Chemical and biological enzyme combined degumming method for apocynum venetum fibers

Abstract

The invention provides a chemical and biological enzyme combined degumming method for apocynum venetum fibers, which comprises the following steps: adding apocynum venetum treated by organic acid into an immobilized enzyme gel treatment solution, and finally adding the apocynum venetum into an oxidant treatment solution to obtain the apocynum venetum fibers. The immobilized enzyme gel treatment liquid can be recycled, the weight loss rate of the prepared apocynum venetum fiber is about 50%, the residual gum rate is about 3%, the whiteness is about 80%, the degumming effect is guaranteed, meanwhile, the concentration of the used alkali liquor is reduced, and the problems that a traditional chemical degumming method is large in alkali consumption and serious in environmental pollution are solved.

Description

Technical Field

[0001] The invention relates to the technical field of degumming methods, in particular to a degumming method for apocynum venetum. Background Art

[0002] The global demand for natural fibers is increasing every year. As a natural fiber, hemp has been used in the textile, food, cosmetics and medical industries. Apocynum ramie is a wild plant that grows in northwest China. It has the softness of cotton, the luster of silk and the stiffness of hemp. It has a wide range of applications in the textile industry due to its good mechanical properties, moisture absorption and air permeability, and antibacterial properties. However, in addition to cellulose, the components of apocynum ramie fiber also include associated substances such as fat wax, pectin, lignin, hemicellulose and water-soluble substances, which are collectively referred to as colloids. However, the colloid components attached to the surface of apocynum ramie fiber seriously affect its spinnability and subsequent processing performance. In order to meet the spinning requirements, the raw apocynum ramie must be degummed to remove all or part of the colloid around the fiber, so that the fiber can be separated and loosened to produce spinnable fibers. However, there is a key technical problem in the extraction process of apocynum ramie fiber, that is, how to effectively remove the colloid substances on the fiber surface. At present, the degumming methods of apocynum ramie mainly include three categories: chemical degumming, physical degumming and biological degumming. Although the traditional chemical degumming method can achieve a certain degumming effect, it is often accompanied by serious environmental pollution problems and may damage the fiber and reduce its quality; physical degumming has problems such as high energy consumption and high cost; although biological degumming is environmentally friendly, it has relatively low degumming efficiency, long reaction time and is sensitive to various physical or chemical factors (such as strong acid, strong alkali, high heat, organic solvents, etc.), which restricts its wide application. Therefore, it is necessary to develop a new degumming method that can both improve degumming efficiency and reduce environmental pollution. Summary of the invention

[0003] Technical problem to be solved: The purpose of the present invention is to overcome the problems existing in traditional physical methods, chemical degumming and biological degumming technologies, and to provide a chemical-biological-enzyme combined degumming method for apocynum fiber with high degumming efficiency, good whiteness and environmental protection.

[0004] Technical solution: A method for degumming apocynum fiber by chemical and biological enzymes, characterized in that it comprises the following steps: S1. Soaking the apocynum venetum in an organic composite acid pretreatment solution and washing to obtain pretreated apocynum venetum; S2. adding the pretreated apocynum venetum in S1 to the immobilized enzyme gel treatment solution, heating the reaction and washing to obtain the apocynum venetum treated with the immobilized enzyme gel; S3. Add the apocynum venetum treated with the immobilized enzyme gel in S2 into the oxidant treatment solution, heat for reaction, wash, dehydrate and dry to obtain apocynum venetum fiber. Preferably, the organic composite acid pretreatment liquid in S1 is composed of a maleic acid solution with a concentration of 0.3-0.6 g / L, a fumaric acid solution with a concentration of 0.3-0.6 g / L and a peroxyformic acid solution with a concentration of 0.3-0.6 g / L, the volume ratio of the maleic acid solution, the fumaric acid solution and the peroxyformic acid solution is 1-2:1-4:2-5, the bath ratio of Apocynum venetum to the organic composite acid pretreatment liquid is 1-30:1-50, the pretreatment temperature is 50-90°C, and the time is 1-1.5 h. Preferably, the components of the immobilized enzyme gel treatment solution in S2 are sodium hydroxide solution with a concentration of 0.2-0.5 g / L, sodium sulfite solution with a concentration of 0.3-0.6 g / L, sodium silicate solution with a concentration of 0.2-0.8 g / L, surfactant solution with a concentration of 0.5-1 g / L and immobilized enzyme gel with a mass fraction of 20-45 wt% of the immobilized enzyme gel treatment solution, the surfactant is one or more of fatty alcohol polyoxyethylene ether solution, alkylphenol polyoxyethylene ether solution, penetrant JFC solution, fatty acid methyl ester sulfonate solution, the reaction time is 1-2 h, the reaction temperature is 50-80° C., and the bath ratio of Apocynum venetum to immobilized enzyme gel treatment solution is 1:30-50. Preferably, the components of the oxidant treatment liquid in S3 are ferric chloride and 1,4-butanediol, the mass ratio of the two is 1-4:80-120, the reaction time is 0.5-1h, the reaction temperature is 90-120°C, and the bath ratio of Apocynum venetum to the immobilized enzyme gel treatment liquid is 1:30-50. Preferably, the preparation of the immobilized enzyme gel comprises the following steps: S1-1. The sodium alginate / aqueous solution and the carboxymethyl cellulose / aqueous solution are mixed to obtain a homogeneous solution A; S1-2. A pectin lyase solution having a mass fraction of 2 to 10 wt% was added to the homogenous solution A and stirred evenly, followed by addition of the hollow covalent organic framework @ branched hollow silica microspheres, and a homogenous suspension was obtained after ultrasound; S1-3. Add the suspension obtained in S1-2 dropwise into a 3-6 wt% calcium chloride solution and harden at 2-4°C to obtain an immobilized enzyme gel. Preferably, the mass ratio of the sodium alginate, carboxymethyl cellulose and hollow covalent organic framework@branched hollow silica microspheres is 1.5-3:1-2:2-3, and the volume ratio of the homogenized solution A to the pectin lyase solution is 10-15:1-2. Preferably, the preparation of the hollow covalent organic framework@branched hollow silica microspheres comprises the following steps: S2-1. Polyparaxylene and cyclopentyl methyl ether in a volume ratio of 5 to 9: 1 to 4 are added to 1,3,5-triamino-2,4,6-trinitrobenzene and 2,5-dihydroxyterephthalic acid in a mass ratio of 4 to 8: 3 to 5, and then propionic acid is added for ultrasonic treatment and degassing; S2-2. The product obtained in S1-1 was heated at 100 to 180°C for 65 to 75h and centrifuged, and then vacuum dried to obtain a hollow covalent organic framework; S2-3. Methyl orthosilicate is added to a mixed solution of cyclohexane and butanol in a volume ratio of 20 to 40: 1 to 15, and after stirring, a homogeneous solution B having a mass fraction of methyl orthosilicate of 5 to 20 wt% is obtained; S2-4 benzethonium chloride is added to the mass fraction of urea / water solution, and after stirring to obtain a homogeneous solution C having a mass fraction of 7 to 25wt% of benzethonium chloride; S2-5. The homogeneous solution B and the homogeneous solution C are mixed in a volume ratio of 1 to 3: 2 to 7 and heated at 100 to 150 ° C for 3 to 5 hours. The resulting product is washed and dried, and calcined at 500 to 650 ° C for 3 hours to obtain dendritic hollow silica microspheres; S2-6. The branched hollow silica microspheres obtained in S2-5 are deposited onto the hollow covalent organic framework obtained in S2-2 to obtain a hollow covalent organic framework@branched hollow silica microspheres. Preferably, the mass ratio of the branched hollow silica microspheres to the hollow covalent organic framework in S2-6 is 1 to 4: 1 to 7. Preferably, the first purpose of the present invention is to explore a method for preparing apocynum fiber by physical, chemical-biological enzymatic methods based on the chemical-biological enzyme method of the present invention, the difference being that the pretreatment method in S1 is adjusted to physical pretreatment, including ultrasound, microwave, light wave, steam explosion and other technologies. Preferably, the second object of the present invention is the apocynum venetum fiber prepared by the method of the present invention. Preferably, the third object of the present invention is to use the apocynum ramie fiber prepared by the method of the present invention in spinning and weaving. Beneficial effects: The chemical and biological enzyme combined degumming method of apocynum ramie fiber provided by the present invention has the following advantages: 1. In the present invention, the organic acid composite liquid is used to pretreat the apocynum venetum, and the maleic acid solution, the fumaric acid solution and the peroxyformic acid solution can promote the removal of impurities and open the channels of the surface pores, which is beneficial to the subsequent enzyme degumming process; 2. The hollow covalent organic framework in the immobilized enzyme gel of the present invention effectively improves the activity and stability of the enzyme by providing more active sites, improving mass transfer efficiency, protecting enzyme molecules, and providing a suitable microenvironment. In addition, the adjustable pore size and pore structure of the dendritic hollow silica microspheres are conducive to the entry and fixation of enzyme molecules, and the dendritic structure has high mechanical stability and chemical inertness, which helps to maintain the activity and selectivity of the enzyme, thereby improving the reusability of the immobilized enzyme gel; 3. The oxidant treatment in the present invention not only improves the degumming effect of Apocynum venetum, but also increases the whiteness of Apocynum venetum. The weight loss rate of the prepared Apocynum venetum is about 50%, the residual glue rate is about 3%, and the whiteness is about 80%. DETAILED DESCRIPTION The present invention will be further described below in conjunction with embodiments, which are explanations of the present invention and are not limited to the following embodiments: Example 1 A method for degumming apocynum fiber by chemical and biological enzymes, characterized in that it comprises the following steps: S1. Take apocynum venetum and soak it in an organic composite acid pretreatment solution, the components are 0.3 g / L maleic acid solution, 0.3 g / L fumaric acid solution and 0.3 g / L peroxy formic acid solution, the volume ratio of maleic acid solution, fumaric acid solution and peroxy formic acid solution is 1:1:2, the bath ratio of apocynum venetum to the organic composite acid pretreatment solution is 1:30, heated at 50°C for 1h and washed to obtain pretreated apocynum venetum; S2. Add the apocynum venetum pretreated in S1 to an immobilized enzyme gel treatment solution, the components of which are a sodium hydroxide solution with a concentration of 0.2 g / L, a sodium sulfite solution with a concentration of 0.3 g / L, a sodium silicate solution with a concentration of 0.2 g / L, a surfactant solution with a concentration of 0.5 g / L, and an immobilized enzyme gel with a mass fraction of 20 wt % of the immobilized enzyme gel treatment solution, the surfactants are a fatty alcohol polyoxyethylene ether solution and an alkylphenol polyoxyethylene ether solution, the bath ratio of the apocynum venetum to the immobilized enzyme gel treatment solution is 1:30, react at 50°C for 1 hour, and then wash to obtain the apocynum venetum treated with the immobilized enzyme gel; S3. adding the apocynum venetum treated with the immobilized enzyme gel in S2 to an oxidant treatment solution (components are ferric chloride and 1,4-butanediol, the mass ratio of the two is 1:80), the bath ratio of apocynum venetum to the immobilized enzyme gel treatment solution is 1:30, reacting at 90°C for 0.5h, then washing, dehydrating and drying to obtain apocynum venetum fiber; Wherein, the preparation of the immobilized enzyme gel comprises the following steps: S1-1. Sodium alginate and carboxymethyl cellulose were prepared in a mass ratio of 1.5:1, and then mixed to obtain a homogeneous solution A; S1-2. A 2 wt% pectin lyase solution was added to the homogenized solution obtained in S1-1, the volume ratio of the homogenized solution A to the pectin lyase solution was 10:1, and then hollow covalent organic framework @ branched hollow silica microspheres were added, the mass ratio of the hollow covalent organic framework @ branched hollow silica microspheres to sodium alginate and carboxymethyl cellulose was 2:1:1.5, and a suspension was obtained after ultrasonic treatment; S1-3. The suspension obtained in S1-2 was added dropwise to a 3 wt% calcium chloride solution and hardened at 2°C to obtain an immobilized enzyme gel; The preparation of the hollow covalent organic framework@branched hollow silica microspheres comprises the following steps: S2-1. Polyparaxylene and cyclopentyl methyl ether in a volume ratio of 5:1 were added to 1,3,5-triamino-2,4,6-trinitrobenzene and 2,5-dihydroxyterephthalic acid in a mass ratio of 4:3, and then propionic acid was added for ultrasonic treatment and degassing; S2-2. The product obtained in S1-1 was heated at 100°C for 65h and centrifuged, and then vacuum dried to obtain a hollow covalent organic framework; S2-3. Methyl orthosilicate was added to a mixed solution of cyclohexane and butanol in a volume ratio of 20:1, and after stirring, a homogeneous solution B with a mass fraction of methyl orthosilicate of 5wt% was obtained; S2-4 benzethonium chloride was added to the mass fraction of urea / water solution, and after stirring to obtain a homogeneous solution C having a mass fraction of 7wt% benzethonium chloride; S2-5. The homogeneous solution B and the homogeneous solution C were mixed in a volume ratio of 1:2, heated at 100 ° C for 3 h, and the resulting product was washed and dried, and calcined at 500 ° C for 3 h to obtain dendritic hollow silica microspheres; S2-6. The branched hollow silica microspheres obtained in S2-5 were immersed and deposited (10 min) onto the hollow covalent organic framework obtained in S2-2, wherein the mass ratio of the branched hollow silica microspheres to the hollow covalent organic framework was 1:1, to obtain a hollow covalent organic framework @ branched hollow silica microspheres. Example 2 A method for degumming apocynum fiber by chemical and biological enzymes, characterized in that it comprises the following steps: S1. Take apocynum venetum and soak it in an organic composite acid pretreatment solution, the components are 0.6 g / L maleic acid solution, 0.6 g / L fumaric acid solution and 0.6 g / L peroxy formic acid solution, the volume ratio of maleic acid solution, fumaric acid solution and peroxy formic acid solution is 2:4:5, the bath ratio of apocynum venetum to the organic composite acid pretreatment solution is 1:50, heat at 90°C for 1.5h and wash to obtain pretreated apocynum venetum; S2. Add the apocynum venetum pretreated in S1 to an immobilized enzyme gel treatment solution, the components of which are a sodium hydroxide solution with a concentration of 0.5 g / L, a sodium sulfite solution with a concentration of 0.6 g / L, a sodium silicate solution with a concentration of 0.8 g / L, a surfactant solution with a concentration of 1 g / L, and an immobilized enzyme gel with a mass fraction of 45 wt% of the immobilized enzyme gel treatment solution, the surfactant is a fatty alcohol polyoxyethylene ether solution and a fatty acid methyl ester sulfonate, the bath ratio of apocynum venetum to the immobilized enzyme gel treatment solution is 1:50, react at 80°C for 2 hours, and then wash to obtain apocynum venetum treated with the immobilized enzyme gel; S3. adding the apocynum venetum treated with the immobilized enzyme gel in S2 to an oxidant treatment solution (components are ferric chloride and 1,4-butanediol, the mass ratio of the two is 4:120), the bath ratio of apocynum venetum to the immobilized enzyme gel treatment solution is 1:50, reacting at 120°C for 1h, then washing, dehydrating and drying to obtain apocynum venetum fiber; Wherein, the preparation of the immobilized enzyme gel comprises the following steps: S1-1. Sodium alginate and carboxymethyl cellulose are prepared in a mass ratio of 3:2, and then mixed to obtain a homogeneous solution A; S1-2. A pectin lyase solution with a mass fraction of 2wt% is added to the homogeneous solution obtained in S1-1, and the volume ratio of the homogeneous solution A to the pectin lyase solution is 10:1, and then hollow covalent organic framework @ branched hollow silica microspheres are added, and the mass ratio of the hollow covalent organic framework @ branched hollow silica microspheres to sodium alginate and carboxymethyl cellulose is 3:2:3, and a suspension is obtained after ultrasonic treatment; S1-3. The suspension obtained in S1-2 was added dropwise to a 6 wt % calcium chloride solution and hardened at 4°C to obtain an immobilized enzyme gel; The preparation of the hollow covalent organic framework@branched hollow silica microspheres comprises the following steps: S2-1. Polyparaxylene and cyclopentyl methyl ether in a volume ratio of 9:4 were added to 1,3,5-triamino-2,4,6-trinitrobenzene and 2,5-dihydroxyterephthalic acid in a mass ratio of 8:5, and then propionic acid was added for ultrasonic treatment and degassing; S2-2. The product obtained in S1-1 was heated at 180°C for 75h and centrifuged, and then vacuum dried to obtain a hollow covalent organic framework; S2-3. Methyl orthosilicate was added to a mixed solution of cyclohexane and butanol in a volume ratio of 40:15, and after stirring, a homogeneous solution B with a mass fraction of methyl orthosilicate of 20wt% was obtained; S2-4 benzethonium chloride was added to the mass fraction of urea / water solution, and after stirring to obtain a homogeneous solution C having a mass fraction of 25wt% benzethonium chloride; S2-5. The homogeneous solution B and the homogeneous solution C were mixed in a volume ratio of 1:2, heated at 100 ° C for 3 h, and the resulting product was washed and dried, and calcined at 650 ° C for 3 h to obtain dendritic hollow silica microspheres; S2-6. The branched hollow silica microspheres obtained in S2-5 were immersed and deposited (60 min) onto the hollow covalent organic framework obtained in S2-2, wherein the mass ratio of the branched hollow silica microspheres to the hollow covalent organic framework was 4:7, to obtain a hollow covalent organic framework @ branched hollow silica microspheres. Example 3 A method for degumming apocynum fiber by chemical and biological enzymes, characterized in that it comprises the following steps: S1. Take apocynum venetum and soak it in an organic composite acid pretreatment solution, the components are 0.4 g / L maleic acid solution, 0.3 g / L fumaric acid solution and 0.5 g / L peroxy formic acid solution, the volume ratio of maleic acid solution, fumaric acid solution and peroxy formic acid solution is 2: 1: 2, the bath ratio of apocynum venetum to the organic composite acid pretreatment solution is 1: 30, 50 ° C heating for 1h and washing, to obtain pretreated apocynum venetum; S2. Add the apocynum venetum pretreated in S1 to an immobilized enzyme gel treatment solution, the components of which are a sodium hydroxide solution with a concentration of 0.2 g / L, a sodium sulfite solution with a concentration of 0.3 g / L, a sodium silicate solution with a concentration of 0.2 g / L, a surfactant solution with a concentration of 0.5 g / L, and an immobilized enzyme gel with a mass fraction of 30 wt % of the immobilized enzyme gel treatment solution, the surfactants are a fatty alcohol polyoxyethylene ether solution and an alkylphenol polyoxyethylene ether solution, the bath ratio of apocynum venetum to the immobilized enzyme gel treatment solution is 1:35, react at 50°C for 1 hour, and then wash to obtain apocynum venetum treated with the immobilized enzyme gel; S3. adding the apocynum venetum treated with the immobilized enzyme gel in S2 to an oxidant treatment solution, the components of which are ferric chloride and 1,4-butanediol, the mass ratio of which is 2:95, the bath ratio of the apocynum venetum to the immobilized enzyme gel treatment solution is 1:45, reacting at 90°C for 0.5h, then washing, dehydrating and drying to obtain apocynum venetum fiber; Wherein, the preparation of the immobilized enzyme gel comprises the following steps: S1-1. Sodium alginate and carboxymethyl cellulose were prepared in a mass ratio of 1.5:1, and then mixed to obtain a homogeneous solution A; S1-2. A 2 wt% pectin lyase solution was added to the homogenized solution obtained in S1-1, the volume ratio of the homogenized solution A to the pectin lyase solution was 10:1, and then hollow covalent organic framework @ branched hollow silica microspheres were added, the mass ratio of the hollow covalent organic framework @ branched hollow silica microspheres to sodium alginate and carboxymethyl cellulose was 2:1:1.5, and a suspension was obtained after ultrasonic treatment; S1-3. The suspension obtained in S1-2 was added dropwise to a 3 wt % calcium chloride solution and hardened at 3°C ​​to obtain an immobilized enzyme gel; The preparation of the hollow covalent organic framework@branched hollow silica microspheres comprises the following steps: S2-1. Polyparaxylene and cyclopentyl methyl ether in a volume ratio of 7:2 were added to 1,3,5-triamino-2,4,6-trinitrobenzene and 2,5-dihydroxyterephthalic acid in a mass ratio of 4:3, and then propionic acid was added for ultrasonic treatment and degassing; S2-2. The product obtained in S1-1 was heated at 100°C for 65h and centrifuged, and then vacuum dried to obtain a hollow covalent organic framework; S2-3. Methyl orthosilicate was added to a mixed solution of cyclohexane and butanol in a volume ratio of 20:1, and after stirring, a homogeneous solution B with a mass fraction of methyl orthosilicate of 5wt% was obtained; S2-4 benzethonium chloride was added to the mass fraction of urea / water solution, and after stirring to obtain a homogeneous solution C having a mass fraction of 7wt% benzethonium chloride; S2-5. The homogeneous solution B and the homogeneous solution C were mixed in a volume ratio of 1:2, heated at 100 ° C for 3 h, and the resulting product was washed and dried, and calcined at 560 ° C for 3 h to obtain dendritic hollow silica microspheres; S2-6. The branched hollow silica microspheres obtained in S2-5 were immersed and deposited (30 min) onto the hollow covalent organic framework obtained in S2-2, wherein the mass ratio of the branched hollow silica microspheres to the hollow covalent organic framework was 2:5, to obtain a hollow covalent organic framework @ branched hollow silica microspheres. Example 4 A method for degumming apocynum fiber by chemical and biological enzymes, characterized in that it comprises the following steps: S1. Take apocynum venetum and soak it in an organic composite acid pretreatment solution, the components are 0.3g / L maleic acid solution, 0.5g / L fumaric acid solution and 0.6g / L peroxyformic acid solution, the volume ratio of maleic acid solution, fumaric acid solution and peroxyformic acid solution is 2:4:3, the bath ratio of apocynum venetum to the organic composite acid pretreatment solution is 1:40, heat at 60°C for 1h and wash to obtain pretreated apocynum venetum; S2. Add the apocynum venetum pretreated in S1 to an immobilized enzyme gel treatment solution, the components of which are a sodium hydroxide solution with a concentration of 0.2 g / L, a sodium sulfite solution with a concentration of 0.4 g / L, a sodium silicate solution with a concentration of 0.2 g / L, a surfactant solution with a concentration of 0.5 g / L, and an immobilized enzyme gel with a mass fraction of 35 wt% of the immobilized enzyme gel treatment solution, the surfactants are a fatty alcohol polyoxyethylene ether solution and an alkylphenol polyoxyethylene ether solution, the bath ratio of apocynum venetum to the immobilized enzyme gel treatment solution is 1:43, react at 50°C for 1.3 h, and then wash to obtain apocynum venetum treated with the immobilized enzyme gel; S3. adding the apocynum venetum treated with the immobilized enzyme gel in S2 to an oxidant treatment solution, the components of which are ferric chloride and 1,4-butanediol, the mass ratio of which is 3:100, the bath ratio of the apocynum venetum to the immobilized enzyme gel treatment solution is 1:50, reacting at 90°C for 0.5h, then washing, dehydrating and drying to obtain apocynum venetum fiber; Wherein, the preparation of the immobilized enzyme gel comprises the following steps: S1-1. Sodium alginate and carboxymethyl cellulose are prepared in a mass ratio of 2:2, and then mixed to obtain a homogeneous solution A; S1-2. A pectin lyase solution with a mass fraction of 5wt% is added to the homogeneous solution obtained in S1-1, and the volume ratio of the homogeneous solution A to the pectin lyase solution is 13:2, and then hollow covalent organic framework @ branched hollow silica microspheres are added, and the mass ratio of the hollow covalent organic framework @ branched hollow silica microspheres to sodium alginate and carboxymethyl cellulose is 3:2:2, and a suspension is obtained after ultrasonic treatment; S1-3. The suspension obtained in S1-2 was added dropwise to a 3 wt% calcium chloride solution and hardened at 2°C to obtain an immobilized enzyme gel; The preparation of the hollow covalent organic framework@branched hollow silica microspheres comprises the following steps: S2-1. Polyparaxylene and cyclopentyl methyl ether in a volume ratio of 5:1 were added to 1,3,5-triamino-2,4,6-trinitrobenzene and 2,5-dihydroxyterephthalic acid in a mass ratio of 4:3, and then propionic acid was added for ultrasonic treatment and degassing; S2-2. The product obtained in S1-1 was heated at 100°C for 65h and centrifuged, and then vacuum dried to obtain a hollow covalent organic framework; S2-3. Methyl orthosilicate was added to a mixed solution of cyclohexane and butanol in a volume ratio of 20:1, and after stirring, a homogeneous solution B with a mass fraction of methyl orthosilicate of 5wt% was obtained; S2-4 benzethonium chloride was added to the mass fraction of urea / water solution, and after stirring to obtain a homogeneous solution C having a mass fraction of 7wt% benzethonium chloride; S2-5. The homogeneous solution B and the homogeneous solution C were mixed in a volume ratio of 1:2, heated at 100 ° C for 3 h, and the resulting product was washed and dried, and calcined at 540 ° C for 3 h to obtain dendritic hollow silica microspheres; S2-6. The branched hollow silica microspheres obtained in S2-5 were immersed and deposited (40 min) onto the hollow covalent organic framework obtained in S2-2, wherein the mass ratio of the branched hollow silica microspheres to the hollow covalent organic framework was 3:7, to obtain a hollow covalent organic framework @ branched hollow silica microspheres. Example 5 A method for degumming apocynum fiber by chemical and biological enzymes, characterized in that it comprises the following steps: S1. Take apocynum venetum and soak it in an organic composite acid pretreatment solution, the components are 0.6 g / L maleic acid solution, 0.3 g / L fumaric acid solution and 0.3 g / L peroxy formic acid solution, the volume ratio of maleic acid solution, fumaric acid solution and peroxy formic acid solution is 2:3:4, the bath ratio of apocynum venetum to the organic composite acid pretreatment solution is 1:50, heat at 60°C for 1.2h and wash to obtain pretreated apocynum venetum; S2. Add the apocynum venetum pretreated in S1 to an immobilized enzyme gel treatment solution (the components are a sodium hydroxide solution with a concentration of 0.2 g / L, a sodium sulfite solution with a concentration of 0.3 g / L, a sodium silicate solution with a concentration of 0.2 g / L, a surfactant solution with a concentration of 0.5 g / L, and an immobilized enzyme gel with a mass fraction of 20 wt% of the immobilized enzyme gel treatment solution, and the surfactant is a fatty alcohol polyoxyethylene ether solution and an alkylphenol polyoxyethylene ether solution), the bath ratio of the apocynum venetum to the immobilized enzyme gel treatment solution is 1 to 30, react at 50°C for 1 hour, and then wash to obtain the apocynum venetum treated with the immobilized enzyme gel; S3. adding the apocynum venetum treated with the immobilized enzyme gel in S2 to an oxidant treatment solution, the components of which are ferric chloride and 1,4-butanediol, the mass ratio of the two being 1:80, the bath ratio of the apocynum venetum to the immobilized enzyme gel treatment solution being 1:30, reacting at 90°C for 0.5h, then washing, dehydrating and drying to obtain apocynum venetum fiber; Wherein, the preparation of the immobilized enzyme gel comprises the following steps: S1-1. Sodium alginate and carboxymethyl cellulose were prepared in a mass ratio of 1.5:1, and then mixed to obtain a homogeneous solution A; S1-2. A 2 wt% pectin lyase solution was added to the homogenized solution obtained in S1-1, the volume ratio of the homogenized solution A to the pectin lyase solution was 10:1, and then hollow covalent organic framework @ branched hollow silica microspheres were added, the mass ratio of the hollow covalent organic framework @ branched hollow silica microspheres to sodium alginate and carboxymethyl cellulose was 3:2:3, and a suspension was obtained after ultrasonic treatment; S1-3. The suspension obtained in S1-2 was added dropwise to a 3 wt% calcium chloride solution and hardened at 2°C to obtain an immobilized enzyme gel; The preparation of the hollow covalent organic framework@branched hollow silica microspheres comprises the following steps: S2-1. Polyparaxylene and cyclopentyl methyl ether in a volume ratio of 5:1 were added to 1,3,5-triamino-2,4,6-trinitrobenzene and 2,5-dihydroxyterephthalic acid in a mass ratio of 4:3, and then propionic acid was added for ultrasonic treatment and degassing; S2-2. The product obtained in S1-1 was heated at 100°C for 65h and centrifuged, and then vacuum dried to obtain a hollow covalent organic framework; S2-3. Methyl orthosilicate was added to a mixed solution of cyclohexane and butanol in a volume ratio of 20:1, and after stirring, a homogeneous solution B with a mass fraction of methyl orthosilicate of 5wt% was obtained; S2-4 benzethonium chloride was added to the mass fraction of urea / water solution, and after stirring to obtain a homogeneous solution C having a mass fraction of 7wt% benzethonium chloride; S2-5. The homogeneous solution B and the homogeneous solution C were mixed in a volume ratio of 1:2, heated at 120°C for 3h, washed and dried, and calcined at 550°C for 3h to obtain dendritic hollow silica microspheres; S2-6. The branched hollow silica microspheres obtained in S2-5 were immersed and deposited (35 min) onto the hollow covalent organic framework obtained in S2-2, wherein the mass ratio of the branched hollow silica microspheres to the hollow covalent organic framework was 2:7, to obtain a hollow covalent organic framework @ branched hollow silica microspheres. Comparative Example 1 The difference between this comparative example and Example 5 is that sulfuric acid with a concentration of 0.4 g / L is used for pretreatment. Comparative Example 2 The difference between this comparative example and Example 5 is that the hollow covalent organic framework exists alone in the solidified enzyme gel without adding the branched hollow silica microspheres. Comparative Example 3 The difference between this comparative example and Example 5 is that the dendritic hollow silica microspheres exist alone in the solidified enzyme gel without adding the hollow covalent organic framework. Comparative Example 4 The difference between this comparative example and Example 5 is that the performance test is performed by using a solution containing 4 g / L hydrogen peroxide and 0.5 g / L sodium hydroxide. The degumming effect of the samples prepared in Examples 1-5 of the present invention and Comparative Examples 1-4 was tested below, and the results are shown in Table 1. Table 1 Degumming effect of different samples Weight loss rate (%) Residual glue rate (%) Whiteness(%) Example 1 52.65 5.53 75.83 Example 2 51.33 5.21 76.50 Example 3 51.15 4.65 71.83 Example 4 50.05 4.37 79.03 Example 5 49.70 3.22 80.21 Comparative Example 1 47.18 5.33 80.50 Comparative Example 2 45.13 6.68 77.43 Comparative Example 3 43.16 7.60 72.93 Comparative Example 4 44.88 7.88 74.27 Note: 1. Weight loss rate (%) = (dry weight of sample - dry weight of sample after degumming) / dry weight of sample × 100%. 2. Determination method of residual rubber rate: refer to GB / T 5889-1986 "Quantitative analysis method of chemical composition of ramie" to test the residual rubber rate of degummed ramie. Residual rubber rate (%) = (dry weight of sample - dry weight of sample after residual rubber extraction) / dry weight of sample × 100% 3. Whiteness test is carried out with reference to GB / T 5881-1986 "Test method for whiteness of ramie fiber". The residual glue rate of 6 batches of samples prepared using the same solidified enzyme gel treatment solution in Example 5 of the present invention was tested. The results are shown in Table 2. Table 2 Residual glue rate of solidified enzyme gel treatment solution after 5 cycles frequency Residual glue rate (%) 1 3.22 2 3.44 3 3.78 4 4.13 5 4.47 6 4.61 The mechanical properties of the samples prepared in Examples 1-5 of the present invention and Comparative Examples 1-4 were tested after degumming. The results are shown in Table 3. Table 3 Single fiber strength of different samples after degumming Single fiber strength (cN) Example 1 11.20 Example 2 11.96 Example 3 12.47 Example 4 13.26 Example 5 13.94 Comparative Example 1 10.23 Comparative Example 2 9.18 Comparative Example 3 8.23 Comparative Example 4 7.67 Note: For strength test, refer to GB5881-86 "Test method for breaking strength of single ramie fiber". Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for degumming apocynum fiber by chemical and biological enzymes, characterized in that: The following steps are involved: S1. Soaking the apocynum venetum in an organic composite acid pretreatment solution and washing to obtain pretreated apocynum venetum; S2. adding the pretreated apocynum venetum in S1 to the immobilized enzyme gel treatment solution, heating the reaction and washing to obtain the apocynum venetum treated with the immobilized enzyme gel; S3. Add the apocynum venetum treated with the immobilized enzyme gel in S2 into the oxidant treatment solution, heat for reaction, wash, dehydrate and dry to obtain apocynum venetum fiber.

2. The method for degumming apocynum fiber by chemical and biological enzymes according to claim 1, characterized in that: The organic composite acid pretreatment liquid in S1 is composed of 0.3-0.6 g / L maleic acid solution, 0.3-0.6 g / L fumaric acid solution and 0.3-0.6 g / L peroxyformic acid solution, the volume ratio of the maleic acid solution, the fumaric acid solution and the peroxyformic acid solution is 1-2:1-4:2-5, the bath ratio of Apocynum venetum to the organic composite acid pretreatment liquid is 1:30-50, the pretreatment temperature is 50-90°C, and the time is 1-1.5 h.

3. The method for degumming apocynum fiber by chemical and biological enzymes according to claim 1, characterized in that: The components of the immobilized enzyme gel treatment solution in S2 are sodium hydroxide solution with a concentration of 0.2-0.5 g / L, sodium sulfite solution with a concentration of 0.3-0.6 g / L, sodium silicate solution with a concentration of 0.2-0.8 g / L, surfactant solution with a concentration of 0.5-1 g / L and immobilized enzyme gel with a mass fraction of 20-45 wt% of the immobilized enzyme gel treatment solution, the surfactant is one or more of fatty alcohol polyoxyethylene ether solution, alkylphenol polyoxyethylene ether solution, penetrant JFC solution, fatty acid methyl ester sulfonate solution, the reaction time is 1-2 h, the reaction temperature is 50-80° C., and the bath ratio of Apocynum venetum to the immobilized enzyme gel treatment solution is 1:30-50.

4. The method for degumming apocynum fiber by chemical and biological enzymes according to claim 1, characterized in that: The components of the oxidant treatment liquid in S3 are ferric chloride and 1,4-butanediol, the mass ratio of the two is 1-4:80-120, the reaction time is 0.5-1h, the reaction temperature is 90-120°C, and the bath ratio of Apocynum venetum to the immobilized enzyme gel treatment liquid is 1:30-50.

5. The method for degumming apocynum fiber by chemical and biological enzymes according to claim 4, characterized in that: The preparation of the immobilized enzyme gel comprises the following steps: S1-1. The sodium alginate / aqueous solution and the carboxymethyl cellulose / aqueous solution are mixed to obtain a homogeneous solution A; S1-2. A pectin lyase solution having a mass fraction of 2 to 10 wt% was added to the homogenous solution A and stirred evenly, followed by addition of the hollow covalent organic framework @ branched hollow silica microspheres, and a suspension was obtained after ultrasound; S1-3. Add 3-6 wt% calcium chloride solution to the suspension obtained in S1-2, and harden at 2-4°C to obtain immobilized enzyme gel.

6. The method for degumming apocynum fiber by chemical and biological enzymes according to claim 5, characterized in that: The mass ratio of the sodium alginate, carboxymethyl cellulose and hollow covalent organic framework@branched hollow silica microspheres is 1.5-3:1-2:2-3, and the volume ratio of the homogenized solution A to the pectin lyase solution is 10-15:1-2.

7. The method for degumming apocynum fiber by chemical and biological enzymes according to claim 6, characterized in that: The preparation of the hollow covalent organic framework@branched hollow silica microspheres comprises the following steps: S2-1. Polyparaxylene and cyclopentyl methyl ether in a volume ratio of 5 to 9: 1 to 4 are added to 1,3,5-triamino-2,4,6-trinitrobenzene and 2,5-dihydroxyterephthalic acid in a mass ratio of 4 to 8: 3 to 5, and then propionic acid is added for ultrasonic treatment and degassing; S2-2. The product obtained in S1-1 was heated at 100 to 180°C for 65 to 75h and centrifuged, and then vacuum dried to obtain a hollow covalent organic framework; S2-3. Methyl orthosilicate is added to a mixed solution of cyclohexane and butanol in a volume ratio of 20 to 40: 1 to 15, and after stirring, a homogeneous solution B having a mass fraction of methyl orthosilicate of 5 to 20 wt% is obtained; S2-4 benzethonium chloride is added to the mass fraction of urea / water solution, and after stirring to obtain a homogeneous solution C having a mass fraction of 7 to 25wt% of benzethonium chloride; S2-5. The homogeneous solution B and the homogeneous solution C are mixed in a volume ratio of 1 to 3: 2 to 7 and heated at 100 to 150 ° C for 3 to 5 hours. The resulting product is washed and dried, and calcined at 500 to 650 ° C for 3 hours to obtain dendritic hollow silica microspheres; S2-6. The branched hollow silica microspheres obtained in S2-5 are deposited onto the hollow covalent organic framework obtained in S2-2 to obtain a hollow covalent organic framework@branched hollow silica microspheres.

8. The method for degumming apocynum fiber by chemical and biological enzymes according to claim 7, characterized in that: The mass ratio of the branched hollow silica microspheres to the hollow covalent organic framework in S2-6 is 1-4:1-7.