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CN-121988285-A - Preparation method of modified activated carbon and application of modified activated carbon in PFASs adsorption

CN121988285ACN 121988285 ACN121988285 ACN 121988285ACN-121988285-A

Abstract

The invention relates to a water treatment technology, and aims to provide a preparation method of modified activated carbon and application of the modified activated carbon in PFASs adsorption. The method comprises the steps of carrying out acid activation treatment on granular activated carbon, washing and drying, dispersing amorphous iron-based alloy powder containing Fe, si and B in ethanol, immersing activated carbon in an inorganic binder, stirring uniformly, adding alloy dispersion liquid for ultrasonic treatment to enable the iron-based alloy and the binder to be uniformly distributed on the surfaces of activated carbon particles, drying a composite material, and roasting in inert atmosphere to obtain granular modified activated carbon. After the activated carbon is modified, the diffusion path is obviously shortened, the adsorption rate can be enhanced, the adsorption rate and capacity of PFASs are improved by small particle size and rich surface active sites, the modified activated carbon has good removal and stabilization effects on the precursor, the GAC-Fe shows excellent performance in the aspect of PFASs in the adsorption AFFF, and the dual purposes of regeneration and pollutant removal can be effectively realized.

Inventors

  • FANG JIANBO
  • CAI PENGTAO
  • ZHAN MINGXIU
  • XU XU
  • FU JIANYING

Assignees

  • 中国计量大学

Dates

Publication Date
20260508
Application Date
20260204

Claims (10)

  1. 1. A method for preparing modified activated carbon, comprising the steps of: (1) Carrying out acid activation pretreatment on granular activated carbon, washing the granular activated carbon with water to be neutral, and drying the granular activated carbon; (2) Dispersing powdery amorphous iron-based alloy containing Fe, si and B in ethanol, and performing ultrasonic treatment to obtain alloy dispersion; (3) Immersing activated carbon into an inorganic binder, stirring uniformly, adding alloy dispersion liquid, and performing ultrasonic treatment to uniformly distribute the iron-based alloy and the binder on the surfaces of the activated carbon particles; (4) And drying the composite material, and then roasting in an inert atmosphere to obtain the granular modified activated carbon.
  2. 2. The method according to claim 1, wherein in the step (1), the particle size of the activated carbon particles is 1.0-1.5 mm, the activated carbon particles are soaked in 1M HCl solution for at least 6 hours during the acid activation pretreatment, and the activated carbon particles are dried at 60-80 ℃ for 12-16 hours after being washed to be neutral by deionized water.
  3. 3. The method according to claim 1, wherein in the step (2), the median particle diameter D50 of the iron-based alloy powder is 50 to 100 μm, the atomic ratio of Fe, si, B in the iron-based alloy is 49 to 54..15 to 17..1.2 to 1.4, and the balance is unavoidable impurities.
  4. 4. The method of claim 1, wherein in step (2), the mass to volume ratio of the iron-based alloy to ethanol in the alloy dispersion is 1g..50mL, and the sonication time is at least 30min.
  5. 5. The method of claim 1, wherein in the step (3), the inorganic binder is a silica sol solution with a mass percentage of 5-10wt%, the mass volume ratio of activated carbon to inorganic binder after activation treatment is 1g..10ml, the addition amount of the alloy dispersion liquid is controlled to enable the iron-based alloy load in the modified activated carbon to be 5-15wt%, and the ultrasonic treatment time is at least 30min.
  6. 6. The method of claim 1, wherein in the step (4), the drying treatment is performed under vacuum condition at 60-80 ℃ for 12-16 hours, the roasting treatment is performed in a tube furnace, and the protection is performed by introducing N 2 at 400-500 ℃ for 1-3 hours.
  7. 7. Use of the modified activated carbon prepared by the method of any one of claims 1 to 6 in PFASs adsorption.
  8. 8. The method for applying modified activated carbon to PFASs adsorption according to claim 7, wherein the modified activated carbon is added into wastewater containing water film-forming foam AFFF, adsorption treatment is carried out under the conditions of stirring at 130-150 rpm and vibration, the temperature is controlled to be 20-35 ℃ for 20-24 hours, and after the treatment is completed, the activated carbon material with saturated adsorption is separated.
  9. 9. The method for regenerating the activated carbon material saturated by adsorption in the application method of claim 8 is characterized in that the activated carbon material saturated by adsorption is added into alkali liquor, hydrothermal reaction is carried out under the stirring condition, the temperature is controlled to 285-325 ℃ for 1-3 hours, the activated carbon material is separated after the reaction is finished, and the activated carbon material is washed to be neutral by water and then dried for standby.
  10. 10. The regeneration method according to claim 10, wherein the alkali solution is NaOH or KOH solution with a concentration of 1 to 3m.

Description

Preparation method of modified activated carbon and application of modified activated carbon in PFASs adsorption Technical Field The invention belongs to the field of water treatment technology and environmental functional materials, and particularly relates to modified activated carbon for efficiently adsorbing and regenerating PFASs-containing wastewater, a preparation method and a regeneration process thereof. Background Perfluoro and polyfluoroalkyl species (Per-and Polyfluoroalkyl Substances, PFASs) are a generic term for artificially synthesized fluorine-containing organic compounds, and are characterized in that the molecule contains one or more stable carbon-fluorine (C-F) bonds, and are also called as permanent chemical substances due to the structure, and are novel persistent organic pollutants which are of great importance in the current scientific and environmental fields. PFASs has attracted extensive attention from scientific and policy formulators, especially because of its toxicity and long-term environmental impact, and has become a major challenge in the world's environmental pollution and public health fields. PFASs not only has high solubility in water, but also its metabolites or precursors further aggravate the pollution problem, so degradation and removal of PFASs become a critical task for current environmental pollution control. Among the various PFASs pollution sources, aqueous Film Forming Foam (AFFF) is a typical and high risk input path, widely used for the suppression of petroleum and chemical fires. The AFFF contains typical PFOS, PFOA and other persistent pollutants, and also contains a large amount of precursor substances with undefined structures and strong conversion potential. At present, the active carbon adsorption technology is widely adopted in engineering to remove PFASs in water, and the technology is one of the mainstream treatment methods due to moderate cost, simple and convenient process and wide application range. However, activated carbon adsorption faces a number of limitations in treating high concentration or high precursor ratio AFFF wastewater. Firstly, PFASs rapidly reduces the treatment efficiency after the adsorption reaches saturation on the surface of the activated carbon, and the adsorbent needs to be frequently replaced or regenerated, so that the pressure of resources and cost is brought. Second, conventional adsorption does not thoroughly destroy PFASs precursors, which even after adsorption, still produce more PFASs through reduction or conversion reactions, thereby impairing abatement. Based on the state of the art, a scheme for preparing brand new modified activated carbon is provided, and has important significance for solving the problems that the activated carbon adsorption technology has pressure on resources and cost and a PFASs precursor cannot be thoroughly destroyed. Disclosure of Invention The invention aims to solve the technical problem of overcoming the defects in the prior art and providing a preparation method of modified activated carbon and application of the modified activated carbon in PFASs adsorption. In order to solve the technical problems, the invention adopts the following solutions: First, a preparation method of modified activated carbon is provided, which comprises the following steps: (1) Carrying out acid activation pretreatment on granular activated carbon, washing the granular activated carbon with water to be neutral, and drying the granular activated carbon; (2) Dispersing powdery amorphous iron-based alloy containing Fe, si and B in ethanol, and performing ultrasonic treatment to obtain alloy dispersion; (3) Immersing activated carbon into an inorganic binder, stirring uniformly, adding alloy dispersion liquid, and performing ultrasonic treatment to uniformly distribute the iron-based alloy and the binder on the surfaces of the activated carbon particles; (4) And drying the composite material, and then roasting in an inert atmosphere to obtain the granular modified activated carbon. In the step (1), the particle size range of the activated carbon particles is 1.0-1.5 mm, during the acid activation pretreatment, 1M HCl solution is adopted for soaking for at least 6 hours, deionized water is used for washing to be neutral, and then the activated carbon particles are dried for 12-16 hours at 60-80 ℃. In the step (2), the median particle diameter D50 of the iron-based alloy powder is 50-100 mu m, the atomic ratio of Fe, si and B in the iron-based alloy is 49-54, 15-17, 1.2-1.4, and the balance is unavoidable impurities. In the step (2), the mass-volume ratio of the iron-based alloy to the ethanol in the alloy dispersion is 1g..50mL, and the ultrasonic treatment time is at least 30min. In the preferred scheme of the invention, in the step (3), the inorganic binder is a silica sol solution with the mass percentage of 5-10wt%, the mass volume ratio of activated carbon to the inorganic binder after activation treatmen