CN111802556A - Composite impregnated cellulose-based aerogel solid matter and preparation method thereof - Google Patents

Abstract

The present invention relates to a composite impregnated cellulose-based aerogel solid and a preparation method thereof. The cellulose aerogel microporous powder of the roots of the broken rice grass has an average particle size of not more than 0.72 μm, and the volume of the micropores accounts for not less than 75%. The composite impregnated cellulose-based aerogel solid matter according to the embodiment of the present invention can delay the occurrence of mildew in the feed and reduce the degree of mildew in the feed; compared with the prior art, the cost is significantly reduced, and the anti-mildew effect is comparable , so as to realize the effective replacement of chemical antifungal agent and compound antifungal agent, green and non-toxic.

Description

A kind of composite impregnated cellulose-based aerogel solid and preparation method thereof

technical field

The invention belongs to the technical field of feed, and in particular relates to a composite impregnated cellulose-based aerogel solid and a preparation method thereof.

Background technique

Feed mildew inhibitor is a commonly used feed additive, which is used to inhibit the production of mold and toxin, prevent the loss of nutrients during storage, slow down the mildew of the feed, and prolong the storage time of the feed. The existing feed mildew inhibitor mainly includes chemical mildew inhibitor, compound mildew inhibitor, and Chinese herbal mildew inhibitor. Chemical antifungal agents mainly include propionic acid and its salts, sodium diacetate, sorbic acid, etc. The disadvantage of chemical antifungal agents is that the antifungal effect is inversely proportional to corrosiveness, and it is easy to produce toxic side effects. The compound antifungal agent is composed of a variety of organic acid or organic acid salt antifungal agents in a certain proportion. The antifungal effect of the compound antifungal agent is better than that of the single chemical antifungal agent, but the compound antifungal agent is easy to destroy the feed. overall nutritional level. The antifungal effect of Chinese herbal antifungal agents is achieved by inhibiting the growth and reproduction of bacteria. It has no residue, no drug resistance, and no toxic side effects. It is an important development direction of antifungal additives in feed. In practical application, the anti-mold additive of Chinese herbal medicine has the following shortcomings: 1) its own stability is not high, in the process of application, it is easily affected by light, heat, moisture, etc., which is not convenient for storage; 2) the slow-release effect is not obvious, The anti-mildew effect is not long-lasting; 3) There are many varieties of Chinese herbal medicines, and how to use appropriate raw materials and preparation processes to obtain excellent anti-mildew effects, reduce raw materials and manufacturing costs, and improve cost performance, it still requires continuous in-depth research.

Broken rice sedge spreads almost all over the country, especially in farmland, it harms the growth of rice, soybean, cotton, vegetables and fruit trees. It is a harmful plant. However, the roots of sedge sedge are rich in unique total alkaloids, which have antibacterial effects. How to turn waste into treasure with low cost and rich sources is worthy of attention and research, and how to ensure its own stability. At the same time, it has a slow-release effect and finally obtains a reasonable anti-fungal and bacteriostatic effect, which is the difficulty of preparation.

SUMMARY OF THE INVENTION

In order to overcome the deficiencies of the prior art, the present invention provides a composite impregnated cellulose-based aerogel solid and a preparation method thereof. The gist of the present invention is as follows:

According to one aspect of the present invention, a composite impregnated cellulose-based aerogel solid is composed of 100 parts by weight of sedge root cellulose aerogel microporous powder and 80-350 parts by weight in parts by weight. The extract of the young leaves of the pear is prepared, wherein the average particle size of the cellulose aerogel microporous powder of the roots of sedge sedge is not more than 0.72 μm, and the volume ratio of the micropores is not less than 75%.

According to another aspect of the present invention, a method for preparing a composite impregnated cellulose-based aerogel solid, the method comprising:

1. Extraction of cellulose from the roots of sedge

1) Pretreatment: cutting, drying, pulverizing and sieving the washed sedge roots to obtain 50 μm sedge root powder;

2) Acidification pretreatment: according to the solid-liquid ratio of 1:30, 0.1 mol/L oxalic acid solution was used to soak the broken sedge root powder at 35 ° C for 60 min, and then dry after suction filtration to obtain the first intermediate product;

3) Alkalization leaching: according to the solid-to-liquid ratio of 1:15, the first intermediate product was leached at 90° C. for 80 min with a 0.2 mol/L sodium hydroxide solution, and dried after suction filtration to obtain the second intermediate product;

4) Purification treatment: according to the solid-liquid ratio of 1:10, use 0.2mol/L sodium hypochlorite solution for the second intermediate product in a constant temperature water bath at 80°C for 60min; use absolute ethanol to wash to neutrality, and obtain broken rice after vacuum drying at 60°C Sedge root cellulose.

2. Preparation of cellulose aerogel microporous powder from the roots of sedge

1) Preparation of cellulose aerogel precursor from the roots of Broken Sedge grass

Activation treatment of sedge root cellulose: adding 100 parts by weight of sedge root cellulose to 280-400 parts by weight of N,N-dimethylacetamide solvent at a constant temperature of 100°C Stir in a water bath for 20min to obtain an activated sedge root cellulose solution;

Dissolving the cellulose of the roots of the broken sedge: cooling the activated cellulose solution of the roots of the broken sedge to 70°C, adding 15 parts by weight of sodium chloride, and stirring at a constant temperature for 2 hours to obtain an intermediate cellulose solution;

Microfibrillation treatment: the intermediate cellulose solution was microfibrillated by using a high-frequency ultrasonic cell disruptor under ice-water bath conditions to obtain a microfibrillated sol;

Preparation of Gel Precursor: The microfibrillated sol was placed at 10±1°C for 8 hours, and washed with absolute ethanol to obtain a cellulose aerogel precursor from the roots of Sedgegrass.

2) Cross-linking treatment

The cross-linking initiation solution was prepared with acetic acid and sodium acetate solution according to the substance ratio of 4:1; at 45 °C ± 2 °C, the cross-linking initiation solution was used to fully conduct the cellulose aerogel precursor from the roots of sedge sedge. Soaking, the soaking time is 5h, and the cross-linking strengthened sedge root cellulose gel is obtained.

3) Purification treatment

The cross-linked reinforced sedge root cellulose gel was immersed in a supercritical purifier stored with anhydrous ethanol for purification.

4) Forming treatment

The purified gel is shaped to obtain a cellulose aerogel microporous powder from the roots of Sedgegrass.

3. Preparation of the extract from the young leaves of the pear tree

At a solid-liquid ratio of 1:15, the young leaves of the pear tree were added to absolute ethanol, ultrasonically extracted for 80 minutes, filtered, and dried and sterilized at 121 °C for 20 s to obtain the extract of the young leaves of the pear pear.

4. Preparation of composite impregnated cellulose-based aerogel solids

The ratio by weight: 100 parts by weight of the cellulose aerogel microporous powder of the roots of Sedge sedge, 80-350 parts by weight of the extract of the young leaves of the pear, and batching;

Add the extract of the young leaves of the pear into absolute ethanol, stir and dissolve fully in the sealed reaction kettle, add the cellulose aerogel microporous powder from the roots of the broken sedge, the pressure in the sealed reaction kettle is set to 5MPa, and the temperature is 60°C. Under electromagnetic stirring for 100 min, the reactor was taken out, and evaporated to dryness to obtain a composite impregnated cellulose-based aerogel solid.

According to an exemplary embodiment of the present invention, during the microfibrillation treatment, the ultrasonic frequency is 15.5-17.5 kHz, the ultrasonic time is 10 min, and the pulse interval is 5 s.

According to an exemplary embodiment of the present invention, during the cross-linking treatment, the concentration of acetic acid is 0.1 mol/L, and the concentration of sodium acetate solution is 0.15 mol/L.

According to an exemplary embodiment of the present invention, during the purification process, the temperature in the supercritical purifier is -5° C., the pressure is 5.2 MPa, and the purification medium is liquid CO ₂ .

According to an exemplary embodiment of the present invention, during the molding process, the molding temperature is 105° C. and the molding time is 2h-6.5h.

In the present invention, the composite impregnated cellulose-based aerogel solid is prepared by extracting cellulose from the roots of sedge, preparing cellulose aerogel microporous powder from the roots of sedge, and preparing the extract from the young leaves of Sedge. . The composite impregnated cellulose-based aerogel solid matter according to the embodiment of the present invention can delay the occurrence of mildew in the feed and reduce the degree of mildew in the feed; compared with the prior art, the cost is significantly reduced, and the anti-mildew effect is comparable , so as to realize the effective replacement of chemical antifungal agent and compound antifungal agent, green and non-toxic.

Description of drawings

FIG. 1 is a comparison diagram of the minimum inhibitory concentration (MIC) value of a composite impregnated cellulose-based aerogel solid sample according to an embodiment of the present invention and a sample of the prior art.

Detailed ways

In order to make the technical solutions and advantages of the present invention clearer, the present invention will be further described in detail through the following specific embodiments. Obviously, the described embodiments are 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 work fall within the protection scope of the present invention.

Example:

Preparation of composite impregnated cellulose-based aerogel solids

1. Extraction of cellulose from the roots of sedge

1) Pretreatment: cutting, drying, pulverizing and sieving the washed sedge roots to obtain 50 μm sedge root powder;

2) Acidification pretreatment: according to the solid-liquid ratio of 1:30, 0.1 mol/L oxalic acid solution was used to soak the broken sedge root powder at 35 ° C for 60 min, and then dry after suction filtration to obtain the first intermediate product;

3) Alkalization leaching: according to the solid-to-liquid ratio of 1:15, the first intermediate product was leached at 90° C. for 80 min with a 0.2 mol/L sodium hydroxide solution, and dried after suction filtration to obtain the second intermediate product;

4) Purification treatment: according to the solid-liquid ratio of 1:10, use 0.2 mol/L sodium hypochlorite solution for the second intermediate product in a constant temperature water bath at 80 °C for 60 minutes; use deionized water and anhydrous ethanol to wash to neutrality, and after vacuum drying at 60 °C Obtain the cellulose of the broken sedge roots.

2. Preparation of cellulose aerogel microporous powder from the roots of sedge

1) Preparation of cellulose aerogel precursor from the roots of Broken Sedge grass

Activation treatment of sedge root cellulose: adding 100 parts by weight of sedge root cellulose to 280-400 parts by weight of N,N-dimethylacetamide solvent at a constant temperature of 100°C Stir in a water bath for 20min to obtain an activated sedge root cellulose solution;

Dissolving the cellulose of the roots of the broken sedge: cooling the activated cellulose solution of the roots of the broken sedge to 70°C, adding 15 parts by weight of sodium chloride, and stirring at a constant temperature for 2 hours to obtain an intermediate cellulose solution;

Microfibrillation treatment: The intermediate cellulose solution was microfibrillated by a high-frequency ultrasonic cell disruptor under ice-water bath conditions. The ultrasonic frequency was 15.5-17.5kHz, the ultrasonic time was 10min, and the pulse interval was 5s to obtain microfibrillation. sol;

Preparation of Gel Precursor: The microfibrillated sol was placed at 10±1°C for 8 hours, and washed with absolute ethanol to obtain a cellulose aerogel precursor from the roots of Sedgegrass.

2) Cross-linking treatment

According to the substance ratio of 4:1, 0.1 mol/L acetic acid and 0.15 mol/L sodium acetate solution were used to prepare a cross-linking initiation solution; at 45°C ± 2°C, the cross-linking initiation solution was used to treat sedge roots. The cellulose aerogel precursor was fully soaked for 5 h, and the cross-linked reinforced sedge root cellulose gel was obtained.

3) Purification treatment

Immerse the cross-linked reinforced sedge root cellulose gel in a supercritical purifier stored with absolute ethanol. The temperature in the supercritical purifier is -5°C, the pressure is 5.2MPa, and the purification medium is liquid CO ₂ . Purify.

4) Forming treatment

The purified gel is subjected to molding treatment, the molding temperature is 105° C., and the molding time is 2h-6.5h, to obtain the cellulose aerogel microporous powder of the roots of sedge sedge.

3. Preparation of the extract from the young leaves of the pear tree

At a solid-liquid ratio of 1:15, the young leaves of the pear tree were added to absolute ethanol, ultrasonically extracted for 80 minutes, filtered, and dried and sterilized at 121 °C for 20 s to obtain the extract of the young leaves of the pear pear.

4. Preparation of composite impregnated cellulose-based aerogel solids

The ratio by weight: 100 parts by weight of the cellulose aerogel microporous powder of the roots of Sedge sedge, 80-350 parts by weight of the extract of the young leaves of the pear, and batching;

Add the extract of the young leaves of the pear into absolute ethanol, stir and dissolve fully in the sealed reaction kettle, add the cellulose aerogel microporous powder from the roots of the broken sedge, the pressure in the sealed reaction kettle is set to 5MPa, and the temperature is 60°C. Under electromagnetic stirring for 100 min, the reactor was taken out, and evaporated to dryness to obtain a composite impregnated cellulose-based aerogel solid.

According to the above preparation method, multiple groups of test preparations were carried out, and the sample groups were respectively numbered as T1, T2, T3, T4 and T5. The proportions of each group of tests are shown in Table 1.

Table 1

Specification testing of cellulose aerogel microporous powder from the roots of sedge sedge

According to the technical scheme of preparing composite impregnated cellulose-based aerogel solids in Example 1, a sample group of cellulose aerogel microporous powder from the roots of Sedge sedge was obtained after the molding treatment, and the sample groups were numbered S1 respectively. , S2, S3, S4 and S5.

According to ASTM E2980-2014 "Standard Test Method for Evaluating the Average Particle Size of Powder by Air Permeability", the average particle size of cellulose aerogel microporous powder from the roots of sedge sedge is determined; according to GB/T 21650-2008 " Determination of pore size distribution and porosity of solid materials by mercury intrusion method and gas adsorption method” to determine the volume ratio of micropores in the cellulose aerogel microporous powder of sedge roots; the measurement results are shown in Table 2.

Table 2

Experiment on anti-mildew effect of composite impregnated cellulose-based aerogel solids

Common feed is used as the anti-mildew effect verification of the composite impregnated cellulose-based aerogel solids prepared in the examples of the present application. The feed formula for the test is: corn 67%, soybean meal 25%, pre-powder 6%, soybean oil 2% ;

The composite impregnated cellulose-based aerogel solids prepared in the examples of this application were used as anti-mildew additives, and added to the test feed. The sample groups were numbered as F1, F2, F3, F4, and F5, and the addition ratio was 0.3 %. Sodium diacetate, citric acid and calcium propionate were used as anti-fungal additives, and were added to the test feed at a ratio of 0.3% to form control groups D1, D2 and D3; the test feed without anti-fungal additives was the control group D4.

The samples of each group were evenly mixed and placed in a constant temperature incubator at 30 °C and a relative humidity of 90%. Five replicates were set for each treatment, and samples were taken on the 1st, 2nd, 4th, 6th, 8th, 10th, 15th and 30th days respectively. Analysis: By observing the odor, agglomeration and mildew of the sample group, the sensory evaluation of each sample group is carried out. Evaluation criteria: whether the odor has peculiar smells such as rancidity and musty odor; whether the morphological viscosity is increased, and whether it is caking , whether there are worms in the feed; the evaluation results are shown in Table 3 (the more the number of "+", the more serious the mildew is).

table 3

It can be seen from Table 3 that the composite impregnated cellulose-based aerogel solids prepared in the examples of the present application can delay the occurrence of mildew in the feed and reduce the degree of mildew in the feed; Under the test conditions, the anti-mildew effect is equivalent.

Antibacterial test of composite impregnated cellulose-based aerogel solids

Test indicator bacteria: Fusarium moniliformes as indicator bacteria.

Test medium: tryptone 1%, yeast extract powder 0.5%, glucose 2%, pH 6.8.

Test method: take a 250 mL conical flask, add 50 mL of culture medium to each bottle, and sterilize at high temperature; use sterile saline to wash the spores of Fusarium moniliformes, and add 0.5 mL of spore water to each bottle of culture medium; The composite impregnated cellulose-based aerogel solids were added to the culture medium as an anti-mildew additive, and the sample groups were numbered as T1, T2, T3, T4 and T5, respectively. Sodium diacetate, citric acid and calcium propionate were used as anti-mildew additives to add to the medium to form control groups d1, d2 and d3; the medium without anti-mildew additives was the control group d4. Under the test conditions of 28°C and 200r/min, cultivate at a constant temperature for 20h, observe the test results, and each additive concentration without mold growth is the minimum inhibitory concentration MIC value (mg/mL).

Table 4

It can be seen from Table 4 and Figure 1 that the composite impregnated cellulose-based aerogel solids prepared in the examples of the present application have antibacterial and mildew-proof effects; The effect is comparable.

The specific embodiments described above further describe the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (6)

1. A composite impregnated cellulose-based aerogel solid is characterized in that, the composite impregnated cellulose-based aerogel solid is composed of 100 parts by weight of broken sedge root cellulose gas in a ratio by weight. The gel microporous powder is prepared from 80-350 parts by weight of the extract of the young leaves of the pear, wherein the average particle size of the cellulose aerogel microporous powder of the roots of the broken sedge is not greater than 0.72 μm, and the volume of the micropores accounts for than not less than 75%. 2. A preparation method of composite impregnated cellulose-based aerogel solids, characterized in that the method comprises: 1. Extraction of cellulose from the roots of sedge 1) Pretreatment: shearing, drying, pulverizing and sieving the washed sedge roots to obtain 50 μm sedge root powder; 2) Acidification pretreatment: according to the solid-liquid ratio of 1:30, 0.1 mol/L oxalic acid solution was used to soak the broken sedge root powder at 35 ° C for 60 min, and then dry after suction filtration to obtain the first intermediate product; 3) Alkalization leaching: according to the solid-to-liquid ratio of 1:15, the first intermediate product was leached at 90° C. for 80 min with a 0.2 mol/L sodium hydroxide solution, and dried after suction filtration to obtain the second intermediate product; 4) Purification treatment: according to the solid-liquid ratio of 1:10, use 0.2mol/L sodium hypochlorite solution for the second intermediate product in a constant temperature water bath at 80°C for 60min; use absolute ethanol to wash to neutrality, and obtain broken rice after vacuum drying at 60°C sedge root cellulose; 2. Preparation of cellulose aerogel microporous powder from the roots of sedge 1) Preparation of cellulose aerogel precursor from the roots of Broken Sedge grass Activation treatment of sedge root cellulose: adding 100 parts by weight of sedge root cellulose to 280-400 parts by weight of N,N-dimethylacetamide solvent at a constant temperature of 100°C Stir in a water bath for 20min to obtain an activated broken sedge root cellulose solution; Dissolving the cellulose of the roots of the broken sedge: cooling the activated cellulose solution of the roots of the broken sedge to 70°C, adding 15 parts by weight of sodium chloride, and stirring at a constant temperature for 2 hours to obtain an intermediate cellulose solution; Microfibrillation treatment: the intermediate cellulose solution was microfibrillated by using a high-frequency ultrasonic cell disruptor under ice-water bath conditions to obtain a microfibrillated sol; Preparation of gel precursor: The microfibrillated sol was placed at 10 ± 1 °C for 8 hours, and washed with absolute ethanol to obtain a cellulose aerogel precursor from the roots of sedge; 2) Cross-linking treatment The cross-linking initiation solution was prepared with acetic acid and sodium acetate solution according to the substance ratio of 4:1; at 45 °C ± 2 °C, the cross-linking initiation solution was used to fully conduct the cellulose aerogel precursor from the roots of sedge sedge. Soaking, the soaking time is 5h, to obtain cross-linked reinforced sedge root cellulose gel; 3) Purification treatment Immerse the cross-linked reinforced sedge root cellulose gel in a supercritical purifier stored with absolute ethanol for purification; 4) Forming treatment The purified gel is subjected to molding treatment to obtain cellulose aerogel microporous powder from the roots of Sedgegrass; 3. Preparation of the extract from the young leaves of the pear tree At a solid-liquid ratio of 1:15, the young leaves of the pear tree were added to absolute ethanol, ultrasonically extracted for 80 min, filtered, and dried and sterilized at 121 °C for 20 s to obtain the extract of the young leaves of pear pear; 4. Preparation of composite impregnated cellulose-based aerogel solids The ratio by weight: 100 parts by weight of the cellulose aerogel microporous powder of the roots of sedge, and 80-350 parts by weight of the extract of the young leaves of pear, and batching; Add the extract of the young leaves of the pear into absolute ethanol, stir and dissolve fully in the sealed reaction kettle, add the cellulose aerogel microporous powder from the roots of the broken sedge, the pressure in the sealed reaction kettle is set to 5MPa, and the temperature is 60°C. Under electromagnetic stirring for 100 min, the reactor was taken out, and evaporated to dryness to obtain a composite-impregnated cellulose-based aerogel solid. 3 . The preparation method according to claim 2 , wherein, during the microfibrillation treatment, the ultrasonic frequency is 15.5-17.5 kHz, the ultrasonic time is 10 min, and the pulse interval is 5 s. 4 . 4. The preparation method according to claim 2, wherein, during the cross-linking treatment, the acetic acid concentration is 0.1 mol/L, and the sodium acetate solution concentration is 0.15 mol/L. 5 . The preparation method according to claim 2 , wherein, during the purification treatment, the temperature in the supercritical purifier is -5° C., the pressure is 5.2 MPa, and the purification medium is liquid CO ₂ . 6 . The preparation method according to claim 2 , wherein, during the molding process, the molding temperature is 105° C. and the molding time is 2h-6.5h. 7 .

Images