阅读说明：本技术 有机溶剂诱导获得具有纳米孔结构的无定形碳酸钙颗粒的制备方法 (Preparation method for obtaining amorphous calcium carbonate particles with nano-pore structure by organic solvent induction ) 是由 傅正义 汪琦航 邹朝勇 于 2020-08-26 设计创作，主要内容包括：本发明属于无机材料技术领域,具体涉及一种有机溶剂诱导获得具有纳米孔结构的无定形碳酸钙颗粒的制备方法,包括以下步骤：(1)将一定浓度的碳酸钠溶液和氯化钙溶液分别降至一定温度；(2)六水碳酸钙的制备：将氯化钙溶液快速加入到碳酸钠溶液中,让混合溶液置于一定温度下进行反应,得到六水碳酸钙晶体；(3)纳米孔结构的晶体状无定形碳酸钙的制备：将得到的六水碳酸钙晶体加入到有机溶剂中搅拌一定时间,即得到了具有纳米孔结构的晶体状无定形碳酸钙。本发明通过机溶剂诱导的方法制备除了具有纳米孔结构的晶体状无定形碳酸钙颗粒,反应条件温和,操作简单,制备周期短,重复性好,制备的无定形碳酸钙存在纳米孔结构,具有较大的比表面积。(The invention belongs to the technical field of inorganic materials, and particularly relates to a preparation method for obtaining amorphous calcium carbonate particles with a nanopore structure by induction of an organic solvent, which comprises the following steps: (1) respectively cooling a sodium carbonate solution and a calcium chloride solution with certain concentrations to certain temperatures; (2) preparing calcium carbonate hexahydrate: quickly adding a calcium chloride solution into a sodium carbonate solution, and reacting the mixed solution at a certain temperature to obtain calcium carbonate hexahydrate crystals; (3) preparation of crystalline amorphous calcium carbonate with nanoporous structure: adding the obtained calcium carbonate hexahydrate crystal into an organic solvent, and stirring for a certain time to obtain the crystalline amorphous calcium carbonate with the nano-pore structure. The method prepares crystalline amorphous calcium carbonate particles with a nano-pore structure by an organic solvent induction method, has mild reaction conditions, simple operation, short preparation period and good repeatability, and the prepared amorphous calcium carbonate has the nano-pore structure and larger specific surface area.)

1. A preparation method for obtaining amorphous calcium carbonate particles with a nano-pore structure by organic solvent induction is characterized by comprising the following steps:

(1) respectively cooling a sodium carbonate solution and a calcium chloride solution with certain concentrations to certain temperatures;

(2) preparing calcium carbonate hexahydrate: quickly adding the calcium chloride solution in the step (1) into a sodium carbonate solution, placing the mixed solution at a certain temperature, stirring and reacting, and performing suction filtration on the reacted solution to obtain calcium carbonate hexahydrate crystals;

(3) preparation of crystalline amorphous calcium carbonate with nanoporous structure: adding the obtained calcium carbonate hexahydrate crystal into an organic solvent, stirring for a certain time, and carrying out suction filtration on the reacted solution to obtain the crystalline amorphous calcium carbonate with the nano-pore structure.

2. The preparation method of amorphous calcium carbonate particles with nanoporous structure induced by organic solvent according to claim 1, characterized in that: in the step (1), the temperatures of the sodium carbonate solution and the calcium chloride solution are both 0-4 ℃.

3. The preparation method of amorphous calcium carbonate particles with nanoporous structure induced by organic solvent according to claim 1, characterized in that: in the step (2), the concentrations of calcium ions and carbonate ions in the mixed solution are the same and are both 10-40 mmol/L.

4. The preparation method of amorphous calcium carbonate particles with nanoporous structure induced by organic solvent according to claim 1, characterized in that: in the step (2), the temperature of a reaction system is 0-4 ℃; the stirring speed is 200-800 r.p.m; the reaction time is 1-1.5 h.

5. The preparation method of amorphous calcium carbonate particles with nanoporous structure induced by organic solvent according to claim 1, characterized in that: in the step (3), the organic solvent is any one of ethanol, methanol and acetone.

6. The preparation method of amorphous calcium carbonate particles with nanoporous structure induced by organic solvent according to claim 1, characterized in that: in the step (3), the stirring speed is 200-1000 r.p.m, and the stirring reaction time is 15 min-2 h.

7. The preparation method of amorphous calcium carbonate particles with nanoporous structure induced by organic solvent according to claim 1, characterized in that: in the step (3), the mass-to-volume ratio of the calcium carbonate hexahydrate crystals to the organic solvent is 1 g: (100-500) mL.

Technical Field

The invention belongs to the technical field of inorganic materials, and particularly relates to a preparation method for obtaining amorphous calcium carbonate particles with a nano-pore structure by induction of an organic solvent.

Background

Calcium carbonate is one of the most widely occurring minerals in nature, and not only is used in large quantities in industrial production, but also plays a crucial role in biomineralization. After long-term research, calcium carbonate currently known has 6 crystal forms, namely calcite, aragonite, vaterite, calcium carbonate monohydrate, calcium carbonate hexahydrate and calcium carbonate hemihydrate, and besides, calcium carbonate exists in some organisms in a thermodynamically unstable amorphous state, Amorphous Calcium Carbonate (ACC) is highly soluble and isotropic compared to calcium carbonate crystals, and is an important mineralized precursor and calcium storage substance in organisms. In the biomineralization process, the ACCs form biominerals on proper mineralization sites under the regulation of proteins and the like, and the mineralization strategy from the ACCs to crystalline calcium carbonate ensures that some organisms can control and synthesize complex multi-level structure and excellent-performance minerals to adapt to the environment very finely. ACC has therefore been extensively studied in order to gain a deeper understanding of biomineralization mechanisms and better biomimetic synthetic materials.

Because ACC cannot exist in an aqueous solution stably, many studies at present focus on preparing stable ACC by using different methods to better understand a biomineralization process, common methods are also to simulate an in vivo mineralization process, and a stabilizer, such as magnesium ions or organic macromolecules such as polyaspartic acid and polyacrylic acid, is added in the process of precipitating ACC from a saturated salt solution of ACC to prevent ACC from crystallizing. However, ACC synthesized by this method is generally spherical nanoparticles. It is difficult to obtain large-scale particles with complex morphology. The use of organic solvents to dehydrate calcium carbonate crystals to prepare ACC having a multi-stage complex structure has not been reported.

Disclosure of Invention

The invention aims to provide a preparation method for obtaining amorphous calcium carbonate particles with a nano-pore structure by organic solvent induction, which has the advantages of mild reaction conditions, simple operation, short experimental period, good experimental repeatability and easy large-scale preparation.

The scheme adopted by the invention for realizing the purpose is as follows:

a preparation method for obtaining amorphous calcium carbonate particles with a nano-pore structure by organic solvent induction comprises the following steps:

(1) respectively cooling a sodium carbonate solution and a calcium chloride solution with certain concentrations to certain temperatures;

(2) preparing calcium carbonate hexahydrate: quickly adding the calcium chloride solution in the step (1) into a sodium carbonate solution, placing the mixed solution at a certain temperature, stirring and reacting, and performing suction filtration on the reacted solution to obtain calcium carbonate hexahydrate crystals;

(3) preparation of crystalline amorphous calcium carbonate with nanoporous structure: adding the obtained calcium carbonate hexahydrate crystal into an organic solvent, stirring for a certain time, and carrying out suction filtration on the reacted solution to obtain the crystalline amorphous calcium carbonate with the nano-pore structure.

Preferably, in the step (1), the temperature of the sodium carbonate solution and the temperature of the calcium chloride solution are both 0-4 ℃.

Preferably, in the step (2), the concentrations of calcium ions and carbonate ions in the mixed solution are the same and are both 10-40 mmol/L.

Preferably, in the step (2), the temperature of the reaction system is 0-4 ℃; the stirring speed is 200-800 r.p.m; the reaction time is 1-1.5 h.

Preferably, in the step (3), the organic solvent is any one of ethanol, methanol and acetone.

Preferably, in the step (3), the stirring speed is 200-1000 r.p.m, and the stirring reaction time is 15 min-2 h.

Preferably, in the step (3), the mass-to-volume ratio of the calcium carbonate hexahydrate crystals to the organic solvent is 1 g: (100-500) mL.

Due to the thermodynamic instability of calcium carbonate hexahydrate, amorphous calcium carbonate can only form the metastable crystal form at low temperature (0-4 ℃), the crystal form contains a large amount of crystal water, and 18 water molecules exist around each calcium carbonate molecule. When the calcium carbonate hexahydrate crystal is in an extreme condition, water molecules are lost before the calcium carbonate hexahydrate is in a metastable state to a steady state, and amorphous calcium carbonate can be obtained. Compared with other methods, the method has the advantages that the organic solvent is used for inducing the water loss of the calcium carbonate hexahydrate, the method is faster, milder and uniform, the dissolution and recrystallization of the calcium carbonate hexahydrate due to untimely water loss can be avoided, and the appearance of the calcium carbonate hexahydrate can be perfectly preserved.

The invention has the following advantages and beneficial effects:

the method prepares the crystalline amorphous calcium carbonate particles with the nano-pore structure by an organic solvent induction method, and has the advantages of mild reaction conditions, simple operation, short preparation period and good repeatability.

The amorphous calcium carbonate prepared by the preparation method has large size, keeps the complex morphology of calcium carbonate hexahydrate crystals, has a nano-pore structure and has larger specific surface area.

Drawings

FIG. 1 is an X-ray diffraction pattern of amorphous calcium carbonate particles prepared in example 1 of the present invention;

FIG. 2 is an infrared spectrum of amorphous calcium carbonate particles prepared in example 1 of the present invention;

FIG. 3 is a SEM photograph of amorphous calcium carbonate particles prepared in example 1 of the present invention, wherein a is a high magnification view of b;

FIG. 4 is a TEM photograph of amorphous calcium carbonate particles prepared in example 1 of the present invention, wherein a is a drawing, and b is a high magnification drawing of c is a drawing;

FIG. 5 is a BET spectrum of amorphous calcium carbonate particles prepared in example 5 of the present invention;

FIG. 6 is an SEM photograph of amorphous calcium carbonate particles prepared in example 6 of the present invention;

FIG. 7 is an SEM photograph of amorphous calcium carbonate particles prepared in example 7 of the present invention.

Detailed Description

The following examples are provided to further illustrate the present invention for better understanding, but the present invention is not limited to the following examples.