A water-retaining rare earth composite ceramic glaze and its preparation method and application

Abstract

The present invention provides a water-retaining rare earth composite ceramic glaze and a preparation method and application thereof. The preparation method of the water-retaining rare earth composite material RE@TDs added in the glaze comprises the following steps: adding a rare earth source compound to ethanol and stirring until completely dissolved, then adding a carbon nitrogen compound and heating to 60-80°C, stirring for 0.5-1 h to obtain a mixture; transferring the mixture into a hydrothermal reactor, reacting at 180-220°C for 4-7 h, concentrating to a dry sample to obtain a precursor; and calcining the precursor at a temperature of 500-800°C in a muffle furnace. The water-retaining rare earth composite material RE@TDs prepared by the present invention is added to the glaze of a ceramic cup, and the rare earth glaze can effectively inhibit the growth of bacteria through ion exchange. This allows ceramic products using rare earth glazes to provide additional health protection while keeping the water fresh.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic glaze preparation, and in particular relates to a water-retaining rare earth composite ceramic glaze and a preparation method and application thereof. Background Art

[0002] As an important part of the quality of life, the importance of healthy diet is self-evident. People not only pursue the nutrition and taste of food, but also begin to pay attention to the quality of daily drinking water. Rare earth elements can be used as effective water treatment media under certain conditions. Their oxides have various forms, large specific surface area, and many surface active sites, which can effectively remove heavy metal ions, residual chlorine and other organic pollutants in water. In addition, rare earth elements have good biocompatibility. Trace amounts of rare earth elements are beneficial to the human body. They can supplement the trace elements needed by the human body and regulate the cellular environment in the human body. The addition of rare earth elements can change the structure of water molecules, making them smaller and more active, thereby improving the permeability and solubility of water. This activated water quality is considered to be more beneficial to the human body, helping to promote metabolism and improve health. Therefore, rare earth functional ceramic cups came into being under such market demand.

[0003] Rare earth functional ceramic containers can increase the dissolved oxygen content in water and adjust the pH value of water: some rare earth elements have the ability to adjust the pH value of water quality, making the water tend to be weakly alkaline. Weakly alkaline water can help neutralize acidic substances in the human body, help maintain the stability of the internal environment, and have a positive effect on physiological processes such as digestion, absorption, and excretion. In addition, rare earth functional ceramics contain more trace elements and minerals: natural water bodies often contain a variety of trace elements and minerals that are beneficial to the human body, such as calcium, magnesium, potassium, etc. Rare earth functional ceramics can activate water quality while slowly releasing these elements that are beneficial to the body, supplementing minerals that may be lacking in the daily diet, and play an important role in promoting bone health and maintaining the normal functioning of the nervous system.

[0004] Rare earth functional ceramics can improve water quality at multiple levels through their unique physical and chemical effects, including promoting the micronization of water molecules, increasing the dissolved oxygen content in water, adjusting the pH value of water, releasing trace elements and minerals, and removing harmful substances. The combined effect of these effects makes water treated with rare earth functional ceramics more suitable for human absorption and utilization, and also healthier and safer.

[0005] Therefore, rare earth activated water quality functional ceramic containers, as an emerging healthy drinking water solution, have demonstrated great application value and development potential. Summary of the invention

[0006] In view of this, the present invention aims to overcome the defects in the prior art and proposes a water-retaining rare earth composite ceramic glaze and a preparation method and application thereof.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] In a first aspect, the present invention provides a method for preparing a water-retaining rare earth composite material RE@TDs, comprising the following steps:

[0009] S1: adding the rare earth source compound to ethanol and stirring until completely dissolved, then adding the carbon nitrogen compound and heating to 60-80°C, stirring for 0.5-1 h to obtain a mixture;

[0010] S2: The mixture is transferred into a hydrothermal reactor, reacted at 180-220 °C for 4-7 h, and then concentrated to a dry sample to obtain a precursor;

[0011] S3: The precursor is calcined in a muffle furnace at a temperature of 500-800 °C to obtain the rare earth composite material RE@TDs.

[0012] Under hydrothermal conditions, the raw material first dissolves in water to form a saturated solution. As the temperature rises, the solubility increases. When a certain supersaturation state is reached, the dicyandiamide in the raw material breaks down through a pyrolysis reaction to form carbon-nitrogen small molecule fragments, which are then continuously connected together to form a template, and the rare earth ions are spliced ​​on the carbon-nitrogen template through carbon-nitrogen ion bonds to form a stable complex structure. At the same time, the rare earth elements themselves can accelerate the recombination process of carbon-nitrogen ions and control the morphology of the product.

[0013] The crystal structure of the rare earth material will be transformed into a hexagonal crystal through the calcination process. The transformation of the crystal structure will lead to changes in the distribution of electronic energy levels, thereby affecting the distribution of surface charges of the material. At the same time, during the calcination process, as the volatile components are removed, a porous structure will be formed, such as Figure 2 As shown, the specific surface area of ​​the material is increased, which helps to improve the antibacterial efficiency and adsorption capacity of the rare earth material.

[0014] Preferably, the rare earth source compound is one or more of rare earth chloride compounds, rare earth nitrate compounds, and rare earth carbonate compounds.

[0015] Preferably, the rare earth nitrate compound is one of lanthanum nitrate hexahydrate, gadolinium nitrate hexahydrate, yttrium nitrate hexahydrate, and cerium nitrate hexahydrate, or a mixture of several of them.

[0016] Preferably, the rare earth chloride is one or more of lanthanum chloride heptahydrate, gadolinium chloride heptahydrate, yttrium chloride heptahydrate, and cerium chloride heptahydrate.

[0017] Preferably, the rare earth carbonate compound is one or more of lanthanum carbonate octahydrate, gadolinium carbonate octahydrate, yttrium carbonate octahydrate, and cerium carbonate octahydrate.

[0018] Preferably, the carbon-nitrogen compound is one or a mixture of urea, dicyandiamide, melamine and cyanuric acid.

[0019] Preferably, the concentration of the rare earth source compound dissolved in ethanol in step S1 is 1.0-3.0 mol / L.

[0020] Preferably, in step S1, the mass ratio of the carbon nitrogen compound to the rare earth source compound is 1:(2-5).

[0021] In a second aspect, the present invention provides a RE@TDs dispersion slurry, and the preparation method of the RE@TDs dispersion slurry is: adding the water-retaining rare earth composite material RE@TDs prepared by the above preparation method to ethylene glycol and a dispersant at a solid content ratio of 25%-35%, wherein the mass ratio of ethylene glycol to the dispersant is (65-75): (5-10), and obtaining a RE@TDs dispersion slurry with a particle size distribution of 300-700 nm of the water-retaining rare earth composite material RE@TDs through wet sand grinding.

[0022] Preferably, the dispersant is HH2120 water-oil universal dispersant.

[0023] In a third aspect, the present invention provides a water-retaining rare earth composite ceramic glaze, which is prepared by adding RE@TDs dispersion slurry to ceramic glaze, wherein the RE@TDs dispersion slurry is added to the ceramic glaze in an amount of 1%-10% by mass based on the mass of the water-retaining rare earth composite material RE@TDs.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] (1) The RE@TDs dispersion slurry prepared by the present invention has a significant effect of purifying water quality. Through the wet sand grinding process, the water-retaining rare earth composite material RE@TDs is converted into nano-scale small particles with a particle size distribution of 300-700 nm, and the slurry obtained after sand grinding can better meet the processing and utilization of the subsequent glazing process.

[0026] (2) The water-retaining rare earth composite material RE@TDs prepared by the present invention is added to the glaze of ceramic cups. The rare earth glaze can effectively inhibit the growth of bacteria through ion exchange. This allows ceramic products with rare earth glaze to maintain the freshness of water while also providing additional health protection.

[0027] (3) The water-retaining rare earth composite material RE@TDs prepared by the present invention can improve the structure and properties of the oxide layer on the surface of ultra-high temperature ceramics by introducing rare earth elements, effectively slowing down the growth rate of the oxide layer and solving the problem of easy peeling. The modified material can still maintain good antioxidant properties under high and low temperature cycles, extending its service life. At the same time, it can improve the fracture toughness and thermal shock resistance of the composite material and reduce material damage caused by temperature changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the infrared spectrum of the precursor;

[0029] Figure 2 This is a scanning electron microscope image of the rare earth composite material La@TDs;

[0030] Figure 3 The particle size distribution data of the rare earth composite material La@TDs;

[0031] Figure 4 The growth of bacterial colonies in different ceramic sample culture media;

[0032] Figure 5 These are the chemical oxygen demand test values ​​of water contained in different ceramic cups. DETAILED DESCRIPTION

[0033] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which the present invention belongs.

[0034] The dicyandiamide, cerium nitrate hexahydrate, lanthanum nitrate hexahydrate, gadolinium nitrate hexahydrate, yttrium nitrate hexahydrate, and ethanol used in the following examples and comparative examples were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. All chemicals were used without further treatment, and deionized water was homemade in the laboratory. E. coli Purchased from Guangdong Huankai Microbiology Technology Co., Ltd.

[0035] The test reagents used in the following examples and comparative examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0036] The present invention will be described in detail below with reference to the embodiments.

[0037] Example 1

[0038] (1) Preparation and synthesis of precursors

[0039] Weigh 40 g of dicyandiamide and 130 g of lanthanum nitrate hexahydrate, add them into 500 mL of ethanol, heat to 80 °C, stir with external magnetic force for 20 min, then transfer into a hydrothermal reactor. After reacting at 220 °C for 6 h, cool the hydrothermal reactor naturally to room temperature, and then dry the reaction solution at 110 °C for 6-8 h to remove most of the moisture.

[0040] The infrared spectrum of the prepared precursor was scanned, and the results were as follows: Figure 1 As shown, it can be seen that 810 cm -1 The peak at 1200 cm represents the stretching vibration absorption peak of the CN single bond on the oxazine ring. -1 The peak at 3200 cm represents the stretching vibration absorption peak of the C=N double bond on the oxazine ring. -1 represents the stretching vibration of NH, 3350cm -1 The represents the stretching vibration of OH. Compared with the simple carbon nitrogen compound C3N4, the vibration intensity of the amino group and the hydroxyl group is significantly reduced after the introduction of lanthanum ions.

[0041] (2) Calcination preparation of rare earth composite materials La@TDs

[0042] The dried precursor was ground into powder and then transferred to a muffle furnace for calcination at 1200 °C for 3 h. The high temperature treatment allowed the nitrogen-containing compound in the precursor to react with the organic metal framework to form the final product, the rare earth composite material La@TDs. The scanning electron microscope image of the final product is shown in Figure 2. Figure 2 shown.

[0043] (3) Wet sand grinding of La@TDs

[0044] The obtained rare earth composite material La@TDs was added with a certain amount of deionized water at a solid content of 35%, and then wet sand-milled using a NETZSCH MINIFER sand mill with a single-machine circulation process. The main machine speed was 3100 rpm, and the sand milling time was 6-10 hours to obtain a nano-scale La@TDs suspension slurry with a particle distribution of about 500 nm.

[0045] 1 mL of La@TDs suspension with a solid content of 35% was directly drawn from the slurry using a disposable dropper and the particle size was analyzed using a Malvern particle size tester. The results are shown in Figure 3 As shown, the particle size distribution range is mainly between 300-700nm, which can reach the quasi-nano level and meet the subsequent glazing process.

[0046] (4) Preparation of water-retaining rare earth composite ceramic glaze and rare earth water-retaining ceramic materials

[0047] The La@TDs dispersion slurry obtained by the wet sand grinding process is directly added into the ceramic glaze at a ratio of 5% of rare earth addition, glazed according to the spraying process, and then sent into the kiln for high-temperature firing to obtain the rare earth water-retaining ceramic material La@TDs.

[0048] The rare earth ceramic glaze components are mixed according to the following mass percentages: 30 parts of quartz, 24 parts of feldspar, 18 parts of pyrophyllite, 2 parts of red clay, 21 parts of mixed clay, and 5 parts of rare earth materials (based on the mass of the rare earth composite material La@TDs).

[0049] Example 2

[0050] The difference from Example 1 is that the rare earth source compound is cerium chloride heptahydrate, and the rare earth water-retaining ceramic material Ce@TDs is obtained.

[0051] Example 3

[0052] The difference from Example 1 is that the rare earth source compound is yttrium carbonate octahydrate, and the rare earth water-retaining ceramic material Y@TDs is obtained.

[0053] Example 4

[0054] The difference from Example 1 is that the rare earth source compound is gadolinium nitrate hexahydrate, and the rare earth water-retaining ceramic material Gd@TDs is obtained.

[0055] Example 5

[0056] The difference from Example 1 is that the carbon-nitrogen compound is urea, and the added amount of lanthanum nitrate hexahydrate is 80 g, thereby obtaining a rare earth water-retaining ceramic material La@TDs-UREA.

[0057] Example 6

[0058] The difference from Example 1 is that the carbon-nitrogen compound is melamine, and the added amount of lanthanum nitrate hexahydrate is 200 g, thereby obtaining a rare earth water-retaining ceramic material La@TDs-MEL.

[0059] Example 7

[0060] The difference from Example 1 is that the carbon-nitrogen compound is cyanuric acid, and the added amount of lanthanum nitrate hexahydrate is 120 g, thereby obtaining a rare earth water-retaining ceramic material La@TDs-CYA.

[0061] Comparative Example 1

[0062] The difference from Example 1 is that the rare earth source compound is europium nitrate hexahydrate, and the rare earth water-retaining ceramic material Eu@TDs is obtained.

[0063] Comparative Example 2

[0064] The difference from Example 1 is that the rare earth source compound is praseodymium carbonate octahydrate, and the rare earth water-retaining ceramic material Pr@TDs is obtained.

[0065] Comparative Example 3

[0066] The difference from Example 1 is that the rare earth source compound is neodymium chloride heptahydrate, and the rare earth water-retaining ceramic material Nd@TDs is obtained.

[0067] Comparative Example 4

[0068] The difference from Example 1 is that the added amount of lanthanum nitrate hexahydrate is 40 g, and the rare earth water-retaining ceramic material La@TDs-1 is obtained.

[0069] Comparative Example 5

[0070] The difference from Example 1 is that the added amount of lanthanum nitrate hexahydrate is 210 g, and the rare earth water-retaining ceramic material La@TDs-2 is obtained.

[0071] Test Example 1 Rare Earth Ceramic Antibacterial Test

[0072] Twelve ceramic materials, including rare earth water-retaining ceramic materials La@TDs, rare earth water-retaining ceramic materials Ce@TDs, rare earth water-retaining ceramic materials Gd@TDs, rare earth water-retaining ceramic materials Y@TDs, rare earth water-retaining ceramic materials La@TDs-UREA, rare earth water-retaining ceramic materials La@TDs-MEL, rare earth water-retaining ceramic materials La@TDs-CYA, rare earth water-retaining ceramic materials Eu@TDs, rare earth water-retaining ceramic materials Pr@TDs, rare earth water-retaining ceramic materials Nd@TDs, rare earth water-retaining ceramic materials La@TDs-1, and rare earth water-retaining ceramic materials La@TDs-2, were fired separately according to the size of 5 cm×5 cm and the thickness of 1 cm. Six pieces of each were prepared, and ceramic pieces fired without adding rare earth functional materials were used as blank control groups. The antibacterial properties of ceramic pieces were evaluated according to the JC / T 897-2014 standard "Antibacterial properties of antibacterial ceramic products". The thoroughly washed and dried ceramic samples were placed under sterile conditions and then incubated with a bacterial solution at a concentration of 1×10 4 The CFU Escherichia coli solution was evenly coated on its surface. Then a 4 cm × 4 cm, 0.01 cm thick polyethylene film was used to cover its surface. After covering for 24 hours, the bacteria on the surface of the polyethylene film were washed off with a 0.85% NaCl saline eluent. Subsequently, the washing solution was serially diluted, and an appropriate amount of the dilution was inoculated on a nutrient agar plate. After 24 hours of cultivation, the number of growing colonies was counted. The antibacterial properties of the sample were evaluated by comparing the number of colonies in the sample with that in the control group (untreated ceramic sample). The results are shown in Figure 2. Figure 4 shown.

[0073] pass Figure 4 It can be seen that the blank ceramic culture medium without any material added is full of colonies, while the number of colonies in the ceramic sample culture medium with the addition of the water-retaining rare earth composite material RE@TDs is greatly reduced, and the number of colonies in the ceramic sample culture medium of the water-retaining rare earth composite material La@TDs is 0, which represents that the rare earth glaze prepared by the water-retaining rare earth composite material La@TDs has a strong antibacterial ability.

[0074] Test Example 2 Determination of Chemical Oxygen Demand (COD) of Water in Different Ceramic Cups

[0075] According to step (4) of Example 1, three ordinary ceramic cups, three La@TDs ceramic cups, three Ce@TDs ceramic cups, three Gd@TDs ceramic cups, three Y@TDs ceramic cups, three La@TDs-UREA ceramic cups, three La@TDs-MEL ceramic cups, three La@TDs-CYA ceramic cups, three Eu@TDs ceramic cups, three Pr@TDs ceramic cups, three Nd@TDs ceramic cups, three La@TDs-1 ceramic cups, and three La@TDs-2 ceramic cups were fired respectively as three parallel tests in each group. 300 mL of deionized water was added to each cup, and then the COD index in the water was directly tested using a chemical oxygen demand meter 0 min and 1 h after the addition of water. The results are shown in FIG. Figure 5 shown.

[0076] from Figure 5 It can be seen from the results that the water quality in the 13 ceramic cups was tested immediately after adding water. At this time, the COD test values ​​of the 13 samples were not much different, basically in the range of 3.3 - 3.7 mg / L. However, after standing for 1 hour, the COD index of the water quality in the ordinary ceramic cups in the blank control group reached 5.7 mg / L, which was a significant increase, indicating that the water quality has changed. The COD index in the ceramic cups with rare earth glaze has decreased, especially the COD index of the water in the cups with La@TDs ceramic glaze has decreased from 3.3 mg / L to 2.4 mg / L. This proves that the ceramic glaze of the present invention can preserve the water quality and prevent the water quality from deteriorating.

[0077] In summary, the rare earth functional material prepared by the present invention is doped into ceramic glaze slurry, and the rare earth functional material is loaded onto the surface of the ceramic product by spraying glazing. The rare earth functional material can be adsorbed onto the cell walls of bacteria and fungi through ion diffusion and electrostatic action, thereby playing an antibacterial role, and also has the effect of long-term water quality preservation.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a water-retaining rare earth composite material RE@TDs, characterized in that: The steps include: S1: Add the rare earth source compound into ethanol and stir until it is completely dissolved, then add the carbon and nitrogen compound and heat to 80°C, stir for 20 min to obtain a mixture; S2: The mixture was transferred into a hydrothermal reactor, reacted at 220 °C for 6 h, and then concentrated to a dry sample to obtain a precursor; S3: The precursor is calcined at 1200 °C in a muffle furnace to obtain a water-retaining rare earth composite material RE@TDs; Wherein, the rare earth source compound is one or more of rare earth chloride, rare earth nitrate, and rare earth carbonate; The rare earth nitrate compound is one or a mixture of lanthanum nitrate hexahydrate, gadolinium nitrate hexahydrate, yttrium nitrate hexahydrate, and cerium nitrate hexahydrate; The rare earth chloride is one or more of lanthanum chloride heptahydrate, gadolinium chloride heptahydrate, yttrium chloride heptahydrate, and cerium chloride heptahydrate; The rare earth carbonate compound is one or more of lanthanum carbonate octahydrate, gadolinium carbonate octahydrate, yttrium carbonate octahydrate, and cerium carbonate octahydrate; The mass ratio of the carbon-nitrogen compound to the rare earth source compound in step S1 is 4:

13.

2. The preparation method according to claim 1, characterized in that: The carbon-nitrogen compound is one of urea, dicyandiamide, melamine and cyanuric acid, or a mixture of several of them.

3. The preparation method according to claim 1, characterized in that: The concentration of the rare earth source compound dissolved in ethanol in step S1 is 0.6 mol / L.

4. A RE@TDs dispersion slurry, characterized in that: The preparation method of the RE@TDs dispersion slurry is: adding the water-retaining rare earth composite material RE@TDs prepared by any preparation method described in claims 1-3 into deionized water at a ratio of 35% solid content, and obtaining a RE@TDs dispersion slurry with a particle size distribution of 300-700 nm of the water-retaining rare earth composite material RE@TDs by wet sand grinding.

5. A water-retaining rare earth composite ceramic glaze, characterized in that: The water-retaining rare earth composite ceramic glaze is prepared by adding the RE@TDs dispersion slurry described in claim 4 to the ceramic glaze, wherein the RE@TDs dispersion slurry is added to the ceramic glaze at a mass ratio of 1%-10% based on the mass of the water-retaining rare earth composite material RE@TDs.

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