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CN-121990565-A - Modified graphene dispersion liquid containing high-concentration salt, preparation method and application thereof

CN121990565ACN 121990565 ACN121990565 ACN 121990565ACN-121990565-A

Abstract

The invention discloses a modified graphene dispersion liquid containing high-concentration salt, a preparation method and application thereof, wherein the method firstly carries out acyl chlorination modification on carboxyl groups on graphene oxide, and then a series of modified graphene oxide with controllable grafting cation quantity and density is synthesized through gradual polymerization reaction, so that the synthesis of the cationic modified graphene oxide with controllable structure is realized. The cationic modified graphene oxide can be stably dispersed in a high-concentration salt solution, and the number of cations required on a side chain can be calculated in advance according to specific salt concentration.

Inventors

  • ZHAO BO
  • CAI SHENGYING
  • CHEN CHEN
  • SUN HAIYAN
  • GAO CHAO

Assignees

  • 杭州高烯科技有限公司
  • 浙江大学绍兴研究院

Dates

Publication Date
20260508
Application Date
20251219

Claims (10)

  1. 1. The modified graphene dispersion liquid containing high-concentration salt is characterized by comprising cationic modified graphene oxide, inorganic salt and water, wherein the cationic modified graphene oxide contains side chains with controllable cation numbers, and the controllable cation numbers n on a single side chain meet the following constraint conditions: C*e/{10*(-lg[H])*ρ}≤n≤C*e/{3*(-lg[H])*ρ}; wherein C is the concentration of inorganic salt, the concentration of hydrogen ions in the unmodified graphene oxide aqueous solution with the concentration of [ H ] of 0.1 weight percent, e is the total number of inorganic salt cation charges, and ρ is the concentration of modified graphene.
  2. 2. A method of preparing the modified graphene dispersion of claim 1, comprising the steps of: (1) Dispersing graphene oxide in a solvent, adding excessive thionyl chloride, stirring and reacting for 4-12 hours, centrifuging, and removing supernatant to obtain acyl chloride graphene oxide, wherein the mass ratio of the thionyl chloride to the graphene oxide is not less than 1:1; (2) Dispersing the acyl chloride graphene oxide obtained in the step (1) in a solvent, adding a hydroxy-alkyne compound and an acid-binding agent, stirring and reacting for 4-12 hours, centrifuging, and removing supernatant to obtain alkynyl graphene oxide, wherein the mass ratio of the acyl chloride graphene oxide to the hydroxy-alkyne compound to the acid-binding agent is 1-20:5-200:1-10; (3) Dispersing the alkynylated graphene oxide obtained in the step (2) in a solvent, adding an azide-amine compound and a copper catalyst, stirring and reacting under the protection of inert gas, centrifuging, and collecting a precipitate to obtain tertiary amino graphene oxide, wherein the mass ratio of the alkynylated graphene oxide to the azide-amine compound to the copper catalyst is 1-20:5-200:3-10; (4) Dispersing the tertiary amino graphene oxide obtained in the step (3) in a solvent, adding bromopropylene, stirring and reacting for 2-12 hours, centrifuging, and collecting a precipitate to obtain alkynyl graphene oxide, wherein the mass ratio of the tertiary amino graphene oxide to the bromopropylene is 1-20:5-200; (5) Repeating the step (3) and the step (4) to obtain the cationic modified graphene oxide; (6) Dissolving inorganic salt in a solvent to form an inorganic salt solution, dispersing the cationic modified graphene oxide obtained in the step (5) in the inorganic salt solution to obtain a modified graphene dispersion liquid containing high-concentration salt, wherein the concentration C of the inorganic salt and the number n of cations on the cationic modified graphene oxide satisfy the following formula: C*e/{10*(-lg[H])*ρ}≤n≤C*e/{3*(-lg[H])*ρ}; wherein C is the concentration of inorganic salt, the concentration of hydrogen ions in the unmodified graphene oxide aqueous solution with the concentration of [ H ] of 0.1 weight percent, e is the total number of inorganic salt cation charges, and ρ is the concentration of modified graphene.
  3. 3. The method according to claim 2, wherein the solvent is water, N-dimethylformamide, dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone or a mixture of the above solvents in any ratio.
  4. 4. The process according to claim 2, wherein in step (2) the hydroxy-alkyne compound is selected from the group consisting of ethynyl alcohol, propynyl alcohol, butynyl alcohol, pentynyl alcohol, hexynyl alcohol, heptynyl alcohol, octynyl alcohol and homologs with a main chain comprising more methylene groups.
  5. 5. The method according to claim 2, wherein the acid-binding agent in step (2) is selected from pyridine, triethylamine, dimethylaminopyridine.
  6. 6. The process according to claim 2, wherein the azide-amine compound in step (3) is selected from the group consisting of dimethyl azidoethyl amine, dimethyl azidopropyl amine, dimethyl azidobutyl amine, dimethyl azidopylamine, dimethyl azidohexyl amine, dimethyl azidoheptyl amine, dimethyl azidohexyl amine and homologs having a main chain containing more methylene groups.
  7. 7. The method of claim 2, wherein the copper catalyst in step (3) is selected from the group consisting of cuprous chloride, cuprous bromide, elemental copper.
  8. 8. The method according to claim 2, wherein the concentration of graphene oxide in step (1), acyl chlorinated graphene oxide in step (2), alkynyl graphene oxide in step (3), and tertiary amino graphene oxide in step (4) is 1 to 20mg/mL.
  9. 9. The method according to claim 2, wherein the cation of the inorganic salt is selected from the group consisting of aluminum ion, calcium ion, sodium ion, potassium ion, and the anion is selected from the group consisting of sulfate ion, chloride ion, nitrate ion.
  10. 10. Use of a modified graphene dispersion containing a high concentration of salt according to claim 1.

Description

Modified graphene dispersion liquid containing high-concentration salt, preparation method and application thereof Technical Field The invention belongs to the field of graphene materials, and particularly relates to a modified graphene dispersion liquid containing high-concentration salt, a preparation method and application thereof. Background Graphene oxide has a unique two-dimensional layered structure and rich surface oxygen-containing functional groups (such as carboxyl, epoxy and hydroxyl), and has a wide application prospect in the fields of energy storage, composite materials, biomedicine, separation membranes and the like. Compared with original graphene, graphene oxide has better hydrophilicity and solution processability, and can form stable colloidal dispersion liquid in water. These characteristics make graphene oxide an ideal base material for preparing various functional materials. The graphene oxide has unsatisfactory long-term stability of dispersion liquid under the environment of high-concentration inorganic salt, and is easy to flocculate and settle. These changes not only affect the dispersion stability of graphene oxide, but can also further affect the subsequent functional modification and the properties of the composite. For many application fields, such as fuel cells, ion separation membranes, etc., it is important to develop graphene oxide materials having excellent dispersion stability under heavy salt conditions. In order to improve the dispersibility of graphene oxide in different media, researchers have developed various modification methods, mainly including surfactant modification, silane coupling agent modification, polymer grafting modification, ionic liquid modification and the like. The prior art has the common limitation that a specific molecular structure cannot be designed aiming at a heavy salt environment, and the long-term stability, redispersibility and function retention of the modified graphene oxide under the heavy salt condition are still not ideal. Disclosure of Invention Aiming at the problem that stable dispersion of graphene oxide dispersion liquid under the condition of heavy salt is difficult to prepare in the prior art, the application provides a modified graphene dispersion liquid containing high-concentration salt, a preparation method and application thereof. The application introduces stable cationic groups through molecular design to enhance electrostatic stabilization in heavy salt environments. In a high ion concentration environment, the cationic modified graphene oxide with a proper degree can generate a strong electrostatic repulsive action through the positive charge on the surface of the cationic modified graphene oxide, so that the damage effect of metal salt ions is effectively resisted, and excellent dispersion stability is maintained. For the cationic side chains with controllable sequences, the distance and the number of the cationic side chains can be accurately designed according to specific ion concentration and types, so that the specific structural design under different environments is realized, and uniform and stable dispersion is realized. In addition, the cationic side chain can introduce new functional characteristics, such as ion exchange capacity, antibacterial activity and the like, for the graphene oxide, so that the application field of the graphene oxide is further expanded. One of the technical schemes of the invention is to provide a modified graphene dispersion liquid containing high-concentration salt, which consists of cationic modified graphene oxide, inorganic salt and water, wherein the cationic modified graphene oxide contains side chains with controllable cation numbers, and the controllable cation numbers n on a single side chain meet the following constraint conditions: C*e/{10*(-lg[H])*ρ}≤n≤C*e/{3*(-lg[H])*ρ}; Wherein C is the concentration of inorganic salt, the concentration of hydrogen ions in the unmodified graphene oxide aqueous solution with the concentration of [ H ] of 0.1 weight percent, e is the total number of inorganic salt cation charges, and ρ is the concentration of modified graphene; the concentration unit of the inorganic salt is mg/mL, and the concentration rho unit of the modified graphene is mg/mL. According to different inorganic salt cation concentrations, cationic modified graphene oxide with different numbers of cation grafts on single side chains can be designed and prepared, and dispersed in an inorganic salt solution, and stirred for 2-4 hours to obtain uniform and stable graphene oxide dispersion liquid containing high-concentration salt. The second technical scheme of the invention is to provide a preparation method of the modified graphene dispersion liquid, which comprises the following steps: (1) Dispersing graphene oxide in a solvent, adding excessive thionyl chloride, stirring and reacting for 4-12 hours, centrifuging, and removing supernatant to obtain acyl chloride graphen