阅读说明：本技术 一种苎麻酶脱-氧漂联合脱胶工艺 (Ramie enzyme-de-oxygen bleaching combined degumming process ) 是由 张小祝 别晓东 杨继前 廖光辉 王惠 于 2020-04-08 设计创作，主要内容包括：本发明公开了一种苎麻酶脱-氧漂联合脱胶工艺,包括如下步骤：S1斩切原麻根部韧皮,将原麻放入第一浸泡液中浸泡,浸泡后放入软麻机中机械处理；S2将S1中软麻后的原麻加至酸性酶制剂溶液中浸泡；S3将S2中酸性酶制剂浸泡后的原麻第一次水洗,第一次水洗后加入第二浸泡液中浸漂,所述第二浸泡液呈碱性,浸漂后进行第二次水洗；S4将S3中第二次水洗后的原麻烘干处理,得到精干麻；所述S2中,按原麻的重量百分比计,酶制剂包括1.5％～3.0％的复合酶和0.2％～1.0％的脱胶助剂。所述S3中,第二浸泡液包括双氧水。本发明通过酶脱-氧漂联合处理苎麻,脱胶效果好、工艺简单、成本低,碱剂的用量少,提高原麻的白度。(The invention discloses a ramie enzyme-removal-oxygen bleaching combined degumming process, which comprises the following steps: s1 chopping bast of original hemp, soaking the original hemp in the first soaking solution, and then mechanically processing the soaked original hemp in a hemp softening machine; s2, adding the raw ramie softened in the S1 into the acid enzyme preparation solution for soaking; s3, washing the original hemp soaked in the acid enzyme preparation in the S2 for the first time, adding the washed original hemp into a second soaking solution for rinsing after the first water washing, wherein the second soaking solution is alkaline, and washing the original hemp for the second time after rinsing; s4, drying the washed raw ramie in S3 for the second time to obtain refined dry ramie; in the S2, the enzyme preparation comprises 1.5-3.0% of complex enzyme and 0.2-1.0% of degumming auxiliary agent according to the weight percentage of the raw ramie. In the step S3, the second soaking solution includes hydrogen peroxide. The invention treats ramie by enzyme dehydration-oxygen bleaching combination, has good degumming effect, simple process, low cost and small dosage of alkaline agent, and improves the whiteness of the original ramie.)

1. A ramie enzyme-removal-oxygen bleaching combined degumming process is characterized by comprising the following steps:

s1 chopping bast of original hemp, soaking the original hemp in the first soaking solution, and then mechanically processing the soaked original hemp in a hemp softening machine;

s2, adding the raw ramie softened in the S1 into the acid enzyme preparation solution for soaking;

s3, washing the original hemp soaked by the acid enzyme preparation in the S2 for the first time, adding the washed original hemp into a second soaking solution for rinsing, wherein the second soaking solution is alkaline, and washing for the second time after rinsing;

s4, drying the washed raw ramie in S3 for the second time to obtain refined dry ramie;

in the S2, the acid enzyme preparation comprises 1.5-3.0% of complex enzyme and 0.2-1.0% of degumming auxiliary agent according to the weight percentage of the raw ramie;

in the step S3, the second soaking solution includes hydrogen peroxide.

2. The ramie enzyme-removal-oxygen bleaching combined degumming process according to claim 1, wherein the second soaking solution further comprises a protection auxiliary agent, the protection auxiliary agent is anthraquinone, danthron or layered crystal sodium disilicate, and the addition amount of the protection auxiliary agent is 1-3% by mass of the raw ramie.

3. The ramie enzyme-de-oxygen bleaching combined degumming process according to claim 1, wherein the weight ratio of the components of the enzyme preparation is, acid pectinase: acid ligninase: the acid hemicellulase is 1-4: 1: 2-3.

4. The ramie enzyme-de-oxygen bleaching combined degumming process according to claim 3, wherein the acid pectinase is immobilized.

5. The ramie enzyme-removal-oxygen bleaching combined degumming process according to claim 4, wherein the immobilization treatment is carried out by an embedding method, wherein the embedding method comprises acid pectinase as a core material, chitosan as a wall material and calcium chloride as a stabilizer.

6. The ramie enzyme-de-oxygen bleaching combined degumming process according to claim 1 or 2, wherein the acid enzyme preparation further comprises 0.5-1.0% polygalacturonase, based on the weight percentage of the raw ramie.

7. The ramie enzyme-de-oxygen bleaching combined degumming process according to claim 1 or 2, wherein the degumming auxiliary comprises at least one of 2-hydroxypropionic acid, sodium tripolyphosphate, sodium metasilicate and 4A zeolite.

8. The ramie enzyme-removal-oxygen bleaching combined degumming process according to claim 1 or 2, wherein a slow-release alkaline agent is added to the second soaking solution in the step S3, the slow-release alkaline agent is magnesium hydroxide or magnesium oxide, and the addition amount of the slow-release alkaline agent is 3-5% by mass of the raw ramie.

9. The ramie enzyme-de-oxidation-bleaching combined degumming process according to claim 1, wherein the first soaking solution comprises 15-20% ethanol; in the step S1, the material-liquid ratio is 1: 10-15, the soaking temperature is 50-70 ℃, and the soaking time is 10-20 min.

Technical Field

The invention belongs to the technical field of ramie degumming, and particularly relates to a ramie enzyme-degumming-oxygen bleaching combined degumming process.

Background

Chemical degumming and biological degumming are commonly used in the degumming process of ramie. The chemical degumming is realized by pickling, boiling with alkali liquor and bleaching with chlorine. However, the pickling process is strictly required, and if the pickling process is improperly controlled, the mechanical strength of the original fibrilia is affected, and the acid liquor has strong corrosivity to equipment; the water consumption and the energy consumption of high-temperature boiling are high, the COD value in the degumming waste liquid is high, and the wastewater treatment difficulty is high; chlorine bleaching has a great influence on the environment. The biological degumming comprises microbial degumming and enzyme degumming, wherein the enzyme degumming is to directly utilize degumming enzyme preparation or enzyme purified by enzyme produced by degumming strain to act on ramie, and utilize the biological activity of the enzyme to degrade a colloid compound wrapped outside the ramie fiber, thereby separating the fiber. However, the enzyme degumming has the problems of high residual gum rate, high cost and low whiteness.

Patent publication No. CN103726108B discloses a jute fiber degumming method, comprising the steps of: (1) degumming by using pectinase, (2) degumming by using xylanase, (3) refining by using caustic soda and soda ash, (4) bleaching by using sodium hypochlorite, (5) pickling by using sulfuric acid, and (6) bleaching again by using hydrogen peroxide.

According to the technical scheme, the whole degumming method is complex to operate, long in degumming period and high in energy consumption.

Disclosure of Invention

Through a large number of researches, the inventor finds that the ramie can well remove pectin, hemicellulose and lignin on bast of the original ramie through enzyme de-oxidation and bleaching combined treatment, and can avoid damage to the cellulose in the degumming process. The degumming process has the advantages of few working procedures, short degumming period and low cost.

Therefore, the invention aims to provide a ramie enzyme de-oxygen bleaching combined degumming process, which comprises the following steps:

s1 chopping bast of original hemp, soaking the original hemp in the first soaking solution, and then mechanically processing the soaked original hemp in a hemp softening machine;

s2, adding the raw ramie softened in the S1 into the acid enzyme preparation solution for soaking;

s3, washing the original hemp soaked in the acid enzyme preparation in the S2 for the first time, adding the washed original hemp into a second soaking solution for rinsing after the first water washing, wherein the second soaking solution is alkaline, and washing the original hemp for the second time after rinsing;

s4, drying the washed raw ramie in S3 for the second time to obtain refined dry ramie;

in the S2, the enzyme preparation comprises 1.5-3.0% of complex enzyme and 0.2-1.0% of degumming auxiliary agent according to the weight percentage of the raw ramie.

In S3, the second soaking solution includes hydrogen peroxide and a protective aid.

According to the method, the ramie is subjected to combined degumming through raw ramie pretreatment, acid biological enzyme degumming, primary water washing, hydrogen peroxide alkaline bleaching degumming and secondary water washing, the colloid can be fully removed, the use amount of acid and alkali reagents is reduced, and the damage to equipment is reduced. In addition, sodium hypochlorite is avoided for bleaching, and the waste liquid after degumming is easy to treat.

Specifically, the original hemp is soaked in the first soaking solution, so that the cellulose in the original hemp can be expanded, but the dispersibility of the fiber is poor, and the fiber can be improved by performing the softening treatment, and the treatment amount is large. The ramie fibers of the raw ramie treated by the combination of the solvent soaking and the soft ramie have good dispersibility, the peel falling degree and the fiber exposure degree are good, the treated fibers are not easy to break, the softness is good, the content of the mixed bacteria of the raw ramie is low, and meanwhile, the raw ramie swells and can promote the dissolution of nutrient contents.

And soaking the raw ramie by an acid enzyme preparation for enzymolysis, wherein the acid enzyme preparation consists of a complex enzyme, and the complex enzyme acts on the raw ramie colloid, so that the raw ramie colloid is degraded and removed. The colloid is subjected to enzymolysis treatment under an acidic condition, so that the enzyme activity of the complex enzyme can be better exerted, the cellulose can be softened, and the dispersing effect of the cellulose is improved. Meanwhile, because the lignin exists in the inner layer of the pectin, the acidification can be beneficial to the lignin to be separated from the pectin and is beneficial to pectinase to act on the pectin, and the acidification can accelerate the breakage of the lignin and accelerate the degumming process.

However, due to the specific action of the enzyme, part of the pectin remains in the raw ramie, and the whiteness of the raw ramie after enzyme degumming is low. After the degumming treatment, the first washing is performed to remove the residual enzymes and sugars from the raw hemp. The original ramie is put into a second soaking solution for bleaching after being washed for the first time, the second soaking solution contains hydrogen peroxide, and the hydrogen peroxide is activated under the alkaline condition and acts on the original ramie to play a role in degumming and bleaching the residual colloid on the original ramie.

The beneficial effects of the invention are as follows:

the ramie is treated by enzyme dehydration and oxygen bleaching, so that the degumming effect is good, the process is simple, the cost is low, the consumption of alkaline agent is low, and the whiteness of the original ramie is improved.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The invention provides a ramie enzyme-removal-oxygen bleaching combined degumming process, which comprises the following steps:

s1 chopping bast of original hemp, soaking the original hemp in the first soaking solution, and then mechanically processing the soaked original hemp in a hemp softening machine;

s2, adding the raw ramie softened in the S1 into the acid enzyme preparation solution for soaking;

s3, washing the original hemp soaked in the acid enzyme preparation in the S2 for the first time, adding the washed original hemp into a second soaking solution for rinsing after the first water washing, wherein the second soaking solution is alkaline, and washing the original hemp for the second time after rinsing;

s4, drying the washed raw ramie in S3 for the second time to obtain refined dry ramie;

in the S2, the enzyme preparation comprises 1.5-3.0% of complex enzyme and 0.2-1.0% of degumming auxiliary agent according to the weight percentage of the raw ramie;

in the step S3, the second soaking solution includes hydrogen peroxide.

In the invention, the second soaking solution further comprises a protection auxiliary agent. Due to the strong oxidation effect of the hydrogen peroxide, the cellulose is oxidized to generate a peeling reaction, so that the damage of the cellulose is caused, and the toughness and the tensile strength of the cellulose are influenced. After the hydrogen peroxide is activated under the alkaline condition, the ineffective decomposition of the hydrogen peroxide is increased, so that the hydrogen peroxide is decomposed too fast to cause the damage of cellulose. The protective additive is added into the hydrogen peroxide, so that the excessive decomposition of the hydrogen peroxide in the degumming process can be inhibited, the decomposition speed of the hydrogen peroxide is stabilized, the degumming stability and uniformity are facilitated, and the effective decomposition of the hydrogen peroxide is increased, so that the damage to cellulose is reduced, the bleaching effect of the hydrogen peroxide is facilitated, the dosage of an alkaline agent is reduced, and the quality of the degummed ramie is improved.

According to the invention, the ineffective decomposition of hydrogen peroxide can be reduced by adding the protective auxiliary agent, so that the oxidation rate of hydrogen peroxide is slowed down, and the damage to cellulose is reduced. Specifically, the protection aid is a chelating protection aid. The chelating type protection auxiliary agent is anthraquinone, danthrone or layered crystal sodium disilicate, and the chelating type protection auxiliary agent reduces the rapid decomposition of metal ions on hydrogen peroxide by chelating the metal ions in the raw ramie. Anthraquinone can rapidly react with aldehyde group at the tail end of cellulose under alkaline conditions to oxidize the aldehyde group into carboxyl, so that termination reaction can rapidly occur, and peeling reaction can be rapidly stopped, thereby avoiding great degradation of cellulose. Anthraquinone also has the functions of complexing iron ions and scavenging free radicals. The danthrone has the effects of complexing and masking iron ions, eliminating excessive strong oxidative free radicals and inhibiting the peeling reaction of cellulose and hemicellulose. The layered crystal sodium disilicate has very high metal ion adsorption capacity, excellent deposition resistance and alkalinity buffering capacity and less pollution.

In the invention, the pectinase has high-efficiency catalytic action, but the problems of poor enzyme stability, volatile stability and low reuse rate exist in the practical application process, and the problems can be overcome by immobilizing the pectinase. The pectinase immobilization treatment is not only beneficial to improving the utilization rate of the enzyme, but also can increase the stability to acid, alkali and temperature.

In the invention, the immobilization treatment adopts an embedding method, and the embedding method takes acid pectinase as a core material, chitosan as a wall material and calcium chloride as a stabilizer. Embedding by adopting a conventional embedding process.

In the invention, the enzyme preparation also comprises 0.5 to 1.0 percent of polygalacturonase according to the weight percentage of the raw ramie. Polygalacturonase is an important component of pectinase, and the enzymolysis of pectin can be improved by adding the polygalacturonase. Polygalacturonase is a pectinase for promoting polygalacturonase chain hydrolysis under the condition of water participation reaction, and can specifically decompose glycosidic bonds between two non-esterified galacturonic acid residues in pectin through hydrolysis, so that high molecular galacturonic acid is degraded into small molecular substances, and the enzymolysis effect on the pectin is further improved.

In the invention, in order to improve the enzymolysis effect, the activity of the enzyme can be improved by adding a chelating agent in the enzymolysis process, and the degumming effect is improved, wherein the degumming auxiliary agent comprises at least one of 2-hydroxypropionic acid, sodium tripolyphosphate, sodium metasilicate and 4A zeolite. The four degumming assistants have strong adsorption capacity on metal ions, are easy to biodegrade, are harmless to aquatic organisms and can soften water. After the four degumming assistants are compounded, the compound enzyme has certain pH buffering property and can ensure that the compound enzyme can exert the maximum enzyme activity.

In the invention, sodium hydroxide is usually used as an activating agent to promote the oxidation of hydrogen peroxide, however, when sodium hydroxide and hydrogen peroxide are added into the degumming bleaching solution, the pH value is too high in the initial stage of the reaction, and the pH value in the whole stage is in an unstable descending trend, so that the decomposition speed of hydrogen peroxide cannot be controlled, and cellulose damage is easily caused. The weak base is used for replacing sodium hydroxide to activate the hydrogen peroxide, so that the effective decomposition of the hydrogen peroxide can be promoted. The diluted alkaline agent is magnesium hydroxide or magnesium oxide. In the degumming bleaching liquor, the solubility of magnesium hydroxide or magnesium oxide can be increased due to the presence of a plurality of components, and simultaneously, the pH value of the degumming bleaching liquor can be controlled within a certain range along with the gradual dissolution of the magnesium hydroxide or magnesium oxide in the degumming bleaching liquor. Meanwhile, the magnesium ions can capture metal ions such as manganese and iron in the raw hemp, which have a strong catalytic effect on the decomposition of hydrogen peroxide, so that the cellulose can be protected.