Diatom ooze coating with purification effect

Technical field of diatom mud paint with purifying effect

[0001] The present invention belongs to the technical field of environmental protection, and specifically relates to a diatom mud paint with purifying effect.

Background technique

[0002] Environmental pollution will induce disease in the human body, which has become a consensus among people. The pathogenic bacteria, PM2.5 fine particles and disease-causing and carcinogenic organics in the living environment have attracted more and more attention. The formaldehyde, volatile organic compounds (VOC), fine dust particles, and toxic generated by indoor decoration materials Composition has become the first concern of consumers after house decoration. Among them, formaldehyde is a colorless gas with a strong pungent odor. It is very volatile at room temperature. The amount of volatilization increases with the increase of temperature. It has a strong stimulating effect on human skin and mucous membranes. It can be converted into methanol in the body, which has an adverse effect on the optic nerve. Long-term exposure to low-dose formaldehyde can easily cause chronic respiratory diseases, pregnancy syndrome, and lower newborn physique. In severe cases, it can even cause nasopharyngeal cancer. High concentrations of formaldehyde have toxic effects on the nervous system, immune system, liver, etc.

[0003] Diatom mud paint is a new high-tech interior wall decoration material. The main component of diatom mud is diatomaceous earth and its appearance is powdery. Diatom mud has 5000-6000 times smaller pores than activated carbon, so it has extremely strong adsorption capacity. The function of diatom mud to adsorb formaldehyde is to absorb a large amount of water to assist, slowly and continuously release negative oxygen ions, which can effectively decompose formaldehyde, toluene and other harmful carcinogens, but under the change of external conditions, formaldehyde is easily desorbed.

[0004] The photocatalyst commonly used in the existing purification coatings is Ti0₂, Ti0₂The photocatalyst has its own limitations. The band gap energy is 3.2eV. Only when ultraviolet light with a wavelength of less than 387.5nm irradiates its surface, the electrons can be excited, and the ultraviolet part of sunlight is less than 5%. And the utilization rate of indoor visible light is lower. In addition, after excitation Ti0₂The generated photogenerated electrons and holes are easy to recombine, resulting in the reduction of the excited hydroxyl radicals with higher oxidation activity, which also limits Ti0 to a certain extent.₂Application in the field of photocatalysis.

[0005] BiNbO₄Because of its good light absorption characteristics, it can photolyse water and effectively degrade organic pollutants under visible light, so it has become a kind of photocatalytic material with development potential, orthorhombic BiNbO₄The optical band gap is between 2.6-2.8eV, which is larger than the 2.OeV band gap required to maximize the use of visible light. Considering that its optical band gap is 2.6eV, its valence band top is higher than that of a standard photodegradation electrode. The required oxidation potential is 0.35eV lower and 0.97eV higher than the reduction potential, so it meets the requirements for the oxidation-reduction potential required for photolysis of water, BiNbO₄Its photocatalytic activity is limited by problems such as poor adsorption performance and easy recombination of photogenerated carriers. Therefore, transition metals, noble metals and non-metals are often doped and modified to improve the photocatalytic activity of photolysis water. , Because Bi vacancy defects are conducive to the separation and migration of photogenerated carriers, the BiNbO with Bi vacancy defects obtained under oxygen-rich conditions₄The system will have better photocatalytic activity. Metal-doped and modified BiNWh photocatalysts are rarely reported, and their application to diatom mud coatings is even less reported. Therefore, research and development of new high-efficiency photocatalysts are very necessary.

Summary of the invention

[0006] The object of the present invention is to provide a diatom mud paint with a purifying effect, without the aid of additional water, in the absence of ultraviolet light indoors, it can also degrade formaldehyde, high application value.

[0007] The technical problems to be solved by the present invention are:

[0008] 1. The existing diatom mud paint needs water assistance and the effect of formaldehyde degradation in a dark room is poor;

[0009] 2. How to increase the degradation rate of indoor formaldehyde;

[0010] 3. How to provide a photocatalyst with high catalytic activity.

[0011] The purpose of the present invention can be achieved through the following technical solutions:

[0012] A diatom mud paint with purifying effect, the weight percentage of each raw material is: diatomaceous earth 5-15%, shell powder 3-6%, light calcium carbonate 20-30%, ethylene-vinyl acetate Copolymer 10-15%, cellulose ether 5-7%, composite photocatalyst 5-8%, guar gum 6-9%, surfactant 0.5-2%, dispersant 1-3%, the balance is Ionized water

[0013] The preparation method of the diatom mud paint is:

[0014] S1. Activation of diatomaceous earth: adding diatomaceous earth to a ball mill to grind and grind, acidify, filter, wash to neutrality, dry, and then put it into a muffle furnace for gradient calcination. After the calcination is over, Naturally cool to room temperature, grind and sieve to obtain activated diatomaceous earth, the particle size of activated diatomaceous earth is 7-80nm;

[0015] S2. Loading of the composite photocatalyst: the composite photocatalyst and deionized water are added to the ball mill and mixed uniformly, the activated diatomaceous earth prepared in step S1 is added, mechanically mixed, the water is evaporated and removed, and placed in the muffle furnace After calcining, the diatomite fixedly supported by the composite photocatalyst is obtained;

[0016] S3, adding the supported composite photocatalyst diatomaceous earth, shell powder, ethylene-vinyl acetate copolymer, cellulose ether, and guar gum to the mixer, stirring at room temperature for 40-60 minutes, and adding light carbonic acid Calcium, after stirring evenly, add dispersant and deionized water, stir for 2h, cool down, add surfactant, stir for 2-3h, and obtain diatom mud paint after filtration. [0017] Further, the composite photocatalyst is Zr-BiNbO₄Photocatalyst, Zr-BiNbO₄The preparation method of the photocatalyst is:

[0018] (1) Dissolve bismuth nitrate in 50-65% concentrated nitric acid, dilute to 5-7mol/L with water while stirring, and obtain a bismuth nitrate solution after stirring;

[0019] Dissolve potassium niobate in 5-7mol/L potassium hydroxide solution, and stir to obtain potassium niobate solution;

[0020] potassium niobate solution was added dropwise while stirring the bismuth nitrate solution, after the addition is complete, stirring for 15-20min;

[0021] (4) Add zirconium nitrate to the mixed solution of step (3), stir to dissolve completely, add dilute nitric acid or dilute potassium hydroxide solution to adjust the pH of the solution to neutral, and continue to stir for 20-30min;

[0022] (5) The mixed solution of step (4) was transferred to a stainless steel hydrothermal kettle lined with polytetrafluoroethylene and sealed for reaction. After the reaction, the reaction kettle was taken out, cooled to room temperature, the supernatant liquid was removed, and centrifuged After washing and drying, Zr-BiNbO is obtained₄Photocatalyst powder.

[0023] Further, the molar ratio of the bismuth nitrate, potassium niobate and zirconium nitrate is 1:1.1-1.3:0.01-0.015.

[0024] Further, the sealed reaction conditions described in step (5) are reacted at 162-168°C for 5-7h.

[0025] Further, the surfactant is fatty alcohol polyoxyethylene ether ammonium sulfate.

[0026] Further, the dispersant is calcium stearate.

[0027] Further, the preparation method of the purifying diatom mud paint is:

[0028] S1. Activation of diatomaceous earth: adding diatomaceous earth to a ball mill for grinding and pulverizing, soaking in 10% nitric acid for 25h, filtering, washing to neutrality, drying, and then placing it in a muffle furnace for gradient calcination , The specific calcining steps are: calcining at 300 °C for 1-1.5h; heating up to 700Ό at a heating rate of 10-15°C/min, and calcining at this temperature for 40-60min; (c) Raise the temperature to 1000°( at a heating rate of 5-7°(:/1^11, and heat and calcinate at this temperature for 20-301^11. After the calcination is completed, cool to room temperature naturally and grind. The activated diatomite is obtained by sieving, and the particle size of the activated diatomite is 780nm;

[0029] S2, the loading of the composite photocatalyst: the composite photocatalyst and deionized water are added to the ball mill and mixed uniformly, the activated diatomaceous earth prepared in step (1) is added, and the composite photocatalyst is mechanically mixed for 2-3.5h. Fully adsorbed between the layers of diatomaceous earth, evaporated to remove water, placed in a muffle furnace for calcination at 500-600 °C for 3-5 h, then the composite photocatalyst fixedly supported diatomaceous earth was obtained;

[0030] S3, adding the supported composite photocatalyst diatomaceous earth, shell powder, ethylene-vinyl acetate copolymer, cellulose ether, and guar gum into the mixer, and stirring at a speed of 30-33 rpm at room temperature for 40- 60min, add light carbonated bait, stir evenly, add dispersant and deionized water, stir at 35-40°C, 35-40rpm speed for 2h, cool to 10-15°C, add surfactant, Stir at a speed of 20-24 rpm for 2-3 hours, and obtain the diatom mud paint after filtration.

[00311 The beneficial effects of the present invention:

[0032] (1) The present invention provides a diatom mud paint with a purifying effect. The ordinary diatomite is acidified and calcined to remove impurities in the diatomite structure layer and dredge the pores of the diatomite , It improves the adsorption activity of diatomite itself; the activated diatomite and the composite photocatalyst are mixed and then added to the ball mill, and mixed by mechanical extrusion, so that the composite photocatalyst is fully supported in the activated diatomite layer, thereby reducing The particle size of the diatomaceous earth is increased, and the specific surface area of the diatomaceous earth and the composite photocatalyst is increased, and the adsorption capacity of the diatomaceous earth is improved; then the obtained supporting compound and the remaining raw materials of the diatom mud paint are added to the mixer After mixing uniformly, a highly active diatom mud paint is obtained. The diatomaceous earth adsorbs formaldehyde to the surface, and the composite photocatalyst degrades the formaldehyde without the aid of additional water. In the absence of ultraviolet light indoors , It can also degrade formaldehyde, with high application value, which solves the problem that the existing diatom mud paint needs water assistance and the formaldehyde degradation effect is poor in the dark room;

(2) Doping Zr into BiNbO₄Modification treatment in the process to improve BiNbO₄In the visible light range, the photo-generated electron-hole recombination is reduced, and its photocatalytic performance is greatly improved. The composite photocatalyst Zr-BiNbO₄Loaded on activated diatomaceous earth increases the catalytic area of the photocatalyst and greatly improves the composite photocatalyst Zr_BiNbO₄The degradation rate of formaldehyde;

[0034] (3) Doping Zr into BiNbO by hydrothermal method₄In the hydrothermal method, due to its relatively low preparation temperature, good crystallinity, good dispersion and narrow particle size distribution, the reaction temperature is controlled at 162-168 °C and the amount of zirconium nitrate added to prepare a composite photocatalyst Zr-BiNbO₄It is an orthorhombic crystal with better photocatalytic performance and provides a photocatalyst with high catalytic activity.

Detailed ways

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

Example 1

[0037] A diatom mud paint with purifying effect, the weight percentage of each raw material is: diatomaceous earth 10%, shell powder 5%, light calcium carbonate 25%, ethylene-vinyl acetate copolymer 12%, fiber 5% plain ether, 5% composite photocatalyst, 6% guar gum, 0.5% surfactant, 1% dispersant, and the balance is deionized water;

[0038] The composite photocatalyst is Zr-BiNbO₄Photocatalyst, Zr-BiNbO₄The preparation method of the photocatalyst is as follows: [0039] (1) Dissolve 10mol of bismuth nitrate in 50% concentrated nitric acid, add water while stirring to dilute to 5mol/L, and stir evenly to obtain a bismuth nitrate acid solution;

[0040] (2) Dissolve 11mol potassium niobate in 5-7mol/L potassium hydroxide solution, and stir to obtain potassium niobate solution.

liquid;

[0041] (3) While stirring the bismuth nitrate solution, the potassium niobate solution was dropped into it, and after the addition was completed, stirred for 15min;

[0042] (4) Add 0.1mol zirconium nitrate to the mixed solution of step (3), stir to dissolve completely, add dilute nitric acid or dilute potassium hydroxide solution to adjust the pH of the solution to neutral, and continue to stir for 20min;

[0043] (5) The mixed solution of step (4) was transferred to a stainless steel hydrothermal kettle lined with polytetrafluoroethylene and sealed, and reacted at 162°C for 7 hours. After the reaction was completed, the reaction kettle was taken out, cooled to room temperature, and removed The supernatant was centrifuged, washed and dried to obtain Zr-BiNbO₄Photocatalyst powder;

[0044] The surfactant is a fatty alcohol polyoxyethylene ether ammonium sulfate;

[0045] The dispersant is calcium stearate;

[0046] A preparation method of diatom mud paint with purifying effect is:

[0047] S1. Activation of diatomaceous earth: 1kg of diatomaceous earth is added to a ball mill for grinding and pulverization, and soaked in 10% nitric acid

2h, filter, wash to neutrality, dry, then put it into the muffle furnace for gradient calcination, the specific calcination steps are: calcining at 300 °C for 1h; heating at a heating rate of ΙθΌ/min To 700 Ό, and heat preservation and calcining at this temperature for 40 minutes; (c) heating up to 1000 ° (3) at a heating rate of 5 °C/min, and heat preservation and calcining at this temperature for 30₁^₁1. After calcining, cool to room temperature naturally, grind and sieve to obtain activated diatomaceous earth, the particle size of activated diatomaceous earth is 7-80nm;

[0048] S2, the loading of the composite photocatalyst: the composite photocatalyst and deionized water are added to the ball mill and mixed uniformly, the activated diatomaceous earth prepared in step (1) is added, and the composite photocatalyst is fully adsorbed for 2 hours. Between the layers of diatomite, evaporate and remove water, put it in a muffle furnace and calcinate at 600°C for 5 hours, and then obtain the diatomite fixedly supported by the composite photocatalyst;

[0049] S3, adding the supported composite photocatalyst diatomaceous earth, shell powder, ethylene-vinyl acetate copolymer, cellulose ether, and guar gum to the mixer, stirring at 30 rpm for 40 min at room temperature, adding light After stirring, add dispersant and deionized water, stir at 40°C at 35rpm for 2h, cool to 15°C, add surfactant, stir at 24rpm for 3h, and it will be ready after filtration. The diatom mud paint is obtained.

Example 2

[00511 A diatom mud paint with purifying effect, the weight percentage of each raw material is: diatomaceous earth 15%, shell powder 3%, light calcium carbonate 30%, ethylene-vinyl acetate copolymer 10%, cellulose 7% ether, 8% composite photocatalyst, 9% guar gum, surfactant 1, dispersant 2%, and the balance is deionized water;

[0052] The composite photocatalyst is Zr-BiNbO₄Photocatalyst, Zr-BiNbO₄The preparation method of the photocatalyst is the same as in Example 1;

[0053] The surfactant is fatty alcohol polyoxyethylene ether ammonium sulfate;

[0054] The dispersant is calcium stearate;

[0055] A preparation method of diatom mud paint with purifying effect is:

[0056] S1. Activation of diatomaceous earth: 1kg of diatomaceous earth is added to a ball mill for grinding and pulverization, and soaked in 10% nitric acid

5h, filter, wash to neutrality, dry, then put it into the muffle furnace for gradient calcination, the specific calcination steps are: calcination at 300 °C for 1.5h; (b) 15 °C/ The heating rate of min is raised to 700Ό, and the temperature is kept and calcined at this temperature for 60min; (c) The heating rate is 7°C/min to 1000Ό, and the temperature is kept and calcined at this temperature for 20min. After the calcination is finished, it is cooled naturally To room temperature, grinding and sieving to obtain activated diatomaceous earth, the particle size of activated diatomaceous earth is 7-80nm;

[0057] S2. Loading of the composite photocatalyst: adding the composite photocatalyst and deionized water to the ball mill and mixing uniformly, adding the activated diatomaceous earth prepared in step (1), and mechanically mixing for 3.5 hours, so that the composite photocatalyst is fully adsorbed To diatomaceous earth

Between the layers, evaporate and remove the water, put it in a muffle furnace and calcinate at 500°C for 4 hours to obtain the diatomite fixedly supported by the composite photocatalyst;

[0058] S3, adding the supported composite photocatalyst diatomaceous earth, shell powder, ethylene-vinyl acetate copolymer, cellulose ether, and guar gum to the mixer, stirring at 33 rpm at room temperature for 60 min, adding light After stirring evenly, add dispersant and deionized water, stir at 35°C for 2h at 35rpm, cool to 10°C, add surfactant, stir at 20rpm for 2h, filter to obtain diatom mud coating.

Example 3

[0060] A diatom mud paint with purifying effect, the weight percentage of each raw material is: diatomaceous earth 5%, shell powder 6%, light calcium carbonate 25%, ethylene-vinyl acetate copolymer 12%, fiber 6% plain ether, 7% composite photocatalyst, 8% guar gum, 0.5% surfactant, 3% dispersant, and the balance is deionized water;

[0061] The composite photocatalyst is Zr-BiNbO₄Photocatalyst, Zr-BiNbO₄The preparation method of the photocatalyst is the same as in Example 1;

[0062] The surfactant is fatty alcohol polyoxyethylene ether ammonium sulfate;

[0063] The dispersant is calcium stearate;

[0064] A preparation method of diatom mud paint with purifying effect is:

[0065] S1. Activation of diatomaceous earth: add 1kg of diatomaceous earth to a ball mill to grind and grind, soak in 10% nitric acid for 4h, filter, wash to neutrality, dry, and then put it in a muffle furnace for gradient forging The specific calcining steps are: calcining at 300 °C for 1.5 hours; (b) heating up to 700 Ό at a heating rate of 12 °C/min, and calcining at this temperature for 50 minutes; (c) Raise the temperature to 1000 °C at a heating rate of 6 °C/min, and heat and calcinate at this temperature for 25 minutes. After the calcination is completed, cool to room temperature naturally, grind and sieve to obtain activated diatomaceous earth, activated diatomaceous earth The particle size is 7-80nm;

[0066] S2. Loading of the composite photocatalyst: the composite photocatalyst and deionized water are added to the ball mill and mixed uniformly, the activated diatomaceous earth prepared in step (1) is added, and the composite photocatalyst is fully absorbed for 3 hours. Between the layers of diatomite, evaporate and remove water, put it in a muffle furnace and calcinate at 550°C for 4 hours to obtain the diatomite fixedly supported by the composite photocatalyst;

[0067] S3, adding the supported composite photocatalyst diatomaceous earth, shell powder, ethylene-vinyl acetate copolymer, cellulose ether, and guar gum to the mixer, stirring at 32 rpm for 50 min at room temperature, adding light After stirring, add dispersant and deionized water, stir for 2h at 38rpm at 36°C, cool to 13°C, add surfactant, stir at 22rpm for 3h, and it will be ready after filtration. The diatom mud paint is obtained.

[0068] Comparative Example 1

[0069] Do not load the composite photocatalyst on diatomaceous earth;

[0070] One kind of diatom mud paint with a purifying effect, the weight percentage of each raw material is: the same as in Example 3;

[00711 The composite photocatalyst is Zr-BiNbO₄Photocatalyst, Zr-BiNbO₄The preparation method of the photocatalyst is the same as in Example 1;

[0072] The surfactant is fatty alcohol polyoxyethylene ether ammonium sulfate;

[0073] The dispersant is calcium stearate;

[0074] A preparation method of diatom mud paint with purifying effect is:

[0075] S1. Activation of diatomaceous earth: add the diatomaceous earth to a ball mill to grind and crush, soak in 10% nitric acid for 25h, filter, wash to neutrality, dry, and then put it into a muffle furnace for gradient calcination , The specific calcining steps are: calcining at 300 °C for 1-1.5h; heating up to 700 Ό at a heating rate of 10-15 °C/min, and heat preservation and calcination at this temperature

40-60min; (c) Raise the temperature to 1000°( at a heating rate of 5-7°(:/1^11, and heat and calcinate at this temperature for 20-301^11. After the calcination is over, cool down naturally to Activated diatomaceous earth is obtained by grinding and sieving at room temperature. The particle size of activated diatomaceous earth is 780nm;

[0076] S2. The composite photocatalyst, activated diatomaceous earth, shell powder, ethylene-vinyl acetate copolymer, cellulose ether, and guar gum are added to the mixer, and stirred at a speed of 30-33 rpm at room temperature for 40- 60min, add light carbonated fish, stir evenly, add dispersant and deionized water, stir at 35-40°C at 35-40rpm for 2h, cool to 10-15°C, add surfactant, Stir at a speed of 20-24 rpm for 2-3 hours, and obtain the diatom mud paint after filtration.

[0077] Comparative Example 2

[0078] The photocatalyst is BiNbO₄; The rest is the same as in Example 3.

[0079] Comparative Example 3

[0080] No photocatalyst is added;

[00811 A diatom mud paint with purifying effect, the weight percentage of each raw material is: diatomaceous earth 5%, shell powder 6%, light calcium carbonate 25%, ethylene-vinyl acetate copolymer 12%, cellulose 6% ether, 8% guar gum, 0.5% surfactant, 3% dispersant, and the balance is deionized water;

[0082] The surfactant is fatty alcohol polyoxyethylene ether ammonium sulfate;

[0083] The dispersant is calcium stearate;

[0084] A preparation method of diatom mud paint with purifying effect is:

[0085] S1. Activation of diatomaceous earth: 1kg of diatomaceous earth is added to a ball mill for grinding and crushing, and soaked in 10% nitric acid

4h, filter, wash until neutral, dry, then put it into the muffle furnace for gradient calcination, the specific calcination steps are: calcining at 300 °C for 1.5 hours; (b) 12°C/ The heating rate of min is raised to 700Ό, and the temperature is kept for 50min; (c) the heating rate is 6°C/min to 1000°C, and the temperature is kept and calcined for 25min. After the calcination is finished, Naturally cool to room temperature, grind and sieve to obtain activated diatomaceous earth, the particle size of activated diatomaceous earth is 7-80nm;

[0086] S2. Add activated diatomaceous earth, shell powder, ethylene-vinyl acetate copolymer, cellulose ether, and guar gum into the mixer, stir at 32 rpm for 50 minutes at room temperature, and add light carbonated bait, After stirring uniformly, add dispersant and deionized water, stir at 36°C at 38rpm for 2h, cool to 13°C, add surfactant, stir at 22rpm for 3h, filter to obtain diatom mud paint.

[0087] The diatom mud paint obtained in the present Example 1-3 and Comparative Example 1-3 was adjusted to a uniform paste with water, and tested according to the industry standard of JC/T2177-2013 "Diatom mud decorative wall material", the result As shown in Table 1:

[0088] Table 1. Performance test results of diatom mud paint

[0089]

<td>Test items</td><td>standard requirement</td><td>Example 1</td><td>Example 2</td><td>Example 3</td><td>Comparative Example 1</td><td>Comparative Example 2</td><td>Comparative Example 3</td>

<td>Constructability</td><td>Easy to mix evenly, construction is barrier-free</td><td>Easy conditions and uniformity, barrier-free construction</td><td>Easy to mix evenly, construction is barrier-free</td><td>Easy to mix evenly, construction is barrier-free</td><td>Easy to mix evenly, construction is barrier-free</td><td>Easy to mix evenly, construction is barrier-free</td><td>Easy to mix evenly, no obstacles in construction</td>

<td>Initial drying and crack resistance (6h)</td><td>No cracks</td><td>No cracks</td><td>No cracks</td><td>No pattern</td><td>No cracks</td><td>No cracks</td><td>No cracks</td>

<td>Lin: Recognition of Miscellaneous (48h)</td><td>No air bubbles, cracks, peeling, ignorant ink change tortoise:</td><td>meets the</td><td>Λ-/Γ ΛPay together</td><td>meets the</td><td>meets the</td><td>meets the</td><td>meets the</td>

<td>Fructus algae ingredients</td><td>Detectable</td><td>Detectable</td><td>Detectable</td><td>Detectable</td><td>Detectable</td><td>Detectable</td><td>Detectable</td>

<td>Formaldehyde purification performance (%)</td><td>80</td><td>98. 6</td><td>99. 2</td><td>98. 8</td><td>85</td><td>86. 5</td><td>80</td>

<td colspan="8">[0090]</td>

<td>#</td><td>^60</td><td>96 6</td><td>97 5</td><td>96.9</td><td>80</td><td>75</td><td>55</td>

[0091] As can be seen from Table 1, the diatom mud coatings prepared in Examples 1-3 have excellent formaldehyde purification performance and good formaldehyde degradation durability, while Comparative Example 1 does not load the composite photocatalyst on diatomaceous earth, The prepared diatom mud paint has qualified performance in removing formaldehyde, but it is not as good as in Examples 1-3; Comparative Example 2 uses BiNbO as the photocatalyst₄Without Zr doping, the performance of diatom mud paint to remove formaldehyde is qualified but not as good as that of Examples 1-3; Comparative Example 3 does not add photocatalyst, and the formaldehyde purification durability of the prepared diatom mud paint is not up to standard. .

[0092] The above content is merely an example and description of the concept of the present invention. Those skilled in the art make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from The idea of the invention or beyond the scope defined by the claims shall fall within the protection scope of the present invention.