Carbon mineralization material coating, preparation method thereof and application of carbon mineralization material coating in formaldehyde removal

Abstract

The invention relates to a carbon mineralization material coating, a preparation method thereof and application of the carbon mineralization material coating in formaldehyde removal, and the preparation method comprises the following steps: uniformly mixing a carbon mineralization base material, activated carbon and water in parts by mass to obtain slurry; wherein the mass ratio of the carbon mineralization base material to the activated carbon is (4-6): 2; and coating a substrate with the slurry, and performing carbonization maintenance and drying in a CO2-N2 alternate atmosphere to obtain the carbon mineralization material coating. Activated carbon with CO2 reversible adsorption / desorption capacity is introduced into an inorganic carbon mineralization base material, carbonization curing is conducted in a CO2-N2 alternate atmosphere, internal homogeneous conversion is achieved under the synergistic effect of external source and internal source carbonization, and then excellent surface compactness, structural stability and substrate bonding strength are obtained; the activated carbon can also perform physical adsorption and partial chemical capture on free formaldehyde in the environment, so that indoor air purification is realized; the coating system provided by the invention can also generate an aragonite whisker component, thereby being beneficial to obtaining excellent coating toughness.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of carbon mineralization coating, in particular to a carbon mineralization material coating, a preparation method thereof and application thereof in removing formaldehyde. BACKGROUND

[0002] With the widespread use of modern interior decoration materials, volatile organic compounds (VOC) such as formaldehyde have become one of the important sources of indoor air pollution. Formaldehyde is widely present in artificial boards, furniture, composite floorings, wall papers and their adhesive systems, and long-term exposure to a closed or poorly ventilated environment can cause respiratory irritation, allergic reactions and eye discomfort, and other health risks. Therefore, controlling and removing formaldehyde has become an important issue in indoor environmental governance. Existing governance methods mostly rely on external adsorbents or chemical scavengers, which can reduce the concentration in the short term, but have problems such as adsorption saturation requiring replacement, potential risks of decomposition by-products, and inability to cope with continuous release sources, resulting in high overall maintenance costs and unstable effects.

[0003] In the direction of functionalization of building materials, existing technologies attempt to compound photocatalysts and adsorbents in carbonized cementitious systems to make the products have mechanical properties and certain formaldehyde removal capacity. However, these technologies are basically external carbonization, that is, the whole product is placed in a CO2 environment for carbonization and curing after molding, so that the product obtains certain mechanical and functional properties.

[0004] Therefore, existing carbon mineralization reactions are mainly concentrated on the surface layer, but this carbon mineralization method is prone to form pores and stress gradients, and the interface stability is limited. In addition, there are often defects such as mismatch in fineness or porosity or poor compatibility between photocatalysts, adsorbents and building materials, resulting in low toughness of the obtained coating. During manual operation, the coating surface is prone to large-scale cracking, and after single-point damage, there are many cracks or powder falling, and other structural instability phenomena, which is difficult to meet the durability and bonding requirements of the exposed surface for a long time. SUMMARY

[0005] The present application aims to overcome the above technical deficiencies and provide a carbon mineralization material coating, a preparation method thereof and application thereof in removing formaldehyde, to solve the technical problem that the coating layer in the prior art cannot balance the bonding strength, structural stability and indoor air purification capacity.

[0006] To achieve the above technical purpose, the technical solution provided by the present application is as follows: In a first aspect, the present application provides a preparation method of a carbon mineralization material coating, comprising the following steps: S1, uniformly mixing carbon mineralization substrate, activated carbon and water by mass fraction to obtain a slurry; wherein the mass ratio of the carbon mineralization substrate to the activated carbon is (4-6):2; S2, coating the slurry on a substrate, and performing CO2-N2 alternating atmosphere carbonization curing and drying to obtain a carbon mineralization material coating.

[0007] In a second aspect, the present application provides a carbon-mineralized material coating prepared by the above method.

[0008] In a third aspect, the present application provides an application of the above carbon-mineralized material coating in removing formaldehyde.

[0009] Compared with the prior art, the present application has the following beneficial effects: The system of the present application realizes the gradient reaction path of "fast densification of surface layer - continuous curing of inner layer" by introducing activated carbon with CO2 reversible adsorption / desorption capacity into the inorganic carbon-mineralized substrate, combining with CO2-N2 alternating atmosphere carbonization curing, realizes internal homogeneous transformation under the synergistic action of exogenous and endogenous carbonization, and further obtains excellent surface densification, structural stability and substrate bonding strength; the CO2 absorbed by the activated carbon during the carbonization stage can be released slowly to the interior of the coating in the subsequent stage, promoting the secondary carbonization transformation of unreacted phases; after the carbonization is completed, the activated carbon can also physically adsorb and partially chemically capture free formaldehyde in the environment, thereby realizing the indoor air purification function; and through CO2-N2 alternating atmosphere carbonization curing, the coating system of the present application can also generate aragonite whisker components, realize the toughening effect of brittle materials, be beneficial to obtaining excellent coating toughness, and can reduce the area damaged during manual operation. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is a structural schematic diagram of the carbon-mineralized material coating of the present application; Figure 2 is a formaldehyde removal principle schematic diagram of the carbon-mineralized material coating of the present application; Figure 3 is a surface photo of the carbon-mineralized material coating of Example 1 of the present application after being impacted by a nail; Figure 4 is an SEM diagram of the carbon-mineralized fiber generated in the carbon-mineralized material coating of Example 1 of the present application; Figure 5 is a surface photo of the carbon-mineralized material coating of Comparative Example 2 after being impacted by a nail. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0012] In view of the defects that the coating cannot consider the bonding strength, structural stability and indoor air purification capacity at present, the application provides a carbon mineralization material coating and a preparation method and application in formaldehyde removal thereof, takes activated carbon with CO2 reversible adsorption / desorption capacity as a near-field carbon source, is used for continuously recarbonizing maintenance of an inner layer after rapid densification of an outer layer, and makes a part of aragonite whiskers through specific atmosphere alternating maintenance system, increases the toughness of the coating through the introduction of the aragonite whiskers, realizes efficient and controllable maintenance under normal pressure and short time, and the obtained coating considers high bonding strength / structural stability and formaldehyde purification capacity.

[0013] In a first aspect, the application provides a preparation method of a carbon mineralization material coating, comprising the following steps: S1, uniformly mixing carbon mineralization substrates, activated carbon and water according to mass parts to obtain a slurry; wherein the mass ratio of the carbon mineralization substrates to the activated carbon is (4-6):2; S2, coating the slurry on a substrate, and performing CO2-N2 alternating atmosphere carbonization maintenance and drying to obtain the carbon mineralization material coating.

[0014] Preferably, in step S1, the carbon mineralization substrates include one or more of γ-C2S, β-C2S, steel slag and magnesium slag. The carbon mineralization substrates of the application are rich in CO3 2- The reaction Ca / Mg silicate mineral phase powder, such as γ-C2S, β-C2S and the like, can be obtained from industrial grade γ-C2S or metallurgical solid waste (steel slag, magnesium slag and the like) containing free / bound Ca and Mg. This component is the main source of mechanical strength of the coating and bonding force of the substrate.

[0015] Preferably, in step S1, the specific surface area of the carbon mineralization substrates is 450-600 m 2 / kg, and the particle size D 50 is 10-45 μm. The carbon mineralization substrates of the application can be mechanically ground before use, for example, put into a vibration mill for about 60 s, so that the particle size Dmax≤45 μm and the specific surface area index is met, and if necessary, the particle distribution is ensured to be stable through classification, so as to avoid excessive water demand caused by too high proportion of superfine powder; the application controls the specific surface area and particle size of the carbon mineralization substrates, so as to ensure sufficient specific surface area and active sites to support rapid surface carbonization, and ensure reasonable gradation to reduce initial capillary pores and improve densification potential.

[0016] Preferably, in step S1, the activated carbon is selected from porous carbon powder obtained by conventional carbonization-activation of raw materials such as coal, coconut shell or wood, and the internal specific surface area is ≥500 m 2 / g (commonly 500-1500 m 2 / g); the activated carbon used in the present application has developed micro / intermediate pore structure and good chemical stability, absorbs CO2 enriched on the surface layer as a "gas buffer library" during the carbonization stage, and desorbs in the later stage with natural curing, providing near-field CO2 to the inner layer; after carbonization is completed, the surface oxygen-containing functional groups and aromatic π structure are relied on to achieve physical / chemical composite adsorption (mainly van der Waals / π-π interaction and hydrogen bonding) of polar VOCs such as formaldehyde, providing continuous purification function.

[0017] Preferably, in step S1, the ratio of the mass of water to the total mass of carbon mineralization substrate and activated carbon (hereinafter referred to as water-binder ratio) is 0.15-0.4. The present application forms a slurry by adding water to provide flowability and ensure operability during operation; at the same time, the water-binder ratio range takes into account the coating rheology and carbonization pore regulation, and the preferred interval can achieve workability (brushing, rolling) and film density.

[0018] Further preferably, the mass ratio of carbon mineralization substrate to activated carbon is (4.5-5):2 by mass parts; and the water-binder ratio is 0.20-0.40.

[0019] Preferably, in step S1, the slurry is prepared by first uniformly dry mixing the carbon mineralization substrate and activated carbon, and then adding water and stirring uniformly. In the present application, the carbon mineralization substrate and activated carbon are uniformly dry mixed (shear mixing or paddle mixing ≥ 2 min) to ensure uniform dispersion of the activated carbon in the substrate system and avoid local enrichment causing pore defects; after adding water, the slurry is quickly stirred for 1-3 min to form a paste-like slurry with good thixotropy, and the operation is preferably carried out at 20±5°C; if the relative humidity of the environment is <40%, the upper limit of the water-binder ratio can be appropriately increased or the subsequent CO2 contact time can be extended to compensate for evaporation loss. The slurry prepared in the present application has good stable flowability and anti-segregation property during the construction period, and does not significantly bleed water and settle after coating.

[0020] Preferably, in step S2, the coating is uniformly coated using a brush or a roller; the coated surface of the substrate includes a plate surface, a brick surface, a concrete wall surface, a gypsum suspended ceiling or a concrete floor surface, etc. When the coated surface of the substrate is a smooth surface, it should be clean, dry, free of oil stains and hydrophobic layers; porous substrates are recommended to be lightly moistened to reduce the water absorption mutation of the interface.

[0021] Preferably, in step S2, the CO2-N2 alternating atmosphere carbonization curing specifically comprises: first carbonization curing under high humidity conditions for 5-15 min, then carbonization curing under low humidity conditions for 3-8 min; thereafter, the curing conditions are switched to a pure nitrogen atmosphere for curing for 3-8 min; finally, the curing conditions are returned to high humidity conditions for carbonization curing for 4-6 h, to complete the CO2-N2 alternating atmosphere carbonization curing; wherein the high humidity conditions include: CO2 concentration of 10% or more, humidity of 75-85%, and temperature of 50-70 DEG C; and the low humidity conditions include: CO2 concentration of 10% or more, humidity of 35-55%, and temperature of 50-70 DEG C.

[0022] It can be understood that, in the CO2-N2 alternating atmosphere carbonization curing of the present application, each stage mainly includes adjustment of the atmosphere and humidity, and the temperature is unchanged.

[0023] In the present application, first carbonization curing is carried out under high humidity conditions, i.e. spraying a gas containing CO2 on the surface of the wet coating, with a recommended stable flow rate and avoiding strong turbulence, to quickly induce carbonization densification of the surface layer and initially obtain mechanical support. The activated carbon has basically absorbed CO2 at this stage. The wet-dry alternating control is combined: after carbonization under high humidity conditions, the curing is switched to lower humidity curing (compared with the high humidity conditions, this operation is equivalent to entering a drying stage), and then the N2 atmosphere is switched; then the CO2-N2 alternating atmosphere carbonization process is adopted: first carbonization under an atmosphere with a higher CO2 concentration, then switching to an N2 atmosphere to realize atmosphere disturbance, and then returning to CO2 atmosphere carbonization, and finally completing the subsequent curing stage under the CO2 atmosphere. This double-cycle control helps to further improve the CaCO3 crystal orientation and interface densification, so that the activated carbon continuously releases CO2 and drives the homogeneous carbonization of the inner layer, and finally a continuous, dense and firmly bonded coating structure with the substrate is obtained.

[0024] Preferably, the drying is carried out at 50-70 DEG C for 4-6 h.

[0025] In a second aspect, the present application provides a carbon mineralization material coating prepared by the above preparation method.

[0026] In a third aspect, the present application provides a use of the above carbon mineralization material coating in removing formaldehyde.

[0027] The curing and performance formation of the carbon mineralization material coating of the present application mainly result from the coupling process of "external rapid carbonization curing-internal slow release recarbonization". This process mainly controls the variables of CO2 partial pressure gradient and water content, realizes continuous carbon mineralization reaction from the surface and the inside, and in time and space, through the rapid carbonate generation induced by external CO2 on the surface layer and the reversible adsorption-desorption of CO2 by the activated carbon (PAC) dispersed in the system, to achieve the unity of high density, high interface bonding strength and air purification function in the later stage. The main action mechanism is as follows: (1) External curing stage (rapid surface carbonization) CO2 applied to the coating surface first reacts with the alkaline phase in the surface layer, preferentially reacting with Ca in calcium / magnesium silicates. 2 + / Mg 2+ Through interaction with hydroxide phases, carbonate crystal phases are generated (calcium-based systems are mainly calcite, but polymorphs such as aragonite / aragonite can also occur; magnesium-based systems can form magnesite / magnesia carbonate), accompanied by the formation of silica gel / silica-rich phases and pore redistribution. The concentration gradient from the surface to the interior at this stage leads to a transient structure of "dense surface layer - relatively sparse inner layer", which is beneficial for quickly obtaining apparent strength and wear-resistant interface. However, if there is a lack of subsequent inner layer CO2 supply, uncarbonized active phase and pore gradient may remain.

[0028] (2) Internal curing stage (near-field carbonization driven by slow release of activated carbon) The activated carbon embedded in the matrix adsorbs CO2 during external curing and serves as a near-field gas source, continuously releasing CO2 into the surrounding microenvironment through diffusion-desorption during the natural curing period. This "in-situ supply" allows CO2 to preferentially react with adjacent unreacted alkaline sites, promoting homogeneous carbonization and secondary crystal growth in the inner layer, reducing the bimodal characteristics of the pore size distribution and capillary connectivity, significantly alleviating the shrinkage gradient and interfacial stress concentration caused by the difference in surface and interior reactions, thereby improving the overall density of the coating and the adhesion strength of the tested surface.

[0029] (3) Atmosphere alternation stage During the CO2 curing stage, the Ca on the coating surface 2+ With CO3 2- The rapid reaction generates primary CaCO3 crystal nuclei; during the N2 stage, the sudden drop in CO2 partial pressure leads to a local increase in Ca content in the solution. 2+ Re-enrichment induces transient supersaturation in the system; when CO2 is reintroduced, the supersaturation rapidly increases, triggering high-speed nucleation to generate needle-like CaCO3 crystals, i.e., aragonite whiskers. Through alternating CO2–N2 atmosphere carbonization, a carbonized layer with a morphological gradient can be formed under normal pressure: the outer layer consists of needle-like and platy "aragonite-like" crystals, while the inner layer is a dense calcite layer, with the two interwoven to form a composite dense structure. The same principle applies to humidity cycling; under high humidity conditions, Ca… 2+ The concentration of Ca decreases at the reaction interface, while Ca decreases when humidity decreases. 2+ A sharp increase in concentration at the reaction interface also favors the formation of aragonite whiskers. The formation of aragonite requires a CaO. 2+ The enriched state at the reaction interface. Compared with single CO2 carbonization, the structure of this invention showed an increase in bonding strength of about 15–25%, a reduction in surface powder shedding rate to 0%, and maintained structural stability after thermal cycling.

[0030] like Figure 1 andFigure 2 As shown, the carbon mineralization material coating of this invention can be directly brushed onto indoor surfaces such as walls, ceilings, and tabletops. After spraying, the coating will form a layer with highly efficient formaldehyde adsorption function, effectively purifying indoor air and removing harmful substances such as formaldehyde.

[0031] The coating material of this invention has high adhesion performance: it is not easy to fall off during use and can provide good protection for the test surface.

[0032] The coating material of this invention has good durability and stability: the calcium carbonate and other minerals formed by the reaction of carbon minerals in the coating with CO2 help to improve the coating's water resistance, wear resistance and aging resistance.

[0033] The coating material involved in this invention has good environmental benefits: This invention adopts a CO2 curing method under normal pressure, which can not only improve the performance of the coating, but also effectively seal CO2, thereby achieving effective sealing of greenhouse gases and having significant environmental benefits.

[0034] The present invention will be further described in detail below through specific embodiments.

[0035] Example 1 A method for preparing a carbon mineralization material coating includes the following steps: S1, weigh 5 g of gamma-type dicalcium silicate (γ-C2S) and 2 g of activated carbon (PAC), mix them thoroughly by dry mixing; then slowly add 2.5 g of water under stirring conditions and mix well to obtain a slurry; S2. The slurry is evenly sprayed onto the wall surface and carbonized under alternating CO2-N2 atmospheres. The curing conditions are as follows: first, carbonization is carried out for 10 minutes under conditions of 20% CO2 concentration, 80% N2, 80% RH, and 60℃; then, carbonization is carried out for 5 minutes under conditions where the humidity is adjusted to 40% RH; subsequently, the atmosphere is switched to pure N2 atmosphere for 5 minutes to achieve atmospheric disturbance; then, carbonization is carried out again under CO2 atmosphere, and finally, the subsequent curing is completed under CO2 atmosphere (20% CO2 concentration, 80% N2, 80% RH, and 60℃) for 6 hours. After curing, drying is performed at 60℃ for 4 hours. A highly efficient carbon mineralized material coating is thus obtained.

[0036] According to GB / T 16777-2008, the adhesive strength of the obtained carbon mineralization material coating was tested, and the result was approximately 3.82 MPa. After nail impact, as... Figure 3 As shown, there are no obvious cracks around the impact site.

[0037] Because the fibers are more abundant near the wall, a portion of the coating was peeled off layer by layer from the wall, and the portion closest to the wall was scanned by electron microscopy. The results are as follows: Figure 4 As shown, it can be seen that obvious aragonite whiskers are formed inside the coating.

[0038] 0.1 g of coating material was placed in an adsorption tube, and a simulated polluted gaseous airflow with a formaldehyde concentration of 500 ppm, a temperature of 25 °C, and a relative humidity of 60% was introduced at a flow rate of 200 mL / min. The breakthrough saturation point was defined as the outlet concentration reaching 10% of the inlet concentration, and the saturated adsorption capacity was 220.2 mg / g.

[0039] Example 2 A method for preparing a carbon mineralization material coating includes the following steps: S1, weigh 4.5g of gamma-type dicalcium silicate (γ-C2S) and 2g of activated carbon (PAC), mix them thoroughly by dry mixing; then slowly add 2.6g of water under stirring conditions and mix well to obtain a slurry; S2. The slurry is evenly sprayed onto the wall surface and cured under alternating CO2-N2 atmospheres. The curing conditions are as follows: carbonization for 10 minutes at 20% CO2 concentration, 80% N2, 80% RH, and 60℃, followed by a 5-minute carbonization stage at 50% RH; then switching to N2 atmosphere for 5 minutes to create atmospheric disturbance, before returning to CO2 atmosphere for further carbonization. Finally, curing is completed in a CO2 atmosphere (20% CO2 concentration, 80% N2, 80% RH, and 60℃) for 6 hours. After curing, drying is performed at 60℃ for 4 hours. This results in a highly efficient carbon mineralized material coating.

[0040] The adhesive strength of the obtained carbon mineralized material coating was measured, and the result was approximately 3.64 MPa. After impact with a nail, no obvious cracks were found around the impact point.

[0041] 0.1 g of coating material was placed in an adsorption tube, and a simulated polluted gaseous airflow with a formaldehyde concentration of 500 ppm, a temperature of 25 °C, and a relative humidity of 60% was introduced at a flow rate of 200 mL / min. The breakthrough saturation point was defined as the outlet concentration reaching 10% of the inlet concentration, and the saturated adsorption capacity was 218.3 mg / g.

[0042] Comparative Example 1 (without activated carbon) A method for preparing a carbon mineralization material coating includes the following steps: S1, Weigh 3 g of dicalcium silicate, and slowly add 0.75 g of water under stirring conditions (since the activated carbon with high water absorption is removed, the amount of water added is adjusted accordingly to ensure that the viscosity of the resulting slurry is basically consistent), and mix well to obtain the slurry; S2. The slurry is evenly sprayed onto the wall surface and then carbonized and cured in alternating CO2-N2 atmospheres. Specifically, this involves: carbonizing and curing for 10 minutes at a CO2 concentration of 20%, N2 concentration of 80%, RH of 80%, and temperature of 60℃; then switching to a carbonization and curing stage at RH of 50% for 5 minutes; followed by switching to an N2 atmosphere for 5 minutes to create atmospheric disturbance; then returning to a CO2 atmosphere for carbonization and curing; and finally completing the subsequent curing in a CO2 atmosphere (CO2 concentration of 20%, N2 concentration of 80%, RH of 80%, and temperature of 60℃) for 6 hours. After curing, the coating is dried at 60℃ for 4 hours. This yields a carbonized mineral material coating.

[0043] The adhesive strength of the obtained carbon mineralized material coating was measured, and the result was approximately 2.68 MPa. After impact with a nail, no obvious cracks were found around the impact point.

[0044] 0.1 g of coating material was placed in an adsorption tube, and a simulated polluted gaseous airflow with a formaldehyde concentration of 500 ppm, a temperature of 25 °C, and a relative humidity of 60% was introduced at a flow rate of 200 mL / min. The breakthrough saturation point was defined as the outlet concentration reaching 10% of the inlet concentration, and the saturated adsorption capacity was 11.03 mg / g.

[0045] Comparative Example 2 (curing using only a single CO2 atmosphere) A method for preparing a carbon mineralization material coating includes the following steps: S1. Weigh 5g of gamma-type dicalcium silicate (γ-C2S) and 2g of activated carbon (PAC), and mix them thoroughly by dry mixing. Then, under stirring conditions, slowly add 2.5g of water and mix well to obtain a slurry. S2. The slurry is evenly sprayed onto the wall surface, and the sprayed surface is placed in a CO2 environment for curing. The curing conditions are as follows: carbonization curing for 6 hours under the conditions of CO2 concentration of 20%, N2 of 80%, RH of 60%, and temperature of 60℃, to obtain a carbonized mineral material coating.

[0046] The bond strength of the obtained carbon mineralization coating was measured, and the result was approximately 2.38 MPa. After impact with a nail, as... Figure 5 As shown, the surrounding surface shell was damaged by the impact, resulting in obvious cracks and exposing the internal structure.

[0047] 0.1 g of coating material was placed in an adsorption tube, and a simulated polluted gaseous airflow with a formaldehyde concentration of 500 ppm, a temperature of 25 °C, and a relative humidity of 60% was introduced at a flow rate of 200 mL / min. The breakthrough saturation point was defined as the outlet concentration reaching 10% of the inlet concentration, and the saturated adsorption capacity was 44.63 mg / g.

[0048] Comparative Example 3 (Cultivation using constant humidity) The only difference from Example 1 is that the alternating curing atmosphere is kept consistent during the curing process, and the RH is kept constant at 60% only when humidity conditions are involved; the other steps and conditions are the same as in Example 1.

[0049] The results showed that the bond strength was approximately 3.18 MPa. After being impacted by a nail, a small number of cracks appeared on the surface surrounding the impact, indicating that its toughness was poor.

[0050] Comparative Example 4 The only difference from Example 1 is that the amount of activated carbon is adjusted to 3g, while the other steps and conditions are the same as in Example 1.

[0051] The results showed that the obtained carbon mineralized material coating exhibited significant powder shedding.

[0052] As can be seen from the above examples and comparative examples, the present invention, by introducing a specific reactant synergistic system and carbonizing and curing in an alternating CO2-N2 atmosphere, greatly accelerates the coating curing process and significantly improves the final bonding strength, toughness and formaldehyde absorption of the material, fully demonstrating the superiority and effectiveness of the internal homogeneous conversion technology path proposed in this invention.

[0053] In summary, unlike existing technologies, the coating of this invention is a carbon mineralization functional coating for the exposed surface of a substrate. By combining a carbon mineralization substrate with activated carbon particles, under the action of external CO2, the surface layer is first rapidly densified to establish initial mechanical support and a wear-resistant interface. Subsequently, relying on the reversible adsorption / desorption of CO2 by activated carbon, CO2 is slowly released in the near field under natural / mild conditions, driving continuous recarbonization and crystal reconstruction of the inner layer, reducing porosity and stress gradient, and improving the adhesion strength with the substrate. This forms a "rapid surface carbonization and densification with exogenous CO2 + activated carbon (PAC)" coating with reversible adsorption / desorption of CO2 as the core. The invention employs a "close-field slow-release driven inner-layer continuous recarbonization" coupling mechanism. The porous structure and surface functional groups of activated carbon provide continuous physical / chemical adsorption of VOCs such as formaldehyde, achieving long-lasting air purification. Simultaneously, a special curing process regulates the crystal form of calcium carbonate within the coating, forming a reinforced and toughened calcium carbonate complex (aragonite crystal form). This complex absorbs impact during manual damage, preventing large-area wall cracking. The resulting coating balances high bonding strength / structural stability with formaldehyde purification capacity, achieving efficient and controllable curing under normal pressure and short-term conditions. Therefore, this invention, through a synergistic reaction path of rapid outer-layer carbonization and slow-release inner-layer recarbonization, enables the coating to achieve a unified high density, high bonding strength, high toughness, and formaldehyde purification capacity under normal pressure and short-term curing. This invention has a wide range of applications, especially for wall decoration and air purification.

[0054] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a carbon mineralization material coating, characterized in that, Includes the following steps: S1, by mass, the carbon mineralized substrate, activated carbon and water are mixed evenly to obtain a slurry; wherein the mass ratio of the carbon mineralized substrate to the activated carbon is (4~6):2; S2, the slurry is applied to the substrate, and then carbonized and dried in an alternating CO2-N2 atmosphere to obtain a carbon mineralized material coating.

2. The method for preparing the carbon mineralization material coating according to claim 1, characterized in that, In step S1, the carbon mineralization substrate includes one or more of γ-C2S, β-C2S, steel slag, and magnesium slag; The specific surface area of ​​the carbon mineralized substrate is 450–600 m². 2 / kg, D 50 The size ranges from 10 to 45 μm.

3. The method for preparing the carbon mineralization material coating according to claim 1, characterized in that, In step S1, the internal specific surface area of ​​the activated carbon is ≥500m². 2 / g.

4. The method for preparing the carbon mineralization material coating according to claim 1, characterized in that, In step S1, the ratio of the mass of water to the total mass of the carbon mineralization substrate and activated carbon is 0.15 to 0.

4.

5. The method for preparing the carbon mineralization material coating according to claim 1, characterized in that, In step S1, the slurry is prepared by first dry mixing carbon mineralization substrate and activated carbon evenly, and then adding water and stirring evenly.

6. The method for preparing the carbon mineralization material coating according to claim 1, characterized in that, In step S2, the coating is applied evenly using a brush or roller.

7. The method for preparing a carbon mineralization material coating according to claim 1, characterized in that, In step S2, the CO2-N2 alternating atmosphere carbonization curing specifically includes: first carbonizing and curing under high humidity conditions for 5-15 minutes, then carbonizing and curing under low humidity conditions for 3-8 minutes; then switching the curing conditions to pure nitrogen atmosphere for 3-8 minutes; finally returning to high humidity conditions for carbonization and curing for 4-6 hours to complete the CO2-N2 alternating atmosphere carbonization curing. The high humidity conditions include: CO2 concentration above 10%, humidity 75-85%, and temperature 50-70℃; The low humidity conditions include: CO2 concentration above 10%, humidity 35-55%, and temperature 50-70℃.

8. The method for preparing a carbon mineralization material coating according to claim 1, characterized in that, In step S2, the drying process is carried out at 50–70°C for 4–6 hours.

9. A carbon mineralization material coating prepared by the preparation method according to any one of claims 1-8.

10. The application of the carbon mineralization material coating as described in claim 9 in formaldehyde removal.

Images