Method for preparing native plant fiber and organic biomass by combining acidification with biological enzyme treatment of straw and application

Abstract

The invention belongs to the technical field of crop resource recycling, and particularly relates to a method for preparing native plant fibers and organic biomass by combining acidification with biological enzyme treatment of straw and application. The method comprises the following steps: dedusting straws, adding a fluoride acid solution for plasticizing pretreatment, tearing, kneading, grinding, cooking and curing to remove lignin, pectin and protein to obtain primary plant fibers, and finally carrying out ultrasonic traditional Chinese medicine liquid assisted secondary curing and filter pressing to obtain the primary plant fibers with high cellulose content. The method has the characteristics of low temperature, no alkali and high efficiency, can be applied to the fields of paper pulp, regenerated fibers, plastic modification, packaging and the like, also provides a biomass extraction method, can be applied to the fields of fertilizer preparation, heavy metal adsorption and soil improvement, and realizes high value-added comprehensive utilization of straw fibers.

Description

Technical Field

[0001] The invention belongs to the technical field of crop biological resource utilization, and particularly relates to a method for preparing native plant fiber and organic biomass. Background Art

[0002] As resources become increasingly scarce and environmental problems become increasingly severe, the rational use of biomass resources has become a global focus. As a renewable resource widely found in nature, plant fiber has shown great application potential in many fields, such as textiles, papermaking, composite materials, and bioenergy. However, the preparation process of traditional plant fibers often has problems such as low efficiency, environmental pollution, and waste of resources, which seriously restricts the sustainable development of the plant fiber industry.

[0003] Bio-enzyme treatment of straw to prepare plant fiber is to use specific types of enzymes (such as cellulase, pectinase, xylanase, etc.) to specifically decompose cellulose, hemicellulose and lignin in straw, thereby releasing cellulose and further processing it into plant fiber, which has the advantages of low energy consumption and low pollution. However, due to the complexity of the internal structure of the straw, the enzymatic hydrolysis process requires a long time and a high enzyme dosage to achieve the ideal treatment effect. The existing patent technology 202210478517.6 discloses a method for preparing straw extracts, the bio-enzyme fermentation time is as long as 72h, and the extract still needs to be anaerobic fermented with poultry and livestock manure for 50-60 days before it can be used, and there are problems such as long production cycle and single application field. Patent 202310769823.X discloses a method for extracting cellulose using crop straw as raw material, in which the stacking fermentation temperature is 8-50℃ and the time is 3-20 days, which also has problems such as long production cycle and single application field. Patent 201810478164.3 proposes a method for extracting cellulose from straw. The method mentions collecting and crushing the straw, mixing it with an alkaline solution and soaking it for 20-50 hours before steam explosion. However, the economic cost of this method is too high and it is only suitable for small-scale processing. At present, this method cannot be used for large-scale processing. Therefore, it is urgent to develop an efficient and clean straw plant fiber preparation and its full component application technology to maximize the economic, ecological and social benefits of straw. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a method and application of efficiently preparing native plant fibers by combining acidification with bio-enzyme treatment of straw.

[0005] The technical solution of the present invention is achieved in this way:

[0006] The present application uses acidic fluoride to pretreat the straw, utilizes the hydrolysis of acid and enzyme on the straw to destroy the lignin and hemicellulose structure in the straw, and then utilizes the strong polarity of F atoms in the acidic environment to form hydrogen bonds with the hydroxyl groups in the cellulose to change the crystallization and ordered supramolecular structure of cellulose, and then undergoes multi-stage enzymatic hydrolysis to improve the separation effect of lignin and hemicellulose to obtain native plant fibers with a high cellulose content. The technology of the present application has the characteristics of low temperature, alkali-free and high efficiency.

[0007] On the one hand, the present application proposes a method for preparing native plant fiber by acidification combined with bio-enzyme treatment of straw, the steps of which are as follows:

[0008] (1) After the straw is dusted, a fluoride acid solution is added to perform plasticization pretreatment to obtain straw fibers;

[0009] (2) tearing, kneading, grinding, and steaming the straw fibers under dripping of an enzyme acid solution to obtain primary plant fibers;

[0010] (3) The primary plant fibers are subjected to secondary ripening and pressure filtration assisted by ultrasonic Chinese medicine solution to obtain a precipitate and a filtrate, and the precipitate is the primary plant fiber.

[0011] Preferably, in the above step (1), the straw is rice straw, wheat straw or corn straw; the fluoride acid solution is an oxalic acid or acetic acid aqueous solution containing at least one of sodium fluoride, sodium monofluorophosphate, stannous fluoride and ammonium fluoride, the fluoride content is 3-15wt%, and the acid content is 8-30wt%; the plasticization pretreatment time is 3-8h.

[0012] Preferably, in the above step (2), the tearing, kneading, grinding, and cooking are continuous processes, and the processing time is 1-3 minutes; the concentration of the biological enzyme acid solution is 1000-8000U / L, and the amount used is 5-20% of the total mass of the straw, and the biological enzymes include cellulase, protease, glucose hydrolase and pectinase; 5-30wt% hydrogen peroxide and 500-2000U / L lignin peroxidase are added during the cooking process; the average length of the primary fiber is 10-30mm, and the lignin content is less than 15wt%.

[0013] Preferably, the ultrasonic secondary ripening in the above step (3) is carried out in a tower reactor, the Chinese medicine liquid is an extract of Prunus mume, Folium isatidis and Herba Lysimachiae, and the concentration is 1-5wt%; the secondary ripening time is 30-90s, and the reaction temperature is 40-80°C; the average length of the native plant fiber is <25mm, the fineness is <30μm, and the total content of hemicellulose and lignin is less than 10wt%.

[0014] Secondly, the application of native plant fibers prepared by the above method in papermaking, regenerated cellulose fibers, plastic replacement modification, and packaging fields realizes the high added value comprehensive utilization of straw fibers.

[0015] On the third aspect, the present application also proposes a method for preparing organic biomass by combining acidification with bio-enzyme treatment of straw, wherein alum and sodium bicarbonate are added to the filtrate obtained in step (3) of the above method to flocculate pectin, protein and oligomeric lignin, and organic biomass rich in potassium, phosphorus and magnesium is obtained after filtration and concentration. The filtrate is returned to the straw plasticizing system through a circulation system for reuse.

[0016] Preferably, the concentration of alum is 3-8wt%; the concentration of sodium bicarbonate is 3-8wt%

[0017] Fourthly, the organic biomass prepared by the above method is used in the preparation of biomass fertilizer, heavy metal adsorption, and saline-alkali land improvement.

[0018] The present invention has the following beneficial effects:

[0019] 1. The present invention uses acidic fluoride to pretreat the straw, and can utilize the hydrolysis effect of acid and enzyme on the straw to destroy the lignin and hemicellulose structure in the straw, and then utilize the strong polarity of F atoms in the acidic environment to form hydrogen bonds with the hydroxyl groups in cellulose to change the crystallization and ordered supramolecular structure of cellulose, and then undergo multi-stage enzymatic hydrolysis to improve the separation effect of lignin and hemicellulose, and obtain native plant fibers with high cellulose content, which can be applied to pulp, recycled fiber, plastic modification, packaging and other fields. This technology has the characteristics of low temperature, alkali-free and high efficiency.

[0020] 2. The addition of the Chinese herbal extract of the present invention is helpful for the separation and extraction of cellulose, and has an antibacterial and fresh-keeping effect on the hydrolyzate, thereby realizing the regeneration and recycling of the hydrolyzate. The entire production process is odor-free, black water-free, and green and environmentally friendly.

[0021] 3. The present invention also provides a method for extracting biomass rich in potassium, phosphorus and magnesium such as pectin, protein, hemicellulose and oligomeric lignin, which can be applied in the fields of fertilizer, heavy metal adsorption and soil improvement, thus realizing the high added value comprehensive utilization of straw fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is the infrared spectrum of the plant fiber extracted in Example 1.

[0024] Figure 2 The length measurement and morphology of the plant fiber extracted in Example 1.

[0025] Figure 3 This is the thermogravimetric curve of cellulose extracted in Example 1.

[0026] Figure 4 This is a morphology diagram of the regenerated cellulose fiber prepared in Example 1. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Unless otherwise specified, the experimental methods used in the following experimental examples are all conventional methods; the materials and reagents used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0029] The present application uses acidic fluoride to pretreat the straw, and can utilize the hydrolysis effect of acid and enzyme on the straw to destroy the lignin and hemicellulose structure in the straw, and then utilize the strong polarity of F atoms in the acidic environment to form hydrogen bonds with the hydroxyl groups in the cellulose to change the crystallization and ordered supramolecular structure of cellulose, and then undergo multi-stage enzymatic hydrolysis to improve the separation effect of lignin and hemicellulose, and obtain plant fibers with a high cellulose content, which can be applied to pulp, recycled fiber, plastic modification, packaging and other fields. The technology of the present application has the characteristics of low temperature, alkali-free and high efficiency.

[0030] Example 1

[0031] This embodiment provides a method and application of preparing plant fiber and organic biomass by acidification combined with bio-enzyme treatment of straw, and the specific steps are as follows:

[0032] (1) After the rice straw is dusted, an acidic fluoride aqueous solution consisting of 4 wt% sodium fluoride and 8 w% acetic acid is added to perform plasticization pretreatment for 3 hours.

[0033] (2) The plasticized rice straw fibers were continuously torn, rubbed, ground, and steamed for 2 minutes, and an acidic solution of 1500U / L bioenzyme was dripped, with the amount being 18% of the total weight of the straw. During the steaming process, 5wt% hydrogen peroxide and 500U / L lignin catalase were added, and the average length of the primary fibers obtained was 10mm and the lignin content was 15wt%.

[0034] (3) The obtained primary fibers are sent to a tower reactor for secondary ripening and filter pressing. During the secondary ripening, extracts of Eleutherodactyla quinquefolia, Folium Isatidis and Herba Lysimachiae with a concentration of 5 wt% of traditional Chinese medicine are added. The reaction time is 70 s and the reaction temperature is 80°C. Native plant fibers with an average length of less than 25 mm and a fineness of less than 30 μm are obtained. The total content of hemicellulose and lignin is 9.5 wt%. The obtained native plant fibers are used for pulp preparation.

[0035] (4) Add 8 wt% of alum and sodium bicarbonate to the solution obtained after filtration, and obtain organic biomass rich in potassium, phosphorus and magnesium after filtration and concentration, which is used as biomass fertilizer. The filtrate is returned to the straw plasticizing system through a circulation system for reuse.

[0036] Figure 1 FT-IR infrared spectrum of the fiber extracted from Example 1, 1116 cm -1 and 1064cm -1 The stretching vibration peak of COC is at 1157cm -1 The characteristic peak at 1400cm is the asymmetric stretching vibration peak of COC (ether bond); -1 The characteristic peak at 1633cm is the CH bending vibration peak; -1 The characteristic peak at 3132cm is the stretching vibration peak of C=O; -1 The peak at 3411cm is the CH stretching vibration peak of the benzene ring, which is an important basis for judging whether the sample may contain lignin. -1 The characteristic peak is usually the stretching vibration peak of -OH (hydroxyl). Figure 2 The length of the fiber extracted from Example 1 was measured, and it can be seen that the fiber length is less than 3000um. Figure 3 The TGA curve of cellulose extracted from Example 1 shows that the thermal decomposition temperature is 184.7°C. The residual carbon content is 54.8% at 500°C. Figure 4 This is the morphology of cellulose.

[0037] Table 1 Example 1 Cellulose, lignin and hemicellulose content

[0038]

[0039] Table 2 Composition of organic biomass in Example 1

[0040]

[0041] Table 1 shows the test results of cellulose, hemicellulose and lignin content in Example 1. Table 2 shows the composition of organic biomass in Example 1, wherein the solid content is 30.65%, and the potassium content is the highest, which is 56264.4 μg / g, and there is no toxic component.

[0042] Example 2

[0043] This embodiment provides a method and application of preparing plant fiber and organic biomass by acidification combined with bio-enzyme treatment of straw, and the specific steps are as follows:

[0044] (1) After the rice straw is dusted, a fluoride acidic aqueous solution consisting of 15 wt% sodium fluoride and 20 w% acetic acid is added to perform plasticization pretreatment for 5 hours.

[0045] (2) The plasticized rice straw fibers were continuously torn, rubbed, ground, and steamed for 2.5 min, and an acidic solution of 2000 U / L bioenzyme was dripped in an amount of 20% of the total mass of the straw. During the steaming process, 30 wt% hydrogen peroxide and 2000 U / L lignin catalase were added, and the average length of the primary fibers obtained was 15 mm and the lignin content was 4 wt%.

[0046] (3) The obtained primary fibers are sent to a tower reactor for secondary ripening and filter pressing. During the secondary ripening, extracts of Eleutherodactyla quinquefolia, Folium Isatidis and Herba Lysimachiae with a concentration of 4 wt% of traditional Chinese medicine are added. The reaction time is 30 s and the reaction temperature is 50°C. Native plant fibers with an average length of less than 25 mm and a fineness of less than 30 μm are obtained. The total content of hemicellulose and lignin is 8.9 wt%. The obtained native plant fibers are used for regenerating cellulose fibers.

[0047] (4) Add 3 wt% of alum and sodium bicarbonate to the solution obtained after filtration, and obtain organic biomass rich in potassium, phosphorus and magnesium after filtration and concentration, which is used as a heavy metal adsorbent. The filtrate is returned to the straw plasticizing system through a circulation system for reuse.

[0048] Example 3

[0049] This embodiment provides a method and application of preparing plant fiber and organic biomass by acidification combined with bio-enzyme treatment of straw, and the specific steps are as follows:

[0050] (1) After the rice straw is dusted, a fluoride acidic aqueous solution consisting of 5 wt% sodium fluoride and 14 w% acetic acid is added to perform plasticization pretreatment for 7 hours.

[0051] (2) The plasticized rice straw fibers were continuously torn, rubbed, ground, and steamed for 3 minutes, and an acidic solution of 3000U / L bioenzyme was dripped in an amount of 15% of the total weight of the straw. During the steaming process, 8wt% hydrogen peroxide and 650U / L lignin catalase were added, and the average length of the primary fibers obtained was 18mm and the lignin content was 13wt%.

[0052] (3) The obtained primary fibers are sent to a tower reactor for secondary ripening and filter pressing. During the secondary ripening, extracts of Eleutherodactyla quinquefolia, Folium Isatidis and Herba Lysimachiae with a concentration of 4.5 wt% of traditional Chinese medicine are added. The reaction time is 90 s and the reaction temperature is 70°C. Native plant fibers with an average length of less than 25 mm and a fineness of less than 30 μm are obtained. The total content of hemicellulose and lignin is 7.9 wt%. The obtained native plant fibers are used for plastic replacement modification.

[0053] (4) Add 7 wt % of alum and sodium bicarbonate to the solution obtained after filtration, and obtain organic biomass rich in potassium, phosphorus and magnesium after filtration and concentration, which is used as a saline-alkali land conditioner. The filtrate is returned to the straw plasticizing system through a circulation system for reuse.

[0054] Example 4

[0055] This embodiment provides a method and application of preparing plant fiber and organic biomass by acidification combined with bio-enzyme treatment of straw, and the specific steps are as follows:

[0056] (1) After the rice straw is dusted, an acidic fluoride aqueous solution consisting of 8 wt % sodium fluoride and 18 w % acetic acid is added to perform plasticization pretreatment for 8 hours.

[0057] (2) The plasticized rice straw fibers were continuously torn, rubbed, ground, and steamed for 1.5 min, and an acidic solution of 5000 U / L bioenzyme was dripped in an amount of 8% of the total mass of the straw. During the steaming process, 25 wt% hydrogen peroxide and 1600 U / L lignin catalase were added, and the average length of the primary fibers obtained was 20 mm and the lignin content was 5 wt%.

[0058] (3) The obtained primary fibers are sent to a tower reactor for secondary ripening and filter pressing. During the secondary ripening, extracts of Eleutherodactyla quinquefolia, Folium Isatidis and Herba Lysimachiae with a concentration of 2.5 wt% of traditional Chinese medicine are added. The reaction time is 80 s and the reaction temperature is 60°C. Native plant fibers with an average length of less than 25 mm and a fineness of less than 30 μm are obtained. The total content of hemicellulose and lignin is 5.6 wt%. The obtained native plant fibers are used in the packaging field.

[0059] (4) 4 wt% of alum and sodium bicarbonate are added to the solution obtained after filtration, and organic biomass rich in potassium, phosphorus and magnesium is obtained after filtration and concentration, which is used as biomass fertilizer. The filtrate is returned to the straw plasticizing system through a circulation system for reuse.

[0060] Example 5

[0061] This embodiment provides a method and application of preparing plant fiber and organic biomass by acidification combined with bio-enzyme treatment of straw, and the specific steps are as follows:

[0062] (1) After the rice straw is dusted, an acidic fluoride aqueous solution consisting of 10 wt% sodium fluoride and 20 w% acetic acid is added to perform plasticization pretreatment for 6 hours.

[0063] (2) The plasticized rice straw fibers were continuously torn, rubbed, ground, and steamed for 3 minutes, and an acidic solution of 7000U / L bioenzyme was dripped in an amount of 7% of the total mass of the straw. During the steaming process, 10wt% hydrogen peroxide and 800U / L lignin catalase were added, and the average length of the primary fibers obtained was 16mm and the lignin content was 13wt%.

[0064] (3) The obtained primary fibers are sent to a tower reactor for secondary ripening and filter pressing. During the secondary ripening, extracts of Eleutherodactyla quinquefolia, Folium Isatidis and Herba Lysimachiae with a concentration of 3 wt% of traditional Chinese medicine are added. The reaction time is 60 s and the reaction temperature is 40°C. Native plant fibers with an average length of less than 25 mm and a fineness of less than 30 μm are obtained. The total content of hemicellulose and lignin is 9.4 wt%. The obtained native plant fibers are used for plastic replacement modification.

[0065] (4) Add 8 wt% of alum and sodium bicarbonate to the solution obtained after filtration, and obtain organic biomass rich in potassium, phosphorus and magnesium after filtration and concentration, which is used as biomass fertilizer. The filtrate is returned to the straw plasticizing system through a circulation system for reuse.

[0066] Example 6

[0067] This embodiment provides a method and application of preparing plant fiber and organic biomass by acidification combined with bio-enzyme treatment of straw, and the specific steps are as follows:

[0068] (1) After the rice straw is dusted, an acidic fluoride aqueous solution consisting of 11 wt% sodium fluoride and 22 w% acetic acid is added to perform plasticization pretreatment for 5 hours.

[0069] (2) The plasticized rice straw fibers were continuously torn, rubbed, ground, and steamed for 2 minutes, and an acidic solution of 8000U / L bioenzyme was dripped in an amount of 5% of the total weight of the straw. During the steaming process, 20wt% hydrogen peroxide and 1400U / L lignin catalase were added, and the average length of the primary fibers obtained was 15mm and the lignin content was 9wt%.

[0070] (3) The obtained primary fibers are sent to a tower reactor for secondary ripening and filter pressing. During the secondary ripening, extracts of Eleutherodactyla quinquefolia, Folium Isatidis and Herba Lysimachiae with a concentration of 1 wt% of traditional Chinese medicine are added. The reaction time is 50 s and the reaction temperature is 80°C. Native plant fibers with an average length of less than 25 mm and a fineness of less than 30 μm are obtained. The total content of hemicellulose and lignin is 8.8 wt%. The obtained native plant fibers are used for regenerating cellulose fibers.

[0071] (4) 4 wt% of alum and sodium bicarbonate are added to the solution obtained after filtration, and organic biomass rich in potassium, phosphorus and magnesium is obtained after filtration and concentration, which is used as a heavy metal adsorbent. The filtrate is returned to the straw plasticizing system through a circulation system for reuse.

[0072] Example 7

[0073] This embodiment provides a method and application of preparing plant fiber and organic biomass by acidification combined with bio-enzyme treatment of straw, and the specific steps are as follows:

[0074] (1) After the rice straw is dusted, a fluoride acidic aqueous solution consisting of 12 wt% sodium fluoride and 25 w% acetic acid is added to perform plasticization pretreatment for 4 hours.

[0075] (2) The plasticized rice straw fibers were continuously torn, rubbed, ground, and steamed for 3 minutes, and an acidic solution of 1000U / L bioenzyme was dripped in an amount of 20% of the total mass of the straw. During the steaming process, 15wt% hydrogen peroxide and 950U / L lignin catalase were added, and the average length of the primary fibers obtained was 12mm and the lignin content was 12wt%.

[0076] (3) The obtained primary fibers are sent to a tower reactor for secondary ripening and filter pressing. During the secondary ripening, extracts of Eleutherodactyla quinquefolia, Folium Isatidis and Lysimachia chinensis with a concentration of 4.5 wt% of traditional Chinese medicine are added. The reaction time is 70 s and the reaction temperature is 60°C. Native plant fibers with an average length of less than 25 mm and a fineness of less than 30 μm are obtained. The total content of hemicellulose and lignin is 6.5 wt%. The obtained native plant fibers are used for pulp preparation.

[0077] (4) Add 5 wt% of alum and sodium bicarbonate to the solution obtained after filtration, and obtain organic biomass rich in potassium, phosphorus and magnesium after filtration and concentration, which is used as a heavy metal adsorbent. The filtrate is returned to the straw plasticizing system through a circulation system for reuse.

[0078] Example 8

[0079] This embodiment provides a method and application of preparing plant fiber and organic biomass by acidification combined with bio-enzyme treatment of straw, and the specific steps are as follows:

[0080] (1) After the rice straw is dusted, a fluoride acidic aqueous solution consisting of 14 wt% sodium fluoride and 27 w% acetic acid is added to perform plasticization pretreatment for 6 hours.

[0081] (2) The plasticized rice straw fibers were continuously torn, rubbed, ground, and steamed for 1 min, and an acidic solution of 6000 U / L of bioenzyme was dripped in the solution, with the amount being 7% of the total mass of the straw. During the steaming process, 14 wt% hydrogen peroxide and 900 U / L lignin catalase were added, and the average length of the primary fibers obtained was 16 mm and the lignin content was 7 wt%.

[0082] (3) The obtained primary fibers are sent to a tower reactor for secondary ripening and filter pressing. During the secondary ripening, extracts of Eleutherodactyla quinquefolia, Folium Isatidis and Herba Lysimachiae with a concentration of 4 wt% of traditional Chinese medicine are added. The reaction time is 45 s and the reaction temperature is 70°C. Native plant fibers with an average length of less than 25 mm and a fineness of less than 30 μm are obtained. The total content of hemicellulose and lignin is 7.4 wt%. The obtained native plant fibers are used in the packaging field.

[0083] (4) Add 6 wt% of alum and sodium bicarbonate to the solution obtained after filtration, and obtain organic biomass rich in potassium, phosphorus and magnesium after filtration and concentration, which is used as biomass fertilizer. The filtrate is returned to the straw plasticizing system through a circulation system for reuse.

[0084] Example 9

[0085] This embodiment provides a method and application of preparing plant fiber and organic biomass by acidification combined with bio-enzyme treatment of straw, and the specific steps are as follows:

[0086] (1) After the rice straw is dusted, a fluoride acidic aqueous solution consisting of 15 wt% sodium fluoride and 30 w% acetic acid is added to perform plasticization pretreatment for 8 hours.

[0087] (2) The plasticized rice straw fibers were continuously torn, rubbed, ground, and steamed for 2 minutes, and an acidic solution of 2500U / L bioenzyme was dripped, with the amount being 14% of the total weight of the straw. During the steaming process, 18wt% hydrogen peroxide and 1300U / L lignin catalase were added, and the average length of the primary fibers obtained was 22mm and the lignin content was 12wt%.

[0088] (3) The obtained primary fibers are sent to a tower reactor for secondary ripening and filter pressing. During the secondary ripening, extracts of Eleutherodactyla quinquefolia, Folium Isatidis and Herba Lysimachiae with a concentration of 1.5 wt% of traditional Chinese medicine are added. The reaction time is 70 s and the reaction temperature is 80°C. Native plant fibers with an average length of less than 25 mm and a fineness of less than 30 μm are obtained. The total content of hemicellulose and lignin is 6.2 wt%. The obtained native plant fibers are used for regenerating cellulose fibers.

[0089] (4) Add 5 wt% of alum and sodium bicarbonate to the solution obtained after filtration, and obtain organic biomass rich in potassium, phosphorus and magnesium after filtration and concentration, which is used as biomass fertilizer. The filtrate is returned to the straw plasticizing system through a circulation system for reuse.

[0090] Example 10

[0091] This embodiment provides a method and application of preparing plant fiber and organic biomass by acidification combined with bio-enzyme treatment of straw, and the specific steps are as follows:

[0092] (1) After the rice straw is dusted, an acidic fluoride aqueous solution consisting of 3 wt% sodium fluoride and 24 w% acetic acid is added to perform plasticization pretreatment for 6 hours.

[0093] (2) The plasticized rice straw fibers were continuously torn, rubbed, ground, and cooked for 3 minutes, and an acidic solution of 5500U / L bioenzyme was dripped, with the amount being 14% of the total weight of the straw. During the cooking process, 25wt% hydrogen peroxide and 1200U / L lignin catalase were added, and the average length of the primary fibers obtained was 18mm and the lignin content was 6.1wt%.

[0094] (3) The obtained primary fibers are sent to a tower reactor for secondary ripening and filter pressing. During the secondary ripening, extracts of Eleutherodactyla quinquefolia, Folium Isatidis and Herba Lysimachiae with a concentration of 1 wt% of traditional Chinese medicine are added. The reaction time is 60 s and the reaction temperature is 80°C. Native plant fibers with an average length of less than 25 mm and a fineness of less than 30 μm are obtained. The total content of hemicellulose and lignin is 8.2 wt%. The obtained native plant fibers are used for pulp preparation.

[0095] (4) Add 6 wt% of alum and sodium bicarbonate to the solution obtained after filtration, and obtain organic biomass rich in potassium, phosphorus and magnesium after filtration and concentration, which is used as biomass fertilizer. The filtrate is returned to the straw plasticizing system through a circulation system for reuse.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing native plant fiber by acidification combined with bio-enzyme treatment of straw, characterized in that: Here are the steps: (1) After the straw is dusted, a fluoride acid solution is added for plasticization pretreatment to obtain straw fiber; (2) Tearing, kneading, grinding, and steaming the straw fibers under dripping of an enzyme acid solution to obtain primary plant fibers; (3) The primary plant fibers are subjected to secondary ripening and filter pressing assisted by ultrasonic Chinese medicine solution to obtain a precipitate and a filtrate, and the precipitate is the primary plant fiber.

2. The method for preparing native plant fiber by acidification combined with bio-enzyme treatment of straw according to claim 1, characterized in that: In step (1), the straw is rice straw, wheat straw or corn straw; the fluoride acid solution is an oxalic acid or acetic acid aqueous solution containing at least one of sodium fluoride, sodium monofluorophosphate, stannous fluoride and ammonium fluoride, the fluoride content is 3-15 wt%, and the acid content is 8-30 wt%; the plasticization pretreatment time is 3-8 h.

3. The method for preparing native plant fiber by acidification combined with bio-enzyme treatment of straw according to claim 2, characterized in that: In the step (2), the tearing, kneading, grinding, and cooking are performed continuously, and the processing time is 1-3 min; the concentration of the bio-enzyme acid solution is 1000-8000 U / L, and the amount used is 5-20% of the total mass of the straw, and the bio-enzyme includes cellulase, protease, glucose hydrolase and pectinase; 5-30 wt% hydrogen peroxide and 500-2000 U / L lignin catalase are added during the cooking process; the length of the primary fiber is 10-30 mm, and the lignin content is less than 15 wt%.

4. The method for preparing native plant fiber by acidification combined with bio-enzyme treatment of straw according to claim 3, characterized in that: The Chinese medicinal liquid in step (3) is an extract of Prunus quinquefolia, Folium isatidis and Herba Lysimachiae, with a concentration of 1-5 wt%; the secondary ripening time is 30-90 s, and the reaction temperature is 40-80°C; the average length of the native plant fiber is less than 25 mm, the fineness is less than 30 μm, and the total content of hemicellulose and lignin is less than 10 wt%.

5. Application of native plant fiber prepared by the method according to any one of claims 1 to 4 in papermaking and regenerated cellulose fiber.

6. Application of the native plant fiber prepared by the method according to any one of claims 1 to 4 in the fields of plastic replacement, modification and packaging.

7. A method for preparing organic biomass by acidification combined with bioenzyme treatment of straw, characterized in that: Alum and sodium bicarbonate are added to the filtrate obtained in step (3) of the method according to claim 1 for flocculation, and the organic biomass is obtained after filtration and concentration.

8. The method for preparing organic biomass by acidification combined with bioenzyme treatment of straw according to claim 7, characterized in that: The concentration of alum is 3-8 wt %, and the concentration of sodium bicarbonate is 3-8 wt %.

9. Use of the organic biomass prepared by the method according to claim 7 or 8 in preparing biomass fertilizer.

10. Use of the organic biomass prepared by the method according to claim 7 or 8 in heavy metal adsorption and saline-alkali land improvement.

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