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CN-121990844-A - High electronegativity silicon carbide flat plate film material and preparation method thereof

CN121990844ACN 121990844 ACN121990844 ACN 121990844ACN-121990844-A

Abstract

The application belongs to the technical field of silicon carbide flat plate films, and particularly provides a high electronegativity silicon carbide flat plate film material and a preparation method thereof. The preparation method of the high electronegativity silicon carbide flat plate film material comprises the following steps: firstly, mixing phytic acid with an organic solvent to prepare a precursor solution, then impregnating a silicon carbide flat membrane matrix with the precursor solution, reacting, then carrying out stage heat treatment, the high electronegativity silicon carbide flat membrane material prepared by the method has higher electronegativity in a wider pH range, higher water permeation flux, less flux attenuation after multiple humic acid pollution-cleaning cycles, and better pollution resistance. When the silica sol is added into the precursor solution, the electronegativity of the silicon carbide flat plate film material can be further improved, so that the pollution resistance of the high electronegativity silicon carbide flat plate film material is further improved.

Inventors

  • ZHANG YUNFEI
  • QI YUANFENG
  • GAO QI
  • SHEN HONGMEI
  • HE JINPING

Assignees

  • 浙江坚膜科技有限公司

Dates

Publication Date
20260508
Application Date
20260409

Claims (10)

  1. 1. The preparation method of the high electronegativity silicon carbide flat plate film material is characterized by comprising the following steps: S1, mixing a phytic acid aqueous solution with a polar organic solvent, and regulating the pH to 2.5-4.0 to obtain a precursor solution; S2, dipping a silicon carbide flat membrane matrix by using a precursor solution, and then carrying out a reaction to obtain a phytic acid modified silicon carbide flat membrane; s3, carrying out stage heat treatment on the phytic acid modified silicon carbide flat membrane, wherein the first stage is to heat up to 180-250 ℃ at the speed of 1-2 ℃ per minute, and keep the temperature for 1-2 hours, the second stage is to heat up to 300-450 ℃ at the speed of 2-3 ℃ per minute, keep the temperature for 1-3 hours, heat up to 600-750 ℃ at the speed of 3-5 ℃ and keep the temperature for 1-2 hours, and naturally cooling after the heat treatment is finished.
  2. 2. The method for preparing a high electronegativity silicon carbide flat plate film material according to claim 1, wherein in the step S1, the polar organic solvent is one or more of ethanol, isopropanol and ethylene glycol; And/or, in the step S1, the mass fraction of the phytic acid in the phytic acid aqueous solution is 10% -90%; and/or, in the step S1, the mass ratio of the phytic acid to the polar organic solvent is 1 (5-20).
  3. 3. The method for preparing a high electronegativity silicon carbide flat plate film material as set forth in claim 1, wherein in the step S2, the reaction condition is that the reaction is carried out under vacuum for 2-6 hours at 60-80 ℃ and then the temperature is raised to 120-180 ℃ at a rate of 2-5 ℃ per minute for 1-3 hours.
  4. 4. The method for preparing the high electronegativity silicon carbide flat plate film material as claimed in claim 1, wherein in the step S2, silicon carbide powder and auxiliary materials are added into water, mixed slurry is prepared through ball milling treatment, and then the mixed slurry is aged at normal temperature, and then the mixed slurry is molded, dried, cut and sintered at high temperature.
  5. 5. The method for preparing a high electronegativity silicon carbide flat plate film material as claimed in claim 4, wherein the mass ratio of the silicon carbide powder to the auxiliary material is 100 (5-25).
  6. 6. The method for preparing a high electronegativity silicon carbide flat plate film material according to claim 4, wherein the auxiliary materials comprise, by weight, 5-20 parts of silica sol, 0.1-6 parts of pore-forming agent, 0.5-3 parts of dispersing agent, 0.5-5 parts of sintering aid and 0.1-1 part of defoaming agent.
  7. 7. The method for preparing a high electronegativity silicon carbide flat plate film material according to claim 6, wherein said pore-forming agent is one or more of glucose powder, starch and polyethylene microspheres.
  8. 8. The method for preparing a high electronegativity silicon carbide flat plate film material as set forth in claim 6, wherein said dispersing agent is one or more of cetyltrimethylammonium bromide, sodium dodecylbenzenesulfonate and polyvinylpyrrolidone.
  9. 9. The method for preparing the high electronegativity silicon carbide flat plate film material according to claim 6, wherein the sintering aid is one or more of graphite, alumina and silicon dioxide, and the defoaming agent is simethicone.
  10. 10. A high electronegativity silicon carbide flat plate film material is characterized by being prepared by the preparation method as set forth in any one of claims 1-9.

Description

High electronegativity silicon carbide flat plate film material and preparation method thereof Technical Field The application belongs to the technical field of silicon carbide flat plate films, and particularly relates to a high electronegativity silicon carbide flat plate film material and a preparation method thereof. Background Silicon carbide has high hardness, excellent chemical resistance, good thermal conductivity and high mechanical strength, and is widely applied to preparing flat membranes, tubular membranes and porous supports. The silicon carbide film has higher stability in the separation process under the environments of high temperature, high pressure, organic solvent and extreme pH value. The Zeta potential of the surface of the silicon carbide flat membrane is a key factor for determining the anti-pollution performance and the interception efficiency of the membrane, and generally, when the surface of the silicon carbide flat membrane has high electronegativity, the adsorption and deposition of negatively charged pollutants on the surface of the membrane can be effectively prevented through electrostatic repulsive interaction, so that higher flux and longer service life are maintained. The silicon carbide flat membrane is usually prepared by a solid-phase sintering method, and the surface of the silicon carbide flat membrane is often covered with an amorphous silicon dioxide layer, and although the silicon dioxide layer can dissociate silanol groups in water to generate certain electronegativity, electronegativity is often insufficient, and in order to improve electronegativity, a polymer with negative charges can be provided by common coating or grafting, but the polymer is easy to fall off, poor in stability and possibly blocks pore channels, so that the flux of the silicon carbide membrane is reduced, and the pollution resistance and the selective separation performance are reduced. Therefore, there is a need to develop a high electronegativity silicon carbide flat plate membrane material with stable structure, strong electronegativity and good durability so as to meet the requirement of high-efficiency separation under a complex system. Disclosure of Invention In order to solve the problems, the application provides a high electronegativity silicon carbide flat plate film material and a preparation method thereof. The application firstly provides a preparation method of a high electronegativity silicon carbide flat plate film material, which comprises the following steps: S1, mixing a phytic acid aqueous solution with a polar organic solvent, and regulating the pH to 2.5-4.0 to obtain a precursor solution; S2, dipping a silicon carbide flat membrane matrix by using a precursor solution, and then carrying out a reaction to obtain a phytic acid modified silicon carbide flat membrane; s3, carrying out stage heat treatment on the phytic acid modified silicon carbide flat membrane, wherein the first stage is to heat up to 180-250 ℃ at the speed of 1-2 ℃ per minute, and keep the temperature for 1-2 hours, the second stage is to heat up to 300-450 ℃ at the speed of 2-3 ℃ per minute, keep the temperature for 1-3 hours, heat up to 600-750 ℃ at the speed of 3-5 ℃ and keep the temperature for 1-2 hours, and naturally cooling after the heat treatment is finished. Further, in the step S1, the polar organic solvent is one or more of ethanol, isopropanol, and ethylene glycol; And/or, in the step S1, the mass fraction of the phytic acid in the phytic acid aqueous solution is 10% -90%; and/or, in the step S1, the mass ratio of the phytic acid to the polar organic solvent is 1 (5-20). Further, in the step S2, the reaction condition is that the reaction is carried out for 2 to 6 hours under the vacuum state at the temperature of 60 to 80 ℃ and then the temperature is raised to 120 to 180 ℃ at the speed of 2 to 5 ℃ per minute, and the reaction is carried out for 1 to 3 hours. In step S2, the silicon carbide flat membrane matrix is prepared by adding silicon carbide powder and auxiliary materials into water, preparing mixed slurry through ball milling treatment, aging the mixed slurry at normal temperature, and then forming, drying, cutting and sintering at high temperature. Further, the mass ratio of the silicon carbide powder to the auxiliary materials is 100 (5-25). Further, the auxiliary materials comprise, by weight, 5-20 parts of silica sol, 0.1-6 parts of pore-forming agent, 0.5-3 parts of dispersing agent, 0.5-5 parts of sintering aid and 0.1-1 part of defoaming agent. Further, the pore-forming agent is one or more of glucose powder, starch and polyethylene microspheres. Further, the dispersing agent is one or more of cetyl trimethyl ammonium bromide, sodium dodecyl benzene sulfonate and polyvinylpyrrolidone. Further, the sintering aid is one or more of graphite, alumina and silicon dioxide. Further, the defoaming agent is simethicone. The application also provides a high electronegativity silicon