Method for producing precipitated single-phase crystalline one-dimensional nanoscale calcite

Abstract

This invention relates to an innovative and environmentally friendly method for producing precipitated single-phase crystalline one-dimensional nanoscale calcite (CaCO3). The method is characterized by the use of a natural plant extract derived from the fruit of Hyphaene thebaika as a chelating agent. The method involves mixing a source of calcium cations (typically calcium chloride (CaCl2)) and carbon dioxide (CO2) in a solvent of water (H2O). The natural extract acts as a biocatalyst, promoting the formation of crystalline CaCO3 with unique properties. The method is characterized by the avoidance of synthetic chelating agents, pH adjusters, and additional heat treatment, making it an environmentally friendly and sustainable approach to CaCO3 production. The resulting calcite exhibits remarkable morphological anisotropy and high porosity, possessing properties beneficial in a variety of application fields.

Description

Technical Field

[0001] Field of the Invention The present invention relates to a method for producing precipitated single phase crystalline 1-D nanoscaled calcite CaCO3. Further, the present invention relates to the use of the product obtained from the production method as a cement binder, nano-fertilizer, drug carrier in the health field, or white pigment.

Background Art

[0002] Background of the Invention In the face of the increasing urgency of climate change, decarbonization processes and related technologies (CO2 immobilization, CO2 recycling, CO2 conversion) are widely studied for the purpose of reducing CO2 on a global scale. Carbonates (XCO3) in general and calcium carbonate (CaCO3) can effectively be produced by utilizing CO2 in the atmosphere and converting it into end products with economic value, such as the main component of cement, white pigments, green fertilizers, or drug carriers in the health and dental fields.

[0003] Calcium carbonate occupies about 4% of the Earth's crust and has been widely studied due to its importance in biomineralization (bio-mineralization), alkalinity generation, and biogeochemical cycling of elements in natural systems. There are three known natural crystal structures in natural calcium carbonate formed in the biomineralization process, which are vaterite, calcite, and aragonite. The first of these is a metastable polycrystal. However, vaterite has attracted the attention of scientists due to its unique optical and biochemical properties. The other two structures of calcium carbonate CaCO3, namely aragonite and calcite, play important roles in various strategic industries such as the cement, paint and coating industries.

[0004] From a synthetic perspective, in addition to known physical and chemical processes and natural biomimetics, methods based on green and sustainable approaches using bioengineering are rapidly developing in the production of CaCO3. U.S. Patent No. 4,824,653 describes a method for improving the color of calcium carbonate by treating limestone slurry with a synthetic chelating agent such as EDTA. This method differs from the present invention in that it does not use natural plant extracts as chelating agents and adjusts the pH to an alkaline range.

[0005] WO 96 / 15985 describes a process for purifying calcium carbonate using chelating agents and carbon dioxide treatment. This process reduces the iron content in calcium carbonate, but does not use natural plant extracts as chelating agents, which is in contrast to the present invention.

[0006] WO 98 / 24725: Requests a process for producing calcium carbonate under controlled pH conditions, resulting in calcium carbonate with low non-calcium metal concentrations. Unlike the present invention, this process does not use natural plant extracts as chelating agents.

[0007] WO 2014 / 147010: This is the most relevant to the present invention and describes precipitated calcium carbonate in the form of nanofibers or nanochains. The main differences are that it does not use natural plant extracts as chelating agents and uses an aqueous solution medium in the process.

[0008] In view of the above, the present inventors propose an improved, environmentally friendly, bioengineering, and energy-intensive process for biosynthesizing single-phase crystalline nanoscale CaCO3 with remarkable shape anisotropy and high porosity, using, for example, a natural extract of the fruit of Hyphaene thebaica, a species of palm tree with edible oval fruits. Verification was confirmed using Hyphaene thebaica, but other natural extracts can also be used. [Overview of the project]

[0009] In a first embodiment of the present invention, the present invention relates to a method (process) for producing precipitated single-phase crystalline one-dimensional nanoscale calcite (CaCO3), wherein the method is To provide a source of calcium cations, To provide a source of carbon dioxide (CO2), To provide a solvent in the form of water (H2O), To supply natural extracts obtained from plant species as chelating agents, and This includes extracting the precipitate.

[0010] In one embodiment, the calcium cation can be obtained from calcium chloride (CaCl2), but other calcium precursors can also be used a priori.

[0011] In yet another embodiment, the natural extract obtained from the plant species is the fruit of Hyphaene thebaica (Thebes dome palm).

[0012] In one embodiment of the present invention, 3.32 g of calcium chloride (CaCl2M = 110.98 g) was added to 100 mL of filtered extract and stirred gently at room temperature for 24 hours.

[0013] Furthermore, CO2 was added by bubbling to allow the precipitate to settle.

[0014] Furthermore, the precipitate was recovered by centrifugation at a range of 3,000 rpm to 5,000 rpm for 10 to 30 minutes, ideally 20 minutes, and at 4,000 rpm in ideal examples.

[0015] Furthermore, the precipitate was washed three times with dH2O, and then centrifuged at a range of 3,000 rpm to 5,000 rpm, ideally at 4,000 rpm, for 5 to 15 minutes (ideally 10 minutes).

[0016] A further important point is that the successful production of single-crystalline one-dimensional nanoscale calcite (CaCO3) precipitates was possible without using the following additional elements, that is, no additional catalyst was used, no additional chemicals for pH adjustment were used, and furthermore, no additional heat treatment was performed during or after the biosynthesis process.

[0017] A second aspect of the present invention is to use the product obtained from the above method (process) for cement binder applications.

[0018] A third aspect of the present invention is to use the product obtained from the above method (process) as a nano-fertilizer.

[0019] A fourth aspect of the present invention is to use the product obtained from the above method (process) as a drug carrier or dental compound in the health field.

[0020] A fifth aspect of the present invention is to use the product obtained from the above method (process) as a drug carrier in the health field.

[0021] A sixth aspect of the present invention is to use the product obtained from the above method (process) as a white pigment.

[0022] A seventh aspect of the present invention is to use the product obtained from the above method (process) to form a stable emulsion in water and exhibit excellent ultraviolet blocking properties when applied to the surface of plants.

[0023] As an example, the product can be diluted with an appropriate amount of water and applied to the affected area using an appropriate spraying device.

[0024] Referring to the accompanying drawings, the method for producing precipitated single-crystalline one-dimensional nanoscale calcite according to the present invention will be described by the following non-limiting examples.

Brief Description of the Drawings

[0025] [Figure 1(a)] Figure 1(a) shows the results of a typical high-resolution transmission electron microscope (HRTEM) of the bioengineered CaCO3 of the present invention. [Figure 1(b)] Figure 1(b) shows the results of a typical high-resolution transmission electron microscope (HRTEM) of the bioengineered CaCO3 of the present invention. [Figure 1(c)] Figure 1(c) shows the results of a typical high-resolution transmission electron microscope (HRTEM) of the bioengineered CaCO3 of the present invention. [Figure 1(d)] Figure 1(d) shows the results of a typical high-resolution transmission electron microscope (HRTEM) of the bioengineered CaCO3 of the present invention. [Figure 1(e)] Figure 1(e) shows the results of a typical selected area electron diffraction (SAED) of the bioengineered CaCO3 of the present invention. [[ID=Y]] [Figure 1(f)] Figure 1(f) shows the results of a typical selected area electron diffraction (SAED) of the bioengineered CaCO3 of the present invention. [Figure 2] Figure 2 shows a typical scanning electron spectroscopy (EDS) profile of the bioengineered nanoscale CaCO3 of the present invention. [Figure 3(a)] Figure 3(a) shows the thermogravimetric analysis (TGA) of the bioengineered nanoscale CaCO3 of the present invention in the temperature range of 25 - 850 °C. [Figure 3(b)] Figure 3(b) shows the corresponding differential scanning calorimetry (DSC) profile in the thermal range of 25 - 900 °C of the present invention. [Figure 4(a)] Figure 4(a) shows the results of the room temperature Fourier transform infrared spectroscopy spectrum of the bioengineered nanoscale CaCO3 of the present invention within the spectral range of 400 - 4000 cm-1. [Figure 4(b)] Figure 4(b) shows an enlarged view of the spectral region of 400 - 1000 cm-1 reporting the characteristic Raman active modes of calcite (CaCO3) at 288 cm-1 (L calcite) and 161 cm-1 (T calcite). [Figure 5(a)] Figure 5(a) shows the room-temperature Raman spectrum of bioengineered CaCO3 nanoparticles in the range of 0–1200 cm⁻¹ according to the present invention. [Figure 5(b)] Figure 5(b) shows a magnified view of the spectral region from 100 to 370 cm⁻¹, which represents the Ca-O characteristic vibrational modes of the calcite CaCO3 of the present invention. [Figure 6] Figure 6 shows the room-temperature light luminescence of biosynthesized nanoscale CaCO3 and intermediate products of Ca(OH)2 and the initial precursor CaCl2 according to the present invention. [Figure 7(a)] Figure 7 shows the Θ-2Θ X-ray diffraction spectra of bioengineered CaCO3-1-dimensional nanoparticles synthesized according to the present invention, in the angular ranges (a) 20-50 degrees and (b) 55-85 degrees, (c) the full XRD profile obtained by MAUD simulation, and (d) the proposed calcite crystal structure. [Figure 7(b)] Figure 7 shows the Θ-2Θ X-ray diffraction spectra of bioengineered CaCO3-1-dimensional nanoparticles synthesized according to the present invention, in the angular ranges (a) 20-50 degrees and (b) 55-85 degrees, (c) the full XRD profile obtained by MAUD simulation, and (d) the proposed calcite crystal structure. [Figure 7(c)] Figure 7 shows the Θ-2Θ X-ray diffraction spectra of bioengineered CaCO3-1-dimensional nanoparticles synthesized according to the present invention, in the angular ranges (a) 20-50 degrees and (b) 55-85 degrees, (c) the full XRD profile obtained by MAUD simulation, and (d) the proposed calcite crystal structure. [Figure 7(d)] Figure 7 shows the Θ-2Θ X-ray diffraction spectra of bioengineered CaCO3-1-dimensional nanoparticles synthesized according to the present invention, in the angular ranges (a) 20-50 degrees and (b) 55-85 degrees, (c) the full XRD profile obtained by MAUD simulation, and (d) the proposed calcite crystal structure. [Figure 8(a)]Figure 8(a) shows the standard diffuse reflectance spectra of bioengineered CaCO3-1-dimensional nanoparticles under perpendicular incidence in the wavelength range of 200–1000 nm, highlighting the increased reflectance in the visible light (VIS) and near-infrared (NIR) solar spectra. [Figure 8(b)] Figure 8(b) is an enlarged view of Figure 8(a), corresponding to the UV-blue wavelength region of 200-345 nm. [Figure 9(a)] Figure 9 shows the evolution of bioengineered CaCO3 1-dimensional nanoparticles using (a) average plant height, (b) average leaf count, and (c) nutrient concentrations in the average number of days to flowering compared to a control sample, highlighting their potential effectiveness as a green fertilizer. [Figure 9(b)] Figure 9 shows the evolution of bioengineered CaCO3 1-dimensional nanoparticles using (a) average plant height, (b) average leaf count, and (c) nutrient concentrations in the average number of days to flowering compared to a control sample, highlighting their potential effectiveness as a green fertilizer. [Figure 9(c)] Figure 9 shows the evolution of bioengineered CaCO3 1-dimensional nanoparticles using (a) average plant height, (b) average leaf count, and (c) nutrient concentrations in the average number of days to flowering compared to a control sample, highlighting their potential effectiveness as a green fertilizer. [Figure 10(a)] Figure 10(a) shows the multiscale porosity of bioengineered CaCO3-1-dimensional nanoparticles. [Figure 10(b)] Figure 10(b) shows the multiscale porosity of bioengineered CaCO3-1-dimensional nanoparticles. [Figure 10(c)] Figure 10(c) shows the multiscale porosity of bioengineered CaCO3-1-dimensional nanoparticles. [Modes for carrying out the invention]

[0026] Details of the invention Regarding light scattering and the application of white pigments, Figure 8(a) shows the standard diffuse reflectance spectrum of bioengineered CaCO3 nanoparticles (pelletized powder form) under perpendicular incidence in the wavelength range of 200–1000 nm. Figure 8(b) shows a zoomed view in the UV-blue wavelength region of 200–345 nm, and the high reflectivity in the visible light (VIS) and near-infrared (NIR) solar spectral regions is a characteristic of highly reflective solar materials comparable to standard white pigments including BaSO4, ZnO, and TiO2. Based on the above, the bioengineered CaCO3 nanoparticles of the present invention are considered to be a potentially promising compound for applications in so-called white pigment coatings.

[0027] Regarding nanofertilizer production, calcium is an essential phytonutrient for maintaining plant cellular metabolism. As a biocatalyst functioning as calcium ion species, these calcium ion species are involved in hydrocarbon metabolism, cell membrane maintenance, leaf morphology, membrane physiology, and protein production. To investigate the effectiveness of currently available bioengineered CaCO3 nanoparticles, they were tested as a bio / nanofertilizer in Lycopersicum esculentum (tomato). The concentrations of the CaCO3 products of this invention were fixed at 0.01, 0.03, and 0.05 g / l and compared to a control group. As a result, average plant height, average leaf count, and average days to flowering were collected. The experimental parameters were the same as those in the following publication: N. Jabeen, Q. Maqbool, T. Bibi, M. Nazar, S. Z. Hussain, T. Hussain, T. Jan, I. Ahmad, M. Maaza, S. Anwaar, Optimized synthesis of ZnO-nanofertilizer by green chemistry: Improving the growth dynamics of economically important Lycopersicum esculentum, IET Nanobiotechnology Vol. 12 Iss. 4, pp. 405-411 (2018).

[0028] Figure 9(a) shows the change in average plant height in relation to CaCO3 nutrient concentration. One conclusion is that plant height is greater than that of the control group, especially at the lowest CaCO3 nutrient concentration of 0.01 g / l. A similar trend is observed in the relationship between the average number of leaves and nutrient concentration (Figure 9(b)). Figure 9(c) shows particularly interesting results. The average number of days to flowering is shown to be shorter in the groups of CaCO3 nutrient concentration compared to the control group. In particular, at 0.01 g / l, flowering was confirmed to be 24 days earlier than in the control group. In conclusion, the plant growth parameters are far superior to those of the control group, and especially at the lowest concentration of 0.01 g / l, these are considered to be optimal values ​​under these experimental conditions.

[0029] Regarding the application of the cement binder, as shown in Figure 1, the bioengineered CaCO3 is nanoscale in size, making it finer than the particles of ordinary Portland cement (OPC) (average 10 μm). This fineness can improve the particle filling properties of concrete and provide an excellent spacer effect. Furthermore, the CaCO3-substituted concrete according to the present invention has a high slump value and improved workability. Moreover, in terms of statistical spatial distribution, the one-dimensional morphology of the CaCO3 nanoparticles of the present invention is advantageous, even if it does not improve the local mechanical strength of the CaCO3 / cement composite material as a local strengthening factor. Furthermore, the porosity of the CaCO3 nanorods (Figure 10) may promote strengthening of the bond due to the high surface area-to-volume ratio of the individual porous CaCO3 nanorods of the present invention.

[0030] Furthermore, the general TGA and DSC fluctuations / trends of the bioengineered CaCO3 of the present invention are equivalent to those of bulk CaCO3, but show a significant shift towards lower temperatures. More precisely, the decomposition and phase transition temperatures are approximately 648.8°C, compared to approximately 750°C for bulk CaCO3. This is thought to be because the nanoscale CaCO3 of the present invention has a higher surface area-to-volume ratio compared to its bulk equivalent. This improves workability in cement composite materials.

Claims

1. Precipitated single-phase crystalline one-dimensional nanoscale calcite (CaCO3) 3 A method for the manufacture of ) To provide a source of calcium cations, Carbon dioxide (CO2) ２ To provide a source of supply for ) Water (H ２ To provide a solvent in the form of O), To supply natural extracts obtained from plant species as chelating agents, The method of extracting precipitates is included, The aforementioned natural extract is Hyphaene thebaica. A method characterized by obtaining the fruit of thebaica.

2. The aforementioned calcium cation is calcium chloride (CaCl ２ ) obtained from the calcium chloride (CaCl ２ The method according to claim 1, wherein the substance is added to the filtered extract and stirred gently at room temperature for 24 hours.

3. The method according to claim 1 or 2, further comprising adding carbon dioxide via bubbling to allow the precipitate to settle.

4. The method according to any one of the preceding claims, wherein the precipitate is recovered by centrifugation at 3,000 rpm to 5,000 rpm for 10 to 30 minutes.

5. The precipitate is deionized with water (dH ２ The method according to any of the preceding claims, further comprising washing three times with O) and then centrifuging at 3,000 rpm to 5,000 rpm for 5 to 15 minutes.

6. The method according to any of the preceding claims, wherein no additional catalysts, pH-adjusting chemicals, or heat treatment are used during or after the biosynthesis process.

7. A product obtained by any one of claims 1 to 6 for use in a cement binder.

8. A product obtained by any one of claims 1 to 6 for use as a nanofertilizer.

9. A product obtained by any one of claims 1 to 6 for use as a drug carrier in the health field.

10. A product obtained by any one of claims 1 to 6 for use as a white pigment.

11. The method according to any one of the preceding claims, wherein the product is used as a water-stable emulsion for coating the surface of a plant to impart solar radiation blocking properties.

12. The method according to claim 11, wherein the product is diluted with water and applied to an area by a spraying device.

13. The method according to any one of the preceding claims, wherein the calcite has high reflectivity in the visible light (VIS) and near-infrared (NIR) solar spectral regions.

14. The calcite is the same as the CaCO 3 The method according to any of the preceding claims, wherein the product concentration is fixed at 0.01, 0.03, and 0.05 g / l and tested as a bio / nanofertilizer in the growth of Lycopersicum esculentum.

15. Bioengineered CaCO 3 The method according to any of the prior claims, wherein the nanorods, due to their fine particle size and porosity, improve the workability and mechanical strength of cement composite materials.

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