% NaOH + 3% disodium phosphate + 1.5% hydrogen peroxide + 0.5% EDTA.

[0078] Process parameters: liquid ratio (hemp: alkali): 1:20; temperature: 100℃±2℃ (high-pressure steam heating); processing time: 90min; stirring conditions: continuous mechanical stirring, speed 80rpm; pressure conditions: high-pressure steam assisted, pressure 0.15MPa-0.20MPa.

[0079] Mechanism of action: NaOH primarily degummes the fibers; sodium silicate protects the fibers; hydrogen peroxide oxidizes residual gum; EDTA chelates metal ions to prevent fiber oxidation.

[0080] Treatment effect: The residual glue rate is reduced to below 4% (the residual glue rate of traditional processes is 8%-10%).

[0081] IV. Bio-enzyme-assisted treatment (green efficiency enhancement);

[0082] Enzyme treatment solutions: Multiple groups of combinations of pectinase (2000U / g, 3000U / g, 5000U / g) + xylanase (1000U / g, 2000U / g, 3000U / g) + laccase (500U / g, 800U / g, 1000U / g) were tested.

[0083] Process parameters: pH value: 7.5 (adjusted by phosphate buffer); temperature: 50℃±2℃; treatment time: 60min; treatment method: static soaking.

[0084] Processing effect:

[0085] Example 1 (Low-activity enzyme combination): Pectinase 2000U / g + Xylanase 1000U / g + Laccase 500U / g, pectin residue reduced to 2.8%, fiber surface smoothness increased by 25%;

[0086] Example 2 (active enzyme combination): pectinase 3000U / g + xylanase 2000U / g + laccase 800U / g, pectin residue reduced to 1.9%, fiber surface smoothness increased by 30%;

[0087] Example 3 (High-activity enzyme combination): Pectinase 5000U / g + Xylanase 3000U / g + Laccase 1000U / g, pectin residue reduced to 1.5%, fiber surface smoothness increased by 35%.

[0088] V. Post-treatment and fiber properties;

[0089] The post-processing steps are as follows:

[0090] High-temperature boiling: Boil the bio-enzyme-treated fiber at 100℃ for 20-25 minutes;

[0091] Wash with water: Rinse with neutral water until pH 7.0-7.5 to remove residual chemicals;

[0092] Drying: Dry with hot air at 80℃ until the moisture content is below 8%.

[0093] Fiber performance indicators: Breaking strength: increased by 20%-25%, reaching 6.5-7.0 cN / dtex; Wetting properties: water droplet contact angle ≤30° (water droplet contact angle of traditional process fibers ≥50°); Whiteness: CIE value ≥80 (under unbleached conditions).

[0094] VI. Verification of experimental data;

[0095] To systematically verify the superiority of this technical solution (formula and ratio), the following three sets of comparative experiments were designed. All experiments used the same batch and specifications of ramie raw materials as raw materials. The control group adopted the traditional high-temperature alkaline boiling degumming process (high alkali concentration, no acid pretreatment and biological enzyme treatment), while the experimental group adopted the complete process described in this invention (acid soaking pretreatment + dynamic alkaline boiling + biological enzyme-assisted treatment).

[0096] 1. Test Conditions

[0097] Untreated raw hemp standard: breaking strength = 2.2 N / tex

[0098] Control group process:

[0099] Alkali boiling: 6% NaOH, liquid ratio 1:15, 100℃, 120min.

[0100] No acid pretreatment, no biological enzyme treatment, and subsequent washing and drying steps are the same as in this invention.

[0101] Experimental group process (this invention):

[0102] Strictly follow the formulas and process parameters described in Parts Two, Three, Four, and Five of this instruction manual.

[0103] Acid leaching pretreatment: 3% H2SO4 + 1% malonic acid + 0.5% oxalic acid + 0.3% sodium dodecylbenzenesulfonate, 85℃, 30min.

[0104] Dynamic alkaline boiling: 4% NaOH + 3% trisodium phosphate + 1.5% hydrogen peroxide + 0.5% EDTA + 2.5% sodium silicate, 100℃, 0.18MPa, 90min.

[0105] Bioenzyme treatment: pectinase (3000U / g) + xylanase (2000U / g) + laccase (800U / g), 50℃, pH=7.5, 60min.

[0106] 2. Data from three comparative experiments (as shown in the table below):

[0107]

[0108] 3. Conclusion and Analysis: The data from the three repeated comparative experiments above show that, compared with traditional degumming processes, the integrated technical solution of "multi-component acid leaching pretreatment - dynamic alkali boiling of a composite alkali system - bio-enzyme-assisted treatment" adopted in this invention has significant advantages:

[0109] Significantly enhanced fiber quality: The fiber breaking strength increased by an average of 36.4% after treatment by the process of this invention (compared to the baseline value of 2.2 N / tex for untreated raw hemp), significantly higher than the "20%-25%" increase claimed in the instructions, and far superior to the traditional process (average increase of only 9.1%). This fully demonstrates the protective effect of buffers, chelating agents, and enzyme treatment on cellulose, effectively avoiding the damage to fibers caused by traditional strong alkali and high temperature processes.

[0110] Improved economic benefits: Degumming costs have decreased by an average of about 30% (from 5,000 yuan / ton to 3,500 yuan / ton), mainly due to reduced chemical usage, shorter reaction time, and lower energy consumption.

[0111] Increased production efficiency: The total degumming time is reduced by an average of about 40%, which is due to the preliminary degradation of the gum by acid pretreatment and the synergistic effect of multiple components, which creates favorable conditions for subsequent alkaline boiling and greatly improves degumming efficiency.

[0112] Excellent degumming effect: The residual gum rate is significantly reduced (from an average of 15% to below 6%), proving that this formula removes ramie gums (such as pectin, hemicellulose, and lignin) more thoroughly.

[0113] Enhanced fiber quality: The average fiber strength is increased by about 20%, thanks to the protective effect of buffers, chelating agents and enzyme treatment on cellulose, avoiding the damage to the fiber caused by traditional strong alkali and high temperature processes.

[0114] The environmental advantages are significant: the average cost of wastewater treatment has decreased by about 40%. Due to the adoption of a mild composite chemical system and biological enzyme treatment, the generation of highly alkaline and high COD wastewater has been reduced, thus lowering the difficulty and cost of end-of-pipe treatment.

[0115] In summary, the experimental data fully verify the comprehensive superiority of the technical solution of this invention in terms of technological advancement, economy, and environmental protection.

[0116] 2. Verification by orthogonal experiment:

[0117] A four-factor (A, B, C, D) three-level orthogonal experimental design was adopted (A is the acid leaching concentration, corresponding to 1%, 3%, and 5% H2SO4; B is the alkaline boiling concentration, corresponding to 2%, 4%, and 6% NaOH; C is the amount of biological enzyme; and D is the treatment temperature).

[0118] Factor C: Water content for bio-enzymes;

[0119] Level 1: Low dosage (pectinase 2000U / g + xylanase 1000U / g + laccase 500U / g);

[0120] Level 2: Medium dosage (pectinase 3000U / g + xylanase 2000U / g + laccase 800U / g, commonly used level in the examples);

[0121] Level 3: High dosage (pectinase 5000U / g + xylanase 3000U / g + laccase 1000U / g).

[0122] Factor D: Critical processing temperature;

[0123] Level 1: Acid leaching at 80℃ + enzyme treatment at 45℃ (low temperature combination);

[0124] Level 2: Acid leaching at 85°C + enzyme treatment at 50°C (standard temperature combination, consistent with the example);

[0125] Level 3: Acid leaching at 90℃ + enzyme treatment at 55℃ (high temperature combination).

[0126] The results are shown in the table below:

[0127]

[0128]

[0129] Experimental results show that, within the parameter range claimed in this invention (A: 1%-5% H2SO4; B: 2%-6% NaOH; C: low-high enzyme dosage; D: relevant temperature combinations), this process can effectively reduce residual glue rate (as low as 2.5%), improve fiber strength (up to 7.5 cN / dtex) and whiteness (up to 88 CIE), while maintaining reasonable energy consumption control. Among them, Experiment No. 5 (A2B2C3D1) and Experiment No. 9 (A3B3C2D1) show particularly excellent overall results.

[0130] Those skilled in the art can adjust parameters such as acid soaking concentration (1%-5% H2SO4), alkali boiling concentration (2%-6% NaOH), and treatment time according to the actual conditions of the raw ramie. The adjusted solution still falls within the protection scope of this invention.

[0131] The above description is only a specific embodiment of the present invention. Any modifications, equivalent substitutions and improvements made within the principles and technical scope of the present invention should be included within the protection scope of the present invention.

[0132] It should be noted that, in this invention, although the specification describes the embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A green degumming method for ramie using acid-base synergistic bio-enzyme assistance, characterized in that, Includes the following steps: (1) Raw material preparation: Select ramie raw fibers with a moisture content of ≤12%, cut them to a length of 30-50cm, and mechanically loosen them to achieve a fiber separation degree of more than 85%; (2) Acid leaching pretreatment: The raw ramie treated in step (1) is placed in an H2SO4 solution with a mass percentage of 1%-5%, wherein a surfactant is added to the H2SO4 solution, namely sodium dodecyl sulfonate or sodium dodecylbenzene sulfonate, and the surfactant has a mass percentage of 0.1%-0.5% in the H2SO4 solution for acid leaching treatment; The process parameters for acid leaching are as follows: the ratio of raw ramie to H2SO4 solution is 1:15, the treatment temperature is 85±2℃, and the treatment time is 30-45 min. (3) Alkali boiling treatment: After washing the ramie fibers after acid soaking in step (2), place them in a NaOH solution with a mass percentage of 2%-6%, wherein the NaOH solution contains sodium silicate with a mass percentage of 2%-3% and hydrogen peroxide with a mass percentage of 1%-3% for alkaline boiling treatment; The process parameters for alkali boiling treatment are as follows: the ratio of ramie fiber to NaOH solution is 1:20, the treatment temperature is 100±2℃, the treatment time is 90-125min, and high-pressure steam is used during the alkali boiling process, with a pressure of 0.15MPa-0.20MPa. After the alkali boiling treatment in step (3), the ramie fibers are first boiled at 100℃ for 20-25 minutes, and then washed with water until the pH value is 7.0-7.5; (4) Bio-enzyme-assisted treatment: After washing the ramie fiber treated in step (3), place it in an enzyme treatment solution containing pectinase and xylanase for bio-enzyme treatment; (5) Post-treatment: The ramie fibers treated with bio-enzymes in step (4) are washed with water until neutral, and then dried until the moisture content is ≤8% to complete the degumming; In step (2), malonic acid and / or oxalic acid are also added to the H2SO4 solution, wherein the mass percentage of malonic acid is 1%-3% and the mass percentage of oxalic acid is 0.5%-2%; In step (3), trisodium phosphate and / or EDTA are also added to the NaOH solution, wherein the mass percentage of trisodium phosphate is 2%-5% and the mass percentage of EDTA is 0.2%-1%. In step (4), laccase is also added to the enzyme treatment solution; The pectinase activity is 2000-5000 U / g, the xylanase activity is 1000-3000 U / g, and the laccase activity is 500-1000 U / g. The process parameters for bio-enzyme treatment are as follows: pH value of enzyme treatment solution is 6-8, treatment temperature is 50±2℃, treatment time is 60min, and treatment method is static soaking.

2. The acid-base synergistic bio-enzyme-assisted green degumming method for ramie according to claim 1, characterized in that, In step (2), the acid leaching treatment is carried out by mechanical stirring at a speed of 30-60 rpm, and the stirring method is intermittent stirring or continuous stirring. When intermittent stirring, stirring is carried out for 1 minute every 5 minutes.

3. The acid-base synergistic bio-enzyme-assisted green degumming method for ramie according to claim 1, characterized in that, In step (3), the alkali boiling treatment is performed by continuous mechanical stirring at a speed of 60-80 rpm.

4. The acid-base synergistic bio-enzyme-assisted green degumming method for ramie according to claim 1, characterized in that, After acid soaking in step (2), the ramie fibers are washed with water until the pH value is 6.5-7.0.

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