A method for preparing a bird's nest-like calcium carbonate
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LANZHOU JIAOTONG UNIV
- Filing Date
- 2026-05-06
- Publication Date
- 2026-08-07
AI Technical Summary
[0017]与现有技术相比，本发明在微乳液体系中以肉桂酸为晶形控制剂成功地诱导碳酸钙形成鸟巢状结构，产品形貌均一，分散性好，比表面积大。
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Figure CN122520109A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for preparing bird's nest-shaped calcium carbonate. Background Technology
[0002] Calcium carbonate is an important inorganic chemical product, widely used in industries such as rubber, plastics, papermaking, coatings, and pharmaceuticals due to its abundant sources, low price, and non-toxicity. Studies have shown that the morphology, size, and crystal form of calcium carbonate have a decisive influence on its properties. Summary of the Invention
[0003] The purpose of this invention is to provide a method for preparing bird's nest-shaped calcium carbonate via microemulsion.
[0004] The technical solution adopted by the present invention to achieve the above objectives is as follows:
[0005] A method for preparing bird's nest-shaped calcium carbonate, comprising:
[0006] (1) A microemulsion is obtained by mixing a surfactant, a co-surfactant, a crystal form control agent, an oil phase and an aqueous phase, wherein the aqueous phase is an ammonia solution of calcium chloride and the crystal form control agent is cinnamic acid;
[0007] (2) Carbon dioxide is introduced into the microemulsion to react and obtain the bird's nest-shaped calcium carbonate.
[0008] Preferably, the surfactant is hexadecyltrimethylammonium bromide, the co-surfactant is n-butanol, and the oil phase is n-hexane.
[0009] Preferably, the mass ratio of the surfactant, co-surfactant and oil phase is 0.3~0.5 : 0.6~1 :1.
[0010] Preferably, the mass ratio of the crystal form control agent to the oil phase is 0.03~0.04 : 1.
[0011] The microemulsion is a water-in-oil microemulsion, preferably with a volume ratio of oil phase to water phase of 8~15:1.
[0012] Preferably, the concentration of calcium chloride in the aqueous phase is 0.5~1 mol / L.
[0013] Preferably, the ammonia concentration in the aqueous phase is 20-25 wt%.
[0014] Preferably, the carbon dioxide flow rate is 300-500 mL / min, and the reaction time is 20-50 min.
[0015] A bird's nest-shaped calcium carbonate prepared according to the above method.
[0016] Beneficial effects
[0017] Compared with the prior art, the present invention successfully induces calcium carbonate to form a bird's nest structure in a microemulsion system by using cinnamic acid as a crystal form control agent, resulting in a product with uniform morphology, good dispersibility, and large specific surface area. Attached Figure Description
[0018] Figure 1 SEM images of calcium carbonate prepared in Examples 1 (a, c, and e) and Examples 2 (b, d, and f).
[0019] Figure 2 The particle size distribution diagrams are for the calcium carbonate prepared in Examples 1(a) and 2(b).
[0020] Figure 3 The XRD patterns of calcium carbonate prepared in Examples 1(a) and 2(b) are shown.
[0021] Figure 4 SEM images of the calcium carbonate prepared in Examples 3(a) and 4(b).
[0022] Figure 5 The particle size distribution diagrams are for the calcium carbonate prepared in Examples 3(a) and 4(b).
[0023] Figure 6 SEM image of calcium carbonate prepared in Comparative Example 1.
[0024] Figure 7 The particle size distribution diagram is shown for the calcium carbonate prepared in Comparative Example 1.
[0025] Figure 8 The XRD pattern of calcium carbonate prepared in Comparative Example 1 is shown.
[0026] Figure 9 SEM images of calcium carbonate prepared for Comparative Example 2(a) and Comparative Example 3(b).
[0027] Figure 10 Particle size distribution of calcium carbonate prepared for Comparative Example 2(a) and Comparative Example 3(b). Detailed Implementation
[0028] The technical solution of the present invention will be further described in detail below with reference to the embodiments.
[0029] The ammonia solution of CaCl2 is obtained by dissolving calcium chloride in ammonia water (analytical grade, 25%).
[0030] Example 1
[0031] Add 1.67 g cetyltrimethylammonium bromide, 3.33 g n-butanol, 5.0 g (7.5 mL) n-hexane and 0.15 g cinnamic acid (CA) to a clean and dry sample vial. After mixing well, slowly add 0.5 mL of 0.5 M CaCl2 ammonia solution. Stir thoroughly at room temperature and let stand to obtain a microemulsion.
[0032] Under light-protected and stirred conditions, CO2 gas (flow rate of 300 mL / min) was introduced into the microemulsion. After 30 min, the gas was stopped, and the mixture was centrifuged at 3000 r / min for 10 min. The solid product was washed with anhydrous ethanol, and the washing and centrifugation were repeated three times. The product was then dried in an oven at 70 °C for 12 h to obtain calcium carbonate.
[0033] As shown in the figure ( Figure 1 As shown in (a, 1c, 1e), the prepared calcium carbonate exhibits a layered, curled structure with a central depression, resembling a bird's nest.
[0034] like Figure 2 As shown in a, the prepared calcium carbonate has a particle size of approximately 1.0-2.8 μm, with an average particle size of approximately 1.94 μm.
[0035] like Figure 3 As shown, the prepared calcium carbonate sample (curve a) exhibits obvious diffraction peaks at positions such as 2θ = 24.9°, 27.0° and 32.8°, all of which correspond to the characteristic crystal planes of vaterite, proving that the sample is vaterite-type calcium carbonate.
[0036] Example 2
[0037] The preparation of the microemulsion was the same as in Example 1.
[0038] Under 254 nm ultraviolet light irradiation and stirring, CO2 gas (flow rate of 300 mL / min) was introduced into the microemulsion. After 30 min, the gas was stopped, and the mixture was centrifuged at 3000 r / min for 10 min. The solid product was washed with anhydrous ethanol, and the washing and centrifugation were repeated three times. The product was then dried in an oven at 70 °C for 12 h to obtain calcium carbonate.
[0039] As shown in Figures (1b, 1d, 1f), after ultraviolet irradiation, the prepared calcium carbonate still has a bird's nest-like structure, and the structure becomes more regular, with the overall particle size significantly increasing.
[0040] like Figure 2As shown in b, after UV irradiation, the particle size of calcium carbonate increased to 2.4-4.5 μm, with an average particle size of approximately 3.59 μm, and the distribution became more concentrated. This result indicates that, within a microemulsion confinement environment, the morphology and particle size of calcium carbonate can be further controlled by utilizing the cis-trans isomerization of cinnamic acid molecules under UV irradiation.
[0041] like Figure 3 As shown, the prepared calcium carbonate sample (curve b) exhibits obvious diffraction peaks at 2θ = 24.9°, 27.0°, and 32.8°, all corresponding to the characteristic crystal planes of vaterite, proving that the sample is mainly vaterite-type calcium carbonate. A weaker diffraction peak appears at 2θ = 29.4°, corresponding to the (104) crystal plane of calcite, indicating that the product also contains a small amount of calcite-type calcium carbonate.
[0042] Example 3
[0043] Add 2.00 g cetyltrimethylammonium bromide, 4.00 g n-butanol, 4.0 g (6.0 mL) n-hexane and 0.15 g cinnamic acid to a clean and dry sample vial. After mixing well, slowly add 0.7 mL of 0.5 M CaCl2 ammonia solution. Stir thoroughly at room temperature and let stand to obtain a microemulsion.
[0044] Under light-protected and stirred conditions, CO2 gas (flow rate of 300 mL / min) was introduced into the microemulsion. After 30 min, the gas was stopped, and the mixture was centrifuged at 3000 r / min for 10 min. The solid product was washed with anhydrous ethanol, and the washing and centrifugation were repeated three times. The product was then dried in an oven at 70 °C for 12 h to obtain calcium carbonate.
[0045] like Figure 4 As shown in Figure a, the prepared calcium carbonate exhibits a layered, curled structure with a central depression, resembling a bird's nest.
[0046] like Figure 5 As shown in a, the prepared calcium carbonate has a particle size of approximately 1.0-2.8 μm and an average particle size of approximately 1.90 μm.
[0047] Example 4
[0048] The preparation method of the microemulsion is the same as in Example 3.
[0049] Under 254 nm ultraviolet light irradiation and stirring, CO2 gas (flow rate of 300 mL / min) was introduced into the microemulsion. After 30 min, the gas was stopped, and the mixture was centrifuged at 3000 r / min for 10 min. The solid product was washed with anhydrous ethanol, and the washing and centrifugation were repeated three times. The product was then dried in an oven at 70 °C for 12 h to obtain calcium carbonate.
[0050] like Figure 4 As shown in b, after ultraviolet irradiation, the prepared calcium carbonate still has a bird's nest-like structure, and the structure becomes more regular, with the overall particle size significantly increasing.
[0051] like Figure 5 As shown in b, after UV irradiation, the particle size of calcium carbonate increased to 2.0-4.0 μm, with an average particle size of approximately 3.29 μm, and the distribution became more concentrated. This result indicates that, within a microemulsion confinement environment, the morphology and particle size of calcium carbonate can be further controlled by utilizing the molecular structural changes of cinnamic acid molecules under UV irradiation.
[0052] Comparative Example 1
[0053] Add 1.67 g cetyltrimethylammonium bromide, 3.33 g n-butanol and 5.0 g n-hexane to a clean and dry sample vial. After mixing well, slowly add 0.5 mL of 0.5 M CaCl2 ammonia solution. Stir thoroughly at room temperature and let stand to obtain a microemulsion.
[0054] Under light-protected and stirred conditions, CO2 gas (flow rate of 300 mL / min) was introduced into the microemulsion. After 30 min, the gas was stopped, and the mixture was centrifuged at 3000 r / min for 10 min. The solid product was washed with anhydrous ethanol, and the washing and centrifugation were repeated three times. The product was then dried in an oven at 70 °C for 12 h to obtain calcium carbonate.
[0055] like Figure 6 As shown, the prepared calcium carbonate particles are predominantly spherical, but no bird's nest-like morphology was observed.
[0056] like Figure 7 As shown, the prepared calcium carbonate has a particle size of approximately 0.1-1.2 μm and an average particle size of approximately 0.48 μm.
[0057] like Figure 8 As shown, the sample exhibits distinct diffraction peaks at 2θ = 24.9°, 27.0°, and 32.8°, all corresponding to characteristic crystal planes of vaterite, indicating that the product is vaterite-type calcium carbonate.
[0058] Comparative Example 2
[0059] Add 1.67 g cetyltrimethylammonium bromide, 3.33 g n-butanol, 5.0 g n-hexane and 0.15 g p-aminoazobenzene to a clean and dry sample vial. After mixing well, slowly add 0.5 mL of 0.5 M CaCl2 ammonia solution. Stir thoroughly at room temperature and let stand to obtain a microemulsion.
[0060] Under light-protected and stirred conditions, CO2 gas (flow rate of 300 mL / min) was introduced into the microemulsion. After 30 min, the gas was stopped, and the mixture was centrifuged at 3000 r / min for 10 min. The solid product was washed with anhydrous ethanol, and the washing and centrifugation were repeated three times. The product was then dried in an oven at 70 °C for 12 h to obtain calcium carbonate.
[0061] like Figure 9 As shown in a, the prepared calcium carbonate mainly consists of spherical or near-spherical particles, and no bird's nest-like morphology was observed.
[0062] like Figure 10 As shown in a, the prepared calcium carbonate has a particle size of approximately 0.4-2.4 μm and an average particle size of approximately 1.38 μm.
[0063] Comparative Example 3
[0064] The microemulsion was prepared in the same manner as in Comparative Example 2.
[0065] Under 365 nm ultraviolet light irradiation and stirring, CO2 gas (flow rate of 300 mL / min) was introduced into the microemulsion. After 30 min, the gas was stopped, and the mixture was centrifuged at 3000 r / min for 10 min. The solid product was washed with anhydrous ethanol, and the washing and centrifugation were repeated three times. The product was then dried in an oven at 70 °C for 12 h to obtain calcium carbonate.
[0066] like Figure 9 As shown in b, the calcium carbonate prepared after ultraviolet irradiation is still mainly composed of spherical or near-spherical particles, and no bird's nest-like morphology appears.
[0067] like Figure 10 As shown in b, after ultraviolet irradiation, the particle size of calcium carbonate was 1.2-2.8 μm, with an average particle size of approximately 1.97 μm. Similar to cinnamic acid, p-aminoazobenzene exhibits photoisomerization properties, undergoing cis-trans isomerization under ultraviolet irradiation. While ultraviolet irradiation increases the particle size, it does not induce the formation of a bird's nest structure in calcium carbonate.
[0068] This indicates that the photoresponsive molecule cinnamic acid can be used as a crystal shape control agent to prepare bird's nest-shaped calcium carbonate particles.
[0069] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing bird's nest-shaped calcium carbonate, comprising: (1) A microemulsion is obtained by mixing a surfactant, a co-surfactant, a crystal form control agent, an oil phase and an aqueous phase, wherein the aqueous phase is an ammonia solution of calcium chloride and the crystal form control agent is cinnamic acid; (2) Carbon dioxide is introduced into the microemulsion to react and obtain the bird's nest-shaped calcium carbonate.
2. The preparation method according to claim 1, characterized in that: The surfactant is hexadecyltrimethylammonium bromide, the co-surfactant is n-butanol, and the oil phase is n-hexane.
3. The preparation method according to claim 2, characterized in that: The mass ratio of the surfactant, co-surfactant, and oil phase is 0.3~0.5 : 0.6~1 :
1.
4. The preparation method according to claim 1, characterized in that: The mass ratio of the crystal form control agent to the oil phase is 0.03~0.04 :
1.
5. The preparation method according to claim 1, characterized in that: The volume ratio of the oil phase to the water phase is 8~15:
1.
6. The preparation method according to claim 1, characterized in that: The concentration of calcium chloride in the aqueous phase is 0.5~1 mol / L.
7. The preparation method according to claim 1 or 5, characterized in that: The ammonia concentration in the aqueous phase is 20-25 wt%.
8. The preparation method according to claim 1, characterized in that: The carbon dioxide flow rate is 300~500 mL / min, and the reaction time is 20~50 min.
9. A bird's nest-shaped calcium carbonate prepared according to any one of claims 1-8.