Nano additive with core-shell structure as well as preparation method and application of nano additive

Abstract

The invention belongs to the field of preparation of nano composite materials, and mainly relates to a nano additive with a'core-shell 'structure as well as preparation and application of the nano additive. And the core-shell structure nano additive comprises three kinds of core part materials and a shell layer coating material. For example, the material of the core part comprises nano natural tourmaline powder, nano selenium and nano silver, and the material of the shell part is silicon dioxide. Wherein the three core part materials respectively have the effects of generating and releasing negative ions, releasing selenium elements and resisting bacteria. In the ceramic sintering process, the coating'shell 'layer protects the chemical composition and the phase structure of the'core' material from being damaged; and the material coated with the'shell 'layer can be diffused into the ceramic material in the ceramic sintering process, so that the selenium element and the antibacterial metal element of the'core' part are controllably released. The core-shell structure nano additive is added into the pottery clay, and the multifunctional health-care ceramic material is obtained by sintering under the condition of medium and high temperature, so that the aim of controlling the release of selenium, antibacterial agent silver and negative ions is fulfilled.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of nanocomposites, and mainly relates to a "core-shell" structure nano additive and its preparation and application. Background Art

[0002] Selenium is an essential trace element for the human body, and has the functions of anti-cancer, detoxification, anti-aging, and enhancing the human immune ability. Research shows that people with low selenium or selenium deficiency can prevent the occurrence of tumors, liver diseases, etc. and improve the body's immune ability by supplementing selenium appropriately. Therefore, selenium supplementation is very important. Selenium-rich ceramics are ceramic products made by adding materials rich in selenium elements. By placing food or water in them, the human body can achieve the purpose of selenium supplementation by ingesting food or water. Chinese Patent CN110483012A discloses a selenium-rich ceramic material and its preparation method, which discloses that common soluble selenious acid or selenite is used as a selenium source to make selenium-rich ceramic materials. However, during the sintering stage of selenium-rich ceramics, a large amount of selenium will be lost. To solve this problem, Chinese Patent CN112159202B discloses an iron-stabilized selenium-rich ceramic material and its preparation method, which can stabilize the selenium element in the ceramic material by adding an iron source and has good selenium release characteristics; for another example, Chinese Patent CN116396057A discloses a low-temperature sintering selenium-containing glaze, which solves the problem of selenium volatilization but makes it difficult for selenium to be released; for another example, Chinese Patent CN116692784A discloses a "core-shell" structure nano selenium-rich additive, which is beneficial to the stable existence of selenium in selenium-rich ceramic materials and can control the amount of selenium released by selenium-rich ceramic materials in water to ensure the safety and reliability of people's selenium supplementation amount.

[0003] It can be seen that the preparation technology of selenium-rich ceramics is becoming more and more mature. However, in order to ensure the release of selenium, selenium-rich ceramic products are not glazed, and bacteria are likely to grow during use and are easily deposited on the surface of selenium-rich ceramics. Therefore, there are certain requirements for the antibacterial property of this special functional ceramic daily necessities of selenium-rich ceramics. Therefore, the method of adding antibacterial agents to selenium-rich ceramic substrates has become a new research direction for the development of selenium-rich ceramics, which can endow selenium-rich ceramics with antibacterial functions. Currently, the commonly used antibacterial agents are inorganic antibacterial agents, which can combine the inherent stability of inorganic materials with the high efficiency and broad spectrum of antibacterial raw materials, and successfully overcome the disadvantages of organic antibacterial agents and natural biological antibacterial agents. In particular, the antibacterial property of silver has long been discovered and utilized, and it has been proved that Ag +It has inhibitory and bactericidal effects on more than 600 kinds of bacteria such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, and will not produce drug resistance. Chinese Patent CN117682841A discloses an antibacterial ceramic powder and its preparation method, antibacterial ceramic coating and application. The antibacterial metal ion solution selected in this patent is silver ion or zinc ion solution. The antibacterial powder is made into an antibacterial ceramic coating and coated on the surface of the packaging material to form a dense ceramic coating, which has extremely high heat resistance, wear resistance, chemical corrosion resistance and antibacterial ability. Chinese Patent CN111187098A discloses an antibacterial silver-loaded ceramic and its preparation method. Using cordierite honeycomb ceramic as the substrate, a nano-silver / polydopamine antibacterial silver-loaded ceramic is prepared, which has excellent antibacterial and bactericidal properties.

[0004] There are also studies showing that tourmaline has the property of spontaneous polarization. Metal cations around can be adsorbed on the surface of the particles, and silver ions can be effectively fixed on the surface of tourmaline particles to achieve the purpose of slow release and antibacterial. In view of tourmaline as a new type of negative ion environmental protection material, it has the ability to generate and release negative ions. It has begun to be applied in daily-use ceramics and endows it with new functions, that is, the function of releasing negative ions and playing its health care role. Chinese Patent CN101684042B discloses a nano-selenium ceramic ball and its preparation method and uses. The selenium ceramic ball embryo is made by adding nano-selenium and tourmaline nano powder. It is considered that the ball embryo makes the purified water rich in trace selenium mineral elements and regulates the immune performance of the human body. However, there are no data reports on the specific selenium content, released selenium content and released negative ion amount. Chinese Patent CN109437846A discloses a production method of negative ion and silver ion functional ceramic tiles, which has good negative ion release and bactericidal and antibacterial effects, and has a certain mildew-proof and antibacterial function, but does not have the function of being rich in selenium or releasing selenium. Chinese Patent CN108774069A discloses a negative ion easy-to-clean functional ceramic additive, which releases negative ions by adding tourmaline, nano-titanium dioxide and nano-zinc oxide to sterilize and inhibit bacteria, and still does not involve the function of being rich in selenium or releasing selenium. Chinese Patent CN108892472A discloses a heat-insulating and health-care ceramic tableware and its production method. The ceramic tableware products fired by adding additives such as selenium-containing compounds and tourmaline powder have strong self-cleaning ability, do not stick to oil stains and dirt, do not rust, are easy to wash, release selenium elements, etc., but do not involve releasing negative ions.

[0005] In summary, the current technologies for separately manufacturing selenium-rich ceramics, negative ion ceramics, and antibacterial ceramics are each relatively mature, and some research has involved the technology of preparing ceramic materials by combining two of the three materials. However, there are few technologies and research reports on combining selenium-rich, negative ion, and antibacterial agents to prepare multifunctional health-care ceramics. Even if there are some reports, the specific selenium content, selenium release amount, negative ion release amount, or bactericidal and antibacterial effects cannot be seen. The main problems it faces are as follows: on the one hand, elemental selenium or selenium-containing compounds and tourmaline are difficult to stably exist in high-temperature sintered ceramic materials; on the other hand, the antibacterial agent silver is not only volatile and unstable but also easily releases an excessive amount and is harmful. These two reasons will lead to low selenium element release and negative ion generation, and it is difficult to control the release amount of antibacterial agent metal ions. Summary of the Invention

[0006] Aiming at the main problems faced by the technology and research of combining selenium-rich, negative ion, and antibacterial agents to prepare multifunctional health-care ceramic materials (on the one hand, elemental selenium or selenium-containing compounds and tourmaline are difficult to stably exist in high-temperature sintered ceramic materials; on the other hand, the antibacterial agent silver is not only volatile and unstable but also easily releases an excessive amount and is harmful. These two reasons will lead to low selenium element release and negative ion generation, and it is difficult to control the release amount of antibacterial agent metal ions), the present invention provides a special "core-shell" structure nano-additive and its preparation and application.

[0007] The object of the present invention is to provide a "core-shell" structure nano-additive, which is beneficial to the stability of the composition and structure of natural tourmaline powder, the stable existence of selenium, and the controlled release of silver ions. The "core-shell" structure nano-additive includes three "core" materials, substances that can generate and release negative ions, metal antibacterial substances, and selenium-containing substances; among them, the substance that can generate and release negative ions is nano-natural tourmaline powder;

[0008] Outside the three "core" materials is a coating "shell" layer;

[0009] Among them, the "core" materials include materials that can generate and release negative ions, selenium elements, and silver ions. The three "core" materials are in a disordered and aggregated state within the coating "shell" layer;

[0010] The coating "shell" layer wraps around the outer layer of the "core" materials. In the early and middle stages of the sintering of multifunctional health-care ceramics, the coating "shell" layer protects the chemical composition and phase structure of the "core" materials from being damaged. In the later stage of sintering, it will diffuse into the clay base material, so that selenium elements, antibacterial agents, and negative ions are generated and controllably released.

[0011] This "core-shell" structure additive has multiple functions of selenium enrichment, antibacterial, and negative ions, so it is called a nano selenium-enriched, antibacterial, and negative ion multifunctional nano additive, and can be used as an additive for preparing high-temperature sintered multifunctional health care ceramic materials, etc.

[0012] Preferably, for the above-mentioned "core-shell" structure nano additive, the metal antibacterial substance is a silver-containing substance, such as a nano silver antibacterial agent. Also It can be other silver antibacterial substances with different valences, such as silver phosphate, silver nitrate, and silver carbonate.

[0013] The selenium-containing element substance is nano selenium, or it can also be other selenium-containing nano materials, such as calcium selenite, calcium selenate, iron selenide, and zinc selenide.

[0014] The material for coating the "shell" layer is silicon dioxide (SiO2), and it can also be titanium dioxide (TiO2), zirconium dioxide (ZrO2), or zirconium silicate (ZrSiO4).

[0015] Preferably, in the "core-shell" structure nano additive, the metal antibacterial substance is nano silver, the selenium-containing element substance is nano selenium, and the coating "shell" layer is silicon dioxide. The "core-shell" structure nano additive made of these several combinations is the best combination of technical features. For example, Figure 1 On the one hand, it enables nano selenium and tourmaline to stably exist in the high-temperature sintered ceramic material, and on the other hand, the antibacterial agent silver also stably exists and is moderately released, so that the release of selenium elements and the generation amount of negative ions are high, and the release amount of antibacterial agent metal ions can be controlled.

[0016] In the "core-shell" structure nano additive, by mass percentage, the selenium element content is 0.01 - 10%, the silver element content is 0.01 - 10%, the nano natural tourmaline powder content is 10 - 80%, and the silicon dioxide content is 10 - 80%. The sum of the mass percentages of the above substances is 100%.

[0017] Preferably, in the "core-shell" structure nano additive, by mass percentage, the selenium element content is 0.1 - 5%, the silver element content is 0.01 - 5%, the nano natural tourmaline powder content is 20 - 80%, and the silicon dioxide content is 40 - 70%. The sum of the mass percentages of the above substances is 100%.

[0018] The present invention provides a preparation method for a "core-shell" structure nano additive, including:

[0019] Making natural tourmaline powder into nano natural tourmaline powder material with a particle size of 10 - 100 nm for standby;

[0020] Reacting an AgNO3 solution containing PVP with a reducing agent to obtain nano silver;

[0021] React the sodium selenite solution containing PVP with a reducing agent to obtain nano-selenium;

[0022] Disperse the above-prepared nano-natural tourmaline powder material, nano-silver and nano-selenium in water, add a surfactant CTAB , adjust the pH to 7.5 - 8.5, and under the condition of stirring at 38 - 45 °C, add an ethanol solution of tetraethyl orthosilicate for reaction, and then centrifuge, wash and dry to obtain a "core-shell" structure nano-additive, denoted as (TM + Ag + Se)@SiO2.

[0023] Among them, add the reducing agent to the sodium selenite solution containing PVP for reaction. When the reaction solution turns orange-red, nano-selenium is obtained; the reducing agent is ascorbic acid or an ascorbic acid solution;

[0024] The (TM + Ag + Se)@SiO2 "core-shell" structure nano-additive prepared by this preparation method protects the complete chemical composition and phase structure of tourmaline and antibacterial agents, improves the slow-release performance of silver elements, and stabilizes selenium in the multifunctional health-care ceramic material, thereby effectively improving the selenium release, generation and release of negative ions, and antibacterial and bacteriostatic properties of the sintered ceramic, and reducing the loss of raw materials.

[0025] Research has shown that the finer the powder particle size and the larger the specific surface area, the more obvious its piezoelectric, pyroelectric and other effects, thus improving the ability to generate and release negative ions.

[0026] Preferably, in the preparation method of the above "core-shell" structure nano-additive, the particle size of the nano-natural tourmaline powder material is 20 - 80 nm.

[0027] The present invention also provides a method for preparing a sintered multifunctional health-care ceramic material using the above "core-shell" structure nano-additive, including weighing clay and the "core-shell" structure nano-additive, and mixing, ball-milling, drying and forming according to the conventional pottery-making process, and obtaining a selenium-rich + antibacterial + negative-ion multifunctional health-care ceramic material sample under high-temperature sintering conditions. The clay can be kaolin or natural clay from different origins. When the "core-shell" structure nano-additive is selected in the range of 0.01 wt% - 10.0 wt%, the selenium content of the prepared multifunctional health-care ceramic material is 10 - 1000 ppm, the silver content is 10 - 1000 ppm, the selenium dissolution amount after soaking in water is 0.01 ppb - 0.05 ppm, the silver dissolution amount is 0.01 ppb - 0.03 ppm, and the number of negative-ion releases is 200 - 2000 pieces / cm 3 , the above release amount range is controllable, and the release amounts of both selenium elements and negative ions are relatively high.

[0028] The present invention provides a method for preparing a multifunctional health-care ceramic using a "core-shell" structured nano-additive as a raw material and its application. Among them, the high-temperature sintering conditions for the multifunctional health-care ceramic are 900 - 1350 °C for heat preservation for 0.5 - 10 h.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The nano selenium-rich + antibacterial + negative ion multifunctional additive with a "core-shell" structure has a new composition and structure, and a multifunctional health-care ceramic material capable of releasing selenium, silver, and negative ions can be obtained; (2) The coated "shell" layer of silica of the nano-additive with a "core-shell" structure can effectively protect the chemical composition and crystal structure of the multifunctional health-care ceramic material under medium and high-temperature sintering conditions, especially in the early and middle stages of sintering. In addition, it can ensure the uniform distribution of each component in the multifunctional health-care ceramic material, thus not affecting the performance of each component; (3) In the later stage of sintering, the outermost "shell" layer of silica can be partially or completely dissolved into the multifunctional health-care ceramic material just right, so as to ensure a high content of selenium in the multifunctional health-care ceramic material and the stable and controllable release of selenium elements, the stable generation and release of negative ions by natural tourmaline, and the stable release of silver in the ceramic material, ultimately ensuring the safety and controllability of the selenium supplementation amount for the human body while enabling the ceramic to have a multifunctional health-care effect.

[0031] The present invention can also achieve the purpose of controlling the generation and release of selenium, silver, and negative ions. Finally, this multifunctional health-care ceramic material can supplement selenium for the human body, adjust the pH value of water (from neutral to weakly alkaline), and has good antibacterial ability. Therefore, the present invention has multiple functions of selenium-rich + antibacterial + negative ions. Description of the Drawings

[0032] Figure 1 is a schematic structural diagram of the "core-shell" structured nano-additive prepared by the present invention.

[0033] Figure 2 is a scanning electron micrograph of the multifunctional health-care ceramic material prepared using the (TM + Ag + Se)@SiO2 nano-additive as a raw material in Example 1, where (a) the scale bar is 50 μm and (b) the scale bar is 2 μm.

[0034] Figure 3 is an X-ray diffraction pattern of the multifunctional health-care ceramic material prepared using the (TM + Ag + Se)@SiO2 nano-additive as a raw material in Example 1. Detailed Embodiments

[0035] In order to enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and the accompanying drawings.

[0036] It should be noted that, in the description of the present invention, the content within the double quotation marks "" is a figurative description of the structure, such as "core-shell" means that there are core and shell in the structure, the coating "shell" layer means that the structure is a shell, and the "core" material means that its position is inside the shell and is the core. In the description of the present invention, the double quotation marks "" are a naming method. Of course, those skilled in the art can also remove the double quotation marks "", such as "core-shell" structure nano-additive is recorded as core-shell structure nano-additive, "core" material is recorded as core material, and the coating "shell" layer is recorded as coating shell layer.

[0037] The present invention has found that when selenium-rich materials are simply blended with antibacterial materials and negative ion releasing materials, there are the following hidden dangers. (1) The unique chemical composition and crystal structure of natural tourmaline are easily destroyed during the ceramic processing process, which reduces the amount of negative ions released and thus reduces the efficiency and effect of negative ion generation and release. (2) Using natural selenium-rich soil as raw material not only has a low selenium content but is also easily affected by heavy metals. (3) Silver element can cause human poisoning due to excessive release. (4) The sintering temperature of artificially added selenium or selenium-containing compounds or raw materials cannot be very high, or the cost of using a reducing atmosphere is very high. Therefore, the preparation technology of effectively compounding negative ion materials with silver sources and selenium sources, so that it can maintain the composition and crystal structure of natural tourmaline under processing conditions such as medium and high temperature sintering to generate and release the powerful function of negative ions, and control the selenium content in the ceramic and effectively and safely release selenium, while controlling the safe and stable release of silver elements during the use of the material has become a bottleneck of the existing technology.

[0038] In order to solve the above technical problems, the present invention first prepares three kinds of "core" materials respectively, including adopting a physical method - high-energy ball milling method to make natural tourmaline powder with the function of generating and releasing negative ions into a nano natural tourmaline "core" material; adopting a chemical reduction method to prepare a nano silver "core" material; utilizing an oxidation-reduction reaction to prepare a nano selenium "core" material, and then dispersing the three "core" materials into water and mixing them evenly, which is recorded as (TM+Ag+Se); and then coating the outer layer with a coating "shell" layer of silicon dioxide, etc., to form a special "core-shell" structure of a nano selenium-rich + antibacterial + negative ion multifunctional additive, which is recorded as (TM+Ag+Se)@SiO2, and the structural schematic diagram is shown in FIG. Figure 1 ; Then, the multifunctional health-care ceramic material is prepared by mixing the nano-selenium-rich + antibacterial + negative ion additive (TM+Ag+Se)@SiO2 with clay raw materials. Finally, the selenium content and the performance of releasing selenium content, the silver content and the performance of releasing silver are tested, and the performance of releasing negative ions is also tested. The results show that the release of selenium and negative ions is high, and the silver release can play an antibacterial and antibacterial role, and meets the national standard (the "National Drinking Water Hygiene Standard" GB5749-2006 stipulates that the silver content is <= 0.05mg / L).

[0039] In the present invention, the representation form of the nano-multi-functional additive with a special "core-shell" structure is not limited to (TM + Ag + Se)@SiO2. Depending on different experimental results, it may also be represented as TM@SiO2, Se@SiO2, Ag@SiO2, (TM + Ag)@SiO2, (TM + Se)@SiO2, (Ag + Se)@SiO2, etc. In this patent, the representation form (TM + Ag + Se)@SiO2 is temporarily selected. No matter what form it is, it will not affect its function or effect, and the effects are the same.

[0040] In the present invention, the coated "shell" layer of silica in (TM + Ag + Se)@SiO2 protects the nano-selenium in the "core" part from being easily oxidized or lost by contacting oxygen during the early and middle stages of the ceramic sintering process; at the same time, it protects the tourmaline crystals in the "core" part from being damaged in terms of their complete chemical composition and phase structure during the high-temperature sintering process, so that it has excellent negative ion release function and controls the release of silver elements; the coated "shell" layer of silica will partially or completely diffuse into the clay base material during the later stage of the multi-functional health-care ceramic sintering, so that the natural tourmaline therein has the powerful function of generating and releasing negative ions, can control the selenium content and the effective and safe selenium release amount in the ceramic, and at the same time controls the safe and stable release of silver to play an antibacterial and bacteriostatic role. The newly developed additive with a new structure and the preparation method of the multi-functional health-care ceramic in the present invention can solve the problems of selenium loss, safe and stable release of silver, and damage to the tourmaline structure during the processing, preparation and sintering of the multi-functional health-care ceramic materials.

[0041] It should be noted that the "core" material in the present invention is nano-selenium or other nano-materials containing selenium elements such as selenium-containing compounds; materials that can generate and release negative ions such as nano-natural tourmaline; nano-silver or metal element compounds with antibacterial effects; the coated "shell" layer is silicate such as silica, zirconia and zirconium silicate. If other "core" materials or "shell" materials are used, the "core-shell" structure nano-additive can be denoted by other symbolic forms. The equivalent substitution of the "core" or "shell" layer of the selenium-rich + antibacterial + negative ion additive of the product of the present invention, the selection of the material addition amount of the "core" or "shell" layer, and the selection of the sintering temperature and holding time of the health-care ceramic product, etc., are all included in the patent protection scope of the present invention by the same token.

[0042] In the description of the present invention, unless otherwise specified, the reagents used are commercially available and the methods used are conventional techniques in the art.

[0043] Description of reagents and equipment:

[0044] Natural tourmaline powder: Purchased from Jin Yu Mineral Products Co., Ltd., Lingshou County.

[0045] Silver nitrate: The relative molecular weight is 169.87, purchased from Xi'an Chemical Reagent Factory.

[0046] High-energy ball mill: TJGN planetary high-energy ball mill, purchased from Tianjin Dongfang Tianjing Technology Development Co., Ltd.

[0047] PVP: Polyvinylpyrrolidone, the relative molecular weight is about 10,000, purchased from Tianjin Damao Chemical Reagent Factory.

[0048] C6H8O6: Ascorbic acid, the relative molecular mass is 176.13, purchased from Tianjin Tianxin Fine Chemical R & D Center.

[0049] Na2SeO3: Sodium selenite, the relative molecular mass is 172.94, purchased from Zhengzhou Chengwang Food Chemical Co., Ltd.

[0050] CTAB: Cetyltrimethylammonium bromide, the relative molecular mass is 364.45, purchased from Tianjin Fuchen Chemical Reagent Factory.

[0051] Ammonia water: The relative molecular weight is 17.03, purchased from Sichuan Xilong Science Co., Ltd.

[0052] TEOS: Tetraethyl orthosilicate, the relative molecular weight is 208.33, purchased from Tianjin Damao Chemical Reagent Factory.

[0053] Kaolin: Kaolin clay, purchased from Tianjin Damao Chemical Reagent Factory.

[0054] Preparation of Na2SeO3 solution containing PVP: The concentration of PVP is 20 mg / mL, the concentration of Na2SeO3 solution is 0.75 mol / L, and the solvent is deionized water.

[0055] Ethanol solution of TEOS: The volume ratio of TEOS to ethanol is 1:1.

[0056] The present invention will be introduced below through some examples.

[0057] Example 1

[0058] In this example, a "core-shell" structure nano-additive, calculated by mass percentage, the raw materials include: 20% natural tourmaline powder, 5% nano-silver, 5% nano-selenium, 70% silicon dioxide; among them, natural tourmaline powder is selected as the raw material of the negative ion release material, and it is ball milled for 10 h using a high-energy ball mill to grind natural tourmaline into a nano-powder material of 20 nm.

[0059] The preparation method of the "core-shell" structure nano-additive is as follows:

[0060] First, under magnetic stirring at 800 r / min, 2.1 mL of 3 mol / L ascorbic acid solution was added dropwise to 9.2 mL of AgNO3 solution containing PVP. Then, distilled water was added to the mixture to make up to 25 mL, and the reaction was maintained under magnetic stirring at room temperature for 0.5 h and then stopped. After centrifugation and washing, silver nanoparticles (Ag NPs) were obtained. Among them, in the AgNO3 solution containing PVP, the concentration of PVP was 20 mg / mL and the concentration of AgNO3 solution was 0.5 mol / L.

[0061] Under magnetic stirring at 800 r / min, 8.4 mL of 3 mol / L ascorbic acid solution was added dropwise to 8.4 mL of Na2SeO3 solution containing PVP; then, distilled water was added to the mixture to make up to 30 mL, and the reaction was maintained under magnetic stirring at room temperature for 6 h, and the reaction solution was orange-red; finally, the mixture was dialyzed in deionized water to remove unreacted sodium selenite and ascorbic acid until the presence of sodium selenite could not be detected in the dialysis solution, and selenium nanoparticles (Se NPs) were obtained. Among them, in the Na2SeO3 solution containing PVP, the concentration of PVP was 20 mg / mL and the concentration of Na2SeO3 solution was 0.75 mol / L.

[0062] Weighed 2.0 g of tourmaline powder, and dispersed the prepared Ag NPs and Se NPs into 25.0 mL of water. Added 12.5 mg of CTAB, adjusted the pH to 8 by adding ammonia water under the condition of stirring in a 40 °C water bath, added 24.3 mL of ethanol solution of TEOS (the volume ratio of TEOS to ethanol was 1:1), after reacting for 6 h, centrifuged at a speed of 7500 r / min, collected the precipitate, washed the precipitate 3 times with deionized water, and dried it in an oven at 80 °C for 8 h to obtain a (TM+Ag+Se)@SiO2 selenium-rich + antibacterial + negative ion nano-additive with a "core-shell" structure.

[0063] Based on the same inventive concept, this embodiment also provides a preparation method of a multifunctional health care ceramic material, as follows:

[0064] Weigh 50 mg of (TM + Ag + Se)@SiO2 nano selenium-rich + antibacterial + negative ion additive (a "core-shell" structure nano additive, and the (TM + Ag + Se)@SiO2 nano selenium-rich + antibacterial + negative ion additive mentioned in the following examples is the "core-shell" structure nano additive, which will not be elaborated in the following examples) and 10 g of kaolin respectively, mix and ball-mill them, dry, granulate with PVA, press into tablets, and sinter at 1100 °C for 2 h to obtain a multifunctional health-care ceramic material sample with a diameter of 10.0 mm and a thickness of 1.5 mm. Under normal temperature and pressure, the selenium content and silver content in the multifunctional health-care ceramic material, and the content of selenium and silver released after 24 h in water at 90 °C are analyzed by a hydride-atomic fluorescence spectrometer and an inductively coupled plasma mass spectrometer, and the number of negative ions released by the multifunctional health-care ceramic material sample is detected by a solid negative ion instrument, and the test distance is 0.5 cm. The test results are as follows: the selenium content in the multifunctional health-care ceramic material is 180 mg / kg, and the silver content is 201 mg / kg. In the multifunctional health-care ceramic material sample actually prepared in the present invention, the selenium content is 180 mg / kg, and the loss rate of selenium is 28%; the silver content is 201 mg / kg, and the loss rate of silver is 19.6%, and the loss rate is relatively low. In the experiment of the present invention, the selenium release amount in 24 h is 8.55 μg / L, the silver release amount is 6.68 μg / L; the negative ion release amount is 1121 pieces / cm 3 . It can be seen that the release amounts of selenium element, silver element and negative ions are all better.

[0065] Example 2

[0066] In this example, a "core-shell" structure nano additive, calculated by mass percentage, the raw materials include: 40% natural tourmaline powder, 1% nano silver, 1% nano selenium, 58% silicon dioxide; among them, natural tourmaline powder is selected as the raw material for the negative ion release material, and a high-energy ball mill is used to ball-mill for 10 h to ball-mill natural tourmaline into a nano powder material of 40 nm.

[0067] The preparation method of the "core-shell" structure nano additive is as follows:

[0068] First, under magnetic stirring at 800 r / min, 0.42 mL of 3 mol / L ascorbic acid solution is added dropwise to 1.85 mL of AgNO3 solution containing PVP. Then, distilled water is added to the mixture to make up to 25 mL, and the reaction is kept under magnetic stirring at room temperature for 0.5 h and then the reaction is stopped. After centrifugal washing, nano silver (Ag NPs) is obtained. Among them, in the AgNO3 solution containing PVP, the PVP concentration is 20 mg / mL, and the AgNO3 solution concentration is 0.5 mol / L.

[0069] Under magnetic stirring at 800 r / min, 1.68 mL of 3 mol / L ascorbic acid solution was added dropwise to 1.68 mL of Na2SeO3 solution containing PVP. Then, distilled water was added to the mixture to make up to 30 mL, and the reaction was maintained for 6 h under magnetic stirring at room temperature. The reaction solution was orange-red. Finally, the mixture was dialyzed in deionized water to remove unreacted sodium selenite and ascorbic acid until the presence of sodium selenite could not be detected in the dialysis solution, and selenium nanoparticles (Se NPs) were obtained. Among them, in the Na2SeO3 solution containing PVP, the concentration of PVP was 20 mg / mL, and the concentration of Na2SeO3 solution was 0.75 mol / L.

[0070] Weigh 4.0 g of tourmaline powder, disperse it with the prepared Ag NPs and Se NPs in 25.0 mL of water, add 12.5 mg of CTAB, adjust the pH to 8 with ammonia water under the condition of stirring in a 40 °C water bath, add 44.0 mL of ethanol solution of TEOS (the volume ratio of TEOS to ethanol is 1:1), after reacting for 6 h, centrifuge at a speed of 7500 r / min, collect the precipitate, wash the precipitate 3 times with deionized water, and dry it in an oven at 80 °C for 8 h to obtain a (TM+Ag+Se)@SiO2 selenium-rich + antibacterial + negative ion nano-additive with a "core-shell" structure.

[0071] Based on the same inventive concept, this embodiment also provides a preparation method of a multifunctional health care ceramic material as follows:

[0072] Weigh 0.8 g of (TM+Ag+Se)@SiO2 nano selenium-rich + antibacterial + negative ion additive and 10 g of clay respectively, mix, ball mill, dry, granulate with PVA, press into shape, and sinter at 1100 °C for 2 h to obtain a multifunctional health care ceramic material sample with a diameter of 10.0 mm and a thickness of 1.5 mm. Test according to the test method of Example 1, and the test results are as follows: the selenium content is 562 mg / kg, and the silver content is 643 mg / kg. The experimentally measured 24-h selenium release amount of the present invention is 7.62 μg / L, the silver release amount is 5.38 μg / L, and the negative ion release amount is 1289 pieces / cm 3 。

[0073] Example 3

[0074] In this example, for a "core-shell" structure nano-additive, calculated by mass percentage, the raw materials include: 80% natural tourmaline powder, 0.1% nano silver, 0.1% nano selenium, and 19.8% silicon dioxide; among them, natural tourmaline powder is selected as the raw material for the negative ion release material, and it is ball milled with a high-energy ball mill for 10 h to grind the natural tourmaline into a nano powder material of 60 nm.

[0075] The preparation method of the "core-shell" structured nano-additive is as follows:

[0076] Firstly, under magnetic stirring at 800 r / min, 4.2 mL of 0.03 mol / L ascorbic acid solution was added dropwise to 1.85 mL of AgNO3 solution containing PVP. Then, distilled water was added to the mixture to make up to 25 mL, and the reaction was kept for 0.5 h under magnetic stirring at room temperature and then stopped. After centrifugation and washing, nano-silver (Ag NPs) was obtained. Among them, in the AgNO3 solution containing PVP, the concentration of PVP was 20 mg / mL, and the concentration of AgNO3 solution was 0.05 mol / L.

[0077] Under magnetic stirring at 800 r / min, 1.68 mL of 0.3 mol / L ascorbic acid solution was added dropwise to 1.68 mL of Na2SeO3 solution containing PVP. Then, distilled water was added to the mixture to make up to 30 mL, and the reaction was kept for 6 h under magnetic stirring at room temperature. The reaction solution was orange-red. Finally, the mixture was dialyzed in deionized water to remove unreacted sodium selenite and ascorbic acid until the presence of sodium selenite could not be detected in the dialysis solution, and nano-selenium (Se NPs) was obtained. Among them, in the Na2SeO3 solution containing PVP, the concentration of PVP was 20 mg / mL, and the concentration of Na2SeO3 solution was 75 mmol / L.

[0078] 8.0 g of nano-tourmaline powder was weighed and dispersed together with the prepared Ag NPs and Se NPs in 25.0 mL of water. 12.5 mg of CTAB was added. Under the condition of stirring in a water bath at 40 °C, ammonia water was added to adjust the pH to 8. 15.0 mL of ethanol solution of TEOS (the volume ratio of TEOS to ethanol was 1:1) was added. After reacting for 6 h, centrifugation was carried out at a speed of 7500 r / min to collect the precipitate. The precipitate was washed 3 times with deionized water and dried in an oven at 80 °C for 8 h to obtain the (TM+Ag+Se)@SiO2 selenium-rich + antibacterial + negative ion nano-additive with a "core-shell" structure.

[0079] Based on the same inventive concept, this embodiment also provides a preparation method of a multifunctional health care ceramic material, as follows:

[0080] Weigh 4.3 g of (TM + Ag + Se)@SiO2 nano selenium-rich, antibacterial and negative ion additive and 10 g of kaolin respectively. Mix them by ball milling, dry them, granulate them with PVA, press them into shape, and sinter them at 1100 °C for 2 h to obtain a multifunctional health care ceramic material sample with a diameter of 10.0 mm and a thickness of 1.5 mm. According to the test method of Example 1, the selenium content is measured to be 204 mg / kg and the silver content is 232 mg / kg. In the experiment of the present invention, the selenium release amount in 24 h is 4.33 μg / L, the silver release amount is 3.12 μg / L, and the negative ion release amount is 1704 pieces / cm 3 .

[0081] Example 4

[0082] In this example, a "core-shell" structure nano additive, calculated by mass percentage, the raw materials include: 60% natural tourmaline powder, 0.5% nano silver, 0.5% nano selenium, 39% silicon dioxide; among them, natural tourmaline powder is selected as the raw material of the negative ion release material, and it is ball milled for 10 h with a high-energy ball mill to grind natural tourmaline into a nano powder material of 80 nm.

[0083] The preparation method of the "core-shell" structure nano additive is as follows:

[0084] First, under magnetic stirring at 800 r / min, 0.21 mL of 3 mol / L ascorbic acid solution is added dropwise to 0.92 mL of AgNO3 solution containing PVP. Then, distilled water is added to the mixture to make up to 25 mL, and the reaction is kept for 0.5 h under magnetic stirring at room temperature and then the reaction is stopped. After centrifugal washing, nano silver (Ag NPs) is obtained. Among them, in the AgNO3 solution containing PVP, the PVP concentration is 20 mg / mL and the AgNO3 solution concentration is 0.5 mol / L.

[0085] Under magnetic stirring at 800 r / min, 0.84 mL of 3 mol / L ascorbic acid solution is added dropwise to 0.84 mL of Na2SeO3 solution containing PVP; then, distilled water is added to the mixture to make up to 30 mL, and the reaction is kept for 6 h under magnetic stirring at room temperature, and the reaction solution is orange-red; finally, the mixture is dialyzed in deionized water to remove unreacted sodium selenite and ascorbic acid until the presence of sodium selenite cannot be detected in the dialysis solution, and nano selenium (Se NPs) is obtained. Among them, in the Na2SeO3 solution containing PVP, the PVP concentration is 20 mg / mL and the Na2SeO3 solution concentration is 0.75 mol / L.

[0086] Weigh 6.0 g of nano-tourmaline powder, disperse it together with the prepared Ag NPs and Se NPs in 25.0 mL of water, add 12.5 mg of CTAB, adjust the pH to 8 with ammonia water under the condition of stirring in a 40 °C water bath, add 29.2 mL of an ethanol solution of TEOS (the volume ratio of TEOS to ethanol is 1:1), after reacting for 6 h, centrifuge at a speed of 7500 r / min and collect the precipitate. The precipitate is washed 3 times with deionized water and dried in an oven at 80 °C for 8 h to obtain a (TM + Ag + Se)@SiO2 selenium-rich + antibacterial + negative ion nano-additive with a "core-shell" structure.

[0087] Based on the same inventive concept, this embodiment also provides a method for preparing a multifunctional health-care ceramic material, as follows:

[0088] Weigh 1.0 g of (TM + Ag + Se)@SiO2 nano selenium-rich + antibacterial + negative ion additive and 10 g of clay respectively, mix and ball-mill, dry, granulate with PVA, press into tablets, and sinter at 1100 °C for 2 h to obtain a multifunctional health-care ceramic material sample with a diameter of 10.0 mm and a thickness of 1.5 mm. According to the testing method of Example 1, it is found that the selenium content is 732 mg / kg and the silver content is 843 mg / kg. The experimentally measured 24-h selenium release amount of this invention is 6.12 μg / L, the silver release amount is 4.78 μg / L, and the negative ion release amount is 1306 pieces / cm 3 。

[0089] This invention also compared the technical effects of the product of this application with the ceramic materials prepared by relevant prior art patents, and tested the number of negative ion releases, selenium release amount and selenium content by the same method. The results are shown in Table 1.

[0090] Table 1 Comparison of relevant patent data

[0091]

[0092]

[0093] As can be seen from Table 1, compared with the disclosure of the Chinese patent: "Core-shell" structure nano selenium-rich additive and its preparation method and application (CN116692784A), the nano material additive prepared by this invention has multiple functions of releasing selenium, silver and negative ions, and the release performance of selenium is not affected after adding negative ion raw materials to form a special "core-shell" structure nano material. The data control range of the selenium and silver contents (10 - 1000 ppm) and the selenium and silver release amounts (0.01 ppb - 0.05 ppm) of this invention is wider, and the applicable range is broader.

[0094] Compared with the disclosure of the Chinese patent: A nano-selenium ceramic ball and its preparation method and uses (CN101684042B), in the nano-material additive prepared by the present invention, the negative ion raw material is made of natural tourmaline powder after high-energy ball milling (10 - 100nm) into a special "core-shell" structure nano-material, which well protects the crystal structure of tourmaline while reducing the potential safety hazards in the subsequent use of the material. The selenium content, selenium release amount, silver content, and silver release amount of the selenium-rich + antibacterial + negative ion additive prepared by the present invention are safe and controllable, with clear data, and can achieve long-term stable release; it has more excellent high-temperature resistance performance, with a tolerance temperature reaching 1400°C, and a wider application range; the number of negative ions released reaches 200 - 2000 ions / cm 3 , and according to the national air negative oxygen ion health concentration grading and evaluation standard, it can reach the secondary standard of the forest area (1500 - 3000 ions / cm 3 ).

[0095] In summary, by making a nano-selenium-rich + antibacterial + negative ion multifunctional additive with a "core-shell" structure coating from the negative ion release material, silver source, and selenium source, it can effectively reduce the damage to the tourmaline crystal structure during the processing and sintering of the multifunctional health care ceramic raw materials and the loss of selenium at high temperatures, without affecting the properties of the high-temperature sintered ceramics, improve the stability of the negative ion release material, selenium source, and silver source materials in the multifunctional health care ceramic matrix, and achieve the purpose of long-term, stable, and safe release of negative ions, selenium, and silver while reducing costs, meeting the requirements of high-temperature sintered ceramic products.

[0096] Figure 2 Figure (a) shows the SEM image of the selenium-rich + antibacterial + negative ion multifunctional health care ceramic material in Example 1. It can be seen that the ceramic matrix is sintered densely, and at the same time, pores with similar sizes are evenly distributed on the surface. These pores are beneficial to the long-term stable release of selenium and negative ions; Figure 2 (b) After etching with 20% HF solution for 10s, it can be seen that the matrix is mainly composed of quartz phase and mullite phase. The slender needle-like structure is the secondary mullite phase, and the blocky morphology is the quartz phase. The needle-like mullite crystals are randomly arranged in all directions to form a three-dimensional network structure. Figure 2 (b) After etching with 20% HF solution for 10s, it can be seen that the matrix is mainly composed of quartz phase and mullite phase. The slender needle-like structure is the secondary mullite phase, and the blocky morphology is the quartz phase. The needle-like mullite crystals are randomly arranged in all directions to form a three-dimensional network structure.

[0097] Figure 3 Figure shows the X-ray diffraction pattern of the selenium-rich + antibacterial + negative ion multifunctional health care ceramic material in Example 1. It can be seen that the selenium-rich + antibacterial + negative ion multifunctional health care ceramic material is mainly composed of quartz phase and mullite phase, and there are also tourmaline phase and silver phase present, which proves that the chemical composition and phase structure of the raw materials are protected during the high-temperature sintering process. This is mutually confirmed with the above SEM image.

[0098] It should be noted that in the formulation of the "core-shell" structured nano-additive, by mass percentage, the selenium element content is 0.01-10%, the tourmaline powder content is 10-80%, and the silicon dioxide content is 10-80%. The sum of the mass percentages of the above substances is 100%; the additive with an equivalent effect to that of Examples 1-4 can also be prepared with the end point values within this formulation.

[0099] It should be noted that when the present invention involves a numerical range, it should be understood that any value between the two endpoints of each numerical range and any one of the two endpoints can be selected. Since the steps and methods adopted are the same as those in the examples, in order to prevent repetition, the present invention describes the preferred embodiments. Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0100] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A "core-shell" structured nano-additive, characterized in that, The "core-shell" structured nano-additive includes three "core" materials, which are substances capable of generating and releasing negative ions, metal antibacterial agents, and selenium-containing substances; the substance capable of generating and releasing negative ions is nano-natural tourmaline powder; The three "core" materials are in a disordered aggregated state within the coating "shell", and an outer coating "shell" is provided for the three "core" materials; The coated "shell" layer protects the chemical composition and structure of the "core" material during the ceramic sintering process. The coated "shell" layer diffuses into the ceramic base material during the ceramic sintering process, enabling the ceramic to have the function of generating and releasing negative ions, and also being able to control the selenium release amount in the ceramic and the stable release of silver. 。 2. The "core-shell" structured nano-additive according to claim 1, characterized in that, The metal antibacterial agent is a silver-containing substance.

3. The "core - shell" structured nano - additive according to claim 2, characterized in that, The silver-containing substance is nano-silver, silver phosphate, or silver nitrate.

4. The "core-shell" structured nano-additive according to claim 3, characterized in that The selenium-containing substance is nano-selenium, calcium selenite, calcium selenate, iron selenide, or zinc selenide.

5. The "core-shell" structured nano-additive according to claim 4, wherein, The coating "shell" is silica, titanium dioxide, zirconium dioxide, or zirconium silicate.

6. The "core-shell" structured nano-additive according to claim 5, characterized in that, The metal antibacterial agent is nano-silver, the selenium-containing substance is nano-selenium, and the coating "shell" is silica.

7. The "core - shell" structured nano - additive according to claim 6, characterized in that, In the "core-shell" structured nano-additive, by mass percentage, the selenium element content is 0.01 - 10%, the silver element content is 0.01 - 10%, the nano-natural tourmaline powder content is 10 - 80%, and the silica content is 10 - 80%. The sum of the mass percentages of the above substances is 100%.

8. The preparation method of the "core-shell" structure nano-additive according to claim 6, characterized in that, including ： Prepare nano-natural tourmaline powder material with a particle size of 10 - 100 nm from natural tourmaline powder for later use; React the AgNO3 solution containing PVP with a reducing agent to obtain nano-silver; Add a reducing agent to the sodium selenite solution containing PVP for reaction. Wait until the reaction solution turns orange-red to obtain nano-selenium; Disperse the prepared nano-natural tourmaline powder material, nano-silver, and nano-selenium in water, add the surfactant CTAB, adjust the pH to 7.5 - 8.5, and add an ethanol solution of tetraethyl orthosilicate for reaction under stirring at 38 - 45 °C to obtain the "core-shell" structured nano-additive, denoted as (TM + Ag + Se)@SiO2.

9. Use of the "core-shell" structured nano-additive according to claim 1 in the preparation of sintered materials, characterized in that, The sintered material is a household ceramic material based on clay.

10. The application according to claim 9, characterized in that, The high-temperature sintering condition of the sintered material is to keep the temperature at 900 - 1350 °C for 0.5 - 10 h.

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