Preparation method and product of a cellulose triacetate-lignosulfonate composite microsphere

Abstract

The present invention discloses a preparation method and product of cellulose triacetate-lignosulfonate composite microspheres, comprising the following steps: dissolving cellulose triacetate in dichloromethane to obtain a first slurry; dissolving lignosulfonate in N,N-dimethylformamide to obtain a second slurry; mixing the first slurry and the second slurry in a fixed ratio, stirring, adding iron oxide nanoparticles after stirring and continuing to stir to obtain a third slurry; adding span 80 to the third slurry and stirring to obtain a fourth slurry; dissolving sodium dodecyl sulfate in deionized water, slowly adding the fourth slurry and evaporating to obtain a crude product; repeatedly washing the crude product with distilled water and absolute ethanol for multiple times, and then drying it under vacuum to obtain cellulose triacetate-lignosulfonate composite microspheres; the composite microsphere product prepared by this method has a good adsorption effect on metal ions.

Description

Technical Field

[0001] The present invention relates to the technical field of cellulose microspheres, and particularly relates to a preparation method and product of a cellulose triacetate-lignosulfonate composite microsphere. Background Art

[0002] Cellulose acetate, also known as cellulose acetate ester, is a man-made fiber prepared by an esterification reaction using acetic acid and cellulose as raw materials. Wood cellulose is processed through acetylation, hydrolysis, drying and other processes to obtain sheet-shaped cellulose diacetate flakes (abbreviation: "acetate flakes"), and the acetate flakes are spun to obtain cellulose diacetate tow (abbreviation: "tow"). Cellulose triacetate can be directly esterified from cellulose such as cotton linters pulp and wood pulp in glacial acetic acid, acetic anhydride, and sulfuric acid conditions, and then partial hydrolysis of cellulose triacetate is carried out to obtain a cellulose diacetate product with an acetyl substitution degree between 2.0 and 2.6.

[0003] Cellulose acetate can have other applications according to its shape differences (such as movie film, film or fiber), and among them, cellulose acetate microspheres are a special field of cellulose acetate application. Cellulose acetate microspheres not only retain the original properties of cellulose acetate, but also have hydrophilicity, porosity, a large specific surface area, good swelling properties, etc., and can be widely used as adsorbents in chromatography and separation technologies. Since the hydroxyl groups in the cellulose molecule are replaced by acetyl groups, the hydrogen bond force is weakened, the intermolecular distance is increased, and the affinity of the active groups hydroxyl and carbonyl in the molecule for precious metals is greatly enhanced, so it can be used as an adsorbent for precious metals. Due to the unique microscopic characteristics and industrial adaptability of cellulose acetate microspheres, they are gradually attracting attention and are expected to be widely used in the fields of environmental protection, biochemistry, bioengineering, medicine, pharmacy, etc.

[0004] However, when the existing cellulose acetate microspheres are used as metal adsorbents, the adsorption effect is poor, and it is necessary to further improve and enhance their adsorption effect. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects or problems existing in the background art, and to provide a preparation method and product of a cellulose triacetate-lignosulfonate composite microsphere. The composite microsphere product prepared by this method has a good adsorption effect on metal ions.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A method for preparing cellulose triacetate-lignosulfonate composite microspheres, comprising the following steps: dissolving cellulose triacetate in dichloromethane to obtain a first slurry; dissolving lignosulfonate in N,N-dimethylformamide to obtain a second slurry; mixing the first slurry and the second slurry in a fixed ratio, stirring, adding iron oxide nanoparticles after stirring and continuing to stir to obtain a third slurry; adding Span 80 to the third slurry and stirring to obtain a fourth slurry; dissolving sodium dodecyl sulfate in deionized water, slowly adding the fourth slurry and then evaporating to obtain a crude product; repeatedly washing the crude product with distilled water and absolute ethanol for multiple times, and then drying it under vacuum to obtain cellulose triacetate-lignosulfonate composite microspheres.

[0008] Further, in the first slurry, the dosage ratio of cellulose triacetate to dichloromethane is 0.8 g:120 mL to 1.2 g:120 mL.

[0009] Further, in the second slurry, the dosage ratio of lignosulfonate to N,N-dimethylformamide is 2.5 g:40 mL to 3.5 g:40 mL.

[0010] Further, in the third slurry, the first slurry and the second slurry are mixed at a volume ratio of 8-12:1, and the dosage ratio of iron oxide to the third slurry is 0.02 g:40 mL to 0.04 g:40 mL.

[0011] Further, in the fourth slurry, the dosage ratio of Span 80 to the third slurry is 0.7 g:40 mL to 0.8 g:40 mL.

[0012] Further, after dissolving the sodium dodecyl sulfate in deionized water, heat it in a water bath at 38°C to 42°C with continuous stirring, and slowly dropwise add the fourth slurry. After the dropping is completed, slowly evaporate; wherein, the dosage ratio of sodium dodecyl sulfate to deionized water is 1 g:200 mL to 2 g:200 mL.

[0013] Further, repeatedly wash the crude product with distilled water and absolute ethanol for multiple times, and dry it under vacuum at 50°C to 70°C.

[0014] In addition, the present invention also provides a cellulose triacetate-lignosulfonate composite microsphere, which is prepared by using the method for preparing cellulose triacetate-lignosulfonate composite microspheres described in any one of the above, and is characterized in that the average particle size of the composite microsphere is 10 μm to 60 μm, and the BET specific surface area is 40 m 2 / g to 60 m 2 / g.

[0015] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0016] The cellulose triacetate-lignosulfonate composite microspheres prepared by the preparation method provided by the present invention have a spherical structure, a smooth and porous surface, a uniform pore size distribution, small holes are also formed inside the microspheres, and lignosulfonate and magnetite nanoparticles are compounded, and the adsorption of metal ions is stronger. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for the description of the embodiments. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings.

[0018] Figure 1 It is a scanning electron microscope schematic diagram of a single composite microsphere prepared by the preparation method of the cellulose triacetate-lignosulfonate composite microspheres provided by the present invention;

[0019] Figure 2 It is a scanning electron microscope schematic diagram of the composite microspheres prepared by the preparation method of the cellulose triacetate-lignosulfonate composite microspheres provided by the present invention;

[0020] Figure 3 It is an enlarged scanning electron microscope schematic diagram of a single composite microsphere prepared by the preparation method of the cellulose triacetate-lignosulfonate composite microspheres provided by the present invention;

[0021] Figure 4 It is a schematic diagram of the removal rate of copper ions by the cellulose triacetate-lignosulfonate composite microspheres provided in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are the preferred embodiments of the present invention and should not be regarded as excluding other embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0023] In the claims, the description and the above-mentioned drawings of the present invention, unless otherwise clearly defined, when using terms such as "first", "second" or "third", etc., are all used to distinguish different objects, rather than for describing a specific order.

[0024] In the claims, the description and the above-mentioned drawings of the present invention, unless otherwise clearly defined, for orientation terms, such as the use of terms "center", "horizontal", "vertical", "level", "vertical", "top", "bottom", "inner", "outer", "upper", "lower", "front", "rear", "left", "right", "clockwise", "counterclockwise", etc. to indicate orientation or positional relationship are based on the orientation and positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, so it should not be construed as limiting the specific protection scope of the present invention.

[0025] In the claims, the description and the above-mentioned drawings of the present invention, unless otherwise clearly defined, if the terms "fixed connection" or "fixedly connected" are used, they should be understood in a broad sense, that is, any connection method without displacement relationship and relative rotation relationship between the two, that is, including non-detachable fixed connection, detachable fixed connection, being integrally connected, and being fixedly connected through other devices or elements.

[0026] In the claims, the description and the above-mentioned drawings of the present invention, if the terms "comprising", "having" and their variants are used, are intended to mean "including but not limited to".

[0027] The present invention provides a method for preparing cellulose triacetate-lignosulfonate composite microspheres, comprising the following steps:

[0028] S1. Dissolve cellulose triacetate in dichloromethane to obtain a first slurry;

[0029] S2. Dissolve lignosulfonate in N,N-dimethylformamide to obtain a second slurry;

[0030] S3. Mix the first slurry and the second slurry in a fixed ratio, stir, and add iron oxide nanoparticles after stirring and continue to stir to obtain a third slurry;

[0031] S4. Add Span 80 to the third slurry and stir to obtain a fourth slurry;

[0032] S5. Dissolve sodium dodecyl sulfate in deionized water, slowly add it to the fourth slurry and evaporate to obtain a crude product;

[0033] S6. Wash the crude product repeatedly with distilled water and absolute ethanol, and then dry it under vacuum to obtain cellulose triacetate-lignosulfonate composite microspheres.

[0034] Wherein, in the first slurry of S1, the dosage ratio of cellulose triacetate to dichloromethane is 0.8 g:120 mL to 1.2 g:120 mL.

[0035] In the second slurry of S2, the dosage ratio of lignosulfonate to N,N-dimethylformamide is 2.5 g:40 mL to 3.5 g:40 mL.

[0036] In the third slurry of S3, the first slurry and the second slurry are mixed at a volume ratio of 8-12:1, and the dosage ratio of the magnetite to the third slurry is 0.02 g:40 mL to 0.04 g:40 mL.

[0037] In the fourth slurry of S4, the dosage ratio of span 80 to the third slurry is 0.7 g:40 mL to 0.8 g:40 mL.

[0038] In S5, after dissolving the sodium dodecyl sulfate in deionized water, it is heated and continuously stirred under the water bath condition of 38°C to 42°C, and the fourth slurry is slowly added dropwise, and after the addition is completed, it is slowly evaporated; wherein, the dosage ratio of the sodium dodecyl sulfate to the deionized water is 1 g:200 mL to 2 g:200 mL.

[0039] In S6, the crude product is repeatedly washed with distilled water and absolute ethanol, and vacuum dried at 50°C to 70°C.

[0040] The present invention also provides a cellulose triacetate-lignosulfonate composite microsphere (PMCLM), which is prepared by the above-mentioned preparation method of the cellulose triacetate-lignosulfonate composite microsphere. The average particle size of the prepared composite microsphere is 10 μm to 60 μm, and the BET specific surface area is 40 m 2 / g to 60 m 2 / g.

[0041] The cellulose triacetate-lignosulfonate composite microsphere prepared by the above method has a spherical structure, a smooth and porous surface, a uniform pore size distribution, small holes are also formed inside the microsphere, and lignosulfonate and magnetite nanoparticles are compounded, and the adsorption of metal ions is stronger.

[0042] Specifically, the specification of the present invention provides the following examples to further illustrate the above method.

[0043] Example 1

[0044] The cellulose triacetate-lignosulfonate composite microsphere is prepared by the following steps:

[0045] S1. Dissolve 0.3 g of cellulose triacetate in 36 mL of dichloromethane to obtain the first slurry;

[0046] S2. Dissolve 1.5 g of lignosulfonate in 20 mL of N,N-dimethylformamide to obtain the second slurry;

[0047] S3. Mix the first slurry and the second slurry in a fixed ratio of 10:1, stir for 15 min, and after stirring, take 40 mL, add 0.03 g of iron oxide nanoparticles and continue to stir for 15 min to obtain the third slurry;

[0048] S4. Add 0.75 g of Span 80 to the third slurry and stir to obtain the fourth slurry;

[0049] S5. Dissolve 1.5 g of sodium dodecyl sulfate in 200 mL of deionized water, heat in a 40 °C water bath and stir continuously, while slowly adding the fourth slurry, and then slowly evaporate for 4 h to obtain the crude product;

[0050] S6. Wash the crude product repeatedly with distilled water and absolute ethanol, and then vacuum dry at 60 °C for 24 h to obtain the cellulose triacetate-lignosulfonate composite microspheres.

[0051] Example 2

[0052] The cellulose triacetate-lignosulfonate composite microspheres are prepared through the following steps:

[0053] S1. Dissolve 0.2 g of cellulose triacetate in 30 mL of dichloromethane to obtain the first slurry;

[0054] S2. Dissolve 2.5 g of lignosulfonate in 40 mL of N,N-dimethylformamide to obtain the second slurry;

[0055] S3. Mix the first slurry and the second slurry in a fixed ratio of 8:1, stir for 15 min, and after stirring, take 40 mL, add 0.02 g of iron oxide nanoparticles and continue to stir for 15 min to obtain the third slurry;

[0056] S4. Add 0.7 g of Span 80 to the third slurry and stir to obtain the fourth slurry;

[0057] S5. Dissolve 1 g of sodium dodecyl sulfate in 200 mL of deionized water, heat in a 40 °C water bath and stir continuously, while slowly adding the fourth slurry, and then slowly evaporate for 4 h to obtain the crude product;

[0058] S6. Wash the crude product repeatedly with distilled water and absolute ethanol, and then vacuum dry at 60 °C for 24 h to obtain the cellulose triacetate-lignosulfonate composite microspheres.

[0059] Example 3

[0060] The cellulose triacetate-lignosulfonate composite microspheres are prepared through the following steps:

[0061] S1. Dissolve 0.3 g of cellulose triacetate in 30 mL of dichloromethane to obtain the first slurry;

[0062] S2. Dissolve 3.5 g of lignosulfonate in 40 mL of N,N-dimethylformamide to obtain a second slurry;

[0063] S3. Mix the first slurry and the second slurry at a fixed ratio of 12:1 and stir for 15 min. After stirring, take 40 mL and add 0.04 g of iron oxide nanoparticles and continue to stir for 15 min to obtain a third slurry;

[0064] S4. Add 0.8 g of Span 80 to the third slurry and stir to obtain a fourth slurry;

[0065] S5. Dissolve 2 g of sodium dodecyl sulfate in 200 mL of deionized water, heat it in a 40 °C water bath and stir continuously. At the same time, slowly add the fourth slurry, and then slowly evaporate for 4 h to obtain a crude product;

[0066] S6. Wash the crude product repeatedly with distilled water and absolute ethanol, and then vacuum dry it at 60 °C for 24 h to obtain cellulose triacetate-lignosulfonate composite microspheres.

[0067] In addition, the specification of the present invention also provides the following comparative examples:

[0068] Comparative Example 1

[0069] Add 0.3 g of cellulose triacetate to a round-bottom flask, then add 20 mL of dichloromethane, and stir continuously on a constant temperature heating magnetic stirrer at 25 °C for 2 hours to dissolve; add 0.375 g of Span 80 to the round-bottom flask and stir for 15 minutes; add 0.03 g of iron oxide nanoparticles to the round-bottom flask and stir for 15 minutes; drop the above mixture into a sodium dodecyl sulfate solution (0.75%, 100 mL), and volatilize for 4 hours to obtain a crude product; wash the crude product with hot distilled water and ethanol, and then vacuum dry it at 60 °C for 24 hours to obtain cellulose triacetate microspheres (PMCM).

[0070] Taking the cellulose triacetate-lignosulfonate composite microspheres prepared in Example 1 as an example, referring to Figures 1 to 3 , the composite microspheres have a spherical structure, a smooth and porous surface, a uniform pore size distribution, and the particle size is mainly concentrated between 20-30 μm. There are many small holes on the surface and inside of the composite microspheres, which increases the specific surface area of the microspheres and helps to promote adsorption. The generation of these microporous structures is because the immiscibility of the dichloromethane solution dissolving cellulose and the aqueous sodium dodecyl sulfonate solution forms a "water-in-oil" emulsion system. When the dichloromethane evaporates in a 40 °C water bath and Span 80 is removed during washing, a porous structure is formed. At the same time, the BET specific surface area of the cellulose triacetate-lignosulfonate composite microspheres prepared in Example 1 is 51.56 m2 / g.

[0071] Experiments were conducted on the dosage of the cellulose triacetate-lignosulfonate composite microspheres and cellulose triacetate microspheres provided in Example 1 and Comparative Example 1 above and their effects on the removal rate of copper ions. The experimental results are as Figure 4 shown. It can be Figure 4 seen that before the dosage of the cellulose triacetate-lignosulfonate composite microspheres (PMCLM) increases to a certain amount, the removal rate of the cellulose triacetate-lignosulfonate composite microspheres prepared in Example 1 is higher than that of the cellulose triacetate microspheres prepared in Comparative Example 1, indicating that the composite microspheres have a better removal effect on copper ions than the conventional microspheres prepared in the comparative example.

[0072] The above description of the specification and examples is used to explain the protection scope of the present invention, but does not constitute a limitation on the protection scope of the present invention. Through the inspiration of the present invention or the above examples, those of ordinary skill in the art, combined with common general knowledge, ordinary technical knowledge in the art and / or prior art, can obtain modifications, equivalent substitutions or other improvements to the embodiments of the present invention or some of its technical features through logical analysis, reasoning or limited experiments, which should be included in the protection scope of the present invention.

Claims

1. A method for preparing cellulose triacetate-lignosulfonate composite microspheres, characterized in that, It includes the following steps: Dissolve cellulose triacetate in dichloromethane to obtain a first slurry; Dissolve lignosulfonate in N,N-dimethylformamide to obtain a second slurry; Mix the first slurry and the second slurry in a fixed ratio, stir, add iron oxide nanoparticles after stirring and continue to stir to obtain a third slurry; Add Span 80 to the third slurry and stir to obtain a fourth slurry; Dissolve sodium dodecyl sulfate in deionized water, slowly add it to the fourth slurry and then evaporate to obtain a crude product; Wash the crude product repeatedly with distilled water and absolute ethanol, and then vacuum dry to obtain cellulose triacetate-lignosulfonate composite microspheres; In the first slurry, the dosage ratio of cellulose triacetate to dichloromethane is 0.8 g:120 mL to 1.2 g:120 mL; In the second slurry, the dosage ratio of lignosulfonate to N,N-dimethylformamide is 2.5 g:40 mL to 3.5 g:40 mL; in the third slurry, the first slurry and the second slurry are mixed at a volume ratio of 8-12:1, and the dosage ratio of iron oxide to the third slurry is 0.02 g:40 mL to 0.04 g:40 mL; In the fourth slurry, the dosage ratio of Span 80 to the third slurry is 0.7 g:40 mL to 0.8 g:40 mL; Dissolve the sodium dodecyl sulfate in deionized water, heat it in a water bath at 38°C to 42°C and stir continuously, while slowly dropping the fourth slurry, and slowly evaporate after dropping; wherein, the dosage ratio of sodium dodecyl sulfate to deionized water is 1 g:200 mL to 2 g:200 mL; Wash the crude product repeatedly with distilled water and absolute ethanol, and vacuum dry it at 50°C to 70°C.

2. A cellulose triacetate-lignosulfonate composite microsphere, which is prepared by using the preparation method of the cellulose triacetate-lignosulfonate composite microsphere as described in claim 1, and is characterized in that, The average particle size of the composite microspheres is from 10 μm to 60 μm, and the BET specific surface area is from 40 m 2 / g to 60 m 2 / g.

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