Load type photocatalytic diatom ooze coating and preparation method thereof

Technical field of supported photocatalytic diatom mud paint and preparation method

[0001] The present invention belongs to the technical field of air purification, and provides a supported photocatalytic diatom mud coating and a preparation method.

Background technique

[0002] Indoor pollution is the third generation of pollution after humans have experienced soot-type pollution and photochemical smog pollution. In the newly renovated houses in my country, the air quality pass rate is less than 20%, and the main reason is that the harmful pollutants such as wall materials, building decoration materials, and various furniture floors are seriously exceeded. These harmful substances mainly include radon, ammonia, Benzene, formaldehyde and other volatile organic compounds, of which formaldehyde has the most content and is the most harmful. Therefore, in recent years, the development of wall building materials, especially building materials with air purification functions, has attracted more attention, and photocatalytic coatings are one of the mainstream development directions.

[0003] Nano-scale titanium dioxide is widely used as a photocatalyst. Due to its excellent gas sensitivity and dielectric properties, it can decompose these harmful substances into carbon dioxide and water without causing secondary pollution. Because titanium dioxide only responds in the ultraviolet region, that is, its photocatalytic activity can only be carried out under ultraviolet light irradiation, and the photogenerated electron-hole pairs of pure titanium dioxide are prone to recombination, so it is necessary to modify the pure nanometer titanium dioxide. It can also carry out photocatalytic activity under sunlight and indoor light.

[0004] The surface of diatomaceous earth has many microporous structures and abundant and prominent molecular sieve structures. It is an excellent catalyst support material, and it has high physical adsorption performance and superior ion exchange performance. Therefore, diatomaceous earth Paint is called "breathing paint". The research and application of using diatomaceous earth as a carrier to prepare photocatalytic coatings containing titanium dioxide has become one of today's hot topics.

[0005] At present, certain results have been achieved in photocatalytic coating technology at home and abroad, especially in diatomite-supported titanium dioxide coatings. Among them, Shi Wenyan and others invented a method for preparing nano-titanium dioxide/diatomite wall coatings (Chinese invention patent application number 201610023299.1). First, diatomite was dispersed in a hydrochloric acid solution; then ammonium sulfate and titanium tetrachloride After blending, add it to diatomaceous earth; transfer the above solution to the sealed bag for copolymerization under electron beam, slowly add silver nitrate to the solution, filter, and repeatedly wash with deionized water; transfer the solution to polytetrafluoroethylene In a lined autoclave, react at 160-180°C for 12 hours; the obtained product is filtered, washed, and dried to obtain nano-titanium dioxide/diatomite wall paint. In addition, Zhu Yuhong invented a diatomite-supported titanium dioxide environmentally friendly paint (Chinese invention patent application number 201710156239.1), which is composed of the following raw materials by weight: tetrabutyl titanate 37-40 weight parts, allyl thiourea 1~2 parts by weight, 3~5 parts by weight of sodium myristate soap, 0.6~1 parts by weight of trimethylolpropane, 1~2 parts by weight of 2-thiol benzimidazole, 3~4 parts by weight of ethylenediamine , 2~3 parts by weight of dodecyl alcohol ester, 20~30 parts by weight of diatomaceous earth, 21~30 parts by weight of styrene, 0.8~1 parts by weight of initiator, 170~200 parts by weight of styrene-acrylic emulsion, sorbitol 2~4 parts by weight of monooleate, the coating of this invention The surface of the material has good toughness, strong antibacterial and toxic gas adsorption, good scratch resistance and superior comprehensive performance.

[0006] It can be seen that the titanium dioxide photocatalytic coating in the prior art is difficult to perform photocatalytic activity under visible light irradiation, and its photogenerated electron-hole pairs are prone to recombination, and the titanium dioxide is easy to agglomerate in the coating and has poor dispersibility, leading to its decomposition. The problem of low efficiency of indoor harmful gases, and the use of diatomaceous earth as a carrier has disadvantages such as insufficient binding strength, easy to fall off, and affect catalytic efficiency.

Summary of the invention

[0007] In view of this situation, the present invention proposes a supported photocatalytic diatom mud coating and a preparation method, which can significantly improve the binding strength of the titanium dioxide photocatalyst and the diatomaceous earth, and improve the catalytic efficiency of the photocatalytic coating.

[0008] In order to achieve the above objectives, the specific technical solutions involved in the present invention are as follows:

[0009] A method for preparing a supported photocatalytic diatom mud paint. The diatomaceous earth is oxidized and modified by hydrogen peroxide and ozone successively, and then added to distilled water with a titanium dioxide precursor, mixed and stirred, dried, and then roasted twice , Obtain the diatomite-supported modified photocatalyst, and finally mix it with water, redispersible rubber powder, zeolite powder, wollastonite powder, bentonite, dispersant, curing agent and defoaming agent to make the supported photocatalytic silicon The specific steps for preparing algae mud paint are as follows:

[0010] (1) The diatomaceous earth was added to hydrogen peroxide, mixed and stirred uniformly, and then placed in a microwave reactor, passed in excess ozone for full oxidation modification, and then filtered, and the obtained filter residue was dried to obtain an oxidation modification Diatomite carrier;

[0011] (2) Add butyl titanate to absolute ethanol, dilute to form a titanium dioxide precursor, and then slowly add the oxidized modified diatomaceous earth obtained in step (1) to distilled water, and stir at 50~60°C Then let it stand for 5~8h, put it in an oven to dry, then move it into a tube furnace, roast it for the first time in an air atmosphere, and grind it into micron-sized powder after cooling, and then continue to put it in the tube furnace. Enter the hydrogen saturated with water vapor for the second roasting, so that the nano titanium dioxide generates oxygen vacancies and is tightly combined with the diatomaceous earth carrier, and cools after it is finished to prepare a fixedly bound diatomaceous earth-loaded modified photocatalyst;

[0012] (3) The diatomaceous earth obtained in step (2) is loaded with modified photocatalyst, water, redispersible rubber powder, zeolite powder, wollastonite powder, bentonite, dispersant, curing agent and defoamer Add the dispersion pot, mechanically stir and mix evenly to obtain the supported photocatalytic diatom mud paint.

[0013] Preferably, the speed of the mixing and stirring in step (1) is 200~250r/min, and the time is 1~3h.

[0014] Preferably, the parts by weight of each raw material in step (1) are 30-50 parts by weight of diatomaceous earth and 50-70 parts by weight of hydrogen peroxide.

[0015] The microwave reactor adopts the world's advanced microwave power automatic frequency conversion control and non-pulse continuous microwave heating technology, and real-time monitoring and control of the temperature in the reaction vessel through a high-precision non-contact infrared temperature sensor. It is equipped with electromagnetic and mechanical stirring methods at the same time. During the reaction, operations such as condensation, reflux, dripping and water separation can be performed. The color liquid crystal display can also be used to observe the reaction changes in the reaction vessel in real time (master the reaction in time, explore Optimal reaction conditions. In addition to being used for synthesis reactions, the instrument can also be used for atmospheric microwave extraction reactions. The present invention uses a microwave reactor to oxidize and modify diatomaceous earth. Preferably, the microwave treatment time is 10-30 minutes. The power is 600~800W.

[0016] Preferably, the temperature of the first firing in step (2) is 940~960°C, and the time is 5~6h.

[0017] Preferably, the temperature of the second firing in step (2) is 900~930°C, and the time is 4~5h.

[0018] Preferably, the parts by weight of each raw material in step (2) are 15-18 parts by weight of butyl titanate, 18-20 parts by weight of anhydrous ethanol, ±16-20 parts by weight of oxidized modified diatoms, and 42 parts by weight of distilled water. 51 parts by weight.

[0019] Preferably, the dispersant in step (3) is at least one of sodium methylene bis-naphthalene sulfonate, sodium methylene bis-methyl naphthalene sulfonate, copolymer of sodium acrylate and propionamide, and sodium polyacrylate Kind.

[0020] Redispersible rubber powder is a modified emulsion powder obtained by spray-drying a binary or ternary copolymer of vinyl acetate and vinyl versatate-VeoVa or ethylene or acrylate. It has good properties The redispersibility of the product is re-dispersed into an emulsion when it is in contact with water, and its chemical properties are exactly the same as the original emulsion. Mainly include the following types: vinyl acetate and ethylene copolymer rubber powder (Vac/E), ethylene and vinyl chloride and vinyl lauric acid ester ternary copolymer rubber powder (E/Vc/VL), vinyl acetate and ethylene and advanced Fatty acid vinyl ester ternary copolymer rubber powder (Vac/E/VeoVa), vinyl acetate and higher fatty acid vinyl ester copolymer rubber powder (Vac/VeoVa), acrylic ester and styrene copolymer rubber powder (A/S), vinyl acetate With acrylic ester and higher fatty acid vinyl ester ternary copolymer rubber powder (Vac/A/VeoVa), vinyl acetate homopolymer rubber powder (PVac), benzene

Ethylene and butadiene copolymer rubber powder (SBR), etc.

[0021] Preferably, the curing agent in step (3) is at least one of vinyltriamine, aminoethylpiperazine, diaminocyclohexane, isophoronediamine, ethylenediamine, and diethylenetriamine One kind.

[0022] Preferably, the defoaming agent in step (3) is one of polydimethylsiloxane, fluorosiloxane, glycol siloxane, and polyoxypropylene oxide ethylene glyceryl ether.

[0023] Preferably, the parts by weight of each raw material in step (3) are 13 to 16 parts by weight of diatomaceous earth-supported modified photocatalyst, 20 to 35 parts by weight of water, 8 to 11 parts by weight of redispersible rubber powder, and zeolite 12 to 14 parts by weight of powder, 18 to 20 parts by weight of wollastonite powder, 11 to 13 parts by weight of bentonite, 1 to 2 parts by weight of dispersant, 1 to 2 parts by weight of curing agent, and 1 to 2 parts by weight of defoamer.

[0024] The present invention first dilutes butyl titanate with absolute ethanol to form a titanium dioxide precursor solution. The titanium dioxide precursor solution is oxygen-deficient type. After mixing with oxidized diatomaceous earth, the nano titanium dioxide can be tightly combined by chemical bonds Used in diatomaceous earth to improve the binding strength of titanium dioxide photocatalyst.

[0025] The present invention also provides a supported photocatalytic diatom mud paint prepared by the above preparation method. The supported photocatalytic diatom mud paint is oxidized and modified diatomaceous earth with hydrogen peroxide and ozone successively, and then added to distilled water with the titanium dioxide precursor, mixed and stirred, dried, and then roasted twice to obtain the modified diatomaceous earth. The photocatalyst is finally mixed with water, redispersible rubber powder, zeolite powder, wollastonite powder, bentonite, dispersant, curing agent and defoamer to be prepared.

[0026] The present invention provides a supported photocatalytic diatom mud coating and a preparation method. Compared with the prior art, its outstanding features and excellent effects are:

[0027] 1. The supported photocatalytic diatom mud paint prepared by the present invention has high photocatalytic efficiency and can be widely used in the field of interior decoration.

[0028] 2. The preparation method of the present invention, by mixing the oxidized diatomaceous earth with the oxygen-deficient nano-titanium dioxide precursor solution, the nano-titanium dioxide is tightly combined in the diatomaceous earth, which not only overcomes the difficulty of dispersing pure nano-titanium dioxide, but also The shortcomings of easy agglomeration, and improve the bonding strength between the two, to prevent particles with large specific surface area from falling off in the paint, improve the photocatalytic efficiency, and prolong the service life of the photocatalytic material in the paint.

[0029] 3. The preparation method of the present invention improves the loading rate of the photocatalytic material, and the preparation process is safe and simple, and the cost is low.

Detailed ways

[0030] The present invention will be further described in detail below through specific embodiments, but it should not be understood that the scope of the present invention is limited to the following examples. Without departing from the above method idea of the present invention, various substitutions or changes made based on common technical knowledge and conventional means in the field should all be included in the scope of the present invention.

Example 1

[0032] 35g of diatomaceous earth was added to 65g of hydrogen peroxide, mixed and stirred for 2.5h at a speed of 210r/min, and then placed in a microwave reactor with a power of 700W, passed in excess ozone for full oxidation modification for 20min, and then filtered , Dry the obtained filter residue to prepare an oxidized modified diatomaceous earth carrier; then add 16g of butyl titanate to 19g of absolute ethanol to dilute to form a titanium dioxide precursor, and then slowly add 17g of oxidized modified diatomite to 48g Stir evenly in distilled water at 52°C, then let it stand for 7h, put it in an oven to dry, then move it into a tube furnace, heat it up to 945°C in an air atmosphere, roast for 6h, cool it and grind it into a micron-level fine powder, and then continue Put it into a tube furnace, pass in hydrogen saturated with water vapor, heat it up to 910°C and roast for 5 hours, then cool it down to prepare a fixed-bound diatomite loaded modified photocatalyst; finally 14g of diatomite loaded modified light catalytic

Agent, 31g water, 9g redispersible rubber powder, 12g zeolite powder, 19g wollastonite powder, 11g bentonite, 2g sodium methylene dinaphthalene sulfonate, 1g vinyl triamine and 1g polydimethylsiloxane are added Disperse the pot, mechanically stir and mix evenly to obtain the supported photocatalytic diatom mud paint.

[0033] Test method:

[0034] Titanium dioxide loading rate of diatomaceous earth: weigh a certain amount of diatom mud paint prepared by the present invention, first accurately weigh the quality of the paint, and calculate the diatom supporting the titanium dioxide photocatalyst according to the amount of each raw material in the preparation The mass m0 of soil, the paint is coated on the tinplate as a sample, and then the mass m1 of the titanium dioxide loaded is obtained by spectral analysis, and the titanium dioxide loading rate is calculated according to the formula m1/m0, and then the sample is placed at a temperature of 50°C and a relative humidity of 60 In a% environment, test the loading rate of titanium dioxide again after 15d, 30d, and 60d.

[0035] The data obtained are shown in Table 1.

Example 2

[0037] Add 45g of diatomaceous earth to 55g of hydrogen peroxide, mix and stir for 1.5h at a rotating speed of 240r/min, then place it in a microwave reactor with a power of 600W, pass in excess ozone for full oxidation modification for 30min, and then filter , Dry the obtained filter residue to prepare an oxidized modified diatomaceous earth carrier; then add 17g of butyl titanate to 19g of absolute ethanol to dilute to form a titanium dioxide precursor, and then slowly add 19g of oxidized modified diatomaceous earth to 45g Stir evenly in distilled water at 58°C, then let it stand for 6h, put it in an oven to dry, then move it into a tube furnace, heat it up to 955°C in an air atmosphere, roast it for 5h, cool it and grind it into a micron-sized powder, then continue Put it into a tube furnace, pass in hydrogen saturated with water vapor, heat it up to 920°C and roast for 4 hours, then cool it down to prepare a fixed-bound diatomite loaded modified photocatalyst; finally 15g of diatomite loaded modified light Catalyst, 24g water, 10g redispersible rubber powder, 13g zeolite powder, 20g wollastonite powder, 12g bentonite, 2g sodium methylene bismethylnaphthalene sulfonate, 2g aminoethylpiperazine and 2g fluorosiloxane are added Disperse the pot, mechanically stir and mix evenly to obtain the supported photocatalytic diatom mud paint.

[0038] The test method is consistent with Example 1, and the data obtained is shown in Table 1.

Example 3

[0040] 40g of diatomaceous earth was added to 60g of hydrogen peroxide, mixed and stirred for 2h at a rotating speed of 230r/min, and then placed in a microwave reactor with a power of 800W, passed in excess ozone for full oxidation modification for 10min, and then filtered, Dry the obtained filter residue to obtain an oxidized modified diatomaceous earth carrier; then add 17g of butyl titanate to 19g of absolute ethanol to dilute to form a titanium dioxide precursor, and then slowly add 18g of oxidized modified diatomaceous earth to 46g of distilled water Stir evenly at 55°C, then let it stand for 6h, put it in an oven to dry, then move it into a tube furnace, heat it up to 950°C in an air atmosphere, roast for 5.5h, cool it and grind it into a micron-sized powder, and then continue Put into a tube furnace, pass in hydrogen saturated with water vapor, heat up to 915°C, roast for 4.5h, cool after completion, and prepare a fixed-bound diatomite-loaded modified photocatalyst; finally 14g of diatomite is loaded and modified Photocatalyst, 29g water, 10g redispersible rubber powder, 13g zeolite powder, 19g wollastonite powder, 12g bentonite, 1g sodium acrylate and propionamide copolymer, 1g diaminocyclohexane and 1g glycol siloxane are added Disperse the pot, mechanically stir and mix evenly to obtain the supported photocatalytic diatom mud paint.

[0041] The test method is consistent with Example 1, and the data obtained is shown in Table 1.

Example 4

[0043] Add 50g of diatomaceous earth to 50g of hydrogen peroxide, mix and stir at 250r/min for 1h, then place it in a microwave reactor with a power of 650W, pass in excess ozone for full oxidation modification for 25min, and then filter, Dry the obtained filter residue to prepare an oxidized modified diatomaceous earth carrier; then add 18 g of butyl titanate to 20 g of absolute ethanol to dilute to form a titanium dioxide precursor, and then slowly add 20 g of oxidized modified diatomaceous earth to 42 g of distilled water Medium, stir evenly at 60°C, and then stand still

5h, put it in an oven to dry, then move it into a tube furnace, heat it up to 960°C in an air atmosphere, roast for 5h, grind it into micron-sized powder after cooling, and then continue to put it in the tube furnace with saturated steam The hydrogen was heated to 930°C and calcined for 4 hours, and then cooled to obtain a fixed and bound diatomite-supported modified photocatalyst; finally 16g diatomite-supported modified photocatalyst, 20g water, 11g redispersible rubber powder, 14g of zeolite powder, 20g of wollastonite powder, 13g of bentonite, 2g of sodium polyacrylate, 2g of isophorone diamine and 2g of polyoxypropylene oxide ethylene glycerol ether are added to the dispersion pot, mechanically stirred and mixed evenly to obtain the supported photocatalytic diatom Mud paint.

[0044] The test method is consistent with Example 1, and the data obtained is shown in Table 1.

Example 5

[0046] 30g of diatomaceous earth was added to 70g of hydrogen peroxide, mixed and stirred at a speed of 200r/min for 3h, and then placed in a microwave reactor with a power of 750W, passed in excess ozone for full oxidation modification for 15min, and then filtered, Dry the obtained filter residue to prepare an oxidized modified diatomaceous earth carrier; then add 15g of butyl titanate to 18g of absolute ethanol to dilute to form a titanium dioxide precursor, and then slowly add 16g of oxidized modified diatomaceous earth to 51g of distilled water Stir uniformly at 50°C, then let it stand for 8h, put it in an oven to dry, then move it into a tube furnace, heat it up to 940°C in an air atmosphere, roast it for 5h, grind it into a micron-sized powder after cooling, and then continue to put it Into the tube furnace, pass in hydrogen saturated with water vapor, heat up to 900°C, roast for 5h, cool after completion, and prepare a fixed-bound diatomite-loaded modified photocatalyst; finally 13g of diatomite-loaded modified photocatalyst , 35g water, 8g redispersible rubber powder, 12g zeolite powder, 18g wollastonite powder, 11g bentonite, 1g sodium methylene dinaphthalene sulfonate, 1g ethylenediamine and 1g polydimethylsiloxane into the dispersion pot , Mechanical stirring and mixing uniformly to obtain the supported photocatalytic diatom mud paint.

[0047] The test method is consistent with Example 1, and the data obtained is shown in Table 1.

Example 6

[0049] 40g of diatomaceous earth was added to 60g of hydrogen peroxide, mixed and stirred at a speed of 220r/min for 2h, and then placed in a microwave reactor with a power of 680W, passed in excess ozone for full oxidation modification for 12min, and then filtered, Dry the obtained filter residue to obtain an oxidized modified diatomaceous earth carrier; then add 16g of butyl titanate to 19g of absolute ethanol to dilute to form a titanium dioxide precursor, and then slowly add 18g of oxidized modified diatomaceous earth to 47g of distilled water Stir uniformly at 55°C, then let it stand for 6h, put it in an oven to dry, then move it into a tube furnace, heat it up to 950°C in an air atmosphere, roast for 5.5h, cool it and grind it into micron-sized fine powder, and then continue. Put it into a tube furnace, pass in hydrogen saturated with water vapor, heat it up to 915°C, roast for 4.5h, cool after completion, and prepare a fixed-bound diatomite-loaded modified photocatalyst; finally 14g of diatomite is loaded and modified Photocatalyst, 28g water, 10g redispersible rubber powder, 13g zeolite powder, 19g wollastonite powder, 12g bentonite, 2g sodium methylene naphthalenesulfonate, 1g diethylenetriamine and 1g fluorosiloxane are added to the dispersion pot , Mechanically agitated and mixed uniformly to obtain the supported photocatalytic diatom mud paint.

[0050] The test method is consistent with Example 1, and the data obtained is shown in Table 1.

[0051] Comparative Example 1

[0052] During the preparation process of the photocatalytic diatom mud paint, the oxidation modification treatment of diatomite was not added, and other preparation conditions were the same as in Example 6.

[0053] The test method is consistent with Example 1, and the data obtained is shown in Table 1.

[0054] Table 1:

[0055]

<td rowspan="2">Performance index 4</td><td colspan="4">Titanium dioxide loading rate of diatomite (%) 2</td>

<td>Initial 2</td><td>15</td><td>3 mouths"</td><td>6 mouthfuls</td>

<td>In the embodiment</td><td>96.5^</td><td>95.7^</td><td>Rush</td><td>92.8^</td>

<td>Example%</td><td></td><td>Nearly 3</td><td>93.9^</td><td>92.4^</td>

<td>Embodiment</td><td></td><td>95.*</td><td>94.1^</td><td>93.1^</td>

<td>Example q</td><td></td><td>M3</td><td>92.9^</td><td>91.</td>

<td>Example "</td><td>g work points</td><td>95.2^</td><td>g.</td><td>92.1^</td>

<td>Example plus</td><td>97.1^</td><td>95.1^</td><td></td><td>9 workers"</td>

<td>In the comparative example</td><td>57.1^</td><td>90.3^</td><td>£ work"</td><td>63.*</td>