Microbial coating and preparation method thereof

Abstract

The invention belongs to the field of coatings, and particularly relates to a microbial coating and a preparation method thereof, the microbial coating comprises a porous silicon-based material containing microorganisms, a curing agent containing calcium ions and a thickening agent; the curing agent containing calcium ions comprises urea, water-soluble calcium salt and water, the microorganisms are microorganisms for producing carbonic anhydrase; and mixing the porous silicon-based material, a thickening agent and a curing agent to obtain the microbial coating. The microbial coating can capture carbon dioxide in air and induce calcium ions in the environment to deposit and separate out calcium carbonate, and can be used for defect repair of walls.

Description

Technical Field

[0001] The invention belongs to the field of coatings, and in particular relates to a microbial coating and a preparation method thereof. Background Art

[0002] The greenhouse effect is a global environmental crisis facing mankind. The construction industry is one of the three major industries with carbon emissions. Concrete materials have the advantages of abundant raw materials, low cost and simple production process, so their usage is increasing. For a long time in the future, concrete will still be an indispensable and main construction material in civil engineering in my country and even in the world. Improving the service life of concrete materials and reducing their usage are important means to reduce carbon emissions. However, in the long-term use of concrete materials and under the influence of the surrounding complex environment, the service life and durability of concrete structures will decrease, and micro cracks and other degrees of damage will inevitably occur. In the long run, there will even be many safety hazards. How to stabilize concrete structures and improve wall strength is of great practical significance to the sustainable development of the concrete industry. Summary of the invention

[0003] In order to solve the problems of large carbon emissions and difficult repair of cracks in concrete materials in the prior art, the present invention mainly provides a microbial coating that can fix carbon and repair cracks, and a preparation method of the microbial coating, and the technical scheme thereof is as follows:

[0004] A microbial coating comprises, by weight, 25 to 35 parts of a porous silicon-based material containing microorganisms, 30 to 50 parts of a curing agent containing calcium ions, and 5 to 8 parts of a thickener; the curing agent containing calcium ions comprises, by weight, the following components: 0.1 to 0.5 parts of urea, 8 to 12 parts of a water-soluble calcium salt, and 22 to 38 parts of water.

[0005] Furthermore, the microorganism is a microorganism that produces carbonic anhydrase; the thickener includes one or more of methyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose or hydroxypropyl methyl cellulose; and the calcium salt is selected from one or more of calcium chloride, calcium nitrate, calcium lactate or calcium acetate.

[0006] A method for preparing the above-mentioned microbial coating comprises the following steps: preparing a silicon-based material, treating the silicon-based material to functionalize the silicon-based material with amino groups to obtain an amino silicon-based material; performing hydrophilic modification on the amino silicon-based material to obtain a modified silicon-based material; then loading microorganisms onto the modified silicon-based material to obtain a porous silicon-based material containing microorganisms; and mixing the porous silicon-based material, a thickener, and a curing agent to obtain a microbial coating.

[0007] Further, the following steps are included:

[0008] a. Sodium aluminate and tetraethylammonium hydroxide are placed in water and fully dissolved, and then kaolin is added and fully dispersed to obtain a precursor; the precursor is crystallized at 160-180°C for 12-15 seconds; after crystallization, it is naturally cooled to room temperature to obtain a crystallized precursor;

[0009] b. Freeze the crystallized precursor at low temperature, then naturally heat it to 0-5°C, add oxalic acid, mix and react for 2-4 hours, then heat it to 40-60°C, continue stirring and react for 6-8 hours, then remove water by rotary evaporation, and then vacuum dry it at 60-80°C to obtain an amino silicon-based material;

[0010] c. hydrophilically modifying the amino silicon-based material to obtain a modified silicon-based material;

[0011] d. Allowing the components of the liquid culture medium to penetrate into the internal pores of the modified silicon-based material to obtain a composite culture solution; the activated bacteria are inoculated in the composite culture solution at an inoculum amount of 1 to 5%, cultured at 25 to 35°C and 100 to 300 rpm for 12 to 48 hours, and the precipitate is separated, collected and dried to obtain a porous silicon-based material containing microorganisms;

[0012] e. Mixing a porous silicon-based material containing microorganisms, a thickener, and a curing agent containing calcium ions to obtain a microbial coating.

[0013] Furthermore, the mass ratio of the sodium aluminate to kaolin in step a is 1:8-10; the mass ratio of the tetraethylammonium hydroxide to kaolin in step a is 1:4-6.

[0014] Furthermore, the molar ratio of oxalic acid to tetraethylammonium hydroxide in step b is 1.1-1.3:1; and the low-temperature freezing in step b is performed at -50--30°C until the core temperature is lower than -18°C.

[0015] Furthermore, the step of allowing the components in the liquid culture medium to penetrate into the internal pores of the modified silicon-based material includes: placing the modified silicon-based material in the liquid culture medium, mixing evenly and then removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution.

[0016] Furthermore, in step d, the mass ratio of the modified silicon-based material to the liquid culture medium is 1:8-10; the culture medium includes one or more of beef extract peptone culture medium, LB culture medium, soybean casein culture medium or MYP culture medium.

[0017] Furthermore, the hydrophilic modification includes the following steps: fully dispersing the amino silicon-based material in an acetic acid buffer solution to make the pH of the system 5 to 6.5; adding a silane coupling agent with a hydrophilic group, fully dispersing it, and stirring the reaction at 60 to 80° C. for 2 to 3 hours; separating and collecting the precipitate, and washing and drying it thoroughly to obtain the product.

[0018] Furthermore, the silane coupling agent is a silane coupling agent containing polyhydroxy groups or the groups contained can be converted into polyhydroxy groups; the mass ratio of the amino silicon-based material to the silane coupling agent is 1:1.3-1.8.

[0019] By adopting the above scheme, the method of the present invention has the following advantages:

[0020] 1. The coating of the present invention is loaded with microorganisms, which can capture carbon dioxide in the air, induce calcium ions in the environment to precipitate calcium carbonate, and cement sand in cracks. It can be used to repair defects in walls, avoid the emission of harmful gases, and save the cost of artificial control repair.

[0021] 2. The microorganisms loaded in the present invention produce carbonic anhydrase, which can accelerate the reversible hydration reaction of carbon dioxide, and effectively accelerate the formation of water-soluble bicarbonate ions from carbon dioxide in the air, thereby increasing the strength and life of the wall while reducing the carbon dioxide content in the air.

[0022] 3. The silicon-based material of the microbial carrier of the present invention has good hydrophilicity, which is conducive to the attachment and colonization of bacteria, and has a large specific surface area and a rough surface, which is conducive to the colonization of bacteria and increases the amount of bacterial attachment.

[0023] 4. During use, the hydrophilic modified silicon-based material of the present invention can allow water vapor in the air to adhere, thereby providing an environment for a reversible hydration reaction of carbon dioxide and ensuring the biological activity of the bacteria.

[0024] 5. The present invention utilizes tetraethylammonium hydroxide used in the process of preparing silicon-based materials, directly acidifies with oxalic acid, introduces amino groups into the pores of the silicon-based materials, captures carbon dioxide in the air, and reduces the impact of the introduction of other substances on cost and microbial activity.

[0025] 6. The porous silicon-based material of the present invention provides mesoporous conditions for capturing water vapor and carbon dioxide, and the presence of pores enables microorganisms to come into contact with water and carbon dioxide more fully, making defect repair and improvement of the overall strength of the wall more uniform.

[0026] 7. The present invention first performs rotary evaporation to remove water during bacterial colonization, and then adds water, which is beneficial for the nutrients in the culture medium to penetrate into the pores of the silicon-based material, attracting microorganisms to colonize in the pores, thereby protecting the microorganisms and facilitating uniform and rapid mineralization.

[0027] 8. The coating of the present invention contains microorganisms to form a dominant bacterial community, thereby preventing the attachment of other harmful organisms and forming an anti-harmful bacteria effect. It has strong practicality and a wide range of applications. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Example 1: (1) 1 part by mass of sodium aluminate and 2 parts by mass of tetraethylammonium hydroxide were fully dissolved in water, and then 8 parts by mass of kaolin were added and fully dispersed to obtain a precursor; the precursor was crystallized at 160° C. for 13 h; after crystallization, it was naturally cooled to room temperature to obtain a crystallized precursor;

[0030] (2) Freeze the crystallized precursor at -40°C until the core temperature is below -18°C, then naturally heat it to 0°C, add oxalic acid in an amount 1.1 times that of tetraethylammonium hydroxide, mix thoroughly for 2 hours, then heat to 50°C, continue stirring for 6 hours, then remove water by rotary evaporation, and then vacuum dry at 60-80°C to obtain an amino silicon-based material;

[0031] (3) placing the amino silicon-based material in an acetic acid buffer solution and fully dispersing it so that the pH of the system is 5; adding γ-glycidyloxypropyltrimethoxysilane in an amount 1.5 times the mass of the amino silicon-based material, after fully dispersing it, stirring and reacting it at 60-80° C. for 2-3 hours; separating and collecting the precipitate, washing it with water and drying it, and obtaining the modified silicon-based material;

[0032] (4) placing the modified silicon-based material in a beef extract peptone liquid culture medium at a mass ratio of 1:8, mixing evenly, removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution; inoculating the activated Bacillus cereus strain in the composite culture solution at an inoculum amount of 3%, culturing at 30° C. and 200 rpm for 24 hours, separating and collecting the precipitate and drying it to obtain a porous silicon-based material containing microorganisms;

[0033] (5) 25 parts by mass of a porous silicon-based material containing microorganisms, 5 to 8 parts by mass of hydroxyethyl cellulose, 0.1 to 0.5 parts by mass of urea, 8 to 12 parts by mass of calcium acetate and 22 to 38 parts by mass of water are mixed to obtain a microbial coating.

[0034] Example 2: (1) 1 part by mass of sodium aluminate and 2 parts by mass of tetraethylammonium hydroxide were fully dissolved in water, and 10 parts by mass of kaolin were added and fully dispersed to obtain a precursor; the precursor was crystallized at 160° C. for 13 h; after crystallization, it was naturally cooled to room temperature to obtain a crystallized precursor;

[0035] (2) Freeze the crystallized precursor at -40°C until the core temperature is below -18°C, then naturally heat it to 0°C, add oxalic acid in an amount 1.1 times that of tetraethylammonium hydroxide, mix thoroughly for 2 hours, then heat to 50°C, continue stirring for 6 hours, then remove water by rotary evaporation, and then vacuum dry at 60-80°C to obtain an amino silicon-based material;

[0036] (3) placing the amino silicon-based material in an acetic acid buffer solution and fully dispersing it so that the pH of the system is 5; adding γ-glycidyloxypropyltrimethoxysilane in an amount 1.5 times the mass of the amino silicon-based material, after fully dispersing it, stirring and reacting it at 60-80° C. for 2-3 hours; separating and collecting the precipitate, washing it with water and drying it, and obtaining the modified silicon-based material;

[0037] (4) placing the modified silicon-based material in a beef extract peptone liquid culture medium at a mass ratio of 1:8, mixing evenly, removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution; inoculating the activated Bacillus cereus strain in the composite culture solution at an inoculum amount of 3%, culturing at 30° C. and 200 rpm for 24 hours, separating and collecting the precipitate and drying it to obtain a porous silicon-based material containing microorganisms;

[0038] (5) 25 parts by mass of a porous silicon-based material containing microorganisms, 5 to 8 parts by mass of hydroxyethyl cellulose, 0.1 to 0.5 parts by mass of urea, 8 to 12 parts by mass of calcium acetate and 22 to 38 parts by mass of water are mixed to obtain a microbial coating.

[0039] Example 3: ((1) 1 part by mass of sodium aluminate and 2 parts by mass of tetraethylammonium hydroxide were placed in water and fully dissolved, and then 8 parts by mass of kaolin were added and fully dispersed to obtain a precursor; the precursor was crystallized at 160° C. for 13 h; after crystallization, it was naturally cooled to room temperature to obtain a crystallized precursor;

[0040] (2) Freeze the crystallized precursor at -40°C until the core temperature is below -18°C, then naturally heat it to 5°C, add oxalic acid in an amount 1.1 times that of tetraethylammonium hydroxide, fully mix and react for 2 hours, then heat to 50°C, continue stirring and reacting for 6 hours, then remove water by rotary evaporation, and then vacuum dry at 60-80°C to obtain an amino silicon-based material;

[0041] (3) placing the amino silicon-based material in an acetic acid buffer solution and fully dispersing it so that the pH of the system is 5; adding γ-glycidyloxypropyltrimethoxysilane in an amount 1.5 times the mass of the amino silicon-based material, after fully dispersing it, stirring and reacting it at 60-80° C. for 2-3 hours; separating and collecting the precipitate, washing it with water and drying it, and obtaining the modified silicon-based material;

[0042] (4) placing the modified silicon-based material in a beef extract peptone liquid culture medium at a mass ratio of 1:8, mixing evenly, removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution; inoculating the activated Bacillus cereus strain in the composite culture solution at an inoculum amount of 3%, culturing at 30° C. and 200 rpm for 24 hours, separating and collecting the precipitate and drying it to obtain a porous silicon-based material containing microorganisms;

[0043] (5) 25 parts by mass of a porous silicon-based material containing microorganisms, 5 to 8 parts by mass of hydroxyethyl cellulose, 0.1 to 0.5 parts by mass of urea, 8 to 12 parts by mass of calcium acetate and 22 to 38 parts by mass of water are mixed to obtain a microbial coating.

[0044] Example 4: (1) 1 part by mass of sodium aluminate and 2 parts by mass of tetraethylammonium hydroxide were fully dissolved in water, and then 8 parts by mass of kaolin were added and fully dispersed to obtain a precursor; the precursor was crystallized at 160° C. for 13 h; after crystallization, it was naturally cooled to room temperature to obtain a crystallized precursor;

[0045] (2) Freeze the crystallized precursor at -40°C until the core temperature is below -18°C, then naturally heat it to 0°C, add oxalic acid in an amount 1.3 times that of tetraethylammonium hydroxide, fully mix and react for 2 hours, then heat to 50°C, continue stirring and react for 6 hours, then remove water by rotary evaporation, and then vacuum dry at 60-80°C to obtain an amino silicon-based material;

[0046] (3) placing the amino silicon-based material in an acetic acid buffer solution and fully dispersing it so that the pH of the system is 5; adding γ-glycidyloxypropyltrimethoxysilane in an amount 1.5 times the mass of the amino silicon-based material, after fully dispersing it, stirring and reacting it at 60-80° C. for 2-3 hours; separating and collecting the precipitate, washing it with water and drying it, and obtaining the modified silicon-based material;

[0047] (4) placing the modified silicon-based material in a beef extract peptone liquid culture medium at a mass ratio of 1:8, mixing evenly, removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution; inoculating the activated Bacillus cereus strain in the composite culture solution at an inoculum amount of 3%, culturing at 30° C. and 200 rpm for 24 hours, separating and collecting the precipitate and drying it to obtain a porous silicon-based material containing microorganisms;

[0048] (5) 25 parts by mass of a porous silicon-based material containing microorganisms, 5 to 8 parts by mass of hydroxyethyl cellulose, 0.1 to 0.5 parts by mass of urea, 8 to 12 parts by mass of calcium acetate and 22 to 38 parts by mass of water are mixed to obtain a microbial coating.

[0049] Example 5: (1) 1 part by mass of sodium aluminate and 2 parts by mass of tetraethylammonium hydroxide were fully dissolved in water, and then 8 parts by mass of kaolin were added and fully dispersed to obtain a precursor; the precursor was crystallized at 160° C. for 13 h; after crystallization, it was naturally cooled to room temperature to obtain a crystallized precursor;

[0050] (2) Freeze the crystallized precursor at -40°C until the core temperature is below -18°C, then naturally heat it to 0°C, add oxalic acid in an amount 1.1 times that of tetraethylammonium hydroxide, mix thoroughly and react for 4 hours, then heat to 50°C, continue stirring and reacting for 6 hours, then remove water by rotary evaporation, and then vacuum dry at 60-80°C to obtain an amino silicon-based material;

[0051] (3) placing the amino silicon-based material in an acetic acid buffer solution and fully dispersing it so that the pH of the system is 5; adding γ-glycidyloxypropyltrimethoxysilane in an amount 1.5 times the mass of the amino silicon-based material, after fully dispersing it, stirring and reacting it at 60-80° C. for 2-3 hours; separating and collecting the precipitate, washing it with water and drying it, and obtaining the modified silicon-based material;

[0052] (4) placing the modified silicon-based material in a beef extract peptone liquid culture medium at a mass ratio of 1:8, mixing evenly, removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution; inoculating the activated Bacillus cereus strain in the composite culture solution at an inoculum amount of 3%, culturing at 30° C. and 200 rpm for 24 hours, separating and collecting the precipitate and drying it to obtain a porous silicon-based material containing microorganisms;

[0053] (5) 25 parts by mass of a porous silicon-based material containing microorganisms, 5 to 8 parts by mass of hydroxyethyl cellulose, 0.1 to 0.5 parts by mass of urea, 8 to 12 parts by mass of calcium acetate and 22 to 38 parts by mass of water are mixed to obtain a microbial coating.

[0054] Example 6: (1) 1 part by mass of sodium aluminate and 2 parts by mass of tetraethylammonium hydroxide were fully dissolved in water, and then 8 parts by mass of kaolin were added and fully dispersed to obtain a precursor; the precursor was crystallized at 160° C. for 13 h; after crystallization, it was naturally cooled to room temperature to obtain a crystallized precursor;

[0055] (2) Freeze the crystallized precursor at -40°C until the core temperature is below -18°C, then naturally heat it to 0°C, add oxalic acid in an amount 1.1 times that of tetraethylammonium hydroxide, fully mix and react for 2 hours, then heat to 50°C, continue stirring and reacting for 8 hours, then remove water by rotary evaporation, and then vacuum dry at 60-80°C to obtain an amino silicon-based material;

[0056] (3) placing the amino silicon-based material in an acetic acid buffer solution and fully dispersing it so that the pH of the system is 5; adding γ-glycidyloxypropyltrimethoxysilane in an amount 1.5 times the mass of the amino silicon-based material, after fully dispersing it, stirring and reacting it at 60-80° C. for 2-3 hours; separating and collecting the precipitate, washing it with water and drying it, and obtaining the modified silicon-based material;

[0057] (4) placing the modified silicon-based material in a beef extract peptone liquid culture medium at a mass ratio of 1:8, mixing evenly, removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution; inoculating the activated Bacillus cereus strain in the composite culture solution at an inoculum amount of 3%, culturing at 30° C. and 200 rpm for 24 hours, separating and collecting the precipitate and drying it to obtain a porous silicon-based material containing microorganisms;

[0058] (5) 25 parts by mass of a porous silicon-based material containing microorganisms, 5 to 8 parts by mass of hydroxyethyl cellulose, 0.1 to 0.5 parts by mass of urea, 8 to 12 parts by mass of calcium acetate and 22 to 38 parts by mass of water are mixed to obtain a microbial coating.

[0059] Example 7: (1) 1 part by mass of sodium aluminate and 2 parts by mass of tetraethylammonium hydroxide were fully dissolved in water, and then 8 parts by mass of kaolin were added and fully dispersed to obtain a precursor; the precursor was crystallized at 160° C. for 13 h; after crystallization, it was naturally cooled to room temperature to obtain a crystallized precursor;

[0060] (2) Freeze the crystallized precursor at -40°C until the core temperature is below -18°C, then naturally heat it to 0°C, add oxalic acid in an amount 1.1 times that of tetraethylammonium hydroxide, mix thoroughly for 2 hours, then heat to 50°C, continue stirring for 6 hours, then remove water by rotary evaporation, and then vacuum dry at 60-80°C to obtain an amino silicon-based material;

[0061] (3) placing the amino silicon-based material in an acetic acid buffer solution and fully dispersing it so that the pH of the system is 6.5; adding γ-glycidyloxypropyltrimethoxysilane in an amount 1.5 times the mass of the amino silicon-based material, after fully dispersing it, stirring and reacting it at 60-80° C. for 2-3 hours; separating and collecting the precipitate, washing it with water and drying it, and obtaining the modified silicon-based material;

[0062] (4) placing the modified silicon-based material in a beef extract peptone liquid culture medium at a mass ratio of 1:8, mixing evenly, removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution; inoculating the activated Bacillus cereus strain in the composite culture solution at an inoculum amount of 3%, culturing at 30° C. and 200 rpm for 24 hours, separating and collecting the precipitate and drying it to obtain a porous silicon-based material containing microorganisms;

[0063] (5) 25 parts by mass of a porous silicon-based material containing microorganisms, 5 to 8 parts by mass of hydroxyethyl cellulose, 0.1 to 0.5 parts by mass of urea, 8 to 12 parts by mass of calcium acetate and 22 to 38 parts by mass of water are mixed to obtain a microbial coating.

[0064] Example 8: (1) 1 part by mass of sodium aluminate and 2 parts by mass of tetraethylammonium hydroxide were fully dissolved in water, and then 8 parts by mass of kaolin were added and fully dispersed to obtain a precursor; the precursor was crystallized at 160° C. for 13 h; after crystallization, it was naturally cooled to room temperature to obtain a crystallized precursor;

[0065] (2) Freeze the crystallized precursor at -40°C until the core temperature is below -18°C, then naturally heat it to 0°C, add oxalic acid in an amount 1.1 times that of tetraethylammonium hydroxide, mix thoroughly for 2 hours, then heat to 50°C, continue stirring for 6 hours, then remove water by rotary evaporation, and then vacuum dry at 60-80°C to obtain an amino silicon-based material;

[0066] (3) placing the amino silicon-based material in an acetic acid buffer solution and fully dispersing it so that the pH of the system is 5; adding γ-glycidyloxypropyltrimethoxysilane in an amount 1.5 times the mass of the amino silicon-based material, after fully dispersing it, stirring and reacting it at 60-80° C. for 2-3 hours; separating and collecting the precipitate, washing it with water and drying it, and obtaining the modified silicon-based material;

[0067] (4) placing the modified silicon-based material in a beef extract peptone liquid culture medium at a mass ratio of 1:10, mixing evenly, removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution; inoculating the activated Bacillus cereus strain in the composite culture solution at an inoculum amount of 3%, culturing at 30° C. and 200 rpm for 24 hours, separating and collecting the precipitate and drying it to obtain a porous silicon-based material containing microorganisms;

[0068] (5) 25 parts by mass of a porous silicon-based material containing microorganisms, 5 to 8 parts by mass of hydroxyethyl cellulose, 0.1 to 0.5 parts by mass of urea, 8 to 12 parts by mass of calcium acetate and 22 to 38 parts by mass of water are mixed to obtain a microbial coating.

[0069] Example 9: (1) 1 part by mass of sodium aluminate and 2 parts by mass of tetraethylammonium hydroxide were fully dissolved in water, and then 8 parts by mass of kaolin were added and fully dispersed to obtain a precursor; the precursor was crystallized at 160° C. for 13 h; after crystallization, it was naturally cooled to room temperature to obtain a crystallized precursor;

[0070] (2) Freeze the crystallized precursor at -40°C until the core temperature is below -18°C, then naturally heat it to 0°C, add oxalic acid in an amount 1.1 times that of tetraethylammonium hydroxide, mix thoroughly for 2 hours, then heat to 50°C, continue stirring for 6 hours, then remove water by rotary evaporation, and then vacuum dry at 60-80°C to obtain an amino silicon-based material;

[0071] (3) placing the amino silicon-based material in an acetic acid buffer solution and fully dispersing it so that the pH of the system is 5; adding γ-glycidyloxypropyltrimethoxysilane in an amount 1.5 times the mass of the amino silicon-based material, after fully dispersing it, stirring and reacting it at 60-80° C. for 2-3 hours; separating and collecting the precipitate, washing it with water and drying it, and obtaining the modified silicon-based material;

[0072] (4) placing the modified silicon-based material in a beef extract peptone liquid culture medium at a mass ratio of 1:8, mixing evenly, removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution; inoculating the activated Bacillus cereus strain in the composite culture solution at an inoculum amount of 3%, culturing at 30° C. and 200 rpm for 24 hours, separating and collecting the precipitate and drying it to obtain a porous silicon-based material containing microorganisms;

[0073] (5) 35 parts by mass of a porous silicon-based material containing microorganisms, 5 to 8 parts by mass of hydroxyethyl cellulose, 0.1 to 0.5 parts by mass of urea, 8 to 12 parts by mass of calcium acetate and 22 to 38 parts by mass of water are mixed to obtain a microbial coating.

[0074] Comparative Example 1: (1) 1 part by mass of sodium aluminate and 2 parts by mass of tetraethylammonium hydroxide were fully dissolved in water, and then 8 parts by mass of kaolin were added and fully dispersed to obtain a precursor; the precursor was crystallized at 160° C. for 13 h; after crystallization, the precursor was naturally cooled to room temperature to obtain a crystallized precursor;

[0075] (2) freezing the crystallized precursor at -40°C until the core temperature is below -18°C, then adding oxalic acid in an amount 1.1 times that of tetraethylammonium hydroxide, heating to 50°C and stirring for 6 hours, then removing water by rotary evaporation, and then vacuum drying at 60-80°C to obtain an amino silicon-based material;

[0076] (3) placing the amino silicon-based material in an acetic acid buffer solution and fully dispersing it so that the pH of the system is 5; adding γ-glycidyloxypropyltrimethoxysilane in an amount 1.5 times the mass of the amino silicon-based material, after fully dispersing it, stirring and reacting it at 60-80° C. for 2-3 hours; separating and collecting the precipitate, washing it with water and drying it, and obtaining the modified silicon-based material;

[0077] (4) placing the modified silicon-based material in a beef extract peptone liquid culture medium at a mass ratio of 1:8, mixing evenly, removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution; inoculating the activated Bacillus cereus strain in the composite culture solution at an inoculum amount of 3%, culturing at 30° C. and 200 rpm for 24 hours, separating and collecting the precipitate and drying it to obtain a porous silicon-based material containing microorganisms;

[0078] (5) 25 parts by mass of a porous silicon-based material containing microorganisms, 5 to 8 parts by mass of hydroxyethyl cellulose, 0.1 to 0.5 parts by mass of urea, 8 to 12 parts by mass of calcium acetate and 22 to 38 parts by mass of water are mixed to obtain a microbial coating.

[0079] Comparative Example 2: (1) 1 part by mass of sodium aluminate and 2 parts by mass of tetraethylammonium hydroxide were fully dissolved in water, and then 8 parts by mass of kaolin were added and fully dispersed to obtain a precursor; the precursor was crystallized at 160° C. for 13 h; after crystallization, it was naturally cooled to room temperature to obtain a crystallized precursor;

[0080] (2) fully dispersing the crystallization precursor in an acetic acid buffer solution to adjust the pH of the system to 5; adding γ-glycidyloxypropyltrimethoxysilane in an amount 1.5 times the mass of the crystallization precursor, and stirring the mixture at 60 to 80° C. for 2 to 3 hours after fully dispersing the mixture; separating and collecting the precipitate, washing the mixture with water, and drying the mixture to obtain a modified silicon-based material;

[0081] (3) placing the modified silicon-based material in a beef extract peptone liquid culture medium at a mass ratio of 1:8, mixing evenly, removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution; inoculating the activated Bacillus cereus strain in the composite culture solution at an inoculum amount of 3%, culturing at 30° C. and 200 rpm for 24 hours, separating and collecting the precipitate and drying it to obtain a porous silicon-based material containing microorganisms;

[0082] (4) 25 parts by mass of a porous silicon-based material containing microorganisms, 5 to 8 parts by mass of hydroxyethyl cellulose, 0.1 to 0.5 parts by mass of urea, 8 to 12 parts by mass of calcium acetate and 22 to 38 parts by mass of water are mixed to obtain a microbial coating.

[0083] Comparative Example 3:

[0084] (1) 1 part by mass of sodium aluminate and 2 parts by mass of tetraethylammonium hydroxide are placed in water and fully dissolved, and then 8 parts by mass of kaolin are added and fully dispersed to obtain a precursor; the precursor is crystallized at 160° C. for 13 hours; after crystallization, it is naturally cooled to room temperature to obtain a crystallized precursor;

[0085] (2) Freeze the crystallized precursor at -40°C until the core temperature is below -18°C, then naturally heat it to 0°C, add oxalic acid in an amount 1.1 times that of tetraethylammonium hydroxide, mix thoroughly for 2 hours, then heat to 50°C, continue stirring for 6 hours, then remove water by rotary evaporation, and then vacuum dry at 60-80°C to obtain an amino silicon-based material;

[0086] (3) placing the amino silicon-based material in a beef extract peptone liquid culture medium at a mass ratio of 1:8, mixing evenly, removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution; inoculating the activated Bacillus cereus strain in the composite culture solution at an inoculum amount of 3%, culturing at 30° C. and 200 rpm for 24 hours, separating and collecting the precipitate and drying it to obtain a porous silicon-based material containing microorganisms;

[0087] (4) 25 parts by mass of a porous silicon-based material containing microorganisms, 5 to 8 parts by mass of hydroxyethyl cellulose, 0.1 to 0.5 parts by mass of urea, 8 to 12 parts by mass of calcium acetate and 22 to 38 parts by mass of water are mixed to obtain a microbial coating.

[0088] Comparative Example 4:

[0089] (1) 1 part by mass of sodium aluminate and 2 parts by mass of tetraethylammonium hydroxide are placed in water and fully dissolved, and then 8 parts by mass of kaolin are added and fully dispersed to obtain a precursor; the precursor is crystallized at 160° C. for 13 hours; after crystallization, it is naturally cooled to room temperature to obtain a crystallized precursor;

[0090] (2) Freeze the crystallized precursor at -40°C until the core temperature is below -18°C, then naturally heat it to 0°C, add oxalic acid in an amount 1.1 times that of tetraethylammonium hydroxide, mix thoroughly for 2 hours, then heat to 50°C, continue stirring for 6 hours, then remove water by rotary evaporation, and then vacuum dry at 60-80°C to obtain an amino silicon-based material;

[0091] (3) placing the amino silicon-based material in an acetic acid buffer solution and fully dispersing it so that the pH of the system is 5; adding γ-glycidyloxypropyltrimethoxysilane in an amount 1.5 times the mass of the amino silicon-based material, after fully dispersing it, stirring and reacting it at 60-80° C. for 2-3 hours; separating and collecting the precipitate, washing it with water and drying it, and obtaining the modified silicon-based material;

[0092] (4) placing the modified silicon-based material in a beef extract peptone liquid culture medium at a mass ratio of 1:8, mixing evenly, inoculating an activated Bacillus cereus strain at an inoculum amount of 3%, culturing at 30° C. and 200 rpm for 24 h, separating and collecting the precipitate and drying it to obtain a porous silicon-based material containing microorganisms;

[0093] (5) 25 parts by mass of a porous silicon-based material containing microorganisms, 5 to 8 parts by mass of hydroxyethyl cellulose, 0.1 to 0.5 parts by mass of urea, 8 to 12 parts by mass of calcium acetate and 22 to 38 parts by mass of water are mixed to obtain a microbial coating.

[0094] Example sample test:

[0095] PO52.5 cement was used to prepare 4cm×4cm×16cm prismatic specimens with a standard cement mortar ratio. When the specimens were not yet fully formed, a metal sheet was inserted into the cement slurry to produce cracks with an average crack width of 0.3mm in the specimens. Then, the coatings of the embodiments and comparative examples were applied to the surface of the cracked specimens and allowed to stand in an environment with a humidity of 50% and a temperature of 26°C. The average crack widths after treatment for 10d, 20d and 30d were calculated. Five parallel specimens were made for each group and the average value was taken. The repair rate was calculated as the ratio of the difference between the average crack widths before and after treatment to the initial average crack width. The results are as follows:

[0096]

[0097] As can be seen from the above table, the 30-day repair rate of each embodiment is above 30%, and the repair ability is good. Among them, in the process of preparing silicon-based materials, the repair rate of Example 2 with a higher kaolin content is not as good as that of Example 1, indicating that more tetraethylammonium hydroxide is conducive to the increase of the specific surface area of ​​silicon-based materials and improves the repair effect. In the amination process, compared with Example 1, the repair ability of Example 3 with a higher initial reaction temperature decreases, and the repair rate of Example 5 with a longer reaction time increases, while the repair rate of Comparative Example 1 without low-temperature reaction is significantly reduced, indicating that the low-temperature reaction process here is conducive to the amination of silicon-based materials. Direct high temperature may cause the reaction to be violent, produce more by-products, or be unfavorable for the close combination of amino compounds in silicon-based materials, affecting the carbon dioxide capture capacity in the later stage. The repair rate of Example 4 with more oxalic acid addition and Example 6 with a longer temperature reaction process time did not change significantly, which may be because the reactions were close to saturation. The repair rate of Comparative Example 2 without amination decreased, indicating that the modification of amination has an important influence on capturing carbon dioxide and shaping an environment conducive to microbial carbon fixation.

[0098] In the hydrophilic modification process of Example 7, the acidity of the system is not as good as that of Example 1, but its final repair rate is higher than that of Example 1, indicating that the acidity is greater, which may be unfavorable for the hydrophilic modification, or may affect the stability of the material in the material, thereby affecting the activity environment of the microorganism. The repair ability of Comparative Example 3 without hydrophilic modification decreased significantly, indicating that improving the hydrophilicity of the matrix is ​​conducive to the mineralization of solidified carbon dioxide and calcium by microorganisms. In the process of microbial colonization, less modified silicon-based materials were added compared to Example 1. In comparison, more nutrients and bacteria were cultivated, and the repair rate of the sample increased significantly. In Comparative Example 4, when the bacteria were colonized, there was no step of first rotary evaporation to remove water and then adding water. The repair rate dropped sharply, indicating that the process of first removing water is conducive to the nutrients in the culture medium to penetrate into the pores of the silicon-based material, thereby attracting microorganisms to colonize in the pores, realizing the protection of microorganisms while promoting the uniform and rapid mineralization. In the process of mixing the coating formula, more porous silicon-based materials were added in Example 9, and the repair rate increased significantly.

[0099] For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A microbial coating, characterized in that: The invention comprises 25 to 35 parts of porous silicon-based materials containing microorganisms, 30 to 50 parts of curing agents containing calcium ions and 5 to 8 parts of thickeners in parts by mass; the curing agent containing calcium ions comprises the following components in parts by mass: 0.1 to 0.5 parts of urea, 8 to 12 parts of water-soluble calcium salts and 22 to 38 parts of water.

2. The microbial coating according to claim 1, characterized in that: The microorganism is a microorganism that produces carbonic anhydrase; the thickener includes one or more of methyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose or hydroxypropyl methyl cellulose; and the calcium salt is selected from one or more of calcium chloride, calcium nitrate, calcium lactate or calcium acetate.

3. A method for preparing the microbial coating according to claim 1, characterized in that: The following steps are involved: Prepare a silicon-based material, treat the silicon-based material to functionalize the amino groups of the silicon-based material, and obtain an amino silicon-based material; perform hydrophilic modification on the amino silicon-based material, and obtain a modified silicon-based material; Then the microorganisms are loaded on the modified silicon-based material to obtain a porous silicon-based material containing microorganisms; the porous silicon-based material, a thickener and a curing agent are mixed to obtain a microbial coating.

4. The method for preparing the microbial coating according to claim 1, characterized in that: The following steps are involved: a. Sodium aluminate and tetraethylammonium hydroxide are placed in water and fully dissolved, and then kaolin is added and fully dispersed to obtain a precursor; the precursor is crystallized at 160-180°C for 12-15 seconds; after crystallization, it is naturally cooled to room temperature to obtain a crystallized precursor; b. Freeze the crystallized precursor at low temperature, then naturally heat it to 0-5°C, add oxalic acid, mix and react for 2-4 hours, then heat it to 40-60°C, continue stirring and react for 6-8 hours, then remove water by rotary evaporation, and then vacuum dry it at 60-80°C to obtain an amino silicon-based material; c. hydrophilically modifying the amino silicon-based material to obtain a modified silicon-based material; d. Allowing the components of the liquid culture medium to penetrate into the internal pores of the modified silicon-based material to obtain a composite culture solution; the activated bacteria are inoculated in the composite culture solution at an inoculum amount of 1 to 5%, cultured at 25 to 35°C and 100 to 300 rpm for 12 to 48 hours, and the precipitate is separated, collected and dried to obtain a porous silicon-based material containing microorganisms; e. Mixing a porous silicon-based material containing microorganisms, a thickener, and a curing agent containing calcium ions to obtain a microbial coating.

5. The method for preparing the microbial coating according to claim 4, characterized in that: The mass ratio of the sodium aluminate to kaolin in step a is 1:8-10; the mass ratio of the tetraethylammonium hydroxide to kaolin in step a is 1:4-6.

6. The method for preparing the microbial coating according to claim 4, characterized in that: The molar ratio of oxalic acid to tetraethylammonium hydroxide in step b is 1.1-1.3:1; the low-temperature freezing in step b is freezing at -50--30°C until the core temperature is lower than -18°C.

7. The method for preparing the microbial coating according to claim 4, characterized in that: The step of allowing the components in the liquid culture medium to penetrate into the internal pores of the modified silicon-based material includes: placing the modified silicon-based material in the liquid culture medium, mixing evenly and then removing water by rotary evaporation, and then adding water to the volume before rotary evaporation to obtain a composite culture solution.

8. The method for preparing the microbial coating according to claim 4, characterized in that: In step d, the mass ratio of the modified silicon-based material to the liquid culture medium is 1:8-10; the culture medium includes one or more of beef extract peptone culture medium, LB culture medium, soybean casein culture medium or MYP culture medium.

9. The method for preparing the microbial coating according to claim 3, characterized in that: The hydrophilic modification comprises the following steps: placing the amino silicon-based material in an acetic acid buffer solution and fully dispersing it so that the pH of the system is 5 to 6.5; adding a silane coupling agent having a hydrophilic group, fully dispersing it, and stirring and reacting it at 60 to 80° C. for 2 to 3 hours; separating and collecting the precipitate, and washing and drying it sufficiently to obtain the product.

10. The method for preparing the microbial coating according to claim 9, characterized in that: The silane coupling agent is a silane coupling agent containing polyhydroxyl groups or the groups contained therein can be converted into polyhydroxyl groups; the mass ratio of the amino silicon-based material to the silane coupling agent is 1:1.3-1.8.

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