Titanium-based biomass coating material, preparation method and application thereof

Abstract

The present application belongs to the technical field of carbon fixation coating, and particularly relates to a titanium-based biomass coating, a preparation method and application thereof. The titanium-based biomass coating provided by the present application is coated on the surface of cement-based material in the plastic stage, and the nucleation effect of nano-titanium dioxide can accelerate the hydration of the surface layer of the cement-based material, refine the size of calcium hydroxide, and provide more reactants for the carbonation reaction. The present application loads carbonic anhydrase on the surface of nano-titanium dioxide, which inhibits the problem of nano-titanium dioxide agglomeration, and the nano-titanium dioxide has good stability and biocompatibility, so that the fixed carbonic anhydrase has good activity and stability. The carbonic anhydrase can accelerate the absorption of carbon dioxide, form high-concentration bicarbonate ions in the pore solution on the surface of the cement-based material, promote the carbonation reaction process, rapidly form calcium carbonate on the surface layer of the cement-based material, and form a dense surface layer structure, so that early rapid carbon fixation is realized in a low-concentration carbon dioxide environment, and the occurrence of sustained carbonation is inhibited.

Description

A titanium-based biomass coating, its preparation method and application Technical Field

[0001] This invention belongs to the field of carbon fixation coating technology, specifically relating to a titanium-based biomass coating, its preparation method, and its application. Background Technology

[0002] With the rapid development of the global economy and industrial construction, greenhouse gases, represented by CO2, are emitted in large quantities, leading to a series of serious environmental problems. Concrete, the most widely used material in the world's construction industry, is primarily composed of cement, which is a major source of carbon emissions in the construction sector. Cement accounts for 36% of all carbon emissions from construction activities and 9% of all anthropogenic carbon dioxide emissions. Therefore, developing carbon reduction technologies for concrete materials is of great significance.

[0003] Besides reducing carbon emissions through changes in cement or concrete production mix proportions or processes, utilizing the carbonization properties of cement-based materials for CO2 absorption is also an effective way to achieve carbon reduction. However, the absorption of CO2 by cement-based materials must be controlled in the early stages to avoid the negative impacts of continuous carbonization.

[0004] Currently, there are two main methods for early carbonation of cement-based materials: internal adsorption of carbon-fixing materials and artificially providing a closed high-concentration CO2 environment. The first method, internal adsorption of carbon-fixing materials, usually results in uneven dispersion, such as agglomeration of the carbon-fixing materials, causing internal defects in the cement-based materials and affecting their mechanical strength. The second method, artificially providing a closed high-concentration CO2 environment, aims to accelerate the early carbonation reaction of cement-based components. However, from an application perspective, providing a high-concentration CO2 environment severely limits the development of carbon fixation technology for ready-mixed cement-based materials. Summary of the Invention

[0005] The purpose of this invention is to provide a titanium-based biomass coating, its preparation method, and its application. The titanium-based biomass coating provided by this invention can achieve carbon fixation in a low-concentration CO2 environment, specifically promote rapid carbonization of the surface of cement-based materials with controllable carbonization depth, and improve the mechanical properties and durability of cement-based materials.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a titanium-based biomass coating, made from raw materials comprising the following weight percentages:

[0008] Ammoniation-modified nano-titanium dioxide / carbonic anhydrase composite microparticles 2-5%, sodium alginate 0.4-2%, pH adjuster and water balance;

[0009] The amount of pH adjuster used is based on adjusting the pH value of the coating to 9.5-10.5;

[0010] The ammonium-modified nano-titanium dioxide / carbonic anhydrase composite microparticles include carbonic anhydrase and ammonium-modified nano-titanium dioxide covalently linked to the carbonic anhydrase; the carbonic anhydrase is loaded on the surface of the ammonium-modified nano-titanium dioxide.

[0011] Preferably, the mass ratio of the ammonified modified nano-titanium dioxide to carbonic anhydrase is 1300–4000:1.

[0012] Preferably, the sodium alginate is sodium alginate.

[0013] Preferably, the preparation method of the ammoniation-modified nano-titanium dioxide / carbonic anhydrase composite microparticles includes the following steps:

[0014] Ammonified titanium dioxide nanoparticles, carbonic anhydrase, phosphate buffer, and activator were mixed, centrifuged, and dried sequentially to obtain ammonified titanium dioxide nanoparticles / carbonic anhydrase composite microparticles.

[0015] Preferably, the mixing temperature is 25–35°C and the pH value is 5–6; the mixing is ultrasonic mixing, and the ultrasonic frequency is 20–25 kHz and the power is 800–950 W.

[0016] Preferably, the preparation method of the ammoniation-modified nano-titanium dioxide includes the following steps:

[0017] A surface modifier, nano-titanium dioxide, and water are mixed to obtain a slurry; the surface modifier is an alkanolamine compound.

[0018] The slurry was dried and then heat-treated to obtain ammoniated modified nano-titanium dioxide.

[0019] Preferably, the mass ratio of the surface modifier to nano-titanium dioxide is 1:3 to 5; and the mass ratio of the nano-titanium dioxide to water is 1:20 to 40.

[0020] This invention also provides a method for preparing the titanium-based biomass coating described above, comprising the following steps:

[0021] Ammoniated modified nano-titanium dioxide / carbonic anhydrase composite microparticles, sodium alginate, and water were mixed to obtain a mixture. The pH of the mixture was then adjusted to 9.5–10.5 using a pH adjuster to obtain a titanium-based biomass coating.

[0022] The present invention also provides the application of the titanium-based biomass coating described in the above scheme or the titanium-based biomass coating obtained by the preparation method described in the above scheme in cement carbon fixation, wherein the environmental CO2 concentration of the cement carbon fixation is the natural environmental CO2 concentration.

[0023] Preferably, the application of the titanium-based biomass coating in cement carbon sequestration includes the following steps:

[0024] Titanium-based biomass coatings are applied to the surface of cement-based materials during the molding stage.

[0025] This invention provides a titanium-based biomass coating. When applied to the surface of cement-based materials in the plastic stage, the nucleation effect of nano-titanium dioxide accelerates the surface hydration of the cement-based material, refines the Ca(OH)2 size, and provides more reactants for the carbonation reaction. This invention loads carbonic anhydrase onto the surface of ammonified nano-titanium dioxide, inhibiting the aggregation of nano-titanium dioxide. Simultaneously, the nano-titanium dioxide exhibits good stability and biocompatibility, serving as a carrier to immobilize the carbonic anhydrase, resulting in good activity and stability of the immobilized carbonic anhydrase. The carbonic anhydrase can accelerate CO2 absorption, forming a high concentration of HCO3 in the pore solution on the surface of the cement-based material. 2+ It promotes the carbonation reaction process, rapidly forming calcium carbonate on the surface of cement-based materials, filling pores and creating a dense surface structure. It can achieve early and rapid carbon fixation in a low-concentration CO2 environment and inhibit the occurrence of continuous carbonation. This avoids the limiting condition of artificially providing high concentrations of CO2, which is conducive to large-scale application.

[0026] The titanium-based biomass coating provided by this invention can not only reduce the CO2 concentration in the atmosphere and achieve precise carbon fixation, but also the carbonization process occurs in the early stage of cement-based materials, which can specifically promote the rapid carbonization of the surface of cement-based materials and the carbonization depth can be controlled. This can suppress the negative impact of continuous carbonization in the later stage on cement-based materials and improve the mechanical properties and durability of cement-based materials, such as mechanical strength.

[0027] This invention also provides a method for preparing the titanium-based biomass coating described above. The preparation method provided by this invention is simple in steps, convenient to operate, has low production cost, and can be industrialized on a large scale.

[0028] This invention also provides the application of the titanium-based biomass coating described in the above-described scheme or the titanium-based biomass coating prepared by the above-described scheme in cement carbon fixation. The titanium-based biomass provided by this invention can be applied to different cement-based materials such as mortar and concrete to achieve the construction of a favorable carbonization layer and has a good carbon fixation effect. Detailed Implementation

[0029] A titanium-based biomass coating is made from raw materials comprising the following percentages by mass:

[0030] Ammoniation-modified nano-titanium dioxide / carbonic anhydrase composite microparticles 2-5%, sodium alginate 0.4-2%, pH adjuster and water balance;

[0031] The amount of pH adjuster used is based on adjusting the pH value of the coating to 9.5-10.5;

[0032] The ammonium-modified nano-titanium dioxide / carbonic anhydrase composite microparticles include carbonic anhydrase and ammonium-modified nano-titanium dioxide covalently linked to the carbonic anhydrase; the carbonic anhydrase is loaded on the surface of the ammonium-modified nano-titanium dioxide.

[0033] The raw materials of the titanium-based biomass coating provided by the present invention include 2-5% of ammonium-modified nano-titanium dioxide / carbonic anhydrase composite microparticles, preferably 2.5-4%, more preferably 3-3.5%; the particle size of the ammonium-modified nano-titanium dioxide / carbonic anhydrase composite microparticles is preferably 80-100 nm, and the mass ratio of the ammonium-modified nano-titanium dioxide to carbonic anhydrase is preferably 1300-4000:1, more preferably 2000-3500:1, and even more preferably 2300-3000:1.

[0034] In this invention, the preparation method of the ammonified modified nano-titanium dioxide / carbonic anhydrase composite microparticles preferably includes the following steps: mixing ammonified modified nano-titanium dioxide, carbonic anhydrase, phosphate buffer and activator, then centrifuging and drying sequentially to obtain ammonified modified nano-titanium dioxide / carbonic anhydrase composite microparticles.

[0035] In this invention, the mass ratio of the ammonified modified nano-titanium dioxide to the phosphate buffer is preferably 1:10-15, more preferably 1:11-14, and even more preferably 1:12-13; the concentration of the phosphate buffer is preferably 0.01-0.05 mol / L, more preferably 0.02-0.04 mol / L, and even more preferably 0.03 mol / L; the pH value is preferably 5-6, more preferably 5.5-6; and the mass ratio of the carbonic anhydrase to the phosphate buffer is preferably 25-50:10. 6 More preferably, 30–45:10 6 A further preferred ratio is 35–40:10 6 The mass ratio of the activator to the phosphate buffer is preferably 1:150-200, more preferably 1:160-190, and even more preferably 1:170-180.

[0036] In this invention, the carbonic anhydrase was purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd., product model number 9001-03-0.

[0037] In this invention, the activator is preferably 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC). This invention utilizes the activator to activate the carboxyl groups on the surface of carbonic anhydrase and promotes the dehydration condensation of amino groups on the surface of nano-titanium dioxide with the activated carboxyl groups of carbonic anhydrase, thereby forming covalent bonds.

[0038] In this invention, the mixing temperature is preferably 25–35°C, more preferably 30°C, and the pH value is preferably 5–6, more preferably 5.5. The mixing is preferably ultrasonic, with a frequency of 20–25 kHz, more preferably 22–23 kHz, a power of 800–950 W, more preferably 850–900 W, and an ultrasonic time of 0.5–1 h, more preferably 0.6–0.8 h. During the mixing process described above, the amino groups on the surface of nano-titanium dioxide undergo dehydration condensation with the carboxyl groups activated by carbonic anhydrase, forming covalent bonds.

[0039] In this invention, the mixing is preferably performed by first sonicating nano-titanium dioxide, carbonic anhydrase and phosphate buffer, and then sonicating the resulting premix and activator a second time; the first sonication time is preferably 15-30 min, more preferably 20-25 min; the second sonication time is preferably 0.5-1 h, more preferably 0.6-0.8 h.

[0040] In this invention, the obtained solid product is preferably washed after centrifugation; the washing reagent is preferably phosphate buffer; the concentration of the phosphate buffer is preferably 0.01-0.05 mol / L, more preferably 0.02-0.04 mol / L; the number of washings is preferably 2-5 times, more preferably 3 times.

[0041] In this invention, the drying is preferably an oven; the drying equipment is preferably an oven; the drying temperature is preferably 30-50°C, more preferably 35-45°C, and the heat preservation time is preferably 15-20 min, more preferably 17 min.

[0042] In this invention, the preferred method for preparing the ammoniated modified nano-titanium dioxide includes the following steps: mixing a surface modifier, nano-titanium dioxide, and water (referred to as the first mixture) to obtain a slurry; the surface modifier is an alkanolamine compound; the slurry is dried (referred to as the first drying) and then heat-treated to obtain the ammoniated modified nano-titanium dioxide.

[0043] In this invention, the alkanolamine compounds preferably include one or more of diethanolamine, 2-hydroxyethylamine, triisopropanolamine, and triethanolamine.

[0044] In this invention, the mass ratio of the surface modifier to nano-titanium dioxide is preferably 1:3 to 5, more preferably 1:4; the mass ratio of the nano-titanium dioxide to water is preferably 1:20 to 40, more preferably 1:25 to 35.

[0045] In this invention, the nano-titanium dioxide preferably has a rutile crystal form and a particle size preferably of 20–50 nm, more preferably 30–40 nm; the water is preferably deionized water. In a specific embodiment of this invention, the nano-titanium dioxide is preferably purchased from Nanjing Haitai Nanomaterials Co., Ltd., and the product model is preferably HTTi-04-HS-Si.

[0046] In this invention, the first mixing is preferably: stirring a surface modifier and water to obtain a surface-modified solution, and then ultrasonicating the surface-modified solution and nano-titanium dioxide; the stirring is preferably magnetic stirring; the stirring speed is preferably 600-800 r / min, more preferably 650-750 r / min, and the stirring time is preferably 5-15 min, more preferably 8-12 min; the ultrasonic frequency is preferably 20-25 kHz, more preferably 22-24 kHz, the power is preferably 800-950 W, more preferably 850-900 W, and the ultrasonic time is preferably 0.5-1 h, more preferably 0.7-0.8 h.

[0047] In this invention, the first drying device is preferably a spray dryer; the feed rate of the spray dryer is preferably 800-1000 mL / h, more preferably 900-950 mL / h, the inlet air temperature is preferably 150-170℃, more preferably 155-165℃, and the outlet air temperature is preferably 70-90℃, more preferably 75-85℃.

[0048] In this invention, the heat treatment equipment is preferably a reaction vessel and an oven; the heat treatment temperature is preferably 150–180°C, more preferably 160–170°C, and the holding time is preferably 0.5–2 h, more preferably 1 h. During the heat treatment process of this invention, the amino groups in the alkanolamine compounds can undergo a self-catalytic grafting reaction with the surface of nano-titanium dioxide under high temperature conditions, completing the ammoniation modification of the nano-titanium dioxide.

[0049] In this invention, the product obtained after heat treatment is preferably washed and dried (referred to as the second drying); the washing reagent is preferably ethanol; the number of washings is preferably 1 to 4 times, more preferably 3 times; the temperature of the second drying is preferably 70 to 80°C, more preferably 73 to 77°C, and the holding time is preferably 10 to 14 hours, more preferably 12 to 13 hours.

[0050] The aminated modified nano-titanium dioxide prepared in this invention has an amino group grafted onto its surface, providing highly active sites for subsequent reactions and preparing for the covalent bonding of amino groups on the nano-titanium dioxide surface and carboxyl groups on the carbonic anhydrase surface.

[0051] The titanium-based biomass coating provided by this invention comprises 0.4-2% sodium alginate, preferably 0.6-1.2%, and more preferably 0.7-1.0%; wherein the sodium alginate is sodium seaweed alginate. This invention uses sodium alginate, which has good biocompatibility, enabling the coating to have appropriate viscosity, ensuring coatability, preventing particle precipitation in the coating, and extending the shelf life of the coating.

[0052] The raw materials of the titanium-based biomass coating provided by the present invention include a pH adjuster; the amount of the pH adjuster is based on adjusting the pH value of the coating to 9.5-10.5, preferably to 10; the pH adjuster is preferably ammonia water; the mass concentration of the ammonia water is preferably 25-30%, more preferably 28-29%.

[0053] The raw materials for the titanium-based biomass coating provided by this invention include water as a remainder; the water is preferably deionized water.

[0054] This invention also provides a method for preparing the titanium-based biomass coating described above, comprising the following steps:

[0055] Ammoniated modified nano-titanium dioxide / carbonic anhydrase composite microparticles, sodium alginate, and water were mixed to obtain a mixture. The pH of the mixture was then adjusted to 9.5–10.5 using a pH adjuster to obtain a titanium-based biomass coating.

[0056] In this invention, the mixing is preferably carried out by mixing and stirring the ammonified modified nano-titanium dioxide / carbonic anhydrase composite microparticles and water (referred to as the first stirring), followed by ultrasonication to obtain a premixed solution, and then stirring the premixed solution with sodium alginate (referred to as the second stirring) to obtain a mixed solution.

[0057] In this invention, the first stirring is preferably magnetic stirring; the stirring speed of the first stirring is preferably 700-900 r / min, more preferably 750-850 r / min, and the stirring time is preferably 10-20 min, more preferably 15 min.

[0058] In this invention, the frequency of the ultrasound is preferably 20-25 kHz, more preferably 22-24 kHz, the power is preferably 800-950 W, more preferably 850-900 W, and the ultrasound duration is preferably 10-20 min, more preferably 15 min.

[0059] In this invention, the stirring speed of the second stirring is preferably 500-700 r / min, more preferably 550-650 r / min, and the stirring time is preferably 10-15 min, more preferably 11-13 min; the addition rate of sodium alginate during the second stirring process is preferably 0.6-1 g / min, more preferably 0.7-0.8 g / min.

[0060] In this invention, the pH value of the mixture is preferably adjusted to 10 using a pH adjuster.

[0061] The present invention also provides the application of the titanium-based biomass coating described in the above scheme or the titanium-based biomass coating obtained by the preparation method described in the above scheme in cement carbon fixation, wherein the environmental CO2 concentration of the cement carbon fixation is the natural environmental CO2 concentration.

[0062] In this invention, the application of the titanium-based biomass coating in cement carbon fixation preferably includes the following steps: coating the titanium-based biomass coating on the surface of cement-based materials in the plastic stage.

[0063] In this invention, the coating is preferably applied by spraying; the coating time is preferably 6-10 hours after the cement mortar is poured into the mold, more preferably 7-9 hours; the coating amount is preferably 400-500 g / m³. 2 More preferably 450g / m 2 The cement-based material is preferably ordinary silicate cement. This invention coats the surface of the cement-based material with a titanium-based biomass coating during the molding stage, ensuring rapid carbon fixation and a dense surface structure in the early stages of the cement-based material's surface, while inhibiting subsequent continuous carbonization.

[0064] In this invention, the resulting product is preferably coated and cured after coating; the curing time is preferably 1 day.

[0065] To further illustrate the present invention, the following detailed description of the embodiments is provided in conjunction with the present invention, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0066] Example 1

[0067] (1) Weigh diethanolamine, nano titanium dioxide and deionized water. The mass ratio of nano titanium dioxide to deionized water is 1:20 and the mass ratio of diethanolamine to nano titanium dioxide is 1:3. Add diethanolamine to deionized water and stir magnetically until completely dissolved. The stirring time is 8 min and the stirring speed is 650 r / min. Then add nano titanium dioxide and ultrasonically disperse for 40 min. The ultrasonic frequency is 20 kHz and the power is 800 W to obtain a uniformly mixed slurry.

[0068] (2) The slurry is dried using a spray dryer to obtain dried powder. Then the dried powder is poured into a reaction vessel and placed in an oven for heat treatment at 180°C for 2 hours to obtain heat-treated powder. The feed rate of the spray dryer is 800 mL / h, the inlet air temperature is 150°C, and the outlet air temperature is 70°C to obtain heat-treated powder.

[0069] (3) The heat-treated powder was washed with ethanol three times and then dried at 70°C for 10 hours to obtain ammoniated modified nano titanium dioxide powder.

[0070] (4) The ammonified modified nano-titanium dioxide powder and carbonic anhydrase were added to 0.02 mol / L phosphate buffer. The mass ratio of the ammonified modified nano-titanium dioxide powder to the phosphate buffer was 1:10. The carbonic anhydrase was added to the phosphate buffer at a ratio of 25 mg / L. The mixture was sonicated for 15 min to ensure uniform dispersion of the nano-titanium dioxide and carbonic anhydrase. Then, EDC was added at a mass ratio of 1:150 to the phosphate buffer, and the mixture was sonicated for another 35 min. During the above process, the pH value was 5.5, the temperature was 25℃, the sonication frequency was 20 kHz, and the power was 800 W to obtain a mixed solution.

[0071] (5) Centrifuge the mixed solution, wash it three times with 0.03 mol / L phosphate buffer, and dry it in an oven at 35°C for 15 min to obtain ammoniated modified nano-titanium dioxide / carbonic anhydrase composite microparticles.

[0072] (6) Weigh 5g of the ammoniated modified nano-titanium dioxide / carbonic anhydrase composite microparticles and add them to 200g of deionized water. Stir magnetically for 15min at a speed of 750r / min. Turn off the magnetic stirring and turn on the ultrasound at a frequency of 25kHz and a power of 800W. After 10min, turn off the ultrasound and turn on the magnetic stirring again at a speed of 500r / min. Slowly add 0.8g of sodium alginate to the solution and adjust the pH of the solution to 10 with ammonia. After 10min, turn off the magnetic stirring to obtain the titanium-based biomass coating.

[0073] The water-cement ratio used in the experiment was 0.5. After the cement mortar was poured into the mold for 8 hours, the above-mentioned coating was applied to the surface of the cement-based material by spraying, with a coating amount of 400 g / m². 2 After coating, the film is covered and cured. After 1 day, the mold is removed. Except for the coated surface, the other 5 surfaces are sealed with paraffin wax and placed in a carbon fixation collection device to test the carbon fixation. When the test age is reached, the test block is taken out to test the carbonization depth and capillary water absorption.

[0074] Example 2

[0075] (1) Weigh 2-hydroxyethylamine, nano titanium dioxide and deionized water, wherein the mass ratio of nano titanium dioxide to deionized water is 1:30 and the mass ratio of 2-hydroxyethylamine to nano titanium dioxide is 1:3.5; add 2-hydroxyethylamine to deionized water and stir magnetically until completely dissolved for 10 min at a stirring speed of 700 r / min; then add nano titanium dioxide and ultrasonically disperse for 45 min at a frequency of 25 kHz and a power of 850 W to obtain a uniformly mixed slurry;

[0076] (2) The slurry is dried using a spray dryer to obtain dried powder. Then the dried powder is poured into a reaction vessel and placed in an oven for heat treatment at 160°C for 1 hour. The feed rate of the spray dryer is 800 mL / h, the inlet air temperature is 160°C, and the outlet air temperature is 80°C to obtain heat-treated powder.

[0077] (3) The heat-treated powder was washed with ethanol three times and then dried at 75°C for 12 hours to obtain ammoniated modified nano titanium dioxide powder.

[0078] (4) The ammonified modified nano-titanium dioxide powder and carbonic anhydrase were added to 0.03 mol / L phosphate buffer. The mass ratio of nano-titanium dioxide to phosphate buffer was 1:12. Carbonic anhydrase was added to phosphate buffer at a ratio of 35 mg / L. The mixture was sonicated for 20 min to ensure uniform dispersion of nano-titanium dioxide and carbonic anhydrase. Then, EDC with a mass ratio of 1:160 to phosphate buffer was added, and the mixture was sonicated for another 40 min. During the above process, the pH value was 5.5, the temperature was 30℃, the sonication frequency was 25 kHz, and the power was 900 W to obtain a mixed solution.

[0079] (5) Centrifuge the mixed solution, wash it three times with 0.03 mol / L phosphate buffer, and dry it in an oven at 40°C for 15 min to obtain ammoniated modified nano-titanium dioxide / carbonic anhydrase composite microparticles.

[0080] (6) Weigh 6g of the ammoniated modified nano-titanium dioxide / carbonic anhydrase composite microparticles and add them to 200g of deionized water. Stir magnetically for 15min at a speed of 800r / min. Turn off the magnetic stirring and turn on the ultrasound at a frequency of 20kHz and a power of 800W. After 12min, turn off the ultrasound and turn on the magnetic stirring again at a speed of 600r / min. Slowly add 1.6g of sodium alginate to the solution and adjust the pH of the solution to 10 with ammonia. After 12min, turn off the magnetic stirring to obtain the titanium-based biomass coating.

[0081] The water-cement ratio used in the experiment was 0.5. After the cement mortar was poured into the mold for 8 hours, the above-mentioned coating was applied to the surface of the cement-based material by spraying, with a coating amount of 450 g / m².2 After coating, the film is covered and cured. After 1 day, the mold is removed. Except for the coated surface, the other 5 surfaces are sealed with paraffin wax and placed in a carbon fixation collection device to test the carbon fixation. When the test age is reached, the test block is taken out to test the carbonization depth and capillary water absorption.

[0082] Example 3

[0083] (1) Weigh triisopropanolamine, nano titanium dioxide and deionized water, wherein the mass ratio of nano titanium dioxide to deionized water is 1:35 and the mass ratio of triisopropanolamine to nano titanium dioxide is 1:5; add triisopropanolamine to deionized water and stir magnetically until completely dissolved for 15 min at a stirring speed of 800 r / min; then add nano titanium dioxide and ultrasonically disperse for 55 min at a frequency of 25 kHz and a power of 950 W to obtain a uniformly mixed slurry;

[0084] (2) The slurry is dried using a spray dryer to obtain dried powder. The dried powder is then poured into a reaction vessel and placed in an oven for heat treatment at 150°C for 0.8h. The feed rate of the spray dryer is 900mL / h, the inlet air temperature is 150°C, and the outlet air temperature is 90°C to obtain heat-treated powder.

[0085] (3) The heat-treated powder was washed with ethanol three times and then dried at 80°C for 14 hours to obtain ammoniated modified nano titanium dioxide powder.

[0086] (4) Weigh the aminated modified nano-titanium dioxide powder and carbonic anhydrase and add them to 0.05 mol / L phosphate buffer. The mass ratio of the aminated modified nano-titanium dioxide powder to the phosphate buffer is 1:15. The carbonic anhydrase is added to the phosphate buffer at a ratio of 45 mg / L. Sonicate for 30 min to make the nano-titanium dioxide and carbonic anhydrase evenly dispersed. Then add EDC at a mass ratio of 1:200 to the phosphate buffer and continue sonicating for 60 min. During the above process, the pH value is 6, the temperature is 35℃, the sonication frequency is 25 kHz, and the power is 950 W to obtain a mixed solution.

[0087] (5) Centrifuge the mixed solution, wash it three times with 0.03 mol / L phosphate buffer, and dry it in an oven at 45°C for 10 min to obtain ammoniated modified nano-titanium dioxide / carbonic anhydrase composite microparticles.

[0088] (6) Weigh 10g of ammoniated modified nano-titanium dioxide / carbonic anhydrase composite microparticles and add them to 200g of deionized water. Stir magnetically for 20min at a speed of 900r / min. Turn off the magnetic stirring and turn on the ultrasound at a frequency of 25kHz and a power of 950W. After 15min, turn off the ultrasound and turn on the magnetic stirring again at a speed of 700r / min. Slowly add 3g of sodium alginate to the solution and adjust the pH of the solution to 10.5 with ammonia. After 15min, turn off the magnetic stirring to obtain titanium-based biomass coating.

[0089] The water-cement ratio used in the experiment was 0.5. After the cement mortar was poured into the mold for 8 hours, the above-mentioned coating was applied to the surface of the cement-based material by spraying, with a coating amount of 500 g / m². 2 After coating, the film is covered and cured. After 1 day, the mold is removed. Except for the coated surface, the other 5 surfaces are sealed with paraffin wax and placed in a carbon fixation collection device to test the carbon fixation. When the test age is reached, the test block is taken out to test the carbonization depth and capillary water absorption.

[0090] Comparative Example 1

[0091] (1) Weigh 2-hydroxyethylamine, nano titanium dioxide and deionized water, wherein the mass ratio of nano titanium dioxide to deionized water is 1:30 and the mass ratio of 2-hydroxyethylamine to nano titanium dioxide is 1:3.5; add 2-hydroxyethylamine to deionized water and stir magnetically until completely dissolved for 10 min at a stirring speed of 800 r / min; then add nano titanium dioxide and ultrasonically disperse for 40 min at a frequency of 25 kHz and a power of 900 W to obtain a uniformly mixed slurry;

[0092] (2) The slurry is dried using a spray dryer to obtain dried powder. Then the dried powder is poured into a reaction vessel and placed in an oven for heat treatment at 170°C for 2 hours. The feed rate of the spray dryer is 800 mL / h, the inlet air temperature is 160°C, and the outlet air temperature is 80°C to obtain heat-treated powder.

[0093] (3) Weigh 6g of the heat-treated powder and add it to 200g of deionized water. Stir magnetically for 15min at a speed of 800r / min. Turn off the magnetic stirring and turn on the ultrasound at a frequency of 20kHz and a power of 800W. After 12min, turn off the ultrasound and turn on the magnetic stirring again at a speed of 600r / min. Slowly add 1.6g of sodium alginate to the solution and adjust the pH of the solution to 10 with ammonia. After 12min, turn off the magnetic stirring to obtain the coating.

[0094] The water-cement ratio used in the experiment was 0.5. After the cement mortar was poured into the mold for 8 hours, the above-mentioned coating was applied to the surface of the cement-based material by spraying, with a coating amount of 450 g / m².2 After coating, the film is covered and cured. After 1 day, the mold is removed. Except for the coated surface, the other 5 surfaces are sealed with paraffin wax and placed in a carbon fixation collection device to test the carbon fixation. When the test age is reached, the test block is taken out to test the carbonization depth and capillary water absorption.

[0095] Comparative Example 2

[0096] (1) Weigh out unmodified nano-titanium dioxide and carbonic anhydrase and add them to 0.03 mol / L phosphate buffer. The mass ratio of nano-titanium dioxide to phosphate buffer is 1:12. Carbonic anhydrase is added to phosphate buffer at a ratio of 35 mg / L. Sonicate for 15 min to make nano-titanium dioxide and carbonic anhydrase evenly dispersed. Then add EDC at a mass ratio of 1:160 to phosphate buffer and continue sonicating for 40 min. During the above process, the pH value is 5.5, the temperature is 30℃, the sonication frequency is 25 kHz, and the power is 900 W to obtain a mixed solution.

[0097] (2) Centrifuge the mixed solution, wash it three times with 0.03 mol / L phosphate buffer, and dry it in an oven at 40°C for 15 min to obtain composite microparticles;

[0098] (3) Weigh 6g of the composite microparticles and add them to 200g of deionized water. Stir magnetically for 15min at a speed of 800r / min. Turn off the magnetic stirring and turn on the ultrasound at a frequency of 20kHz and a power of 800W. After 12min, turn off the ultrasound and turn on the magnetic stirring again at a speed of 600r / min. Slowly add 1.6g of sodium alginate to the solution and adjust the pH of the solution to 10 with ammonia. After 12min, turn off the magnetic stirring to obtain the coating.

[0099] The water-cement ratio used in the experiment was 0.5. After the cement mortar was poured into the mold for 8 hours, the above-mentioned coating was applied to the surface of the cement-based material by spraying, with a coating amount of 450 g / m². 2 After coating, the film is covered and cured. After 1 day, the mold is removed. Except for the coated surface, the other 5 surfaces are sealed with paraffin wax and placed in a carbon fixation collection device to test the carbon fixation. When the test age is reached, the test block is taken out to test the carbonization depth and capillary water absorption.

[0100] Blank group

[0101] The water-cement ratio used in the experiment was 0.5. The cement mortar was demolded 1 day after being poured into the mold. Except for the top surface, the other 5 sides were sealed with paraffin wax and placed in a carbon fixation collection device to test the carbon fixation. When the test age was reached, the test blocks were taken out to test the carbonation depth and capillary water absorption. The size of the test blocks and the corresponding tests are shown in Table 1. The carbonation depth and carbon fixation of the blank group, Examples 1-3 and Comparative Examples 1-2 were tested at 7 days and 28 days, and capillary water absorption was also tested.

[0102] Table 1. Molding dimensions of specimens from the blank group, Examples 1-3, and Comparative Examples 1-2.

[0103] The test block size corresponds to a 40mm×40mm×160mm specimen for carbonization depth and a 100mm×100mm×100mm specimen for capillary water absorption. surface

[0104] 1. Results of carbonization depth test

[0105] After demolding the test blocks 1 day later, all five sides except the coated surface were sealed with paraffin wax to ensure one-dimensional CO2 diffusion. The test blocks of the blank group, Examples 1-3, and Comparative Examples 1-2 were placed in a sealed carbonization chamber (CO2 concentration constant at 500ppm±0.5%, humidity constant at 70±0.5%, and temperature constant at 30±5℃). They were removed at the specified test ages of 7 days and 28 days. The carbonization depth of the test blocks was tested by spraying 1.5% phenolphthalein indicator on the cross-section. The test results are shown in Table 2.

[0106] Table 2. Carbonization depth (mm) of the test blocks from the blank group, Examples 1-3, and Comparative Examples 1-2.

[0107] Carbonization Time Blank Group Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 27d 1.9 2.6 2.9 2.7 2.0 2.3 28d 4.5 3.1 3.2 3.1 4.0 3.8 surface

[0108] As shown in Table 2, the untreated blank group underwent continuous carbonization, with the carbonization depth increasing continuously in the first 28 days. Compared with the blank group, the carbonization depth of the comparative examples decreased to some extent, but the effect was not significant. Compared with the blank group and comparative examples 1-2, Examples 1-3 showed a faster increase in carbonization depth in the first 7 days, causing the cement-based material to carbonize rapidly. Furthermore, the carbonization depth remained almost unchanged from 7 to 28 days, increasing by only 0.3-0.5 mm. This indicates that the coating of the present invention can accelerate CO2 absorption, causing the cement-based material to carbonize rapidly in the early stages, resulting in a denser surface structure, thereby inhibiting the occurrence of continuous carbonization of the cement-based material in the later stages.

[0109] 2. CO2 absorption test results

[0110] After demolding the test blocks 1 day later, all five sides except the coated surface were sealed with paraffin wax to ensure one-dimensional CO2 diffusion. The test blocks of the blank group, Examples 1-3, and Comparative Examples 1-2 were then placed in a carbon sequestration collection device (CO2 concentration constant at 500ppm±0.5%, humidity constant at 70±0.5%, and temperature constant at 30±5℃). The CO2 absorption was recorded at 3 days and 28 days of testing. The results are shown in Table 3.

[0111] Table 3. CO2 absorption (kg / m2) of test blocks in the blank group, Examples 1-3, and Comparative Examples 1-2

[0112] Carbonization Time Blank Group Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 27d 0.188 0.299 0.315 0.308 0.211 0.225 28d 0.468 0.356 0.368 0.365 0.430 0.412 surface

[0113] As shown in Table 3, at an age of 7 days, the CO2 absorption rate of the blank group test blocks was slow. However, for Examples 1-3, due to the use of carbon-fixing coating, the cement-based materials could rapidly absorb CO2 in the early stage. From 7 to 28 days, the amount of CO2 absorbed was somewhat lower than that of the blank group and Comparative Examples 1-2, but the CO2 absorption rate (considering the carbonization depth) was still higher than that of the blank group and Comparative Examples 1-2. This indicates that the coating of the present invention can not only accelerate the early CO2 absorption of cement-based materials, but also inhibit the occurrence of continuous carbonization of cement-based materials in the later stage due to the increased surface density of cement-based materials.

[0114] 3. Capillary water absorption test results

[0115] Capillary water absorption tests were conducted on cement mortar specimens at 7 days and 28 days of carbonization curing. The cement mortar specimens were dried in a 60℃ oven, and weighed during the drying process. If the weights did not change between two weighings, the capillary water absorption test was performed. The dried cement mortar specimens were placed with the coated side down on a support in a water tank, and the other five sides were sealed with paraffin wax. The water level was no more than 5 mm above the cement mortar specimens. The mass of the specimens was measured after 48 hours of water absorption testing to obtain the capillary water absorption. The results are shown in Table 4.

[0116] Table 4. Capillary water absorption of cement mortar test blocks after 48 hours (g·m³) -2 )

[0117]

[0118] As shown in Table 4, the untreated blank test blocks had a high capillary water absorption rate. The capillary water absorption rate of the test blocks in Comparative Examples 1 and 2 decreased to some extent, while the decrease in capillary water absorption rate of the test blocks in Examples 1 and 3 was significantly increased. Since the capillary water absorption rate of cement-based materials is closely related to the microstructure of cement-based materials, it indicates that the surface porosity of the blank test blocks is high. The use of the coating of the present invention makes the surface of cement-based materials more compact. Moreover, the durability of cement-based materials is also closely related to the transport of liquid water and porosity of cement-based materials. It can be seen that the coating of the present invention can also significantly improve the durability of cement-based materials.

[0119] As can be seen from the above embodiments, the titanium-based biomass coating provided by the present invention can achieve carbon fixation in a low-concentration CO2 environment. It can not only reduce the CO2 concentration in the atmosphere and achieve the purpose of precise carbon fixation, but also the carbonization process occurs in the early stage of cement-based materials, which can specifically promote the rapid carbonization of the surface of cement-based materials and the carbonization depth can be controlled. It can suppress the negative impact of continuous carbonization in the later stage on cement-based materials, improve the mechanical strength and durability of cement-based materials, and can be applied to different cement-based materials such as mortar and concrete to achieve the construction of a favorable carbonization layer and has a good carbon fixation effect.

[0120] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A titanium-based biomass coating, comprising the following raw materials in weight percentages: 2-5% ammonium-modified nano-titanium dioxide / carbonic anhydrase composite microparticles, 0.4-2% sodium alginate, pH adjuster, and water as the balance; wherein the amount of pH adjuster is sufficient to adjust the pH value of the coating to 9.5-10.5; wherein the ammonium-modified nano-titanium dioxide / carbonic anhydrase composite microparticles comprise carbonic anhydrase and ammonium-modified nano-titanium dioxide covalently linked to the carbonic anhydrase; wherein the carbonic anhydrase is loaded on the surface of the ammonium-modified nano-titanium dioxide.

2. The titanium-based biomass coating according to claim 1, characterized in that, The mass ratio of the ammonified modified nano-titanium dioxide to carbonic anhydrase is 1300–4000:

1.

3. The titanium-based biomass coating according to claim 1, characterized in that, The sodium alginate is sodium seaweed.

4. The titanium-based biomass coating according to claim 1, characterized in that, The preparation method of the ammonified modified nano-titanium dioxide / carbonic anhydrase composite microparticles includes the following steps: mixing ammonified modified nano-titanium dioxide, carbonic anhydrase, phosphate buffer and activator, then centrifuging and drying sequentially to obtain ammonified modified nano-titanium dioxide / carbonic anhydrase composite microparticles.

5. The titanium-based biomass coating according to claim 4, characterized in that, The mixing temperature is 25–35°C, and the pH value is 5–6; the mixing is ultrasonic mixing, and the ultrasonic frequency is 20–25 kHz, and the power is 800–950 W.

6. The titanium-based biomass coating according to claim 1 or 2, characterized in that, The preparation method of the ammonium-modified nano-titanium dioxide includes the following steps: mixing a surface modifier, nano-titanium dioxide and water to obtain a slurry; the surface modifier is an alkanolamine compound; the slurry is dried and then heat-treated to obtain ammonium-modified nano-titanium dioxide.

7. The titanium-based biomass coating according to claim 6, characterized in that, The mass ratio of the surface modifier to nano-titanium dioxide is 1:3 to 5; the mass ratio of the nano-titanium dioxide to water is 1:20 to 40.

8. A method for preparing the titanium-based biomass coating according to any one of claims 1 to 7, comprising the following steps: Ammoniated modified nano-titanium dioxide / carbonic anhydrase composite microparticles, sodium alginate, and water were mixed to obtain a mixture. The pH of the mixture was then adjusted to 9.5–10.5 using a pH adjuster to obtain a titanium-based biomass coating.

9. The application of the titanium-based biomass coating according to any one of claims 1 to 7 or the titanium-based biomass coating obtained by the preparation method according to claim 8 in cement carbon fixation, wherein the ambient CO2 concentration of the cement carbon fixation is the natural ambient CO2 concentration.

10. The application according to claim 9, characterized in that, The application of the titanium-based biomass coating in cement carbon fixation includes the following steps: coating the titanium-based biomass coating on the surface of cement-based materials in the plastic stage.

Images