Preparation method of Mg < 2 + >-mediated Eu-containing amorphous calcium carbonate luminescent nanomaterial

Abstract

The invention discloses a preparation method of an Mg < 2 + >-mediated Eu-containing amorphous calcium carbonate luminescent nano material, and belongs to the technical field of solid-state photoluminescent materials. According to the method, Ca salt, Eu salt and Mg salt serve as raw materials to prepare mineralization mother liquor, then (NH4) 2CO3 solid is decomposed into CO2 and NH3 through an ammonium carbonate diffusion method (ADM), the CO2 and the NH3 penetrate through a gas-liquid interface to be diffused into the mother liquor to be subjected to mineralization reaction, nucleation and growth of calcite, aragonite and other crystal forms are delayed due to existence of Mg < 2 + > at the moment, and the mineralization effect is achieved. The service life of the amorphous calcium carbonate is prolonged, and Eu < 3 + > is sealed in the structure of the amorphous calcium carbonate, so that the Eu-containing amorphous calcium carbonate luminescent nano material with high rare earth doping concentration and highly uniform distribution is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid-state photoluminescent materials, and particularly relates to a Mg 2+ A method for preparing Eu-mediated amorphous calcium carbonate luminescent nanomaterials. Background Art

[0002] Nano-calcium carbonate materials are widely used in industry, agriculture, and manufacturing due to their high specific surface area, good dispersibility, and reinforcing properties. In industry, nano-calcium carbonate is primarily used as a reinforcing filler in plastics and rubber materials, significantly improving their strength and durability. It plays a particularly important role in the automotive and electronics manufacturing sectors. In agriculture, it can be used as a soil conditioner to improve acidic soil and increase fertility. It can also serve as a carrier for pesticides and fertilizers, enabling controlled release. In manufacturing, nano-calcium carbonate is used in paints and coatings to improve wear resistance and corrosion resistance, and in paper production to enhance paper strength and smoothness. However, the preparation of nano-calcium carbonate materials faces technical difficulties such as difficult crystal control and poor dispersibility. Furthermore, the relatively low surface activity of calcite calcium carbonate limits its ability to bond with other materials, affecting the performance of composite materials. Amorphous calcium carbonate materials offer greater advantages over calcite calcium carbonate in industry, agriculture, and manufacturing. Amorphous calcium carbonate has a higher specific surface area and surface activity, enabling better interaction with other substances, enhancing adsorption and reactivity. For example, in agriculture, amorphous calcium carbonate reacts more easily with acidic substances in the soil, quickly improving the soil environment; in manufacturing, the better dispersibility and adhesion ability of amorphous calcium carbonate make its performance in coatings and composite materials more stable and uniform.

[0003] Rare earth doped nano calcium carbonate materials have shown broad application prospects in the fields of biomedical imaging, sensor detection, photocatalysis, etc., and have gradually become a hot area in recent years. 3+ 、Tb 3+ etc.) have unique fluorescence properties and can be introduced into nano-calcium carbonate materials through doping to give the materials spectral response capabilities, and achieve specific functions such as photocatalysis or bioimaging through light energy excitation, effectively overcoming their original limitations, giving the materials new optical functions and thus expanding the application range of the materials.

[0004] Existing rare earth doped calcium carbonate synthesis methods (such as CN112322286A a kind of rare earth ion doped different morphology nano calcium carbonate luminescent material and its preparation method and application) are mostly carbonization methods, which need to be prepared under high temperature conditions and have various problems. On the one hand, the product is usually a calcite crystal form, the grain size is difficult to control, and the dispersion is poor; on the other hand, it is difficult to accurately control the concentration and distribution of rare earth doping, resulting in unstable performance of the material. In summary, it is necessary to develop a synthesis method for preparing a rare earth doped nano calcium carbonate material that is more stable, highly dispersed, and has a controllable doping concentration. Summary of the Invention

[0005] The present invention aims to solve the problems that the existing preparation methods of rare earth doped nano calcium carbonate materials mostly produce calcite crystals, the grain size is difficult to control, the dispersion is poor, the rare earth doping concentration and distribution are difficult to accurately control, resulting in unstable performance. 2+ A method for preparing Eu-mediated amorphous calcium carbonate luminescent nanomaterials.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] The present invention provides a Mg 2+ The preparation method of Eu-containing amorphous calcium carbonate luminescent nanomaterials under the guidance of a novel nanostructured luminescent material comprises the following steps: using Ca salt, Eu salt and Mg salt as raw materials to prepare a mineralization mother solution; subjecting the mineralization mother solution and ammonium carbonate powder to a carbonate mineralization reaction through an ammonium carbonate diffusion method (ADM); and then centrifuging and drying to obtain the Mg 2+ Eu-mediated amorphous calcium carbonate luminescent nanomaterials.

[0008] Technical principle:

[0009] The present invention first uses Ca salt, Eu salt and Mg salt as raw materials to prepare mineralization mother liquor, and then uses ammonium carbonate diffusion method (ADM) to decompose (NH4)2CO3 solid into CO2 and NH3, and diffuses them into the mother liquor through the gas-liquid interface to carry out mineralization reaction. 2+ The presence of delays the nucleation and growth of calcite and aragonite, prolongs the life of amorphous calcium carbonate and 3+ It is enclosed in the structure of amorphous calcium carbonate, thereby obtaining a luminescent nanomaterial containing Eu amorphous calcium carbonate with high rare earth doping concentration and highly uniform distribution.

[0010] Furthermore, the Ca in the mineralization mother solution 2+ 、Eu 3+ and Mg 2+ The molar concentration ratio is 1:1:(1-5).

[0011] Furthermore, the Ca in the mineralization mother solution 2+ The concentration of Eu 3+ The concentration of Mg is 100mmol / L, 2+ The concentration is 100-500mmol / L.

[0012] Furthermore, the Ca salt is selected from CaCl2; the Eu salt is selected from EuCl3; and the Mg salt is selected from MgCl2.

[0013] Furthermore, the volume ratio of the mineralization mother solution to the mass ratio of the ammonium carbonate powder is 50:2 (mL / g).

[0014] Furthermore, the temperature of the carbonate mineralization reaction is 20-30° C., and the reaction time is 11-12 hours.

[0015] Furthermore, the centrifugation is specifically as follows: the reaction solution obtained after the carbonate mineralization reaction is centrifuged once and the supernatant is removed, and the lower precipitate is washed and separated by centrifugation twice with ethanol.

[0016] Furthermore, the rotation speed of each centrifugation is 3000-3500 rad / min, and the duration of each centrifugation is 5-10 min.

[0017] Furthermore, the drying temperature is 90-100° C. and the drying time is greater than 90 minutes.

[0018] The present invention also provides Mg prepared by the preparation method described in the above technical solution 2+ Eu-mediated amorphous calcium carbonate luminescent nanomaterials.

[0019] Compared with the prior art, the present invention has the following advantages and technical effects:

[0020] 1. The present invention achieves the successful preparation of Eu-containing amorphous calcium carbonate luminescent nanomaterials with controllable rare earth distribution and rare earth doping concentration up to 78.3 mol%.

[0021] 2. The Eu-containing amorphous calcium carbonate luminescent nanomaterial synthesized by the present invention has controllable luminescence performance, excellent brightness, and a simple preparation process.

[0022] 3. The Eu-containing amorphous calcium carbonate luminescent nanomaterial prepared by the present invention can be used as a light conversion agent and applied to agricultural plastic films, playing the role of a light conversion agent, which is beneficial to reducing plant diseases and insect pests. At the same time, it converts ultraviolet rays that cause oxidative degradation of agricultural plastic films (polyethylene films) into blue-violet light and red-orange light, thereby promoting plant photosynthesis.

[0023] 4. The present invention adopts Mg 2+The regulated ADM mineralization process makes up for the technical gap in the field of rare earth element doped amorphous calcium carbonate nanomaterials, expands the rare earth doping technology process route, and effectively improves the stability of the product and extends its service life.

[0024] 5. This invention not only introduces rare earth elements through a simple method, but also, compared to other wet-process phosphors, the calcium carbonate-based phosphor precursor is mostly amorphous and can emit light without high-temperature calcination. This not only significantly reduces costs but also better conforms to energy conservation and environmental protection concepts. Furthermore, the industrial preparation technology of calcium carbonate is quite mature, laying a solid foundation for the large-scale synthesis of luminescent materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 Mg prepared in Example 1 2+ XRD pattern of Eu-containing amorphous calcium carbonate luminescent nanomaterials under mediated conditions;

[0027] Figure 2 Mg prepared in Example 2 2+ XRD pattern of Eu-containing amorphous calcium carbonate luminescent nanomaterials under mediated conditions;

[0028] Figure 3 Mg prepared in Example 3 2+ XRD pattern of Eu-containing amorphous calcium carbonate luminescent nanomaterials under mediated conditions;

[0029] Figure 4 This is the XRD pattern of the nanomaterial prepared in Comparative Example 1;

[0030] Figure 5 Mg prepared in Example 3 2+ SEM image of Eu-containing amorphous calcium carbonate luminescent nanomaterials under mediated conditions;

[0031] Figure 6 Mg prepared in Example 3 2+ TEM BF images and HAADF STEM-EDS analysis results of Eu-containing amorphous calcium carbonate luminescent nanomaterials under mediated conditions;

[0032] Figure 7 Mg prepared in Example 1-3 2+ Luminescence image of Eu-containing amorphous calcium carbonate luminescent nanomaterials under 393nm irradiation;

[0033] Figure 8PL-PLE spectra of the nanomaterials prepared in Examples 1-3 and Comparative Example 1;

[0034] Figure 9 Schematic diagram of the apparatus used for the carbonate mineralization reaction in step (2) of Examples 1-3 and Comparative Example 1. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] The embodiment of the present invention provides a Mg 2+ The preparation method of Eu-containing amorphous calcium carbonate luminescent nanomaterials under the guidance of a novel nanostructured luminescent material comprises the following steps: using Ca salt, Eu salt and Mg salt as raw materials to prepare a mineralization mother solution; subjecting the mineralization mother solution and ammonium carbonate powder to a carbonate mineralization reaction through an ammonium carbonate diffusion method (ADM); and then centrifuging and drying to obtain the Mg 2+ Eu-mediated amorphous calcium carbonate luminescent nanomaterials.

[0038] In a preferred embodiment, the Ca in the mineralization mother liquor is 2+ 、Eu 3+ and Mg 2+ The molar concentration ratio of Mg is 1:1:(1-5). 2+ The concentration of Mg can be used to control the doping concentration of Eu in amorphous calcium carbonate luminescent nanomaterials. Within the above range, as Mg 2+ As the concentration increases, the doping concentration of Eu increases accordingly.

[0039] In a preferred embodiment, the Ca in the mineralization mother liquor is 2+ The concentration of Eu 3+ The concentration of Mg is 100mmol / L, 2+ The concentration is 100-500mmol / L.

[0040] In a preferred embodiment, the Ca salt is selected from CaCl2; the Eu salt is selected from EuCl3; and the Mg salt is selected from MgCl2.

[0041] In a preferred embodiment, the ratio of the volume of the mineralization mother solution to the mass of the ammonium carbonate powder is 50:2 (mL / g).

[0042] In a preferred embodiment, the temperature of the carbonate mineralization reaction is 20-30° C., and the reaction time is 11-12 hours. The present invention prevents the amorphous calcium carbonate from transforming into a more stable crystalline form by carrying out the carbonate mineralization reaction at a lower temperature.

[0043] In a preferred embodiment, the centrifugation is specifically as follows: the reaction solution obtained after the carbonate mineralization reaction is centrifuged once and the supernatant is removed, and the lower precipitate is washed and separated by centrifugation twice with ethanol.

[0044] In a preferred embodiment, the rotation speed of each centrifugation is 3000-3500 rad / min, and the duration of each centrifugation is 5-10 min.

[0045] In a preferred embodiment, the drying temperature is 90-100° C. and the drying time is >90 min.

[0046] The present invention also provides Mg prepared by the preparation method described in the above technical solution 2+ Eu-mediated amorphous calcium carbonate luminescent nanomaterials.

[0047] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0048] In the following examples and comparative examples, CaCl2, EuCl3, and MgCl2 are all analytically pure chemicals.

[0049] Example 1

[0050] A Mg 2+ The preparation method of Eu-containing amorphous calcium carbonate luminescent nanomaterial under mediated conditions comprises the following steps:

[0051] (1) Using CaCl2, EuCl3 and MgCl2 as raw materials to prepare mineralization mother liquor, the Ca 2+ The concentration of Eu 3+ The concentration of Mg is 100 mM, 2+ The concentration of Ca in the mineralization mother solution is 100mM 2+ 、Eu 3+ and Mg 2+ The molar concentration ratio of is 1:1:1);

[0052] (2) A beaker containing 50 mL of mineralization mother liquor and a beaker containing 2 g of ammonium carbonate powder were placed on a multi-connected magnetic stirrer at the same time, and carbonate mineralization reaction was carried out under stirring, closed, normal pressure, and 25 ± 3 ° C conditions (see the schematic diagram of the device used for carbonate mineralization reaction for details). Figure 9 ), after reacting for 11 hours, a reaction solution was obtained;

[0053] (3) The reaction solution obtained in step (2) was poured into a centrifuge tube, centrifuged once using a low-speed centrifuge, and then the supernatant was sucked out, the precipitate was retained, and the precipitate was washed and separated twice by centrifugation with ethanol, the speed of each centrifugation was 3500 rad / min, and the duration of each centrifugation was 5 minutes; after the centrifugation, the precipitate obtained by centrifugation was placed in a glass culture dish, placed in a blast drying oven at 90°C for 90 minutes, and Mg was obtained. 2+ Eu-mediated amorphous calcium carbonate luminescent nanomaterials.

[0054] The Mg prepared in Example 1 2+ The XRD analysis of Eu-containing amorphous calcium carbonate luminescent nanomaterials under the mediated Figure 1 .from Figure 1 It can be seen that the crystal form of the nanomaterial obtained in Example 1 conforms to the characteristics of amorphous calcium carbonate, and there is a peak with calcite. <104> The crystal diffraction pattern is consistent with the PDF standard card (JCPDS:05-0586), indicating that the nanomaterial is an amorphous calcium carbonate with a trace amount of calcite crystal structure.

[0055] Example 2

[0056] The difference from Example 1 is that in step (1), the Mg in the mineralization mother solution is 2+ The concentration of Ca in the mineralization mother solution is 200mM 2+ 、Eu 3+ and Mg 2+ The molar concentration ratio of the mixture is 1:1:2), and the rest is the same as in Example 1.

[0057] The Mg prepared in Example 2 2+ The XRD analysis of Eu-containing amorphous calcium carbonate luminescent nanomaterials under the mediated Figure 2 .from Figure 2 It can be seen that the crystal form of the nanomaterial obtained in Example 2 conforms to the characteristics of amorphous calcium carbonate, and there is a peak with calcite. <104> The crystal diffraction pattern is consistent with the PDF standard card (JCPDS:05-0586), indicating that the nanomaterial is an amorphous calcium carbonate with a trace amount of calcite crystal structure.

[0058] Example 3

[0059] The difference from Example 1 is that in step (1), the Mg in the mineralization mother solution is 2+ The concentration of Ca in the mineralization mother solution is 500mM 2+ 、Eu 3+ and Mg 2+ The molar concentration ratio of the mixture is 1:1:5), and the rest is the same as in Example 1.

[0060] The Mg prepared in Example 3 2+ The XRD analysis of Eu-containing amorphous calcium carbonate luminescent nanomaterials under the mediated Figure 3 .from Figure 3 It can be seen that the crystal form of the nanomaterial obtained in Example 3 conforms to the characteristics of amorphous calcium carbonate as a whole.

[0061] Figure 5 Mg prepared in Example 3 2+ SEM image of Eu-containing amorphous calcium carbonate luminescent nanomaterials mediated by Figure 5 It can be seen that the Eu-containing amorphous calcium carbonate luminescent nanomaterial particles prepared in Example 3 are uniform.

[0062] Figure 6 Mg prepared in Example 3 2+ TEM BF image and HAADF STEM-EDS analysis results of Eu-containing amorphous calcium carbonate luminescent nanomaterials under mediated conditions. In the figure, from left to right are TEM BF image, HAADF STEM-EDS analysis results of Ca, and HAADF STEM-EDS analysis results of Eu. Figure 6 It can be seen that Eu is evenly distributed in the nanomaterials.

[0063] Comparative Example 1

[0064] The difference from Example 1 is that step (1) is: using CaCl2 and EuCl3 as raw materials to prepare a mineralization mother solution, and the Ca 2+ The concentration of Eu 3+ The concentration of is 100 mM; other details are the same as in Example 1.

[0065] The nanomaterial prepared in Example 1 was subjected to XRD analysis, and the results are shown in FIG. Figure 4 By Figure 4 The data in the table were compared with the PDF standard card (JCPDS: 05-0586), and it was determined that the nanomaterial prepared in Comparative Example 1 had a calcite-type crystal structure.

[0066] The nanomaterials prepared in Examples 1-3 and Comparative Example 1 were characterized by ICP-OES to obtain Eu 3+ The results are shown in Table 1.

[0067] Table 1 Eu in the nanomaterials prepared in Examples 1-3 and Comparative Example 1 3+ Doping amount

[0068]

[0069] As can be seen from Table 1, in the absence of Mg 2+ In the case of mediated 3+ The addition amount in calcium carbonate is 49.6 mol%, and by increasing the Mg content in the mineralization mother liquor 2+ The concentration can further enhance the Eu 3+ Incorporation amount in amorphous calcium carbonate nanomaterials.

[0070] Figure 7 Mg prepared in Example 1-3 2+ Actual picture of Eu-containing amorphous calcium carbonate luminescent nanomaterials under 393nm irradiation. Figure 7 It can be seen that the nanomaterials prepared in Examples 1-3 can all emit bright red light, among which the red light emitted by the nanomaterial prepared in Example 3 is the brightest.

[0071] Figure 8 PL-PLE spectra of the nanomaterials prepared in Examples 1-3 and Comparative Example 1. Figure 8 It can be seen that in the same Eu 3+ concentration, by increasing the Mg content in the mineralization mother liquor 2+ The concentration can further enhance the luminescence properties of the material.

[0072] Figure 9 Schematic diagram of the device used for the carbonate mineralization reaction in step (2) of Examples 1-3 and Comparative Example 1. Figure 9 It can be seen that (NH4)2CO3 solid decomposes into CO2 and NH3 through the ammonium carbonate diffusion method, and CO2 and NH3 diffuse into the mother liquor through the gas-liquid interface to produce CO3 2- , CO3 2- With Ca in the mother liquor 2+ The reaction produces calcium carbonate.

[0073] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A Mg 2+ The method for preparing Eu-containing amorphous calcium carbonate luminescent nanomaterials under the guidance of a catalyst is characterized in that: The following steps are involved: Using Ca salt, Eu salt and Mg salt as raw materials to prepare mineralization mother liquor; The mineralization mother solution and ammonium carbonate powder are subjected to carbonate mineralization reaction by ammonium carbonate diffusion method, and then centrifuged and dried to obtain the Mg 2+ Eu-mediated amorphous calcium carbonate luminescent nanomaterials.

2. The preparation method according to claim 1, characterized in that The mineralization mother liquor contains Ca 2+ 、Eu 3+ and Mg 2+ The molar concentration ratio is 1:1:(1-5).

3. The preparation method according to claim 2, characterized in that The mineralization mother liquor contains Ca 2+ The concentration of Eu 3+ The concentration of Mg is 100mmol / L, 2+ The concentration is 100-500mmol / L.

4. The preparation method according to claim 1, characterized in that The Ca salt is selected from CaCl2; and / or, the Eu salt is selected from EuCl3; and / or, the Mg salt is selected from MgCl2.

5. The preparation method according to claim 1, characterized in that The volume ratio of the mineralization mother solution to the mass ratio of the ammonium carbonate powder is 50:2 (mL / g).

6. The preparation method according to claim 1, characterized in that The temperature of the carbonate mineralization reaction is 20-30° C., and the reaction time is 11-12 hours.

7. The preparation method according to claim 1, characterized in that The centrifugation is specifically as follows: the reaction solution obtained after the carbonate mineralization reaction is centrifuged once and the supernatant is removed, and the lower precipitate is washed and separated by centrifugation twice with ethanol.

8. The preparation method according to claim 8, characterized in that The speed of each centrifugation was 3000-3500 rad / min, and the duration of each centrifugation was 5-10 min.

9. The preparation method according to claim 1, characterized in that The drying temperature is 90-100° C. and the drying time is >90 min.

10. Mg prepared by the preparation method according to any one of claims 1 to 9 2+ Eu-mediated amorphous calcium carbonate luminescent nanomaterials.

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