Preparation method of porous phytic acid chitosan globules

Abstract

The invention relates to the technical field of functional polymer materials, in particular to a preparation method of porous phytic acid chitosan microspheres. The preparation method of the porous phytic acid chitosan globules provided by the invention comprises the following steps: S1, adding chitosan into an organic acid solution, and uniformly mixing to obtain a chitosan solution; s2, adding calcium chloride into the chitosan solution, uniformly mixing, adding a phytic acid solution, and uniformly mixing to obtain a phytic acid chitosan solution; and S3, dropwise adding a sodium hydroxide solution into the phytic acid chitosan solution to generate a small spherical precipitate, and sequentially carrying out solid-liquid separation and freeze drying to obtain the porous phytic acid chitosan globules. The method is simple in process, an organic solvent does not need to be used, and the prepared product is spherical and has a porous structure and high adsorption performance.

Description

Technical Field

[0001] This invention relates to the field of functional polymer materials technology, and in particular to a method for preparing porous phytic acid chitosan microspheres. Background Technology

[0002] With increasing emphasis on green and environmental protection, environmental factors are becoming crucial in the research and development of materials. In daily life, environmentally friendly products made from natural materials are gradually gaining a dominant position, and the concept of green and environmental protection is increasingly taking root in people's hearts.

[0003] Phytic acid and chitosan are both naturally derived bio-based materials. Phytic acid is a phosphate compound widely found in plant seeds, containing multiple phosphate groups and exhibiting strong integrative capacity and acidity. Chitosan is a linear polysaccharide obtained by deacetylation of chitin, rich in amino and hydroxyl groups, and easily chemically modified and functionalized. Phytic acid and chitosan can form stable complexes through electrostatic interactions, which have wide applications in flame retardancy, preservation, and adsorption.

[0004] Traditional phytic acid-chitosan composite materials often present as amorphous powders or flocculent forms, which have problems such as small specific surface area, limited adsorption performance, and poor formability.

[0005] In existing technologies, the synthesis of phytic acid chitosan often relies on organic solvents to promote precipitation, which not only involves complex processes but also poses risks of solvent residue and environmental pollution.

[0006] Therefore, developing a green, efficient method for synthesizing phytic acid chitosan that can impart a porous structure to materials is of great significance for improving their application performance.

[0007] In view of this, the present invention is hereby proposed. Summary of the Invention

[0008] The purpose of this invention is to provide a method for preparing porous phytic acid chitosan microspheres. This method is simple, does not require the use of organic solvents, and produces a spherical product with a porous structure and high adsorption performance.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: This invention provides a method for preparing porous phytic acid-chitosan microspheres, comprising the following steps: S1. Add chitosan to the organic acid solution and mix well to obtain a chitosan solution; S2. Add calcium chloride to the chitosan solution and mix well, then add phytic acid solution and mix well to obtain phytic acid-chitosan solution. S3. Sodium hydroxide solution is added dropwise to the phytic acid-chitosan solution to form small spherical precipitates. These precipitates are then subjected to solid-liquid separation and freeze-drying to obtain the porous phytic acid-chitosan spheres.

[0010] Further, in step S1, the organic acid solution includes one or more of formic acid, acetic acid, and citric acid.

[0011] Furthermore, in step S1, the pH of the organic acid solution is ≤5.

[0012] Further, in step S1, the mass ratio of chitosan to organic acid in the organic acid solution is (0.2~5):1.

[0013] Further, in step S2, the mass ratio of phytic acid to chitosan in the phytic acid solution is (0.5~2):1.

[0014] Further, in step S2, the mass ratio of calcium chloride to phytic acid in the phytic acid solution is (0.1~0.2):1.

[0015] Furthermore, in step S2, the mass concentration of the phytic acid solution is 50%.

[0016] Furthermore, in step S3, the mass concentration of the sodium hydroxide solution is 5% to 10%.

[0017] Further, in step S3, the sodium hydroxide solution is added dropwise using a syringe with a needle inner diameter of 0.3~0.5mm.

[0018] Furthermore, in step S3, the freeze-drying time is 24 hours.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention discloses a method for preparing porous phytic acid-chitosan microspheres, which involves forming a mixed solution of organic acid, chitosan, calcium chloride, and phytic acid, adding sodium hydroxide solution dropwise to the mixed solution, and then obtaining phytic acid-chitosan microspheres with a porous structure after solid-liquid separation and freeze-drying. The introduction of calcium ions facilitates the formation of precipitates and regular sphere formation of phytic acid-chitosan without the need for toxic organic solvents. The freeze-drying process promotes the formation of pore structures, significantly improving the specific surface area and adsorption capacity. Furthermore, the method is simple and the reaction conditions are mild. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0021] In some embodiments of the present invention, a method for preparing porous phytic acid-chitosan microspheres is provided, comprising the following steps: S1. Add chitosan to the organic acid solution and mix well to obtain a chitosan solution; S2. Add calcium chloride to the chitosan solution and mix well, then add phytic acid solution and mix well to obtain phytic acid-chitosan solution. S3. Sodium hydroxide solution is added dropwise to phytic acid chitosan solution. After the formation of small spherical precipitates, the precipitates are then subjected to solid-liquid separation and freeze-drying to obtain porous phytic acid chitosan spheres.

[0022] The method for preparing porous phytic acid-chitosan microspheres of the present invention involves forming a mixed solution of organic acid, chitosan, calcium chloride and phytic acid, adding sodium hydroxide solution dropwise to the mixed solution to promote the formation of spherical precipitates of phytic acid-chitosan, and then obtaining phytic acid-chitosan microspheres with a porous structure after solid-liquid separation and freeze-drying.

[0023] In the preparation method of porous phytic acid-chitosan microspheres of the present invention, both chitosan and phytic acid are bio-based materials of natural origin. Using natural bio-based materials as raw materials, the sources are wide-ranging and green and safe.

[0024] The method for preparing porous phytic acid chitosan microspheres of the present invention is simple, mild, and the reaction is carried out at room temperature without the need for toxic or harmful organic solvents.

[0025] In the preparation method of porous phytic acid-chitosan microspheres of the present invention, the introduction of calcium ions enhances the interaction between phytic acid and chitosan, which is conducive to the formation of phytic acid-chitosan precipitate without the need for toxic organic solvents to promote precipitation.

[0026] In the preparation method of porous phytic acid chitosan microspheres of the present invention, a freeze-drying process is used to form spherical materials with a porous structure, which significantly improves the specific surface area and adsorption capacity of the product.

[0027] The porous phytic acid-chitosan microspheres prepared by the method of the present invention have high specific surface area and high adsorption performance, and are suitable for heavy metal ion adsorption, drug carrier and other fields.

[0028] In some embodiments of the present invention, in step S1, the organic acid solution includes one or more of formic acid, acetic acid, and citric acid.

[0029] In some embodiments of the present invention, in step S1, the organic acid is dissolved in water to obtain an organic acid solution.

[0030] In some embodiments of the invention, in step S1, the pH of the organic acid solution is ≤5; typically, but not limitingly, for example, in step S1, the pH of the organic acid solution can be 1, 2, 3, 4, 5, and any value between any two of them.

[0031] In some embodiments of the present invention, in step S1, the mass ratio of chitosan to organic acid in the organic acid solution is (0.2~5):1; typically, but not limitingly, for example, in step S1, the mass ratio of chitosan to organic acid in the organic acid solution can be 0.2:1, 1:1, 2:1, 3:1, 4:1, 5:1, and any value between any two of these.

[0032] In some embodiments of the present invention, in step S2, the mass ratio of phytic acid to chitosan in the phytic acid solution is (0.5~2):1; typically, but not limitingly, for example, in step S2, the mass ratio of phytic acid to chitosan in the phytic acid solution can be 0.5:1, 1:1, 1.5:1, 2:1, and any value between any two of them.

[0033] In some embodiments of the present invention, in step S2, the mass ratio of calcium chloride to phytic acid in the phytic acid solution is (0.1~0.2):1; typically, but not limitingly, for example, in step S2, the mass ratio of calcium chloride to phytic acid in the phytic acid solution can be 0.1:1, 0.12:1, 0.14:1, 0.16:1, 0.18:1, 0.2:1, and any value between any two of these.

[0034] In the preparation method of porous phytic acid-chitosan microspheres of the present invention, calcium ions are introduced by adding an appropriate amount of calcium chloride, thereby strengthening the interaction between phytic acid and chitosan, promoting precipitation formation, and inducing it to become spherical. If the amount of calcium chloride is too small, the strengthening of the interaction between phytic acid and chitosan is limited, and complete microspheres cannot be formed; if the amount of calcium chloride is too large, calcium phytate precipitation will form, which also prevents the formation of microspheres.

[0035] In some embodiments of the present invention, in step S2, the phytic acid solution comprises an aqueous solution of phytic acid.

[0036] In some embodiments of the present invention, in step S2, the mass concentration of the phytic acid solution is 50%.

[0037] In some embodiments of the present invention, in step S3, the sodium hydroxide solution comprises an aqueous solution of sodium hydroxide.

[0038] In some embodiments of the present invention, in step S3, the mass concentration of the sodium hydroxide solution is 5% to 10%; typically, but not limitingly, for example, in step S3, the mass concentration of the sodium hydroxide solution can be 5%, 6%, 7%, 8%, 9%, 10%, and any value between any two of these.

[0039] In some embodiments of the present invention, in step S3, sodium hydroxide solution is added dropwise to the phytic acid-chitosan solution to neutralize the system. The role of sodium hydroxide is to neutralize the acidity of the solution, making the solution neutral; the amount added depends on the degree of acidity of the solution.

[0040] In some embodiments of the present invention, in step S3, a needle syringe with a needle inner diameter of 0.3 to 0.5 mm is used to drip sodium hydroxide solution; typically, but not limitingly, for example, in step S3, the needle inner diameter of the needle syringe can be 0.3 mm, 0.4 mm, 0.5 mm, and any value between any two of them.

[0041] In the preparation method of porous phytic acid chitosan microspheres of the present invention, a sodium hydroxide solution with a mass concentration of 5% to 10% is added dropwise using a syringe with a needle inner diameter of 0.3 to 0.5 mm. This ensures that the solution gradually and stably precipitates and forms regular spheres, which is beneficial for forming porous phytic acid chitosan microspheres with small size, relatively uniform size, and good sphericity.

[0042] In some embodiments of the present invention, in step S3, the freeze-drying time is 24 hours. Porous phytic acid-chitosan microspheres with a distinct pore structure can be obtained through freeze-drying.

[0043] In some embodiments of the present invention, the porous phytic acid chitosan microspheres have a macroporous structure.

[0044] In some embodiments of the present invention, the porosity of the porous phytic acid chitosan microspheres is 85% to 95%.

[0045] Example 1 The method for preparing porous phytic acid-chitosan microspheres provided in this embodiment includes the following steps: S1. Weigh 2g of citric acid and dissolve it in 100mL of deionized water. Stir until completely dissolved to obtain an organic acid solution with a pH of 2.3. Add 2g of chitosan powder to the organic acid solution and stir until completely dissolved to obtain a light yellow chitosan solution. S2. Add 0.4g of calcium chloride to the chitosan solution and stir to dissolve; then slowly add 2g of 50% phytic acid solution and stir until homogeneous to obtain phytic acid-chitosan solution. S3. Using a syringe with a needle inner diameter of 0.3 mm, a 5% sodium hydroxide solution was added dropwise to the phytic acid-chitosan solution to make the system neutral. White spherical precipitates were observed to form. After filtration, the precipitates were freeze-dried for 24 hours to obtain porous phytic acid-chitosan spheres.

[0046] Example 2 The method for preparing porous phytic acid-chitosan microspheres provided in this embodiment includes the following steps: S1. Measure 10 mL of acetic acid and dissolve it in 100 mL of deionized water. Stir until completely dissolved to obtain an organic acid solution with a pH of 2.5. Add 2g of chitosan powder to the organic acid solution and stir until completely dissolved to obtain a light yellow chitosan solution. S2. Add 0.3g of calcium chloride to the chitosan solution and stir to dissolve; then slowly add 2g of 50% phytic acid solution and stir until homogeneous to obtain phytic acid-chitosan solution. S3. Using a syringe with a needle inner diameter of 0.4 mm, an 8% sodium hydroxide solution was added dropwise to the phytic acid chitosan solution to make the system neutral. White spherical precipitates were observed to form. After filtration, the precipitates were freeze-dried for 24 hours to obtain porous phytic acid chitosan spheres.

[0047] Example 3 The method for preparing porous phytic acid-chitosan microspheres provided in this embodiment includes the following steps: S1. Measure 10 mL of formic acid and dissolve it in 100 mL of deionized water. Stir until completely dissolved to obtain an organic acid solution with a pH of 1.9. Add 2g of chitosan powder to the organic acid solution and stir until completely dissolved to obtain a light yellow chitosan solution. S2. Add 0.2g of calcium chloride to the chitosan solution and stir to dissolve; then slowly add 2g of 50% phytic acid solution and stir until homogeneous to obtain phytic acid-chitosan solution. S3. Using a syringe with a needle inner diameter of 0.5 mm, a 10% sodium hydroxide solution was added dropwise to the phytic acid chitosan solution to make the system neutral. White spherical precipitates were observed to form. After filtration, the precipitates were freeze-dried for 24 hours to obtain porous phytic acid chitosan spheres.

[0048] Comparative Example 1 The preparation method of the phytic acid chitosan material provided in this comparative example is the same as that in Example 1, except that calcium chloride is not added in step S2; the final product, phytic acid chitosan material, is a flocculent precipitate that does not form regular small spheres and has poor adsorption performance.

[0049] Comparative Example 2 The preparation method of the phytic acid chitosan material provided in this comparative example is the same as that in Example 1, except that in step S3, freeze drying is replaced by forced air drying at 80°C for 12 hours; the final product, phytic acid chitosan microspheres, has an indistinct pore structure and reduced adsorption capacity.

[0050] Test case The shape and porosity of the porous phytic acid chitosan microspheres prepared in Examples 1-3 and the phytic acid chitosan materials prepared in Comparative Examples 1-2 are shown in Table 1.

[0051] Table 1

[0052] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A method for preparing porous phytic acid-chitosan microspheres, characterized in that, Includes the following steps: S1. Add chitosan to the organic acid solution and mix well to obtain a chitosan solution; S2. Add calcium chloride to the chitosan solution and mix well, then add phytic acid solution and mix well to obtain phytic acid-chitosan solution. S3. Sodium hydroxide solution is added dropwise to the phytic acid-chitosan solution to form small spherical precipitates. These precipitates are then subjected to solid-liquid separation and freeze-drying to obtain the porous phytic acid-chitosan spheres.

2. The method for preparing porous phytic acid-chitosan microspheres according to claim 1, characterized in that, In step S1, the organic acid solution includes one or more of formic acid, acetic acid, and citric acid.

3. The method for preparing porous phytic acid-chitosan microspheres according to claim 1, characterized in that, In step S1, the pH of the organic acid solution is ≤5.

4. The method for preparing porous phytic acid-chitosan microspheres according to claim 1, characterized in that, In step S1, the mass ratio of chitosan to organic acid in the organic acid solution is (0.2~5):

1.

5. The method for preparing porous phytic acid-chitosan microspheres according to claim 1, characterized in that, In step S2, the mass ratio of phytic acid to chitosan in the phytic acid solution is (0.5~2):

1.

6. The method for preparing porous phytic acid-chitosan microspheres according to claim 1, characterized in that, In step S2, the mass ratio of calcium chloride to phytic acid in the phytic acid solution is (0.1~0.2):

1.

7. The method for preparing porous phytic acid-chitosan microspheres according to claim 1, characterized in that, In step S2, the phytic acid solution has a mass concentration of 50%.

8. The method for preparing porous phytic acid-chitosan microspheres according to claim 6, characterized in that, In step S3, the mass concentration of the sodium hydroxide solution is 5% to 10%.

9. The method for preparing porous phytic acid-chitosan microspheres according to claim 8, characterized in that, In step S3, the sodium hydroxide solution is added dropwise using a syringe with a needle inner diameter of 0.3~0.5mm.

10. The method for preparing porous phytic acid-chitosan microspheres according to claim 9, characterized in that, In step S3, the freeze-drying time is 24 hours.

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