A method for the synthesis of hydroxyapatite with uniform and controllable size

Abstract

The application provides a synthesis method of hydroxyapatite with uniform and controllable size, wherein a calcium source reaction solution is mixed with a phosphorus source reaction solution, a reaction is carried out under stirring after pH adjustment, and a particle size adjusting agent and a charge interference agent are added after the reaction is completed, so that hydroxyapatite with controllable single crystal size and uniform particle size is obtained. The application has the beneficial effect that: hydroxyapatite is synthesized by using the reactor, the liquid flow rate and the rotation speed of the reactor have great influence on the formation of particles and the uniformity of particle size distribution, controllable single crystal size and uniform particle size of hydroxyapatite can be obtained by controlling parameters such as flow rate and rotation speed, and adding additives such as particle size adjusting agent and charge interference agent, and the back mixing process can promote the size uniformity of particles. In addition, the reactor is a large continuous reactor, which can continuously sample and obtain products at the same time, and has good effect on the preparation of large-scale hydroxyapatite with limited agglomeration.

Description

Technical Field

[0001] This invention relates to a hydroxyapatite synthesis reactor with uniform and controllable dimensions, belonging to the field of functional materials. Background Technology

[0002] Hydroxyapatite (HAP) is a calcium phosphate biomaterial with the chemical formula Ca. 10 (PO4)6(OH)2, a major inorganic component of teeth and bones, is non-toxic and biocompatible, and is widely used in the medical, pharmaceutical, and chemical industries. The synthesis methods of hydroxyapatite mainly include wet chemical methods, sol-gel methods, emulsion methods, chemical precipitation methods, hydrothermal reactions, and mechanochemical synthesis. Different synthesis methods can produce HAP with different morphologies, such as nanoparticles, needle-like particles, and fibrous structures. Among these processes, wet chemical processes are widely used due to their simplicity, and the single-crystal size and particle size can be changed by controlling reaction parameters. However, no synthesis system can integrate feeding, parameter control, reaction process control, and system homogenization to achieve controllable single-crystal size of hydroxyapatite. In recent years, hydroxyapatite particles have attracted significant attention due to their unique properties and potential applications in various fields. Since the properties of hydroxyapatite depend on its size and morphology, colloidal wet chemical processes have been widely used to synthesize hydroxyapatite particles. Morphological modification of hydroxyapatite particles in solution is a developing trend in the chemical synthesis of hydroxyapatite. To obtain and utilize the novel properties and high performance of hydroxyapatite particles, it is essential to achieve not only controllable single-crystal size but also a uniform size distribution of the particles. An urgent task is to develop a reliable reactor for controlling the single-crystal size of hydroxyapatite particles with high product quality, enabling the wider and more widespread application of high-performance hydroxyapatite particles. Summary of the Invention

[0003] While the wet chemical synthesis process for hydroxyapatite can significantly alter its size, issues such as agglomeration, poor single-crystal size control, and uneven particle size frequently arise during production. These problems reduce the quality of the hydroxyapatite product, making it unsuitable for various applications.

[0004] The purpose of this invention is to provide a hydroxyapatite synthesis reactor with uniform and controllable dimensions, comprising the following steps:

[0005] After mixing the calcium source reaction solution and the phosphorus source reaction solution, the pH was adjusted and the reaction was carried out under stirring conditions. After the reaction was completed, a particle size regulator and a charge interference agent were added to obtain hydroxyapatite with controllable single crystal size and uniform particle size.

[0006] The calcium source reaction solution is selected from one or more of calcium nitrate, calcium chlorate, calcium sulfate, calcium perchlorate, calcium bicarbonate, and calcium dihydrogen phosphate.

[0007] The phosphorus source reaction solution is selected from one or more of dihydrogen phosphate, hydrogen phosphate, and orthophosphate.

[0008] The starting material molar concentrations of the calcium source reaction solution and the phosphorus source reaction solution are between 0.5 and 5 M, and the molar ratio (Ca / P) of calcium atoms in the calcium source reaction solution to phosphorus atoms in the phosphorus source reaction solution is 1.6-1.8, preferably 1.67.

[0009] During the reaction, the pH of the alkaline phosphate solution was adjusted to 9-12.

[0010] The reaction process is a continuous reaction process, wherein the flow rates of the calcium source reaction solution and the phosphorus source reaction solution are 100-700 mL / min, respectively; during the stirring reaction, the stirring speed is 1500-3000 r / min.

[0011] The particle size modifier in the reaction process is ethylene glycol (EG), and the charge interference agent is potassium chloride (KCl, 99.9%).

[0012] During the reaction process, the particle size regulator has a mass fraction of 0.1-0.5 wt%, and the charge interference agent concentration is between 0.01-0.1 M.

[0013] In a preferred embodiment of the present invention, the obtained hydroxyapatite has a size of 98 nm.

[0014] This invention addresses the process and cost deficiencies in the prior art. During the synthesis of hydroxyapatite, the liquid flow rate and reactor rotation speed significantly influence HAP particle formation; the single-crystal size of hydroxyapatite can be controlled by adjusting these parameters. Additives such as particle size modifiers and charge interference agents greatly affect the uniformity of particle size distribution; the uniformity of HAP size can be enhanced by controlling the amount of these additives and the remixing process. Furthermore, this reactor is a large-scale continuous reactor, allowing for continuous sample feeding and simultaneous product acquisition, demonstrating excellent effectiveness in preparing large-scale hydroxyapatite with limited agglomeration. Attached Figure Description

[0015] Figure 1 The reactor is a hydroxyapatite synthesis reactor with uniform and controllable dimensions, comprising: a calcium source reaction solution storage tank 1, a phosphorus source reaction solution storage tank 2, a pump 3, a valve 4, an outlet pipe 5, an inlet 1 6-1, an inlet 2 6-2, a stirring paddle 7, a stirring shaft 8, a spray device 1 9-1, a spray device 2 9-2, an air inlet 10, and a synthesis reactor 11.

[0016] Figure 2 The image shows a SEM image of the hydroxyapatite prepared in Example 2.

[0017] Figure 3 The image shows a SEM image of the hydroxyapatite prepared in Example 4.

[0018] Figure 4 The image shows a SEM image of the hydroxyapatite prepared in Example 5.

[0019] Figure 5 The image shows a SEM image of the hydroxyapatite prepared in Example 8. Detailed Implementation

[0020] Example 1

[0021] A hydroxyapatite single crystal size controllable synthesis reactor, wherein a calcium source reaction liquid storage tank 1 is connected to the liquid inlet 6-1 at the bottom of the synthesis reactor 11 via a pressure pump;

[0022] The phosphorus source reaction liquid storage tank 2 is connected to the liquid inlet 6-2 at the bottom of the synthesis reactor 11 via a pressure pump;

[0023] The liquid inlet 6-1 or the liquid inlet 6-2 is connected to the spray device 9-1 and the spray device 9-2 installed in the synthesis reactor 11, respectively, so that the material is sprayed inward and upward.

[0024] The synthesis reactor 11 is also equipped with a stirring shaft 8, on which multiple stirring paddles 7 are mounted. The stirring shaft 8 is connected to the electrode 12 mounted at the top and is used to achieve stirring.

[0025] The bottom of the synthesis reactor 11 is connected to the storage tank 15 via the liquid outlet pipe 5, and the storage tank 15 is connected to the upper part of the synthesis reactor 11 via a pressure pump.

[0026] The synthesis reactor 11 is provided with an air inlet 10 at the top and an air outlet 13 at the top. The synthesis reactor 11 is also provided with a temperature sensing system 14.

[0027] Example 2

[0028] Using the above-described apparatus, the calcium source was a 1.67 M calcium chloride solution, and the phosphorus source was a 1 M sodium phosphate solution. The pH was adjusted to 9, and the flow rates of the calcium and phosphorus sources were controlled at 300 mL / min, the rotation speed at 1000 rpm, and the temperature at 25 °C. No particle size modifiers or charge interference agents were added. After reaction in this synthesis reactor, hydroxyapatite particles with a size of 50-130 nm and a D50 of 104 nm were obtained. The morphology consisted of solid spherical particles, with a certain amount of aggregation. The obtained SEM images are shown below. Figure 2 As shown.

[0029] Example 3

[0030] The difference between this embodiment and Embodiment 2 is that the rotation speed is set to 1500 rpm. After the reaction in this synthesis reactor, the hydroxyapatite obtained has a particle size of 40-110 nm, of which D50 is about 78 nm. The morphology is solid spherical particles with uneven particle size.

[0031] Example 4

[0032] The difference between this embodiment and Embodiment 2 is that the rotation speed is set to 2000 rpm. After reaction in this synthesis reactor, the hydroxyapatite obtained has a particle size of 10-60 nm, with a D50 of 41 nm. The morphology consists of solid spherical particles with non-uniform particle size. The obtained SEM image is shown below. Figure 3 As shown.

[0033] Example 5

[0034] The difference between this embodiment and Embodiment 2 is that the rotation speed is set to 3000 rpm. After reaction in this synthesis reactor, the hydroxyapatite obtained has a particle size of 10-40 nm, with a D50 of 22 nm. The morphology consists of solid spherical particles with non-uniform particle size. The obtained SEM image is shown below. Figure 4 As shown.

[0035] Example 6

[0036] The difference between this embodiment and Example 2 is that the flow rate is set to 500 mL / min. After the reaction in the synthesis reactor, the hydroxyapatite obtained has a particle size of 150-500 nm, with a D50 of 314 nm. The morphology is solid spherical particles with non-uniform particle size.

[0037] Example 7

[0038] The difference between this embodiment and Example 2 is that the flow rate is set to 700 mL / min. After the reaction in the synthesis reactor, the hydroxyapatite obtained has a particle size of 380-650 nm, with a D50 of 521 nm. The morphology is solid spherical particles with non-uniform particle size.

[0039] Example 8

[0040] The difference between this embodiment and Example 2 is that after the reaction, 0.5 wt% of a particle size modifier and 0.1 M of a charge interference agent were added. After the reaction in this synthesis reactor, the hydroxyapatite obtained had a particle size of 88-105 nm, with a D90 of 98 nm. The morphology consisted of solid spherical particles with clear morphology and uniform size. The obtained SEM images are shown below. Figure 5 As shown.

[0041] Example 9

[0042] The difference between this embodiment and Embodiment 2 is that the rotation speed is set to 2000 rpm, and after the reaction is completed, 0.5 wt% of particle size regulator and 0.1 M of charge interference agent are added. After the reaction in this synthesis reactor, hydroxyapatite with a particle size of 36-50 nm and a D90 of 45 nm is obtained. The morphology is solid spherical particles with clear morphology and uniform size.

[0043] Example 10

[0044] The difference between this embodiment and Embodiment 2 is that the rotation speed is set to 3000 rpm, and after the reaction is completed, 0.5 wt% of particle size regulator and 0.1 M of charge interference agent are added. After the reaction in this synthesis reactor, hydroxyapatite with a particle size of 19-21 nm and a D90 of 24 nm is obtained. The morphology is solid spherical particles with clear morphology and uniform size.

[0045] Example 11

[0046] The difference between this embodiment and Example 2 is that the flow rate is set to 500 mL / min, and after the reaction is completed, 0.5 wt% of particle size regulator and 0.1 M of charge interference agent are added. After the reaction in this synthesis reactor, hydroxyapatite with a particle size of 265-313 nm, of which D70 is 305 nm, is obtained. The morphology is solid spherical particles with clear morphology and uniform size.

[0047] Example 11

[0048] The difference between this embodiment and Example 2 is that the flow rate is set to 700 mL / min, and after the reaction is completed, 0.5 wt% of particle size regulator and 0.1 M of charge interference agent are added. After the reaction in this synthesis reactor, hydroxyapatite with a particle size of 488-605 nm and a D70 of 516 nm is obtained. The morphology is solid spherical particles with clear morphology and uniform size.

[0049] Example 12

[0050] The difference between this embodiment and Example 2 is that 0.1 M of charge interference agent is added after the reaction is completed. After the reaction in the synthesis reactor, the hydroxyapatite obtained has a particle size of 50-135 nm, of which D50 is 110 nm. The morphology is solid spherical particles with uniform particle size dispersion.

[0051] Example 13

[0052] The difference between this embodiment and Example 2 is that 1.0 wt% of a particle size regulator was added after the reaction. After the reaction in the synthesis reactor, the hydroxyapatite obtained had a particle size of 56-78 nm, of which D70 was 63 nm. The morphology was solid spherical particles with relatively dispersed particle size, but some adhesion and aggregation occurred between the particles.

[0053] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for synthesizing hydroxyapatite with uniform and controllable dimensions, characterized in that, Includes the following steps: After mixing the calcium source reaction solution and the phosphorus source reaction solution, the pH was adjusted and the reaction was carried out under stirring conditions. After the reaction was completed, a particle size regulator and a charge interference agent were added to obtain hydroxyapatite with controllable single crystal size and uniform particle size. The reaction process is a continuous reaction process, wherein the flow rates of the calcium source reaction solution and the phosphorus source reaction solution are 100-700 mL / min, respectively; during the stirring reaction, the stirring speed is 1500-3000 r / min; the particle size regulator is ethylene glycol; the charge interference agent is 99.9% potassium chloride; the mass fraction of the particle size regulator is between 0.1-0.5 wt%; and the concentration of the charge interference agent is between 0.01-0.1 M.

2. The synthesis method according to claim 1, characterized in that, The calcium source reaction solution is selected from one or more of calcium nitrate, calcium chlorate, calcium sulfate, calcium perchlorate, calcium bicarbonate, and calcium dihydrogen phosphate.

3. The synthesis method according to claim 1, characterized in that, The phosphorus source reaction solution is selected from one or more of dihydrogen phosphate, hydrogen phosphate, and orthophosphate.

4. The synthesis method according to claim 1, characterized in that, The starting material molar concentrations of the calcium source reaction solution and the phosphorus source reaction solution are between 0.5 and 5 M, and the molar ratio of calcium atoms in the calcium source reaction solution to phosphorus atoms in the phosphorus source reaction solution is 1.6 to 1.

8.

5. The synthesis method according to claim 4, characterized in that, The molar ratio of calcium atoms in the calcium source reaction solution to phosphorus atoms in the phosphorus source reaction solution is 1.67.

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