CN111576069A - Ramie bone microfibrillated cellulose and preparation method and application thereof - Google Patents

Abstract

The invention provides ramie bone microfibrillated cellulose and a preparation method and application thereof, belonging to the technical field of adsorption materials. The preparation method of the ramie bone microfibrillated cellulose comprises the following steps: mixing the ramie bone powder with water and then carrying out steam explosion pretreatment; mixing the obtained pretreated ramie bone powder with a sodium hydroxide solution, and then carrying out alkali treatment; mixing the obtained ramie bone coarse cellulose, an acetic acid buffer solution and a sodium hypochlorite aqueous solution, and then carrying out bleaching treatment; mixing the obtained ramie bone cellulose with water to obtain ramie bone cellulose suspension, homogenizing the ramie bone cellulose suspension, performing solid-liquid separation on the system obtained after the homogenization, and freeze-drying the obtained solid material to obtain the ramie bone microfibrillated cellulose. The ramie bone microfibrillated cellulose prepared by the method has a loose porous reticular structure, has a good adsorption effect on dye when being used as an adsorbent, and is rich in raw material resources, simple in process and low in production cost.

Description

A kind of ramie bone microfibrillated cellulose and its preparation method and application

technical field

The invention relates to the technical field of adsorption materials, in particular to a ramie bone microfibrillated cellulose and a preparation method and application thereof.

Background technique

With the rapid development of industry, the problem of environmental pollution caused by wastewater has become increasingly prominent. Among them, dyes have strong chemical stability and are not easy to biodegrade, so the treatment of printing and dyeing wastewater is a difficult task. Traditional printing and dyeing wastewater treatment methods mainly include flocculation sedimentation method, chemical oxidation method, membrane separation method and biodegradation method. Although these methods can reduce the content of dyes in printing and dyeing wastewater to a certain extent, they still have various defects, such as large limitations in practical application, high cost, poor operability, and easy to cause secondary pollution, etc. .

In recent years, the adsorption method has been favored due to its advantages of low cost, safety, non-toxicity, and simple operation. In the process of printing and dyeing wastewater treatment using the adsorption method, the dye pollutants in the water are mainly adsorbed and separated by the adsorbent. In the purification and treatment of printing and dyeing wastewater, in this process, the selection of adsorbents is crucial to the final treatment effect of printing and dyeing wastewater. Therefore, the development of new high-efficiency and low-cost adsorbents is of great practical significance in the field of printing and dyeing wastewater treatment.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a ramie bone microfibrillated cellulose and a preparation method and application thereof. The ramie bone microfibrillated cellulose prepared by the method provided by the present invention has a loose porous network structure, which is used as an adsorbent for The dye has good adsorption effect, rich raw material resources, simple process and low production cost.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

A preparation method of ramie bone microfibrillated cellulose, comprising the following steps:

(1) carrying out steam explosion pretreatment after mixing the ramie bone meal with water to obtain the pretreated ramie bone meal;

(2) carrying out alkali treatment after mixing the pretreated ramie bone powder and sodium hydroxide solution in the described step (1) to obtain the crude ramie bone cellulose;

(3) performing bleaching after mixing the crude ramie bone cellulose, acetic acid buffer and sodium hypochlorite aqueous solution in the step (2) to obtain the ramie bone cellulose;

(4) mixing the ramie bone cellulose and water in the step (3) to obtain a ramie bone cellulose suspension, subjecting the ramie bone cellulose suspension to a homogenization treatment, and subjecting the obtained system to solidification after the homogenization treatment. The liquid is separated, and the obtained solid material is freeze-dried to obtain ramie bone microfibrillated cellulose.

Preferably, in the step (1), the mass ratio of ramie bone meal to water is 1:4-6, the temperature of the steam explosion pretreatment is 110-130°C, and the time is 20-30min.

Preferably, the number of times of alkali treatment in the step (2) is 2 to 3 times.

Preferably, the concentration of the sodium hydroxide solution is 5-8 wt.%, and the dosage ratio of the solid material and the sodium hydroxide solution in the system during the alkali treatment is 1 g: 10-15 mL;

The temperature of the alkali treatment is 75-85°C, and the time of a single alkali treatment is 1.5-2.5h.

Preferably, the number of times of bleaching treatment in the step (3) is 2 to 3 times.

Preferably, the acetate buffer is prepared by mixing sodium hydroxide, glacial acetic acid and water, the amount of sodium hydroxide in the acetate buffer is 30g/L, and the amount of glacial acetic acid is 70mL/L; the sodium hypochlorite The concentration of the aqueous solution is 1-2 wt.%; the dosage ratio of the solid material in the system to the acetic acid buffer solution and the aqueous sodium hypochlorite solution is 1 g: 5-10 mL: 5-10 mL during the bleaching treatment;

The temperature of the bleaching treatment is 75-85° C., and the time of a single bleaching treatment is 0.5-1.5 h.

Preferably, the number of times of homogenization in the step (4) is 8 to 10 times.

Preferably, the solid content of the system is 4-6 wt.% during the homogenization treatment;

The rotating speed of the homogenizing treatment is 20000-25000 rpm, and the time of a single homogenizing treatment is 5-8 min.

The present invention provides the ramie bone microfibrillated cellulose prepared by the preparation method described in the above technical solution.

The present invention provides the application of the ramie bone microfibrillated cellulose described in the above technical solution as an adsorbent in the field of printing and dyeing wastewater treatment.

The invention provides a preparation method of ramie bone microfibrillated cellulose, comprising the following steps: (1) mixing ramie bone powder with water and then performing steam explosion pretreatment to obtain pretreated ramie bone powder; (2) mixing the step (1) Alkaline treatment is carried out after mixing the pretreated ramie bone powder with the sodium hydroxide solution to obtain the crude ramie bone cellulose; (3) the crude ramie bone cellulose, the acetic acid buffer and the aqueous sodium hypochlorite solution in the step (2) are mixed and then performing bleaching treatment to obtain ramie bone cellulose; (4) mixing the ramie bone cellulose with water in the step (3) to obtain a ramie bone cellulose suspension, and homogenizing the ramie bone cellulose suspension treatment, the system obtained after homogenization treatment is subjected to solid-liquid separation, and the obtained solid material is freeze-dried to obtain ramie bone microfibrillated cellulose. The invention utilizes steam explosion pretreatment and alkali treatment to obtain crude ramie bone cellulose, and then in the bleaching process, sodium hypochlorite can remove residual lignin and other components attached to the ramie bone cellulose, specifically, residual lignin Oxidation reaction occurs with sodium hypochlorite, and the soluble components formed by fragmentation are dissolved in the solvent and removed, and sodium hypochlorite will also oxidize the ramie bone cellulose, thereby reducing the strength of the ramie bone cellulose to a certain extent, which is conducive to making it through subsequent homogenization. Treatment to form ramie bone microfibrillated cellulose with loose porous network structure. The ramie bone microfibrillated cellulose prepared by the method provided by the invention has higher specific surface area and larger microporous structure, and can have higher adsorption capacity for dyes without chemical modification and modification. In addition, the invention uses ramie bone as a raw material to prepare ramie bone microfibrillated cellulose as an adsorbent, and has rich raw material resources, simple process and low production cost.

Description of drawings

Fig. 1 is the SEM image of the ramie bone microfibrillated cellulose prepared in Example 1;

2 is the FT-IR absorption spectrum of ramie bone cellulose and ramie bone microfibrillated cellulose prepared in Example 1.

Detailed ways

The invention provides a preparation method of ramie bone microfibrillated cellulose, comprising the following steps:

(1) carrying out steam explosion pretreatment after mixing the ramie bone meal with water to obtain the pretreated ramie bone meal;

(2) carrying out alkali treatment after mixing the pretreated ramie bone powder and sodium hydroxide solution in the described step (1) to obtain the crude ramie bone cellulose;

(3) performing bleaching after mixing the crude ramie bone cellulose, acetic acid buffer and sodium hypochlorite aqueous solution in the step (2) to obtain the ramie bone cellulose;

(4) mixing the ramie bone cellulose and water in the step (3) to obtain a ramie bone cellulose suspension, subjecting the ramie bone cellulose suspension to a homogenization treatment, and subjecting the obtained system to solidification after the homogenization treatment. The liquid is separated, and the obtained solid material is freeze-dried to obtain ramie bone microfibrillated cellulose.

In the invention, the ramie bone powder is mixed with water and then subjected to steam explosion pretreatment to obtain the pretreated ramie bone powder. In the present invention, the particle size of the ramie bone powder is preferably 20-40 meshes, and the ramie bone powder is preferably obtained by crushing the ramie bone. The invention uses the ramie bone as the raw material to prepare the ramie bone microfibrillated cellulose as the adsorbent, has rich raw material resources and low cost, not only solves the problem of environmental pollution by burning the ramie bone, but also improves the comprehensive utilization value of the ramie resource.

In the present invention, the mass ratio of the ramie bone meal to water is preferably 1:4-6, more preferably 1:5; the temperature of the steam explosion pretreatment is preferably 110-130°C, more preferably 115-125°C °C, more preferably 121 °C; the time of steam explosion pretreatment is preferably 20-30 min. The invention utilizes steam explosion pretreatment to keratinize and rearrange the cellulose in the ramie bone powder, partially degrade the hemicellulose and lignin in the ramie bone, and soften the fibers, which is favorable for disintegrating into microfibers after subsequent homogenization treatment. chemical fiber. In the present invention, after the steam explosion pretreatment is completed, the present invention preferably filters the obtained system, and the obtained solid material (ie, pretreated ramie bone powder) is directly mixed with sodium hydroxide solution for subsequent alkali treatment.

After the pretreated ramie bone powder is obtained, in the present invention, the pretreated ramie bone powder is mixed with a sodium hydroxide solution and then subjected to alkali treatment to obtain crude ramie bone cellulose. In the present invention, the number of times of the alkali treatment is preferably 2 to 3 times, the concentration of the sodium hydroxide solution is preferably 5 to 8 wt.%, and the ratio of the amount of solid material to the sodium hydroxide solution in the system when the alkali treatment is performed Preferably, it is 1 g: 10-15 mL; the temperature of the alkali treatment is preferably 75-85° C., and the time of a single alkali treatment is preferably 1.5-2.5 h. In the present invention, the alkali treatment is preferably performed under stirring conditions, and the rotational speed of the stirring is preferably 100 to 150 rpm. In the present invention, preferably, alkali treatment and filtration are carried out after mixing the pretreated ramie bone powder with sodium hydroxide solution, the obtained filter residue is mixed with sodium hydroxide solution, and alkali treatment and filtration are carried out again, wherein, with sodium hydroxide The operation of solution mixing-alkali treatment-filtration is carried out 2 to 3 times in total; after each alkali treatment is completed, the present invention preferably allows the obtained system to stand for 50 to 70 minutes, more preferably for 60 minutes, and then filter to increase the pretreatment The contact time between the ramie bone meal and the sodium hydroxide solution makes the lignin in it fully degrade and dissolve in the sodium hydroxide solution. After the last filtration is completed, in the present invention, the obtained filter residue is preferably dried to obtain crude ramie bone cellulose.

The invention destroys the primary wall of fibers by alkali treatment, depolymerizes cellulose macromolecules, and at the same time partially dissolves cellulose with a low degree of polymerization; uses NaOH to interact with lignin to make lignin in a three-dimensional cross-linked network structure The chemical bonds of ramie are broken, and the lignin macromolecules are degraded to form a number of fragments or even low-molecular substances, which are dissolved in the lye, thereby obtaining crude ramie bone cellulose.

After the crude ramie bone cellulose is obtained, the present invention mixes the crude ramie bone cellulose, an acetic acid buffer and an aqueous sodium hypochlorite solution, and then performs bleaching treatment to obtain the ramie bone cellulose. In the present invention, the acetate buffer is preferably prepared by mixing sodium hydroxide, glacial acetic acid and water, the dosage of sodium hydroxide in the acetate buffer is preferably 30 g/L, and the dosage of glacial acetic acid is preferably 70 mL/L L, specifically mix 30g sodium hydroxide with 70mL glacial acetic acid, and dilute to 1L with water; the concentration of the sodium hypochlorite aqueous solution is preferably 1～2wt.%; the solid material in the system, the acetic acid buffer, and the sodium hypochlorite aqueous solution during bleaching treatment The dosage ratio is preferably 1g:5-10mL:5-10mL; the temperature of the bleaching treatment is preferably 75-85°C, more preferably 80°C; the time of a single bleaching treatment is preferably 0.5-1.5h, more preferably 1h . In the present invention, the bleaching treatment is preferably performed under stirring conditions, and the rotational speed of the stirring is preferably 100-150 rpm. In the present invention, preferably, the crude ramie bone cellulose, acetic acid buffer and sodium hypochlorite aqueous solution are mixed and then subjected to bleaching treatment and filtration in turn, the obtained filter residue is mixed with acetic acid buffer and sodium hypochlorite aqueous solution, and bleaching treatment and filtration are performed again, Wherein, the operations of mixing with acetate buffer and sodium hypochlorite aqueous solution-bleaching-filtering are carried out 2 to 3 times in total; after the last filtration is completed, the present invention preferably washes the obtained filter residue with water, and then performs drying to obtain ramie bone cellulose. In the present invention, the water consumption for the washing is preferably 8 to 10 times the mass of the filter residue, and the number of washings is preferably 3 to 5 times.

In the bleaching treatment process of the present invention, sodium hypochlorite can remove residual lignin and other components attached to the ramie bone cellulose. Specifically, the residual lignin undergoes oxidation reaction with sodium hypochlorite, and is fragmented to form soluble components that dissolve in the solvent It is removed, and sodium hypochlorite will also oxidize the ramie bone cellulose, thereby reducing the strength of the ramie bone cellulose to a certain extent. The function of the acetic acid buffer is to soften the pH value of the system and prevent the pH value during the bleaching process. Lead to an impact on the properties of ramie bone cellulose; the present invention adopts a relatively mild bleaching system (ie sodium hypochlorite aqueous solution and acetic acid buffer), which is conducive to the subsequent homogenization of the obtained ramie bone cellulose to form ramie bone with a loose porous network structure. Microfibrillated cellulose.

After the ramie bone cellulose is obtained, the present invention mixes the ramie bone cellulose with water to obtain a ramie bone cellulose suspension, the ramie bone cellulose suspension is subjected to homogenization treatment, and the obtained system after the homogenization treatment is subjected to homogenization treatment. Solid-liquid separation, the obtained solid material is freeze-dried to obtain ramie bone microfibrillated cellulose. In the present invention, the solid content of the system is preferably 4-6 wt.% during the homogenization treatment, the rotation speed of the homogenization treatment is preferably 20000-25000 rpm, and the time of a single homogenization treatment is preferably 5-8 min. In the present invention, preferably, the ramie bone cellulose is mixed with water to obtain a ramie bone cellulose suspension, the ramie bone cellulose suspension is subjected to homogenization treatment and filtration, the obtained filter residue is mixed with water, and the Homogenization treatment and filtration are carried out, wherein the operations of mixing with water - homogenization treatment and filtration are carried out for 8 to 10 times, and finally the obtained filter residue is freeze-dried to obtain ramie bone microfibrillated cellulose. The present invention has no special limitation on the freeze-drying, and a method well known to those skilled in the art can be used.

In the present invention, the ramie bone cellulose is treated by homogenization, and the fibers are broken and decomposed to form the ramie bone microfibrillated cellulose with a loose porous network structure, which has a large specific surface area, a large number of polar hydroxyl groups exposed on the surface, and has strong adsorption. dye ability; and no chemical reagents are used, the problem of environmental pollution is avoided, the production process is simplified, the efficiency is high, and the production cost is low.

The present invention provides the ramie bone microfibrillated cellulose prepared by the preparation method of the above technical solution, the ramie bone microfibrillated cellulose has a loose and porous network structure, and its specific surface area is preferably 20-100 m ² /g , the diameter is preferably 100-1000 nm, and the porosity is preferably 90-95%.

The present invention provides the application of the ramie bone microfibrillated cellulose described in the above technical solution as an adsorbent in the field of printing and dyeing wastewater treatment. The ramie bone microfibrillated cellulose provided by the invention has higher specific surface area and larger microporous structure, and can have higher adsorption capacity for dyes without chemical modification and modification. The present invention does not specifically limit the specific use method of the ramie bone microfibrillated cellulose, and an appropriate amount can be selected according to actual needs; in the embodiments of the present invention, taking the treatment of methyl blue solution as an example, the methyl The concentration of the base blue solution is 50-300mg/L, the addition amount of the ramie bone microfibrillated cellulose is 200-400mg/L, and the pH value of the system is 6.5-7.5 (preferably using 1mol/L hydrochloric acid to adjust the pH value) , room temperature, and 100-150 rpm for 60-90 min of adsorption, and the adsorption capacity of ramie bone microfibrillated cellulose to methyl blue is 110-150 mg/g.

The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

Mix 100 g of ramie bone powder (granularity of 20-40 mesh) with 500 mL of water, carry out steam explosion treatment at 121 ° C for 20 min, take 50 g of ramie bone powder after steam explosion treatment, add 500 mL of NaOH solution with a concentration of 5wt.%, Alkali treatment was carried out at 80 ° C and 100 rpm for 2 hours, and then allowed to stand for 1 hour. The obtained system was suction filtered, and the obtained filter residue was repeatedly mixed with sodium hydroxide solution - alkali treatment - standing - suction filtration operation 2 times, the final obtained The filter residue was dried to obtain 19.62g of ramie bone crude cellulose;

Mix 30 g of NaOH with 70 mL of glacial acetic acid, and dilute to 1 L with water to obtain acetate buffer; 10 g of ramie bone crude cellulose, 50 mL of acetic acid buffer and 50 mL of sodium hypochlorite aqueous solution with a concentration of 2 wt.% are mixed at 80 ° C and 100 rpm. Bleaching treatment was carried out for 1 h, the obtained system was subjected to suction filtration, and the obtained filter residue was repeatedly mixed with acetic acid buffer and sodium hypochlorite aqueous solution-bleaching treatment-suction filtration operation 2 times, and the final obtained filter residue was washed 3 times with 10 times the mass of water, and dried. After drying, 8.62g of ramie bone cellulose was obtained;

The ramie bone cellulose is mixed with water to prepare a ramie bone cellulose suspension with a concentration of 4 wt.%, the ramie bone cellulose suspension is subjected to homogenization treatment at 20,000 rpm for 5 minutes, and the obtained system is filtered, The obtained filter residue was mixed with water - homogenized treatment - filtration operation was repeated 9 times, and finally the obtained filter residue (white gelatinous substance) was vacuum freeze-dried to obtain powdered ramie bone microfibrillated cellulose.

Example 2

Mix 100g of ramie bone powder (granularity of 20-40 mesh) with 500mL of water, carry out steam explosion treatment at 121°C for 30min, take 50g of ramie bone powder after steam explosion treatment, add 750mL of NaOH solution with a concentration of 8wt.%, Alkali treatment was carried out at 80 ° C and 150 rpm for 2 h, then left standing for 1 h, the obtained system was suction filtered, and the obtained filter residue was repeatedly mixed with sodium hydroxide solution - alkali treatment - standing - suction filtration operation 2 times, the final obtained The filter residue was dried to obtain 18.65g of ramie bone crude cellulose;

Mix 30 g of NaOH with 70 mL of glacial acetic acid, and dilute with water to 1 L to obtain acetate buffer; 10 g of ramie bone crude cellulose, 100 mL of acetic acid buffer and 100 mL of sodium hypochlorite aqueous solution with a concentration of 1.5 wt. Bleaching treatment was carried out for 1 h under the conditions, the obtained system was suction filtered, the obtained filter residue was repeatedly mixed with acetic acid buffer and sodium hypochlorite aqueous solution-bleaching treatment-suction filtration operation twice, and the final obtained filter residue was washed 5 times with 10 times the mass of water, After drying, 8.45g of ramie bone cellulose was obtained;

The ramie bone cellulose is mixed with water to prepare a ramie bone cellulose suspension with a concentration of 6 wt.%, the ramie bone cellulose suspension is subjected to homogenization treatment at 25000 rpm for 8 minutes, and the obtained system is filtered, The obtained filter residue is mixed with water - homogenized treatment - filtration operation is repeated 7 times, and finally the obtained filter residue (white gelatinous substance) is vacuum freeze-dried to obtain powdery ramie bone microfibrillated cellulose.

Characterization and Performance Testing:

FIG. 1 is a SEM image of the ramie bone microfibrillated cellulose prepared in Example 1. It can be seen from FIG. 1 that the ramie bone microfibrillated cellulose has a loose and porous network structure. The average diameter of ramie bone microfibrillated cellulose measured by Nano Measurer was 112 nm; the average specific surface area of ramie bone microfibrillated cellulose measured by BET method was 32 m ² /g, and the average porosity was 92.32%.

Figure 2 is the FT-IR absorption spectrum of the ramie bone cellulose and the ramie bone microfibrillated cellulose prepared in Example 1. It can be seen from Figure 2 that the peak positions of the ramie bone cellulose and the ramie bone microfibrillated cellulose are basically Consistent, but the characteristic peaks of ramie bone microfibrillated cellulose are more obvious, in which the absorption peaks at 1048 cm ^-1 and 896 cm ^-1 are derived from the CH deformation of the glycosidic bond caused by ring vibration and OH bending vibration, which are the glucose β-glycosides in cellulose. Bonded characteristic absorption peaks; and no characteristic peaks (1509 cm ^-1 and 1426 cm ^-1 ) of lignin benzene ring skeleton were seen in the spectrum, indicating that lignin was removed during cellulose separation.

The characterization results of the ramie bone microfibrillated cellulose prepared in Example 2 are similar to those of the ramie bone microfibrillated cellulose prepared in Example 1, both of which are loose and porous network structures.

20g of ramie bone microfibrillated cellulose prepared in Example 1 was added to 100mL of methyl blue solution with a concentration of 50mg/L, the pH value of the system using 1mol/L hydrochloric acid was adjusted to 7, and stirred at room temperature and 100rpm. Adsorption was carried out for 60min; after that, the adsorption amount of ramie bone microfibrillated cellulose to methyl blue was calculated to be 124.38mg/g by spectrophotometry.

The adsorption performance of the ramie bone microfibrillated cellulose prepared in Example 2 was tested according to the above method, and the results showed that the adsorption capacity of the ramie bone microfibrillated cellulose prepared in Example 2 to methyl blue was 135.62 mg/g.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. a preparation method of ramie bone microfibrillated cellulose, is characterized in that, comprises the following steps: (1) carrying out steam explosion pretreatment after mixing the ramie bone meal with water to obtain the pretreated ramie bone meal; (2) carrying out alkali treatment after mixing the pretreated ramie bone powder and sodium hydroxide solution in the described step (1) to obtain the crude ramie bone cellulose; (3) performing bleaching after mixing the crude ramie bone cellulose, acetic acid buffer and sodium hypochlorite aqueous solution in the step (2) to obtain the ramie bone cellulose; (4) mixing the ramie bone cellulose and water in the step (3) to obtain a ramie bone cellulose suspension, subjecting the ramie bone cellulose suspension to a homogenization treatment, and subjecting the obtained system to solidification after the homogenization treatment. The liquid is separated, and the obtained solid material is freeze-dried to obtain ramie bone microfibrillated cellulose. 2. preparation method according to claim 1 is characterized in that, in described step (1), the mass ratio of ramie bone meal and water is 1: 4～6, and the temperature of described steam explosion pretreatment is 110～130 ℃ , the time is 20 to 30 minutes. 3 . The preparation method according to claim 1 , wherein the number of times of alkali treatment in the step (2) is 2 to 3 times. 4 . 4. preparation method according to claim 3 is characterized in that, the concentration of described sodium hydroxide solution is 5～8wt.%, and the consumption ratio of solid material and sodium hydroxide solution in the system when carrying out alkali treatment is 1g: 10～15mL; The temperature of the alkali treatment is 75-85°C, and the time of a single alkali treatment is 1.5-2.5h. 5 . The preparation method according to claim 1 , wherein the number of times of bleaching in the step (3) is 2 to 3 times. 6 . 6. preparation method according to claim 5, is characterized in that, described acetic acid buffer solution is formed by mixing sodium hydroxide, glacial acetic acid and water, and the consumption of sodium hydroxide in described acetic acid buffer solution is 30g/L , the dosage of glacial acetic acid is 70mL/L; the concentration of the sodium hypochlorite aqueous solution is 1～2wt.%; the dosage ratio of solid material to acetic acid buffer and sodium hypochlorite aqueous solution in the system during bleaching treatment is 1g: 5～10mL: 5～ 10mL; The temperature of the bleaching treatment is 75-85° C., and the time of a single bleaching treatment is 0.5-1.5 h. 7 . The preparation method according to claim 1 , wherein the number of times of homogenizing treatment in the step (4) is 8 to 10 times. 8 . 8. The preparation method according to claim 7, wherein the solid content of the system is 4 to 6 wt.% during homogenization treatment; The rotating speed of the homogenizing treatment is 20000-25000 rpm, and the time of a single homogenizing treatment is 5-8 min. 9. The ramie bone microfibrillated cellulose prepared by the preparation method according to any one of claims 1 to 8. 10. The application of the ramie bone microfibrillated cellulose of claim 9 as an adsorbent in the field of printing and dyeing wastewater treatment.

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