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CN-121974342-A - High-hydrophobicity active carbon and preparation method thereof

CN121974342ACN 121974342 ACN121974342 ACN 121974342ACN-121974342-A

Abstract

The invention relates to the field of activated carbon modification, in particular to highly hydrophobic activated carbon and a preparation method thereof. According to the technical scheme, the biomass material is ground, then aluminum salt and/or magnesium salt-containing solution is added to carry out hydrothermal reaction to obtain a hydrothermal precursor, carbonization is carried out under the protection of inert gas after drying to obtain a carbonized precursor, activation is carried out to obtain an activated precursor, and finally high-hydrophobicity activated carbon is obtained after cleaning and drying, wherein in the activation step, steam is firstly introduced to carry out activation reaction on the carbonized precursor, then plasma gas is circularly introduced to carry out further reaction to obtain the activated precursor, and the plasma gas is plasma gas obtained by mixing acetylene and fluorobenzene. The method has the advantages of simple process, no need of complex equipment, short whole preparation process period, low cost, easy industrialization, high hydrophobicity, good oil absorption and large specific surface area of the prepared activated carbon.

Inventors

  • FANG BOREN
  • NI CONGBING
  • DU JUAN
  • GUAN JIALE
  • WEI CHANGQING

Assignees

  • 上海开鸿环保科技有限公司

Dates

Publication Date
20260505
Application Date
20260116

Claims (11)

  1. 1. A preparation method of high-hydrophobicity active carbon is characterized in that biomass materials are ground, then aluminum salt-containing and/or magnesium salt-containing solutions are added for hydrothermal reaction to obtain a hydrothermal precursor, carbonization is carried out under the protection of inert gas after drying to obtain a carbonized precursor, activation is carried out to obtain an activated precursor, and finally the activated precursor is washed and dried to obtain the high-hydrophobicity active carbon; In the activation step, water vapor is firstly introduced to perform an activation reaction on the carbonized precursor, then plasma gas is circularly introduced to perform a further reaction to obtain the activated precursor, wherein the plasma gas is plasma gas obtained by mixing acetylene and fluorinated benzene.
  2. 2. The method for preparing highly hydrophobic activated carbon according to claim 1, wherein in the activation step, the plasma gas is a mixed plasma gas of acetylene and fluorinated benzene in a mixing mass ratio of 1:1-0.3.
  3. 3. The method for preparing highly hydrophobic activated carbon according to claim 1, wherein in the activation step, the flow rate of the circularly introduced plasma gas is controlled to be 3-10g/min, the total amount of the introduced plasma gas is equal to the mass of the biomass material, the reaction time is 0.5-2h, and the temperature is 700-900 ℃.
  4. 4. The method for preparing highly hydrophobic activated carbon according to claim 1, wherein in the activation step, the flow rate of the introduced steam is 10-30g/min, the reaction time is 0.5-24h, and the temperature is 700-900 ℃.
  5. 5. The method for preparing highly hydrophobic activated carbon as claimed in any one of claims 1 to 4, wherein the biomass is at least one of wood, coconut shell or bamboo.
  6. 6. The method of preparing highly hydrophobic activated carbon as claimed in any one of claims 1 to 4, wherein in the hydrothermal reaction step, the aluminum salt is at least one of sodium metaaluminate, aluminum sulfate, aluminum nitrate or alum, and the magnesium salt is at least one of magnesium sulfate, magnesium acetate or magnesium nitrate.
  7. 7. The method for preparing highly hydrophobic activated carbon as claimed in any one of claims 1 to 4, wherein in the hydrothermal reaction step, the mass ratio of water to aluminum salt and/or magnesium salt to biomass material is 100 (0.1 to 1): 2 to 10.
  8. 8. The method for preparing highly hydrophobic activated carbon as claimed in any one of claims 1 to 4, wherein in the hydrothermal reaction step, the hydrothermal reaction is performed under microwave conditions, the microwave treatment power is 500 to 1000W, the pressure of the reaction kettle is 0.1 to 5MPa, and the time is 0.5 to 2 hours.
  9. 9. The method for preparing highly hydrophobic activated carbon as claimed in any one of claims 1 to 4, wherein in the carbonization step, the carbonization temperature is 300 to 800 ℃ and the carbonization time is 3 to 5 hours.
  10. 10. The method for preparing highly hydrophobic activated carbon as claimed in any one of claims 1 to 4, wherein in the washing step, 1mol/L hydrochloric acid solution and 1mol/L sodium bicarbonate solution are used for washing until the pH value of the activated precursor reaches 6.5 to 7.
  11. 11. A highly hydrophobic activated carbon produced by the production method according to any one of claims 1 to 10.

Description

High-hydrophobicity active carbon and preparation method thereof Technical Field The invention relates to the field of activated carbon modification, in particular to highly hydrophobic activated carbon and a preparation method thereof. Background The activated carbon has stronger adsorptivity, and the surface has more functional groups, so that in the process of treating waste gas and wastewater by the activated carbon, the internal absorption pore channels of the activated carbon can reduce the capacity of absorbing other substances and reduce the real adsorption capacity of the activated carbon due to the capillary action and the existence of partial hydrophilic groups. Therefore, it is necessary to modify the surface of the material to increase the hydrophobicity of the material so that the material can absorb more non-aqueous substances. Water is a substance having a relatively high surface energy, so that substances having a lower surface energy than water (e.g., silicon-and fluorine-containing materials) exhibit hydrophobicity, and water is condensed into a sphere at these surfaces. For hydrophobic materials (contact angle >90 °), the rougher the surface, the more hydrophobic. This is because the roughened surface will lock more air, reducing the area of direct contact of water with solids, creating a lotus-like "air cushion effect". For hydrophilic materials (contact angle <90 °), an increase in roughness instead allows water to spread more easily and become more hydrophilic, so by introducing plasma gas for carbonization, increasing the roughness and subjecting the surface thereof to a hydrophobization treatment, the hydrophobicity thereof can be improved. The prior art generally adds a layer of hydrophobic film on the surface of the activated carbon, such as the technical proposal disclosed in CN112796093A and CN 116081623A, but the internal pores of the activated carbon are reduced and the surface area of the activated carbon is reduced by adding hydrophobic substances. CN116474724a discloses a system and method for preparing super-hydrophobic high wear-resistant active carbon. The prepared active carbon is placed in a plasma reactor, and the plasma reactor is filled with modified gas and subjected to dielectric barrier discharge, so that hydrophobic groups of the modified gas and carbon-carbon bonds of the active carbon to be modified are mutually combined after being broken, and a super-hydrophobic layer is formed on the surface of the active carbon to be modified. In this way, the silane is easy to fall off due to the excessively low reaction temperature. Disclosure of Invention The invention aims to solve the technical problems and provide the high-hydrophobicity active carbon with high hydrophobicity, high specific surface area and high oil absorption. The invention also provides a preparation method of the Gao Shushui activated carbon, which is simple in process and low in cost. Grinding a biomass material, adding an aluminum salt-containing solution and/or a magnesium salt-containing solution to perform hydrothermal reaction to obtain a hydrothermal precursor, drying, carbonizing under the protection of inert gas to obtain a carbonized precursor, activating to obtain an activated precursor, and finally cleaning and drying to obtain the high-hydrophobicity active carbon; In the activation step, water vapor is firstly introduced to perform an activation reaction on the carbonized precursor, then plasma gas is circularly introduced to perform a further reaction to obtain the activated precursor, wherein the plasma gas is plasma gas obtained by mixing acetylene and fluorinated benzene. In the activation step, the plasma gas is the plasma gas mixed by acetylene and fluorinated benzene with the mixing mass ratio of 1:1-0.3. In the activation step, the flow speed of circularly introducing plasma gas is controlled to be 3-10g/min, the total introduced amount is equal to the mass of the biomass material, the reaction time is 0.5-2h, and the temperature is 700-900 ℃. In the activation step, the flow rate of the introduced steam is 10-30g/min, the reaction time is 0.5-24h, and the temperature is 700-900 ℃. Activated carbon with different pores is prepared by activating with different steam contents and flow rates. The biomass is at least one of wood, coconut shell or bamboo. In the hydrothermal reaction step, the aluminum salt can be at least one of sodium metaaluminate, aluminum sulfate, aluminum nitrate or alum, the magnesium salt can be at least one of magnesium sulfate, acetic acid or magnesium nitrate, and metal ions of the aluminum/magnesium salt are combined with raw materials in the hydrothermal reaction, so that a rough precursor pore structure is built in advance, and a foundation is laid for subsequent hydrophobicity improvement. In the hydrothermal reaction step, the mass ratio of water to aluminum salt and/or magnesium salt to biomass material is 100 (0.1-1) to 2-10. In the hydrothermal