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CN-121974627-A - Microcapsule self-regeneration-based long-acting formaldehyde-removing cement and preparation method thereof

CN121974627ACN 121974627 ACN121974627 ACN 121974627ACN-121974627-A

Abstract

The invention discloses microcapsule self-regeneration-based long-acting formaldehyde-removing cement and a preparation method thereof, belonging to the field of building materials and environmental functional materials. The material consists of silicate cement clinker and a functional composite additive, wherein the additive comprises Zn 2+ modified zeolite, a manganese-based catalyst, pH response slow-release microcapsules and alpha-hemihydrate gypsum. The invention combines the selective adsorption of zeolite, the non-photocatalytic oxidation of manganese-based catalyst in alkaline environment and the self-regeneration of microcapsule triggered by pH to form the closed loop of adsorption-catalysis-regeneration function, thereby realizing the efficient and durable removal of formaldehyde under the condition of no light without damaging the mechanical property of cement matrix. The preparation method is characterized in that the functional components are pre-compounded and then co-ground with the cement clinker, the process is simple, and the preparation method is suitable for industrial production.

Inventors

  • TANG TAO
  • XIA YANQING
  • KANG YANGYANG
  • ZHANG KEYING
  • ZHANG YUQING
  • LIANG ZHIYUAN

Assignees

  • 嘉华特种水泥股份有限公司

Dates

Publication Date
20260505
Application Date
20260129

Claims (10)

  1. 1. The microcapsule self-regeneration-based long-acting formaldehyde-removing cement is characterized by comprising the following components in parts by weight: 100 parts of silicate cement clinker; 9.5-29.5 parts of functional composite additive; wherein the functional composite additive consists of the following components: 5-15 parts of Zn 2+ modified zeolite; 1-5 parts of manganese-based catalyst; 0.5-1.5 parts of pH responsive slow release microcapsule; 3-8 parts of alpha-hemihydrate gypsum.
  2. 2. The microcapsule self-regeneration-based long-acting formaldehyde-removing cement according to claim 1, wherein the Zn 2+ modified zeolite is prepared by carrying out ion exchange reaction on natural zeolite for 1.5-2.5 hours at 70-90 ℃ through ZnCl 2 solution with concentration of 0.3-0.8 mol/L.
  3. 3. The microcapsule self-regeneration-based long-acting formaldehyde-removing cement according to claim 1, wherein the pore diameter of the Zn 2+ modified zeolite is 0.4-0.5nm, and the particle diameter D 50 is less than or equal to 5 μm.
  4. 4. The microcapsule self-regeneration-based long-acting formaldehyde-removing cement according to claim 1, wherein the manganese-based catalyst is a composite particle formed by loading MnO 2 on a nano SiO 2 carrier, and the molar ratio of Mn element to Si element is 1 (1.5-2.5).
  5. 5. The microcapsule self-regeneration-based long-acting formaldehyde-removing cement according to claim 4, wherein the particle size D 90 of the composite particles is less than or equal to 100 nm.
  6. 6. The microcapsule self-regeneration-based long-acting formaldehyde-removing cement according to claim 1, wherein the pH-responsive slow-release microcapsule takes chitosan as a wall material to encapsulate Ca (OH) 2 particles, the molecular weight of the chitosan is 50-100 kDa, and the encapsulation rate of Ca (OH) 2 particles is more than or equal to 85%.
  7. 7. The microcapsule self-regeneration-based long-acting formaldehyde-removing cement according to claim 1, wherein the particle size D 50 of the pH-responsive slow-release microcapsule is 10-50 μm.
  8. 8. A method for preparing the formaldehyde-removing cement according to any one of claims 1 to 7, comprising the steps of: S1, carrying out ion exchange reaction on natural zeolite in ZnCl 2 solution with the mass concentration of 0.3-0.8 mol/L at 70-90 ℃ for 1.5-2.5 hours, washing, drying and grinding the natural zeolite until the particle size D 50 is less than or equal to 5 mu m after the reaction to obtain Zn 2+ modified zeolite; S2, adopting a sol-gel method to deposit MnO 2 on the surface of a nano SiO 2 carrier to obtain a manganese-based catalyst with the molar ratio of Mn element to Si element of 1 (1.5-2.5) and the particle size D 90 of the composite particles of less than or equal to 100 nm; S3, dispersing Ca (OH) 2 particles in chitosan acetic acid solution, and performing spray drying to obtain the pH response type slow release microcapsule with the molecular weight of the chitosan of 50-100 kDa, the coating rate of Ca (OH) 2 of more than or equal to 85 percent and the particle size D 50 of 10-50 mu m; S4, carrying out dry mixing on Zn 2+ modified zeolite, a manganese-based catalyst, a pH response type slow release microcapsule and alpha-hemihydrate gypsum to obtain a homogeneous functional composite additive; S5, grinding the functional composite additive and the silicate cement clinker together until the specific surface area is more than or equal to 350 m 2 /kg, and obtaining the formaldehyde-removing cement.
  9. 9. The preparation method according to claim 8, wherein in S1, the ratio of the ZnCl 2 solution to the natural zeolite is (5-15) mL:1g, in S3, the mass concentration of the chitosan acetic acid solution is 1% -3%, and the ratio of Ca (OH) 2 particles to the chitosan acetic acid solution is (5-20) mL:1g.
  10. 10. The preparation method according to claim 8, wherein in S5, the grinding aid triethanolamine is added during co-grinding, and the addition amount of the triethanolamine is not more than 0.1% of the total mass of the functional composite additive and the Portland cement clinker.

Description

Microcapsule self-regeneration-based long-acting formaldehyde-removing cement and preparation method thereof Technical Field The invention relates to the technical field of building materials and environmental functional materials, in particular to microcapsule self-regeneration-based long-acting formaldehyde-removing cement and a preparation method thereof. Background Formaldehyde is the main volatile organic pollutant generated after interior decoration, and the long-term contact is extremely harmful to human health. At present, main technical paths for endowing building materials with formaldehyde removal function include a physical adsorption method and a photocatalytic oxidation method. Physical adsorption processes typically incorporate porous materials such as activated carbon, diatomaceous earth, zeolites, etc. into a cementitious matrix. For example, chinese patent CN101941821a discloses an activated carbon composite cement that adsorbs formaldehyde using the specific surface area of activated carbon. The method has the obvious defects that the adsorption capacity is limited, the saturation is easy to achieve, the desorption regeneration is not carried out after the saturation, the function is lost, the method can become a secondary pollution source, and the regeneration usually needs high temperature or vacuum and other complex conditions and is difficult to realize on a construction site. The photocatalytic oxidation method mainly uses semiconductor materials such as nano titanium dioxide (TiO 2) and the like to generate strong oxidizing substances under the excitation of ultraviolet rays to decompose formaldehyde. Patent CN116589880a discloses a TiO 2 formaldehyde-removing putty. However, this approach relies heavily on uv light sources, which suddenly drop in efficiency or even fail in indoor no-or low-light environments. In addition, nano TiO 2 is easy to agglomerate and deactivate in a cement high-alkali environment, and can be deactivated due to the fact that the surface is covered by intermediate products after long-term action. Meanwhile, whether the physical adsorption or photocatalysis material is adopted, the interface combination of the functional phase and the cement matrix is weak, defects are easy to be introduced, and the mechanical property of the material is reduced. In summary, it is difficult to realize long-acting, stable and self-regeneration of formaldehyde removal performance of cement-based materials without external energy (such as illumination) and manual intervention in the prior art. Therefore, development of a novel composite cement material integrating efficient adsorption, non-photocatalytic oxidation and intelligent regeneration is needed. Disclosure of Invention The invention aims at overcoming the defects, and the core innovation of the invention is to construct an adsorption-catalysis-regeneration three-in-one function cooperation and circulation regeneration system. The system takes a cement matrix as a structural carrier, through the precise design and dynamic matching of functional components, the selective capture and enrichment of formaldehyde molecules are realized by utilizing modified zeolite, and then in an alkaline medium formed by cement hydration, the non-photocatalytic oxidative degradation of formaldehyde is realized by means of a manganese-based catalyst. The regeneration mechanism can be automatically triggered, and the activity of the material is recovered, so that the formaldehyde removal function with long-acting and maintenance-free performance is realized. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: On the one hand, the long-acting formaldehyde-removing cement based on microcapsule self-regeneration is provided, and comprises the following components in parts by weight: 100 parts of silicate cement clinker; 9.5-29.5 parts of functional composite additive; wherein the functional composite additive consists of the following components: 5-15 parts of Zn 2+ modified zeolite; 1-5 parts of manganese-based catalyst; 0.5-1.5 parts of pH responsive slow release microcapsule; 3-8 parts of alpha-hemihydrate gypsum. Further, the Zn 2+ modified zeolite is prepared by carrying out ion exchange reaction on natural zeolite for 1.5-2.5 hours at 70-90 ℃ through ZnCl 2 solution with the concentration of 0.3-0.8 mol/L. Further, the aperture of the Zn 2+ modified zeolite is 0.4-0.5nm, and the grain diameter D 50 is less than or equal to 5 mu m. Further, the manganese-based catalyst is composite particles formed by loading MnO 2 on a nano SiO 2 carrier, wherein the molar ratio of Mn element to Si element is 1 (1.5-2.5). Further, the particle size D 90 of the composite particles is less than or equal to 100 nm. Further, the pH response type slow release microcapsule takes chitosan as a wall material to wrap Ca (OH) 2 particles, the molecular weight of the chitosan is 50-100 kDa, and the wrapping rate of the C