Cotton straw holocellulose high-yield extraction method and application

Abstract

The invention relates to a cotton straw holocellulose high-yield extraction method and application, and the method comprises the following steps: accurately weighing 7.5 g of cotton straw crushed to 80 meshes or more, carrying out acidification treatment for 1 hour by using 75 mL of 4.5-20.5% (wt%) sulfuric acid solution, and collecting a filter cake; putting the collected filter cake into a beaker, adding 75mL of NaOH solution with the concentration of 0-0.5%, and uniformly stirring; adding 0.75 g of urea and 0.75 to 8.25 g of a surfactant hexadecyl trimethyl ammonium bromide into the beaker in sequence to obtain a mixed material; the mixed material is stirred for 0-0.5 h at the rotating speed of 400-800 rmp, ultrasonic vibration is conducted for 20 min, then centrifugation and suction filtration treatment are conducted at the rotating speed of 1500-2000 rmp, drying, smashing and weighing are conducted at the temperature of 35-45 DEG C, and the cotton straw holocellulose is obtained. The method is low in raw material consumption and lower in cost, the holocellulose extraction rate reaches up to 94%, the method is successfully applied to liquorice seed pelleting, the germination rate is remarkably increased, high-valued application of holocellulose is achieved, and the application field is expanded.

Description

Technical Field

[0001] The present invention relates to the technical field of extraction of holocellulose, and specifically to a method for high-yield extraction of cotton straw holocellulose and its application. Background Art

[0002] Cellulose is a macromolecular polysaccharide composed of glucose, insoluble in water and common organic solvents, and is the main component of plant cell walls. Cellulose is the polysaccharide with the widest distribution and the largest content in nature, accounting for more than 50% of the carbon content in the plant kingdom.

[0003] Cotton straw contains extremely rich cellulose and lignin, and these compounds have become important raw materials for preparing high-strength materials and nanocellulose. Through the research and development of cotton straw, various new materials can be developed. The cellulose content of cotton is close to about 60%, which is the purest natural cellulose source. In general wood, cellulose accounts for 40 - 60%, and there are also 10 - 20% hemicellulose and 10 - 20% lignin.

[0004] Holocellulose is all the polysaccharides remaining after removing lignin from defatted plant fiber raw materials, that is, the sum of cellulose and hemicellulose.

[0005] Existing technologies for extracting cellulose include: in the doctoral thesis of Dr. Zhou Ling from South China University of Technology, Chapter 2, Preparation and Characterization of Cotton Straw Nanocellulose, pages 30 and 34, cotton straw powder is dried at 105°C for 1 hour to remove most of the moisture, and then soaked in an aqueous solution with a NaOH mass fraction of 17.5% and a solid-liquid ratio of 5 mL / g. After stirring and dispersing evenly, it is transferred to a KRP horizontal rotary digester, and the extraction conditions are 0.8 MPa, 160°C, and 1 h. The highest comprehensive extraction rate of cellulose and hemicellulose is 87.4%; Chinese Patent CN202211205263.7 discloses a method for high-yield extraction of rice straw holocellulose and its application. In the process of extracting rice straw cellulose, a 3 mol / L NaOH-urea aqueous system is used, consuming a large amount of NaOH and urea (accounting for 50% of the raw material weight) and having a long stirring time (the stirring time is 6 h), and the extraction rate of rice straw holocellulose is only 90.27%. Through literature retrieval, no report on extracting holocellulose from cotton straw has been found, and even less on the application of cotton straw holocellulose in seed pelleting materials. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for high-yield extraction of cotton straw holocellulose and its application, which can improve the yield of holocellulose, consume less raw materials, be more energy-efficient, and realize the high-value application of cotton straw. As a seed pelleting material, it has a wide application prospect in shortening the germination time and increasing the germination rate.

[0007] To achieve the above object, the technical solution adopted by the present invention is: to provide a method for extracting cotton straw holocellulose with a high yield, comprising the following steps:

[0008] (1) Accurately weigh 7.5 g of cotton straw crushed to 80 mesh or above, acidify it with 75 mL of sulfuric acid solution with a concentration of 4.5% - 20.5% (wt%), filter it after 1 hour of acidification treatment, and collect the filter cake;

[0009] (2) Put the filter cake collected in step (1) into a beaker, add 75 mL of sodium hydroxide solution with a concentration of 0 - 0.5%, and stir evenly;

[0010] (3) Add 0.75 g of urea and 0.75 - 8.25 g of surfactant cetyltrimethylammonium bromide to the beaker in sequence to obtain a mixed material;

[0011] (4) Place the mixed material in step (3) on a magnetic stirrer and stir it at a speed of 400 - 800 rmp for 0 - 1 hour;

[0012] (5) Vibrate the stirred mixed material in step (4) with a ultrasonic extractor with a power of 200 W for 20 minutes;

[0013] (6) Dropwise add dilute sulfuric acid solution to the mixed material to adjust the pH to 7 to terminate the reaction;

[0014] (7) Pour the mixed material in step (6) into a centrifuge tube in sequence, centrifuge it at a speed of 1500 rmp for 10 minutes, discard the supernatant, add a certain amount of distilled water and centrifuge it again for 10 minutes, and then discard the supernatant;

[0015] (8) After subjecting the mixed material to suction filtration treatment, dry it at a temperature of 35 - 45 °C, pulverize and weigh it to obtain the cotton straw holocellulose.

[0016] The concentration of the sulfuric acid solution is 12% (wt%), the concentration of the sodium hydroxide solution is 0.3%, the dosage of urea is 0.75 g, the dosage of the surfactant is 1 g, and the stirring time is 0.5 hour.

[0017] The vibration mode of the ultrasonic extractor is ultrasonic for 3 seconds and intermittent for 4 seconds.

[0018] Application of the cotton straw holocellulose extracted by the method in seed pelleting, the holocellulose is used for preparing licorice seed pelleting powder, and the powder formula includes: 50% of holocellulose, 20% of diatomaceous earth, 10% of granulating agent and 20% of talcum powder, and 6 kg of the powder is used for 1 kg of licorice seeds.

[0019] The proportion of the cotton straw holocellulose powder in the pelleting powder is 30% - 70%.

[0020] The powder includes 50% of the cotton straw holocellulose extracted by the method according to any one of claims 1-3, 20% of diatomaceous earth, 10% of granulating agent, and 20% of talcum powder.

[0021] A method for granulating licorice seeds, which uses the said powder to granulate licorice seeds, and 6 kg of the said powder is used for 1 kg of licorice seeds.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. Optimization of raw materials and process: Treatment is carried out with sulfuric acid (4.5% - 20.5%) and sodium hydroxide (0 - 0.5%) at lower concentrations. Compared with existing research (such as 12.5% NaOH or 3mol / L NaOH-urea system), the dosage of chemical reagents is significantly reduced, and the cost and environmental impact are reduced.

[0024] 2. The extraction rate is significantly improved, up to over 94% at most, far higher than the prior art (such as 85% or 90.27%).

[0025] 3. The stirring time is short (0 - 1 hour), and a high extraction rate (92.4%) can still be achieved without ultrasonic conditions, and the process is more energy-saving and efficient.

[0026] 4. Using cetyltrimethylammonium bromide as a surfactant, the dosage is only 13% of the straw raw material, significantly lower than the dosage of urea and surfactant in the prior art (such as 50%), further reducing the cost.

[0027] 5. High-value application: The extracted holocellulose is used for granulating licorice seeds, significantly improving the germination rate and germination potential, showing good application prospects. For example, the germination rate in Example 2 is comparable to that of a commercially available cellulose granulation formula, and is 44.3% higher than the formula without added cellulose.

[0028] 6. Multiple embodiments are provided, proving that the method can achieve efficient extraction under different conditions, the process is simple, highly operable, and suitable for large-scale industrial application. Description of the Drawings

[0029] Figure 1 Analysis of variance diagram of cotton straw holocellulose.

[0030] Figure 2 Physical diagram of cotton straw holocellulose.

[0031] Figure 3 It is a physical diagram of the germination rate after granulating licorice seeds.

[0032] Figure 4An X-ray diffraction pattern was made of the synthesized material. The pattern showed that a weak broad peak appeared at 2θ = 16.2° for the cotton stalk holocellulose, which belonged to the diffraction intensity of the amorphous region, and the strongest diffraction peak appeared at 2θ = 22.16°. The 2θ values corresponding to these diffraction peaks were consistent with those of cellulose type I. Detailed implementation mode

[0033] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] Example 1

[0035] This example is an instance of the method for extracting cotton stalk holocellulose with a high yield according to the present invention, and includes the following steps:

[0036] (1) Accurately weigh 7.5 g of cotton stalks, crush and sieve them to 80 mesh, acidify them with 75 mL of 20.5% (wt%) sulfuric acid solution for 1 h, then filter, collect the filter cake, and recycle the filtrate;

[0037] (2) Put the filter cake collected in step (1) into a beaker, add 75 mL of sodium hydroxide solution with a concentration of 0.5%, and stir evenly;

[0038] (3) Add 0.8 g of urea and 8.25 g of cetyltrimethylammonium bromide to the beaker in sequence to obtain a mixed material;

[0039] (4) Place the mixed material in step three on a magnetic stirrer and stir at a speed of 500 rmp for 1 h;

[0040] (5) Vibrate the stirred mixed material in step four with an ultrasonic extractor with a power of 200 W for 20 min;

[0041] (6) Dropwise add dilute sulfuric acid solution to the mixed material to adjust the pH to 7 to terminate the reaction;

[0042] (7) Pour the mixed material into a centrifuge tube in sequence, centrifuge at a speed of 1500 rmp for 10 min, then slowly discard the supernatant. After adding a certain amount of distilled water and centrifuging for 10 min again, take it out and discard the supernatant;

[0043] (8) After subjecting the mixed material to suction filtration treatment, dry it at a temperature of 35 - 45 °C, crush and weigh it to obtain the dry mass of cotton stalk holocellulose.

[0044] (9) The moisture content of the holocellulose of the dry mass of cotton straw was determined using the Chinese national standard GB / T 2677.2-2011 "Determination of moisture content of papermaking raw materials". After measurement and calculation, the intermediate product of the holocellulose of cotton straw can reach 78.3%.

[0045] (10) The sample was extracted with an organic solvent, then the extract was evaporated and the sample was air-dried. According to the moisture content result, the content of the substances extracted by the solvent was quantitatively determined. GB / T 2677.6-94 "Determination of the content of organic solvent extracts in papermaking raw materials" was used.

[0046] (11) The total amount of holocellulose after treating the sample from which the resin has been extracted with sodium chlorite and glacial acetic acid to remove the contained lignin. GB / T 2677.10-1995 "Determination of the content of holocellulose in papermaking raw materials" was used. After measurement and calculation, the content of holocellulose can reach 83.9%.

[0047] Example 2

[0048] This example is another example of the method for extracting holocellulose from cotton straw with a high yield according to the present invention, and includes the following steps:

[0049] (1) Accurately weigh 7.5 g of cotton straw, crush and sieve it to 80 mesh, acidify it with 75 mL of 12% (wt%) sulfuric acid solution for 1 h, then filter it, collect the filter cake, and the filtrate is recycled;

[0050] (2) Put the filter cake collected in step one into a beaker, add 75 mL of sodium hydroxide solution with a content of 0.3%, and stir evenly.

[0051] (3) Add 0.75 g of urea and 1 g of cetyltrimethylammonium bromide to the beaker in sequence to obtain a mixed material;

[0052] (4) Place the mixed material in step three on a magnetic stirrer and stir it at a speed of 500 rmp for 0.5 h;

[0053] (5) Vibrate the stirred mixed material in step four with an ultrasonic extractor with a power of 200 W for 20 min;

[0054] (6) Dropwise add dilute sulfuric acid solution to the mixed material to adjust the pH to 7 to terminate the reaction;

[0055] (7) Pour the mixed material into a centrifuge tube in sequence, centrifuge it at a speed of 1500 rmp for 10 min, then slowly discard the supernatant. After adding a certain amount of distilled water and centrifuging for 10 min again, take it out and discard the supernatant;

[0056] (8) After subjecting the mixed material to suction filtration, it is dried at a temperature of 35-45 °C, pulverized, and weighed to obtain the holocellulose of cotton straw with dry mass.

[0057] (9) The moisture content of the holocellulose of cotton straw with dry mass is measured. Using the Chinese national standard GB / T2677.2-2011 "Determination of moisture content in papermaking raw materials", it is calculated that the intermediate product of the holocellulose of cotton straw can reach 84.4%.

[0058] (10) The sample is extracted with an organic solvent, then the extract is evaporated and the sample is air-dried. According to the moisture result, the content of the substance extracted by the solvent is quantitatively determined. GB / T2677.6-94 "Determination of the content of organic solvent extracts in papermaking raw materials" is used.

[0059] (11) The total amount of holocellulose after treating the sample from which the resin has been extracted with sodium chlorite and glacial acetic acid to remove the contained lignin. Using GB / T2677.10-1995 "Determination of the holocellulose content in papermaking raw materials", it is calculated that the holocellulose content can reach 94.1%.

[0060] Example 3

[0061] This example is another example of the method for extracting holocellulose from cotton straw with high yield according to the present invention, and includes the following steps:

[0062] (1) Accurately weigh 7.5 g of cotton straw, pulverize and sieve it to 80 mesh, acidify it with 75 mL of 4.5% (wt%) sulfuric acid solution for 1 h, then filter, collect the filter cake, and recycle the filtrate;

[0063] (2) Put the filter cake collected in step one into a beaker, add 75 mL of sodium hydroxide solution with a content of 0%, and stir evenly.

[0064] (3) Add 0.7 g of urea and 0.75 g of cetyltrimethylammonium bromide to the beaker in sequence to obtain a mixed material;

[0065] (4) Place the mixed material in step three on a magnetic stirrer and stir at a speed of 500 rmp for 0 h;

[0066] (5) Vibrate the stirred mixed material in step four with an ultrasonic extractor with a power of 200 W for 20 min;

[0067] (6) Dropwise add dilute sulfuric acid solution to the mixed material to adjust the pH to 7 to terminate the reaction;

[0068] (7) Pour the mixed materials into centrifuge tubes in sequence. After centrifuging at a speed of 1500 rmp for 10 min, slowly discard the supernatant. After adding a quantitative amount of distilled water and centrifuging for another 10 min, take out the mixture and discard the supernatant.

[0069] (8) After performing suction filtration on the mixed materials, dry them at a temperature of 35 - 45 °C, pulverize and weigh them to obtain the holocellulose of cotton straw with dry mass.

[0070] (9) Determine the moisture content of the holocellulose of cotton straw with dry mass. Adopt the Chinese national standard GB / T2677.2 - 2011 "Determination of Moisture Content of Papermaking Raw Materials". After measurement and calculation, it can be obtained that the intermediate product of the holocellulose of cotton straw can reach 80.4%.

[0071] (10) Extract the sample with an organic solvent, then evaporate the extract and air-dry the sample. According to the moisture result, quantitatively determine the content of the substances extracted by the solvent. Adopt GB / T2677.6 - 94 "Determination of Content of Organic Solvent Extractives in Papermaking Raw Materials".

[0072] (11) Use sodium chlorite and glacial acetic acid to treat the sample from which the resin has been extracted to remove the contained lignin, and then determine the total amount of holocellulose. Adopt GB / T2677.10 - 1995 "Determination of Holocellulose Content in Papermaking Raw Materials". After measurement and calculation, it can be obtained that the holocellulose content can reach 84.8%.

[0073] Example 4

[0074] This example is the fourth example of the method for extracting holocellulose from cotton straw with high yield according to the present invention, and includes the following steps:

[0075] (1) Accurately weigh 7.5 g of cotton straw, pulverize and sieve it to 80 mesh, acidify it with 75 mL of 12% (wt%) sulfuric acid solution for 1 h, then filter it, collect the filter cake, and recycle the filtrate.

[0076] (2) Put the filter cake collected in step one into a beaker, add 75 mL of sodium hydroxide solution with a content of 0.3%, and stir evenly.

[0077] (3) Add 0.75 g of urea and 1 g of cetyltrimethylammonium bromide to the beaker in sequence to obtain a mixed material.

[0078] (4) Place the mixed material in step three on a magnetic stirrer and stir it at a speed of 500 rmp for 0.5 h.

[0079] (5) Dropwise add dilute sulfuric acid solution to the mixed material to adjust the pH to 7 to terminate the reaction.

[0080] (6) Pour the mixed materials into centrifuge tubes in sequence. After centrifuging at a speed of 1500 rmp for 10 min, slowly discard the supernatant. After adding a certain amount of distilled water and centrifuging for another 10 min, take out and discard the supernatant;

[0081] (7) After subjecting the mixed materials to suction filtration, dry them at a temperature of 35 - 45 °C, crush and weigh them to obtain the holocellulose of cotton straw with dry mass.

[0082] (8) Measure the moisture content of the holocellulose of cotton straw with dry mass. Adopt the Chinese national standard GB / T2677.2 - 2011 "Determination of Moisture Content in Papermaking Raw Materials". After measurement and calculation, it can be obtained that the intermediate product of the holocellulose of cotton straw can reach 96.5%.

[0083] (9) Extract the sample with an organic solvent, then evaporate the extract and air-dry the sample. According to the moisture result, quantitatively determine the content of the substances extracted by the solvent. Adopt GB / T2677.6 - 94 "Determination of Content of Organic Solvent Extractives in Papermaking Raw Materials".

[0084] (10) Use sodium chlorite and glacial acetic acid to treat the sample from which the resin has been extracted to remove the contained lignin, and then measure the total amount of holocellulose. Adopt GB / T2677.10 - 1995 "Determination of Content of Holocellulose in Papermaking Raw Materials". After measurement and calculation, it can be obtained that the content of holocellulose can reach 90.5%.

[0085] Example 5

[0086] This example is the fifth example of the method for extracting holocellulose from cotton straw described in the present invention, and includes the following steps:

[0087] (1) Accurately weigh 7.5 g of cotton straw, crush and sieve it to 80 mesh, acidify it with 75 mL of 4.5% (wt%) sulfuric acid solution for 1 h, then filter, collect the filter cake, and recycle the filtrate;

[0088] (2) Put the filter cake collected in step one into a beaker, add 75 mL of sodium hydroxide solution with a content of 0%, and stir evenly.

[0089] (3) Add 0.7 g of urea and 0.75 g of cetyltrimethylammonium bromide to the beaker in sequence to obtain a mixed material;

[0090] (4) Place the mixed material in step three on a magnetic stirrer and stir it at a speed of 500 rmp for 0 h;

[0091] (5) Dropwise add dilute sulfuric acid solution to the mixed material to adjust the pH to 7 to terminate the reaction;

[0092] (6) Pour the mixed materials into centrifuge tubes in sequence. After centrifuging at a speed of 1500 rmp for 10 min, slowly discard the supernatant. After adding a quantitative amount of distilled water and centrifuging for another 10 min, take out and discard the supernatant.

[0093] (7) After subjecting the mixed materials to suction filtration, dry them at a temperature of 35 - 45 °C, crush and weigh them to obtain the holocellulose of cotton straw with dry mass.

[0094] (8) Determine the moisture content of the holocellulose of cotton straw with dry mass. Adopt the Chinese national standard GB / T 2677.2 - 2011 "Determination of moisture content in papermaking raw materials". After measurement and calculation, it can be obtained that the intermediate product of the holocellulose of cotton straw can reach 92.2%.

[0095] (9) Extract the sample with an organic solvent, then evaporate the extract and air-dry the sample. According to the moisture content result, quantitatively determine the content of the substances extracted by the solvent. Adopt GB / T 2677.6 - 94 "Determination of the content of organic solvent extracts in papermaking raw materials".

[0096] (10) Use sodium chlorite and glacial acetic acid to treat the sample from which the resin has been extracted to remove the contained lignin, and then determine the total amount of holocellulose. Adopt GB / T 2677.10 - 1995 "Determination of holocellulose content in papermaking raw materials". After measurement and calculation, it can be obtained that the holocellulose content can reach 92.4%.

[0097] Comparative Example 1

[0098] A method for extracting holocellulose from cotton straw includes the following steps:

[0099] (1) Accurately weigh 7.5 g of cotton straw, crush and sieve it to 80 mesh, acidify it with 75 mL of 20.5% (wt%) sulfuric acid solution for 1 h, then filter, collect the filter cake, and recycle the filtrate;

[0100] (2) Put the filter cake collected in step (1) into a beaker, add 75 mL of sodium hydroxide solution with a content of 0.5%, and stir evenly.

[0101] (3) Add 0.8 g of urea and 8.25 g of cetyltrimethylammonium bromide to the beaker in sequence to obtain a mixed material;

[0102] (4) Place the mixed material in step (3) on a magnetic stirrer and stir at a speed of 500 rmp for 1 h;

[0103] (5) Dropwise add dilute sulfuric acid solution to the mixed material to adjust the pH to 7 to terminate the reaction;

[0104] (6) Pour the mixed materials into centrifuge tubes in sequence. After centrifuging at a speed of 1500 rmp for 10 min, slowly discard the supernatant. After adding a certain amount of distilled water and centrifuging for another 10 min, take out and discard the supernatant;

[0105] (7) After subjecting the mixed materials to suction filtration, dry them at a temperature of 35 - 45 °C, pulverize and weigh to obtain the holocellulose of cotton straw with dry mass.

[0106] (8) Determine the moisture content of the dry mass of the cotton straw holocellulose. Adopt the Chinese national standard GB / T2677.2 - 2011 "Determination of Moisture Content of Papermaking Raw Materials". After measurement and calculation, it can be obtained that the intermediate product of cotton straw holocellulose can reach 80.44%.

[0107] (9) Extract the sample with an organic solvent, then evaporate the extract and air-dry the sample. According to the moisture result, quantitatively determine the content of the substances extracted by the solvent. Adopt GB / T2677.6 - 94 "Determination of the Content of Organic Solvent Extractives in Papermaking Raw Materials".

[0108] (10) Use sodium chlorite and glacial acetic acid to treat the sample from which the resin has been extracted to remove the contained lignin, and then determine the total amount of holocellulose. Adopt GB / T2677.10 - 1995 "Determination of Holocellulose Content in Papermaking Raw Materials". After measurement and calculation, it can be obtained that the holocellulose content can reach 74.8%.

[0109] Table 1 Extraction Method of Cotton Straw Holocellulose

[0110]

[0111] Remarks:

[0112] From the test results in Table 1, it can be seen that by using the method of the present invention, the extraction rate of cotton holocellulose can reach up to 94%. The concentration of sodium hydroxide solution is only 0.3%, the stirring time is only 0.5 h, the dosage of urea is 10% of the straw raw material, and the dosage of surfactant is 13% of the straw raw material. Even without ultrasonic conditions, the extraction rate of cotton holocellulose can reach up to 92.4%. The operation steps are simple, the operability is strong, and it saves costs and increases efficiency.

[0113] Example 6

[0114] This example is the application of the cotton straw holocellulose extracted by the method of the present invention in seed pelleting, including:

[0115] The extracted cotton straw cellulose is used for the pelletization of licorice seeds. The pelletization powder formula is as follows: 50% of total cellulose, 20% of diatomite, 10% of granulating agent, 20% of talcum powder. 6 kg of powder is used for 1 kg of licorice seeds. The germination rate and germination time of licorice seeds under the condition of 0.8% NaCl salt stress are investigated. The results are shown in Table 2:

[0116] Table 2 Germination rate and germination time of licorice seeds under the condition of 0.8% NaCl salt stress

[0117]

[0118] Remarks: # Germination potential: It refers to the percentage of germinated seeds when the number of germinated seeds per day reaches the peak during the germination process, accounting for the number of seeds in the test sample. It is based on the percentage of the number of germinated seeds within the first 1 / 3 period of the specified germination test period to the number of seeds for testing.

[0119]

[0120] The germination rate data in Table 2 is represented by the mean of four replicates. It can be seen from the results in Table 2:

[0121] 1. The germination potential of the pelletization formula without adding cellulose for licorice seeds is 45.0%, and the germination rate is 49.0%.

[0122] 2. Comparison conclusion between Examples 1, 2, 3 and Comparative Example 1: When the proportion of cotton straw total cellulose powder in the pellet powder is 45% - 55%, the germination rate of licorice seeds (88%) is equivalent to that of the commercially available cellulose pelletization formula (84%). This provides a basis for the high-value application of cotton straw total cellulose as a raw material in seed pelletization.

[0123] 3. The germination rate of licorice seeds using cotton straw total cellulose as the formula is 3.9% - 44.3% higher than that of the pelletization formula without adding cellulose in Comparative Example 2.

Claims

1. A method for extracting high-yield holocellulose from cotton straw, characterized in that, It includes the following steps: (1) Accurately weigh 7.5 g of cotton straw crushed to 80 mesh or above, acidify it with 75 mL of sulfuric acid solution with a concentration of 4.5% - 20.5% (wt%), filter it after 1 hour of acidification treatment, and collect the filter cake; (2) Put the filter cake collected in step (1) into a beaker, add 75 mL of sodium hydroxide solution with a concentration of 0 - 0.5%, and stir evenly; (3) Add 0.75 g of urea and 0.75 - 8.25 g of surfactant cetyltrimethylammonium bromide to the beaker in sequence to obtain a mixed material; (4) Place the mixed material in step (3) on a magnetic stirrer and stir it at a speed of 400 - 800 rmp for 0 - 1 hour; (5) Vibrate the stirred mixed material in step (4) with a ultrasonic extractor with a power of 200 W for 20 minutes; (6) Dropwise add dilute sulfuric acid solution to the mixed material to adjust the pH to 7 to terminate the reaction; (7) Pour the mixed material in step (6) into a centrifuge tube in sequence, centrifuge it at a speed of 1500 rmp for 10 minutes, discard the supernatant, add a certain amount of distilled water and centrifuge it for 10 minutes again, then discard the supernatant; (8) After subjecting the mixed material to suction filtration treatment, dry it at a temperature of 35 - 45 °C, pulverize and weigh it to obtain the cotton straw holocellulose.

2. The extraction method according to claim 1, wherein The concentration of the sulfuric acid solution is 12% (wt%), the concentration of the sodium hydroxide solution is 0.3%, the dosage of urea is 0.75 g, the dosage of the surfactant is 1 g, and the stirring time is 0.5 hour.

3. The extraction method according to claim 1, wherein The vibration mode of the ultrasonic extractor is ultrasonic for 3 seconds and intermittent for 4 seconds.

4. Use of the cotton stalk holocellulose extracted by the method according to any one of claims 1-3 in seed pelleting, characterized in that, The holocellulose is used for preparing the granulation powder of licorice seeds, and the powder formula includes: 50% of holocellulose, 20% of diatomaceous earth, 10% of granulating agent, and 20% of talcum powder. 6 kg of the powder is used for 1 kg of licorice seeds.

5. The application according to claim 4, wherein The proportion of the cotton straw holocellulose powder in the granulation powder is 30% - 70%.

6. A powder for licorice seed pelletization, characterized in that, The powder includes 50% of cotton straw holocellulose extracted by the method according to any one of claims 1 - 3, 20% of diatomaceous earth, 10% of granulating agent, and 20% of talcum powder.

7. A method for granulating licorice seeds, characterized in that, Use the powder according to claim 6 to granulate licorice seeds, and 6 kg of the powder is used for 1 kg of licorice seeds.

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