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CN-121972167-A - Biochar-based composite catalyst and preparation method and application thereof

CN121972167ACN 121972167 ACN121972167 ACN 121972167ACN-121972167-A

Abstract

A biochar-based composite catalyst and a preparation method and application thereof belong to the technical field of environmental catalysis and comprise the following steps of (1) cleaning waste biochar precursors, calcining, cooling and grinding to obtain a biochar matrix; the preparation method comprises the steps of (1) mixing and stirring the obtained biochar matrix with KOH in water, then drying to obtain a mixed precursor, (3) calcining the obtained mixed precursor to obtain a biochar material B, (4) adding cobalt nitrate, aluminum nitrate and urea into water, stirring and dissolving to obtain a mixed solution, (5) adding the obtained biochar material B into the mixed solution, uniformly mixing and then drying to obtain a composite precursor, and (6) calcining the obtained composite precursor to obtain the biochar-based composite catalyst. The catalyst prepared by the invention has rich pore structure and active site, can catalyze persulfate with high efficiency, enhance electron transfer capability and remarkably improve the catalytic activity of pollutant degradation.

Inventors

  • HONG JUNMING
  • ZHANG RUPING
  • XU WENFENG
  • FENG HAN
  • CHEN MING
  • LIN RONG

Assignees

  • 华侨大学
  • 福建省厦门环境监测中心站(九龙江流域生态环境监测中心)
  • 江西理工大学

Dates

Publication Date
20260505
Application Date
20260119

Claims (9)

  1. 1. The preparation method of the biochar-based composite catalyst is characterized by comprising the following steps of: (1) Cleaning the waste biochar precursor, calcining at 500-600 ℃, cooling and grinding to obtain a biochar matrix; (2) Mixing the biochar matrix obtained in the step (1) with KOH in water, stirring, and then drying to obtain a mixed precursor; (3) Calcining the mixed precursor obtained in the step (2) at 500-600 ℃ to obtain a biochar material B; (4) Adding cobalt nitrate, aluminum nitrate and urea into water according to the molar ratio of (2-4.5): (1.5-2.5): (10-15), and stirring for dissolving to obtain a mixed solution; (5) Adding the biochar material B obtained in the step (3) into the mixed solution obtained in the step (4), uniformly mixing, standing until the upper liquid is transparent clear liquid, and drying to obtain a composite precursor; (6) Calcining the composite precursor obtained in the step (5) at 600-800 ℃ to obtain the biochar-based composite catalyst.
  2. 2. The method for preparing a biochar-based composite catalyst according to claim 1, wherein in the step (1), the calcination time is 1-2 hours.
  3. 3. The method for preparing a biochar-based composite catalyst according to claim 1, wherein in the step (2), the mass ratio of the biochar matrix to KOH is 1:0.8-1.2.
  4. 4. The method for preparing the biochar-based composite catalyst according to claim 1, wherein in the step (2), stirring is performed for 20-28 hours.
  5. 5. The method for preparing a biochar-based composite catalyst according to claim 1, wherein in the step (3), the calcination time is 1-2 hours.
  6. 6. The method for preparing a biochar-based composite catalyst according to claim 1, wherein in the step (6), the calcination time is 1-3 hours.
  7. 7. A biochar-based composite catalyst is characterized by being prepared by the preparation method of any one of claims 1-6.
  8. 8. The method of claim 7, wherein the biochar-based composite catalyst is used for treating organic contaminated water.
  9. 9. The method according to claim 8, wherein the persulfate and the biochar-based composite catalyst are used to form a catalytic system, and the organic pollutants in the water are degraded by activating the persulfate through the biochar-based composite catalyst.

Description

Biochar-based composite catalyst and preparation method and application thereof Technical Field The invention relates to the technical field of environmental catalysis, in particular to a biochar-based composite catalyst and a preparation method and application thereof. Background The persulfate advanced oxidation technology is a high-efficiency water treatment process for degrading organic pollutants based on sulfate radicals. It is generally believed that the bi-metal oxide, due to the synergistic effect of its bi-metal components, is capable of significantly activating the persulfate to generate free radicals, exhibiting superior catalytic performance over the single metal oxide. However, nano-scale bi-metal oxide particles present two significant challenges in practical applications, first, poor cycling stability. In the continuous catalytic reaction and recovery process, the nano particles are easy to agglomerate and run off, so that the catalytic activity is rapidly attenuated. Second, metal ion leaching problems. Particularly in an acidic or neutral water environment, the leaching of the active metal cobalt ions not only can cause secondary pollution, but also can inactivate the catalyst, thereby severely restricting the large-scale application prospect. To solve the above problems, a bimetal oxide may be supported on a porous support. However, the traditional physical mixing or simple impregnation loading method often has the defects of weak binding force and weak loading, and the falling off and leaching of active components can not be effectively inhibited in the reaction process. Disclosure of Invention The invention aims to solve the problems in the prior art and provide a biochar-based composite catalyst with high catalytic activity, good stability and low metal leaching rate, and a preparation method and application thereof. In the high-temperature calcination process, KOH is used as a classical activator to etch the biochar to create a rich pore structure, and more importantly, the KOH is used as an effective adhesive to construct a stable chemical bridge between the metal oxide and the biochar framework. The strong interface coupling effect firmly anchors the active site on the carbon substrate, thereby remarkably enhancing the structural stability of the prepared composite material, greatly reducing the leaching of metal ions, and finally obtaining the composite functional material with high catalytic activity and excellent cycle service life. In order to achieve the above purpose, the invention adopts the following technical scheme: The preparation method of the biochar-based composite catalyst comprises the following steps: (1) Cleaning the waste biochar precursor, calcining at 500-600 ℃, cooling and grinding to obtain a biochar matrix; (2) Mixing the biochar matrix obtained in the step (1) with KOH in water, stirring, and then drying to obtain a mixed precursor; (3) Calcining the mixed precursor obtained in the step (2) at 500-600 ℃ to obtain a biochar material B; (4) Adding cobalt nitrate, aluminum nitrate and urea into water according to the molar ratio of (2-4.5): (1.5-2.5): (10-15), and stirring for dissolving to obtain a mixed solution; (5) Adding the biochar material B obtained in the step (3) into the mixed solution obtained in the step (4), uniformly mixing, standing until the upper liquid is observed to be transparent clear liquid, and drying to obtain a composite precursor; (6) Calcining the composite precursor obtained in the step (5) at 600-800 ℃ to obtain the biochar-based composite catalyst. In the step (1), the temperature rising rate of calcination is 10-20 ℃ per minute, and the calcination time is 1-2 hours. In the step (2), the mass ratio of the biochar matrix to KOH is 1:0.8-1.2. In the step (2), stirring time is 20-28 h. In the step (3), the temperature rising rate of calcination is 10-20 ℃ per minute, and the calcination time is 1-2 hours. In the step (6), the temperature rising rate of calcination is 5-15 ℃ per minute, and the calcination time is 1-3 hours. The biochar-based composite catalyst is prepared by the preparation method. The biochar-based composite catalyst is used for treating organic polluted water. Specifically, a catalyst system is formed by persulfate and a biochar-based composite catalyst, and organic pollutants in water are degraded by activating the persulfate through the biochar-based composite catalyst. The persulfate is peroxymonosulfate such as potassium hydrogen persulfate. The organic pollutant comprises at least one of acetaminophen, cyclohexanone, carbamazepine, metronidazole, naproxen, ciprofloxacin and rhodamine B. The waste biochar precursor comprises peanut shells, straws, wood, leaves and the like. According to the invention, through stirring treatment for a long time of 20-28 hours, the purpose of promoting the complete dispersion and introduction of KOH in the biochar material is achieved, and then the biochar carrier with potassium