Method for producing calcium carbonate-blended silicate-coated metal ion compound composite composition

Abstract

To provide a method for producing a calcium carbonate-blended silicate-coated metal ion compound composite composition which can be blended as components of food, livestock feed, fertilizer, cosmetics or quasi drug or components of a coating agent by using a more safe and relieved material to enhance a photocatalytic effect without using an existing high technology or an expensive material, on the background of concern about health of titanic oxide as a nanomaterial, which is recently cried out in an EU Europe area.SOLUTION: A method for producing a calcium carbonate-blended silicate-coated metal ion compound composite composition includes coating a calcium carbonate-blended metal ion compound with porous silicate by treating calcium carbonate containing natural products such as fossil coral with a silicic acid solution and a cation solution in the existence of metal ion without using titanic oxide typical as photocatalyst metal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a calcium carbonate-containing silicate-coated metal ion compound composite composition using calcium carbonate, which does not use existing advanced technology or expensive materials, and does not use titanium dioxide as a photocatalytic metal, but instead uses a simpler method and inexpensive, safe and reliable materials to enhance the photocatalytic effect, and which can be incorporated as an ingredient in foods, feeds, fertilizers, cosmetics, or quasi-drugs, or as an ingredient in coating agents. [Background technology]

[0002] Titanium oxide has traditionally been used in a variety of applications, including as a paint, coloring agent, and food additive, not to mention as a photocatalyst, and in particular, JP 2007-169164 A (see Patent Document 1) has proposed using a material with photocatalytic function, titanium oxide coated with apatite, as an environmentally cleansing cosmetic ingredient. When titanium oxide photocatalyst is incorporated into cosmetics, a coating structure such as apatite on the photocatalytic metal is essential to prevent the activation and decomposition power of light energy from being directly exerted on the base material, the skin, but no mention has been made of the particle size of titanium oxide with regard to the effects on health, such as skin permeability, when nano-sized titanium oxide is used as a cosmetic ingredient.

[0003] Furthermore, JP 2014-184349 A (see Patent Document 2), paragraph 0021, discloses a manufacturing method for improving the activity of titanium oxide as a cosmetic or food additive containing metal ions and calcium carbonate, but makes no mention of the effects on human health when the titanium oxide ingested as a food additive is nano-sized.

[0004] Japanese Patent No. 7193192 (see Patent Document 3) discloses a method for producing titanium oxide coated with a silicate containing metal ions, but this is a production method in which conventional titanium oxide is compounded as a base material having photocatalytic function, and is fundamentally different from the present application, which does not use titanium oxide. On the other hand, as highly active photocatalysts that do not use titanium oxide, Japanese Patent Laid-Open No. 2015-54299 (see Patent Document 4) discloses a method for producing a photocatalyst that does not use titanium oxide, in which iron oxide is used, and Japanese Patent Laid-Open No. 2016-10750 (see Patent Document 5) discloses a method for producing a photocatalyst that does not use titanium oxide, in which iron oxyhydroxide particles are bonded to the surface and interior of copper oxide particles.

[0005] Furthermore, in recent years, progress has been made in the development of technology that uses iron oxyhydroxide to achieve photocatalytic performance that surpasses that of titanium oxide (see Non-Patent Document 6), and iron oxide-based materials in which dinuclear iron ions are stabilized with porous silica as an alternative to titanium oxide (see Non-Patent Document 7). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2007-169164 A [Patent Document 2] JP 2014-184349 A [Patent Document 3] Patent No. 7193192 [Patent Document 4] JP 2015-54299 A [Patent Document 5] JP 2016-10750 A [Non-Patent Document 6] Tokyo University of Science, "Press Release", [online], February 27, 2020, [Retrieved January 6, 2023], Internet<URL:https: / / www.tus.ac.jp / today / archive / 20200227001.html> [Non-Patent Document 7] Hiroshima University, "Research Results," [online], May 26, 2022, [Retrieved January 6, 2023], Internet<URL:https: / / www.hiroshima-u.ac.jp / news / 71669> Summary of the Invention [Problem to be solved by the invention]

[0007] Titanium dioxide, which is also a coloring agent and photocatalytic metal, is widely used around the world as a food additive, cosmetic and pharmaceutical raw material, paint, and industrial material. In particular, its antibacterial and germ-killing properties have attracted attention as an effective means of combating the threat of recent new viruses in applications such as building materials and germ-killing filters, and technological development is underway.

[0008] However, when titanium dioxide is prepared into nanoparticles, international organizations have recently reported that there is a risk of lung cancer from inhaling dust over a long period of time in workplaces where titanium dioxide dust flies around, and that animal experiments have shown concerns of genotoxicity, and in particular, the European Union has gone so far as to ban the use of titanium dioxide as a food additive in January 2022 due to food safety concerns. Against a backdrop of health concerns about titanium dioxide as a nanomaterial, including nano-sized raw materials, there is an urgent need to develop safer and more reliable photocatalytic materials.

[0009] The present invention was conceived against the background of such a world situation regarding the effects that photocatalytic nanomaterials may have on human health. In other words, we started to develop a safer photocatalytic material that has the same effect as titanium oxide, but does not use titanium oxide, which is a typical photocatalytic metal, and devised a complex composition that highly blends calcium compounds such as CaCO3 and CaO, cationic solutions containing calcium ions and magnesium ions, and silicic acid compounds or silicic acid solutions containing silicate ions, in the presence of metal ions such as Fe ions, Mg ions, Ag ions, and Cu ions.

[0010] CaCO3 is a porous material, as typified by fossil coral, and Fe-based oxides are expected to be visible light responsive photocatalytic materials. The application technology of Fe-based oxides to photocatalytic materials has also developed, and materials comparable to titanium oxide have been developed, but the production of highly active photocatalytic materials using Fe-based oxides requires advanced technology and a large amount of cost, and they have not yet been practically used for general purposes. In consideration of these issues, we attempted to develop a photocatalytic material that does not use titanium oxide by blending a hybrid of calcium compounds such as calcium carbonate, metal ions, and silicates, rather than using titanium oxide as the base material as the photocatalytic metal, and arrived at this invention. [Means for solving the problem]

[0011] Therefore, Fe ions, Cu ions, and Ag ions Hmm? One or more metal ions selected from hmm( Hereafter, they are collectively referred to as "metal ions" hmm" (hereinafter referred to as "cation solution"), which does not contain a silicate compound or silicate ion, but contains one or more of Ca ions, Mg ions, and metal ions (hereinafter referred to as "cation solution"), and Ca ions and The method for producing a calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention was developed for the purpose of providing a method for producing a photocatalytic material that does not rely on titanium oxide, by producing a calcium carbonate-containing silicate-coated metal ion compound composite composition by simply fusing a silicic acid compound or a silicic acid solution containing silicate ions but not containing Mg ions (hereinafter referred to as a "silicic acid solution"), and calcium carbonate containing natural materials such as fossil coral.

[0012] In the method for producing the calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention, the calcium carbonate-containing silicate-coated metal ion compound composite composition is characterized in that calcium carbonate containing naturally occurring calcium carbonate such as fossil coral is premixed, and the mixture is treated with a silicic acid solution and a cation solution in the presence of metal ions.

[0013] In the method for producing the calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention, N The calcium carbonate, including calcium carbonate derived from natural sources such as fossil coral, is treated with the cationic solution and the silicic acid solution in the presence of metal ions, and the calcium carbonate-containing metal ion compound composite composition is coated with porous silicate.

[0014] In the method for producing a calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention, the cationic solution is N The compound has an acidity sufficient to dissolve part or all of naturally occurring calcium carbonate such as fossil coral when added to a cationic solution, and when calcium carbonate is mixed with the cationic solution, the dissolved calcium carbonate reacts with the cationic solution to produce a calcium carbonate-containing metal ion compound. By further treating the compound with a silicic acid solution, the calcium carbonate-containing metal ion compound is coated with a porous silicate, resulting in a composite composition.

[0015] The calcium carbonate-containing silicate-coated metal ion compound complex composition is a complex composition coated with silicate produced by mixing a silicic acid solution with a calcium carbonate-containing metal ion compound obtained by mixing calcium carbonate with a cation solution to which metal ions have been added. The calcium carbonate-containing metal ion compound refers to a compound that has not yet been coated with silicate, and has not been treated with both a cation solution and a silicic acid solution in the presence of metal ions (treated only with either a cation solution or a silicic acid solution).

[0016] In the calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention, the porous calcium carbonate derived from natural products contained in the calcium carbonate is a fossil coral, which is a coral colony with a hard calcareous skeleton that has been weathered over a long period of time and eroded by the action of waves into lumps or granules that are deposited and stratified on the seabed, and is a natural substance collected in the Nansei Islands including the main island of Okinawa and Yonaguni Island, which has the characteristics of having adsorption properties due to its porous structure, containing many minerals mainly calcium, and dissolving well in acidic solutions and ionizing, and has favorable adsorption properties for metals and minerals due to its porous structure, and adsorbs metal ions well. In addition, powders of calcined and crushed limestone, shell fossils, shells, oyster shells, etc., which have been classified by particle size, can be suitably used as porous calcium carbonate derived from other natural products.

[0017] The cationic solution can be adjusted so that the concentrations of Ca ions and Mg ions are mixed at any desired ratio. For example, the cationic solution can be mixed with 90 mol % Ca ions and 10 mol % Mg ions, or with 10 mol % Ca ions and 90 mol % Mg ions, or with only Ca ions (100 mol %) or only Mg ions (100 mol %).

[0018] In the method for producing a silicate-coated metal ion compound composite composition containing calcium carbonate of the present invention, the silicic acid solution and the cation solution contain nanocellulose, which is a fibrous material obtained by nanofiberizing chitin and chitosan, or cellulose-derived cellulose-derived fibrous proteins such as silk, or a chemical structure similar to cellulose. The porous silicate produced in the presence of fibrous proteins such as silk and fibrous materials such as nanocellulose becomes finer, improving the adsorption and biocompatibility, and allowing more effective adsorption of substances that cause dirt and odor.

[0019] The fibroin obtained by removing sericin from the silk is obtained by using silk thread or natural cocoons as silk powder, decomposing and extracting the silk protein called fibroin contained in the silk fibers, and then heat-treating it to produce a molecular-level amino acid powder. These fibrous substances can be mixed with the calcium carbonate in a ratio of 0.001 to several parts by weight.

[0020] Chitin is a natural material found in many living organisms, including shrimp and crabs. Its structure is similar to cellulose, but it is an amino polysaccharide consisting of long chains of N-acetyl-D-glucosamine. When chitin is treated with alkali, the acetyl groups are removed and it is converted into chitosan, which is mainly composed of D-glucosamine units. By treating with alkali, the proportion of D-glucosamine units increases to about 70-95%, and it becomes soluble in an acid solution. Chitin and chitosan have attracted attention for their bioabsorbability, antibacterial and antifungal properties, and porous gel-forming properties, and are polymeric materials that are expected to have advanced functions and harmony with the environment.

[0021] In the calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention, the calcium carbonate and the metal ion hmm, The amount of the silicic acid solution and the cation solution is determined so that the calcium carbonate is composed of fossil coral alone, calcium carbonate alone, or a mixture thereof, and the amount of the metal ions relative to the calcium carbonate is determined so that the amount of the silicic acid solution and the cation solution is determined so that the amount of the metal ions relative to the calcium carbonate ... N It is also characterized in that the content is 0.001 to 20 parts by weight, with the remainder consisting of calcium carbonate and porous silicate.

[0022] In the method for producing a calcium carbonate-containing silicate-coated metal ion compound complex composition of the present invention, the calcium carbonate-containing silicate-coated metal ion compound complex composition is characterized in that it can be incorporated as a component of foods, feeds, fertilizers, cosmetics, quasi-drugs, agricultural, forestry and fishery supplies, water quality / environmental purification agents, coating agents, pet foods, deodorants, paints, cutting oils, etc. Effect of the Invention

[0023] In the manufacturing method of the calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention, the calcium carbonate-containing silicate-coated metal ion compound composite composition has an effect of decomposing and removing dirt, odor, bacteria, etc. adsorbed by the porous silicate or fossil coral by oxidation-reduction action when irradiated with light. Silicate has a function of adsorbing and retaining dirt, odor, bacteria, etc. For example, it is a (ceramic) material that can adsorb nitrogen oxides, lipid peroxides, ammonia, aldehydes, bacteria such as E. coli, and viruses. In addition, the composite composition may further be blended with zeolite, diatomaceous earth, or charcoal, which are porous materials with an adsorption function. [Brief description of the drawings]

[0024] [Figure 1] Graph showing the effect of adding metal ions in Example 1 of the manufacturing method of the calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention. The photocatalytic effect is realized by coating the metal ion compound with porous silicate based on the blending of calcium carbonate (fossil coral). As the measurement conditions, 100 mg of each sample was mixed with 10 ml of methylene blue (concentration that gives an absorbance of 0.854 at a wavelength of 660 nm) and irradiated with ultraviolet light (2 mW / cm2). [Diagram 2] 1 is a graph showing the effect of adding metal ions in Example 2 of the manufacturing method of the calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention. As the measurement conditions, 100 mg of each sample was mixed with 10 ml of methylene blue (concentration at which the absorbance at a wavelength of 660 nm becomes 0.824) and irradiated with ultraviolet light (2 mW / cm2). Even if calcium carbonate (fossil coral) is added to any one of Fe ions, Mg ions, and silicate ions, no photocatalytic action is exhibited. In other words, a calcium carbonate-containing metal ion compound containing only metal ions and calcium carbonate does not exhibit a photocatalytic action. [Diagram 3]3 is a graph showing the effect of adding Fe ions, silicic acid solution, and cationic solution in Example 3 of the manufacturing method of calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention. As the measurement conditions, 10 ml of methylene blue (concentration at which the absorbance at 660 nm wavelength becomes 0.824) was mixed with 10 mg of each sample, and ultraviolet light (2 mW / cm2) was irradiated. The photocatalytic action is expressed by treating the Fe ion compound produced by mixing calcium carbonate (fossil coral) with a cationic solution containing Fe ions with a silicic acid solution. As shown in FIG. 3, the photocatalytic reaction is significantly promoted by adding 2 parts by weight (relative to calcium carbonate (fossil coral)) or more of Fe ions to the cationic solution. [Figure 4] 4 is a graph showing the effect of adding Mg ions, silicic acid solution, and cationic solution in Example 4 of the manufacturing method of the calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention. As the measurement conditions, 100 mg of each sample was mixed with 10 ml of methylene blue (concentration at which the absorbance at 660 nm wavelength becomes 0.824) and irradiated with ultraviolet light (2 mW / cm2). A photocatalytic reaction occurs when a Mg ion compound is generated by mixing calcium carbonate (fossil coral) with a cationic solution containing Mg ions and treating the Mg ion compound with a silicic acid solution. As shown in FIG. 4, the photocatalytic reaction is most promoted by adding 10 parts by weight (relative to calcium carbonate (fossil coral)) of Mg ions to the cationic solution. [Diagram 5] 5 is a graph showing the effect of adding Fe ions, silicic acid solution, and cationic solution in Example 5 of the manufacturing method of calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention. As the measurement conditions, 10 ml of methylene blue (concentration at which the absorbance at 660 nm wavelength becomes 0.824) was mixed with 100 mg of each sample, and ultraviolet light (2 mW / cm2) was irradiated. A photocatalytic reaction occurs when an Fe ion compound is generated by mixing calcium carbonate (fossil coral) with a cationic solution containing Fe ions and treating it with a silicic acid solution. 2 parts by weight of Fe ions (relative to calcium carbonate (fossil coral)) were added to the cationic solution. As shown in FIG. 5, the photocatalytic action occurs when 5 parts by weight or more of silicate ions are added. [Figure 6] Graph showing the effect of adding Fe ions, Cu ions, Ag ions, silicic acid solution, and cationic solution in Example 6 of the manufacturing method of calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention. As the measurement conditions, 100 mg of each sample was mixed with 10 ml of methylene blue (concentration at which the absorbance at 660 nm wavelength becomes 0.886) and irradiated with ultraviolet light (2 mW / cm2). By treating each metal ion compound produced by compounding calcium carbonate (fossil coral) with a cationic solution containing 0.2 parts by weight of Ag ions, a cationic solution containing 0.6 parts by weight of Cu ions (relative to calcium carbonate (fossil coral)), and a cationic solution containing 1 part by weight of Fe ions (relative to calcium carbonate (fossil coral)), with a silicic acid solution, a remarkable photocatalytic effect is exhibited. [Figure 7] 1 is a graph showing the effect of adding a metal ion compound composite composition and a silicic acid solution produced by adding Fe ions and Pt colloid in Example 7 of the manufacturing method of the calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention. As the measurement conditions, 100 mg of each sample was mixed with 10 ml of methylene blue (concentration at which the absorbance at a wavelength of 660 nm becomes 0.854) and irradiated with ultraviolet light (2 mW / cm2). [Figure 8] 1 is a graph showing the effect of adding silk protein in Example 8 of the manufacturing method of calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention. As the measurement conditions, 100 mg of each sample was mixed with 10 ml of methylene blue (concentration at which the absorbance at 660 nm wavelength becomes 0.854) and irradiated with ultraviolet light (2 mW / cm2). [Figure 9] 1 is a graph showing the effect of adding nanocellulose fiber in Example 9 of the manufacturing method of the calcium carbonate-blended silicate-coated metal ion compound composite composition of the present invention. As the measurement conditions, 100 mg of each sample was mixed with 10 ml of methylene blue (concentration at which the absorbance at a wavelength of 660 nm becomes 0.854) and irradiated with ultraviolet light (2 mW / cm2). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, the embodiment of the method for producing a calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention will be described in detail based on examples. EXAMPLES

[0026] <Method of producing the composition of the present invention> The present invention provides a method for producing a composite composition in which a metal ion compound containing calcium carbonate, which is produced by compounding calcium carbonate with metal ions, is coated with a porous silicate without using titanium oxide.

[0027] In the present invention, the blending amounts of metal ions and calcium carbonate are such that the calcium carbonate consists of fossil coral alone or calcium carbonate alone, or a mixture thereof, the metal ions are 0.001 to 20 parts by weight relative to the calcium carbonate, and the remainder consists of calcium carbonate and porous silicate.

[0028] In the blending example of this embodiment, the calcium carbonate is composed of fossil coral powder:calcium carbonate powder = 1:1, and as metal ions, Fe ions are 1 part by weight relative to the calcium carbonate, and the remainder is composed of calcium carbonate and porous silicate. The valence of the metal ions used in the present invention can be appropriately determined in consideration of the relationship with other blending ingredients.

[0029] Powder of calcium carbonate (fossil coral powder: calcium carbonate powder = 1:1) is mixed in advance, and the mixture is blended with a cationic solution in which 1 part by weight of Fe ions is added to calcium carbonate, and then a silicic acid solution is mixed to generate porous silicate on the surface of the calcium carbonate-blended metal ion compound, and then the mixture is fired at 50°C to 700°C for 10 to 480 minutes. For example, calcium carbonate powder is immersed in a cationic solution and dried, then immersed in a silicic acid solution and dried, and then fired. At this time, for example, fibrous protein or fibrous cellulose can be added to the cationic solution or silicic acid solution in an amount of 0.001 to several parts by weight relative to calcium carbonate.

[0030] FIG. 1 is a graph showing the photocatalytic effect of a calcium carbonate-containing, silicate-coated, metal ion compound complex composition in Example 1 of the method for producing a calcium carbonate-containing, silicate-coated, metal ion compound complex composition of the present invention. It is clear that a photocatalytic composite composition capable of achieving a photocatalytic reaction without using titanium oxide, which is generally used as a photocatalytic metal, has been obtained.

[0031] The cation solution and silicic acid solution used herein have, for example, the following compositions: Cation solution = 100-300 mM (90 mol% Ca ion, 10 mol% Mg ion) CaCl2+MgCl2 / Tris-HCl containing 1 part by weight of Fe ion (relative to calcium carbonate) Silicic acid solution = 10-1000mM Na2SiO3 solution

[0032] In this example, the porosity and coverage of the porous silicate can be controlled by changing the composition, temperature, and immersion time of the cation solution and silicic acid solution. When the ion concentration of the silicate ion and cation is low, the coverage of the porous silicate tends to decrease. In addition, the adsorption effect of dirt substances and the like can be controlled by adjusting the acidity of the cation solution containing calcium carbonate, including calcium carbonate derived from natural products such as fossil coral. When the acidity of the cation solution is low, the amount of calcium carbonate dissolved is reduced, and the adsorption effect of the calcium carbonate-containing silicate-coated metal ion compound complex composition for dirt and the like tends to be improved due to the adsorption property of the porous calcium carbonate that remains in large amounts. EXAMPLES

[0033] <Method for producing the composition of the present invention> A calcium carbonate-containing Fe ion compound was prepared by mixing calcium carbonate (fossil coral alone) with a cationic solution containing 2 parts by weight of Fe ion and then calcining. Similarly, a calcium carbonate-containing Mg ion compound was prepared by mixing calcium carbonate with a cationic solution containing 10 parts by weight of Mg ion, and a calcium carbonate-containing silicic acid compound was prepared by mixing calcium carbonate with a silicic acid solution containing 10 parts by weight of silicate ion. Each calcium carbonate-containing metal ion compound prepared in this example is a simple calcium carbonate-containing metal ion compound that is simply mixed with calcium carbonate (fossil coral alone) with Fe ions, Mg ions, and silicic acid ions, and is treated with only one of the cationic solution or silicic acid solution (not coated with silicate salt).

[0034] Fig. 2 is a graph showing the photocatalytic effect of calcium carbonate-containing metal ion compound in Example 2 of the manufacturing method of calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention, and shows comparative data on methylene blue decomposition of metal ion compounds (not coated with silicate) that are treated only with either a cation solution or a silicic acid solution by simply mixing calcium carbonate with only a cation solution containing Fe ions or Mg ions, or with only a silicic acid solution containing silicate ions. As shown in Fig. 2, even if calcium carbonate is mixed with only one of the components Fe ions, Mg ions, and silicic acid ions, no photocatalytic effect is exhibited. In other words, photocatalytic effect is not exhibited in a calcium carbonate-containing metal ion compound in which metal ions are simply mixed with calcium carbonate. EXAMPLES

[0035] <Method for producing the composition of the present invention> FIG. 3 is a graph showing the effect of adding metal ions in Example 3 of the manufacturing method of the calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention, and shows comparative data on methylene blue decomposition showing the effect of silicate ions as metal ions and the effect of the amount of Fe ions added.

[0036] As in Example 1, powders of calcium carbonate (fossil coral powder: calcium carbonate powder = 1:1) are mixed in advance, and the mixture is blended with a cationic solution containing metal ions. After that, a silicic acid solution is added to generate porous silicate on the surface of the calcium carbonate-blended metal ion compound, and then the mixture is fired at 50°C to 700°C for 10 to 480 minutes. In this case, calcium carbonate is mixed with a cationic solution containing 0, 1, 2, or 3 parts by weight of Fe ions as metal ions relative to calcium carbonate, and a silicic acid solution containing 10 parts by weight of silicate ions relative to calcium carbonate, thereby obtaining a calcium carbonate-containing silicate-coated metal ion compound composite composition in which calcium carbonate is treated with a cationic solution and a silicic acid solution in the presence of metal ions (Fe ions).

[0037] FIG. 3 is a graph showing the photocatalytic effect of the calcium carbonate-containing, silicate-coated, metal ion compound complex composition in Example 3 of the method for producing the calcium carbonate-containing, silicate-coated, metal ion compound complex composition of the present invention. As can be seen from FIG. 3, while no effect was observed with the calcium carbonate-containing metal ion compound alone, which was prepared by merely mixing calcium carbonate and metal ions in Example 2, by adding a mixture of silicic acid solution and cation solution to coat the calcium carbonate-containing metal ion compound with silicate, a photocatalytic composite composition that obtains a photocatalytic reaction without using a commonly used photocatalytic metal such as titanium oxide can be obtained.

[0038] The cation solution and silicic acid solution used here have, for example, the following compositions. Cation solution = 100-300 mM CaCl2+MgCl2 / Tris-HCl (90 mol% Ca ion, 10 mol% Mg ion) containing 0, 1, 2, and 3 parts by weight of Fe ion Silicic acid solution = Na2SiO3 solution containing 10 parts by weight of silicate ions EXAMPLES

[0039] <Method for producing the composition of the present invention> FIG. 4 is a graph showing the effect of adding metal ions in Example 4 of the manufacturing method for the calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention, and shows comparative data on methylene blue decomposition showing the effect of silicate ions and the influence of the amount of Mg ions added when Mg ions were added as metal ions.

[0040] As in Example 1, calcium carbonate powder (fossil coral powder: calcium carbonate powder = 1:1) is mixed in advance, the mixture is mixed with a cationic solution containing metal ions, a silicic acid solution is added to generate porous silicate on the surface of the calcium carbonate-containing metal ion compound, and then the mixture is baked for 10 to 480 minutes at 50 ° C. to 700 ° C. In this case, by treating with a cationic solution containing 0, 5, 10, and 20 parts by weight of Mg ions as metal ions relative to calcium carbonate, and a silicic acid solution containing 10 parts by weight of silicate ions relative to calcium carbonate, a calcium carbonate-containing silicate-coated metal ion compound composite composition can be obtained in which the calcium carbonate-containing metal ion compound is treated with a cationic solution and a silicic acid solution in the presence of metal ions (Mg ions).

[0041] The cation solution and silicic acid solution used herein have, for example, the following compositions: Cation solution = 100-300 mM CaCl2 / Tris-HCl containing 0, 5, 10, and 20 parts by weight of Mg ion Silicic acid solution = Na2SiO3 solution containing 10 parts by weight of silicate ions

[0042] As can be seen from FIG. 4, while no effect was observed with the calcium carbonate-blended metal ion compound in Example 2, which was prepared by merely blending calcium carbonate and metal ions, a photocatalytic composite composition that obtains a photocatalytic reaction without using a commonly used photocatalytic metal such as titanium oxide was obtained by coating the silicate with a silicic acid solution and a cation solution. EXAMPLES

[0043] <Method for producing the composition of the present invention> 5 is a graph showing the effect of adding metal ions in Example 5 of the manufacturing method of the calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention. The graph shows comparative data on methylene blue decomposition showing the effect of silicate ions and the influence of the amount of silicate ions added when Fe ions were added as metal ions.

[0044] In the same manner as in Example 1, calcium carbonate powder (fossil coral powder: calcium carbonate powder = 1:1) is mixed in advance, the mixture is mixed with a cationic solution containing metal ions, a silicic acid solution is added to generate porous silicate on the surface of the calcium carbonate-containing metal ion compound, and then the mixture is fired at 50°C to 700°C for 10 to 480 minutes. At that time, by treating with a cationic solution containing 2 parts by weight of Fe ions relative to calcium carbonate and a silicic acid solution containing 0, 5, 10, and 20 parts by weight of silicate ions relative to calcium carbonate, a calcium carbonate-containing silicate-coated metal ion compound composite composition can be obtained in which the calcium carbonate-containing metal ion compound is treated with a cationic solution and a silicic acid solution in the presence of metal ions (Fe ions).

[0045] The cation solution and silicic acid solution used here have, for example, the following compositions: Cation solution = 100-300 mM CaCl2+MgCl2 / Tris-HCl (90 mol% Ca ion, 10 mol% Mg ion) containing 2 parts by weight of Fe ion Silicic acid solution = Na2SiO3 solution containing 0, 5, 10, and 20 parts by weight of silicate ions

[0046] 5, it can be seen that, whereas no effect was observed with the calcium carbonate-containing metal ion compound in which calcium carbonate and metal ions were merely mixed in Example 2, a photocatalytic composite composition that obtains a photocatalytic reaction without using a commonly used photocatalytic metal such as titanium oxide was obtained by coating the calcium carbonate-containing metal ion compound with silicate by adding treatment with a silicic acid solution and a cation solution. Also, no effect can be expected in the absence of silicate ions. EXAMPLES

[0047] <Method for producing the composition of the present invention> FIG. 6 is a graph showing the effect of adding metal ions in Example 6 of the method for producing a calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention, and shows comparative data on the decomposition of methylene blue when Fe ions, Cu ions, and Ag ions are used as metal ions.

[0048] Powder of calcium carbonate (fossil coral powder: calcium carbonate powder = 1:1) was mixed in advance, and the mixture was mixed with a cationic solution containing 1 part by weight of Fe ions and 0.2 parts by weight of Ag ions relative to the calcium carbonate. Next, a silicic acid solution containing 3 parts by weight of silicate ions relative to the calcium carbonate was mixed to generate porous silicate on the surface of the calcium carbonate-containing metal ion compound, and then the mixture was fired at 50°C to 700°C for 10 to 480 minutes to obtain a calcium carbonate-containing silicate-coated metal ion compound composite composition. Similarly, powder of calcium carbonate (fossil coral powder: calcium carbonate powder = 1:1) was mixed, and the mixture was mixed with a cationic solution containing 1 part by weight of Fe ions and 0.6 parts by weight of Cu ions relative to the calcium carbonate. Next, a silicic acid solution containing 3 parts by weight of silicate ions relative to the calcium carbonate was added to generate porous silicate on the surface of the calcium carbonate-containing metal ion compound, and the mixture was then fired at 50°C to 700°C for 10 to 480 minutes to obtain a calcium carbonate-containing silicate-coated metal ion compound composite composition.

[0049] The cation solution and silicic acid solution used herein have, for example, the following compositions: Cation solution = 100-300 mM CaCl2 / Tris-HCl containing 1 part by weight of Fe ion and 0.2 parts by weight of Ag ion or 0.6 parts by weight of Cu ion relative to calcium carbonate Silicic acid solution = Na2SiO3 solution containing 3 parts by weight of silicate ions EXAMPLES

[0050] <Method for producing the composition of the present invention> FIG. 7 is a comparative graph of methylene blue decomposition showing the effect of adding Pt colloid in Example 7 of the method for producing a calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention.

[0051] As in Example 6, calcium carbonate powder (fossil coral powder: calcium carbonate powder = 1:1) was mixed, and the mixture was added to a cationic solution containing 1 part by weight of Fe ions relative to the calcium carbonate and a Pt colloidal liquid containing 0.01 part by weight of Pt. Next, a silicic acid solution containing 3 parts by weight of silicate ions relative to the calcium carbonate was added to generate porous silicate on the surface of the calcium carbonate-containing metal ion compound, and then the mixture was fired at 50°C to 700°C for 10 to 480 minutes to obtain a calcium carbonate-containing silicate-coated metal ion compound composite composition.

[0052] The cation solution and silicic acid solution used herein have, for example, the following compositions: Cation solution = 100-300 mM CaCl2 / Tris-HCl containing 1 part by weight of Fe ions and 0.01 part by weight of Pt relative to calcium carbonate Silicic acid solution = Na2SiO3 solution containing 3 parts by weight of silicate ions EXAMPLES

[0053] <Method for producing the composition of the present invention> FIG. 8 is a graph showing the effect of adding silk protein in Example 8 of the manufacturing method of the calcium carbonate-containing silicate-coated metal ion compound composite composition of the present invention, and shows comparative data on methylene blue decomposition when Fe ions are used as metal ions and silk protein is further added.

[0054] As in Example 1, calcium carbonate powder (fossil coral powder: calcium carbonate powder = 1:1) is mixed in advance, and the mixture is blended with a cationic solution in which 1 part by weight of Fe ions is added to calcium carbonate, and then a silicic acid solution is mixed to generate porous silicate on the surface of the calcium carbonate-blended metal ion compound, followed by firing for 10 to 480 minutes at 50°C to 700°C. In this example, 0.01 part by weight of fibroin obtained by removing sericin from silk is added to the cationic solution relative to calcium carbonate.

[0055] The cation solution and silicic acid solution used herein have, for example, the following compositions: Cation solution = 100-300 mM (90 mol% Ca ion, 10 mol% Mg ion) CaCl2+MgCl2 / Tris-HCl containing 1 part by weight of Fe ion and 0.01 part by weight of silk protein relative to calcium carbonate Silicic acid solution = Na2SiO3 solution containing 3 parts by weight of silicate ions EXAMPLES

[0056] <Method for producing the composition of the present invention> FIG. 9 is a graph showing the effect of adding nanocellulose plant fiber in Example 9 of the manufacturing method for a calcium carbonate-blended silicate-coated metal ion compound composite composition of the present invention, and shows comparative data on methylene blue decomposition when Fe ions are used as metal ions and nanocellulose fiber is further added.

[0057] A silicate-coated metal ion compound composite composition containing calcium carbonate was obtained in the same manner as in Example 8, except that the silk fiber in Example 8 was replaced with nanocellulose fiber. At that time, 0.1 parts by weight of a 0.2 wt% aqueous solution of cellulose nanofiber derived from cell walls and chitin nanofiber, which has a chemical structure similar to cellulose, was added to the silicic acid solution relative to the calcium carbonate.

[0058] The cation solution and silicic acid solution used herein have, for example, the following compositions: Cation solution = 100-300 mM CaCl2+MgCl2 / Tris-HCl (90 mol% Ca ion, 10 mol% Mg ion) containing 1 part by weight of Fe ion relative to calcium carbonate Silicic acid solution = Na2SiO3 solution containing 0.1 parts by weight of cellulose nanofiber (0.2 wt% aqueous solution) or chitin nanofiber (0.2 wt% aqueous solution) and 3 parts by weight of silicate ions relative to calcium carbonate

[0059] The calcium carbonate-containing silicate-coated metal ion compound composite composition obtained in the above manner can be used safely and securely as a substitute for titanium oxide, which is already used as a cosmetic base material, food additive, quasi-drug, or coating agent, and is particularly effective as a food additive in place of titanium oxide, taking into account the health effects of titanium oxide.

Claims

1. 1. A method for producing a calcium carbonate-containing silicate-coated metal ion compound composite composition, comprising mixing calcium carbonate with a cationic solution (hereinafter referred to as "cationic solution") which does not contain a silicic acid compound or silicate ions, but contains one or more of Ca ions, Mg ions, and metal ions, and dissolving a part or all of the calcium carbonate to produce a calcium carbonate-containing metal ion compound, and mixing the resulting compound with a silicic acid solution (hereinafter referred to as "silicic acid solution") which does not contain Ca ions or Mg ions, but contains a silicic acid compound or silicate ions, thereby coating the calcium carbonate-containing metal ion compound with porous calcium silicate, magnesium silicate, or calcium magnesium silicate, wherein the cation solution and the silicic acid solution further contain a fibrous material.

2. The method for producing a calcium carbonate-blended silicate-coated metal ion compound composite composition according to claim 1, characterized in that the cationic solution contains 0.001 to 20 parts by weight of one or more metal ions or colloids selected from Fe ions, Ag ions, Cu ions, and Pt colloids (hereinafter referred to as "the metal ions, etc.") based on calcium carbonate.

3. The method for producing a calcium carbonate-containing silicate-coated metal ion compound composite composition according to claim 1, characterized in that the cationic solution has an acidity that dissolves calcium carbonate by mixing the metal ions, etc.

4. The method for producing a calcium carbonate-containing silicate-coated metal ion compound composite composition according to claim 1, characterized in that the fibrous material is a fibrous protein of silk-derived sericin or fibroin.

5. The method for producing a calcium carbonate-containing silicate-coated metal ion compound composite composition according to claim 1, characterized in that the fibrous material is a fibrous material made by nanofiberizing cellulose derived from cell walls, or chitin having a chemical structure similar to cellulose, and chitosan.

6. The method for producing a calcium carbonate-containing silicate-coated metal ion compound composite composition according to claim 1, wherein the calcium carbonate and the metal ions, etc. are blended in an amount of 0.001 to 20 parts by weight of the calcium carbonate, with the remainder being calcium carbonate and porous silicate.

7. The method for producing the calcium carbonate-containing silicate-coated metal ion compound composite composition according to claim 1, characterized in that the surface of the calcium carbonate-containing metal ion compound is coated with porous silicate, and then calcined at 50°C to 700°C.

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