WO2024251202A1 - 一种赤泥改性制备多孔碳材料的方法及应用 - Google Patents

一种赤泥改性制备多孔碳材料的方法及应用 Download PDF

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WO2024251202A1
WO2024251202A1 PCT/CN2024/097780 CN2024097780W WO2024251202A1 WO 2024251202 A1 WO2024251202 A1 WO 2024251202A1 CN 2024097780 W CN2024097780 W CN 2024097780W WO 2024251202 A1 WO2024251202 A1 WO 2024251202A1
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red mud
carbon material
porous carbon
fluorine
adsorption
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French (fr)
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李彬
张利平
王建城
曾和平
钱文敏
杨花
彭庆收
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Binzhou Weiqiao National Science And Technology Advanced Technology Research Institute
Kunming University of Science and Technology
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Binzhou Weiqiao National Science And Technology Advanced Technology Research Institute
Kunming University of Science and Technology
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/30—Active carbon
    • C01B32/312—Preparation
    • C01B32/318—Preparation characterised by the starting materials
    • C01B32/324—Preparation characterised by the starting materials from waste materials, e.g. tyres or spent sulfite pulp liquor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes

Definitions

  • the present application belongs to the technical field of solid waste resource utilization, and specifically relates to a method for preparing porous carbon materials by modifying red mud and its application.
  • Red mud is a major solid waste generated during the production of alumina. Depending on the quality of alumina and the production process, red mud can be divided into Bayer red mud , sintering red mud and combined red mud. Red mud contains a large amount of metal oxides such as Fe2O3 , Al2O3 and TiO2 , and has the potential to become an effective material for treating atmospheric pollutants.
  • the traditional method of treating red mud is mainly stockpiling, which not only occupies land resources, but also the heavy metals in the red mud will penetrate into the ground through surface water and rainwater leaching, polluting the surrounding soil and causing soil salinization. At the same time, small particles on the surface of red mud will also diffuse into the air, causing air pollution. Therefore, improving its comprehensive utilization rate is the key to solving the problem of large-scale accumulation of red mud.
  • plastic As an organic polymer material, plastic is widely used in industrial production and daily life because of its convenience, low cost, lightness, high strength and corrosion resistance. However, plastic is prone to aging and damage during use, has a short service life, and is difficult to degrade in the natural environment. If untreated waste plastic is directly discharged into the environment, it will cause white pollution and trigger a serious ecological crisis.
  • the main methods for treating plastics include landfill, incineration and pyrolysis. Although landfill is the simplest method, it requires a lot of land resources; and the incineration process will produce a large amount of harmful gases, which will cause secondary pollution if leaked into the air.
  • the emission reduction technologies for PFCs are mainly combustion, cracking, catalysis and adsorption.
  • adsorption is considered to be a promising technology for capturing PFCs due to its low energy consumption, low cost and easy management.
  • porous carbon materials are widely used due to their low preparation cost, large specific surface area, developed pore structure, good chemical and mechanical stability, and relatively easy regeneration.
  • a certain amount of pore structure can be obtained by treating carbon materials with physical or chemical activation methods, physical activation requires very high temperatures and a long time, and the increase in the specific surface area of the activated carbon materials is relatively limited.
  • the carbon materials after chemical activation need to be cleaned to remove the activator residues in the pores, which further increases the cost of the reaction.
  • the treatment of red mud and waste plastics in China in terms of adsorbents mainly focuses on using acid and alkali to treat red mud or activating agents to treat waste plastics to prepare adsorbents.
  • the materials prepared in this way cannot fully utilize the metal oxides, specific surface area and pore structure contained therein, making it difficult to achieve efficient adsorption and purification performance, and it is difficult to achieve the goal of solid waste resource utilization.
  • the present application provides a method for preparing porous carbon materials by combining red mud with plastic modification and for adsorbing and treating fluorine-containing gases.
  • the method adopts a catalytic activation method, utilizes the abundant metal oxides such as Fe2O3 in red mud to dope with carbon materials, and then activates them to increase the surface active points of the micropores inside the carbon materials, so that the micropores are transformed into mesopores, thereby improving the adsorption effect of the porous carbon adsorbent and achieving the effect of purifying the fume of electrolytic aluminum.
  • the present application uses red mud and waste plastic bottles as raw materials, and through simple carbonization and activation, the prepared porous carbon adsorbent has better adsorption properties, which can not only remove PFCs in the flue gas of electrolytic aluminum, but also reduce the pollution of red mud to the environment and realize the resource utilization of red mud. At the same time, it realizes the environmentally friendly utilization of waste within the aluminum industry, reduces the cost of environmental governance, and achieves the purpose of synergistic efficiency improvement of pollution reduction and carbon reduction.
  • a method for preparing porous carbon material by modifying red mud the specific steps are as follows:
  • the citric acid in the citric acid solution in step (1) accounts for 1-10% of the mass of the red mud powder.
  • the main component of the waste plastic bottles in step (2) is polyethylene (PE).
  • the carbonization in step (2) is: heating to 450-600°C at a heating rate of 5°C/min and calcining for 3h under N2 atmosphere.
  • the mass ratio of the carbon material to the red mud powder is 1:2-4.
  • the rotation speed of the magnetic stirring in step (1) and step (2) is independently 300-500 rpm; and the equipment for magnetic stirring is a magnetic stirrer.
  • the vacuum drying temperature in step (3) is 60-80° C., and the vacuum drying time is 12 h.
  • the calcination activation in step (3) is: heating to 500-800°C at a heating rate of 5°C/min under N2 atmosphere and calcining for 3h.
  • the present application also provides an application of the red mud-based porous carbon material prepared by the method described in the above technical scheme for adsorbing and treating fluorine-containing gases, and the application is: placing the red mud-based porous carbon material in a fixed bed reactor, pretreating it at 300°C for 2h under a N2 atmosphere, passing fluorine-containing gas after cooling to 120°C, and performing adsorption purification. After the red mud-based porous carbon material is saturated with adsorption, heating it to 150°C for desorption, collecting the desorbed gas, and using the red mud-based porous carbon material again as an adsorption material after desorption to adsorb and purify the fluorine-containing gas.
  • the fluorine-containing gas includes 2% C 2 F 6 , 2% CF 4 , 2% CO 2 , and 94% N 2 .
  • the flow rate of the fluorine-containing gas is 200 mL/min.
  • the desorption is N2 purging desorption; and the desorption time is 3h.
  • the adsorption amount of perfluorocarbon by the red mud-based porous carbon material is 1.75 mmol/g, 2.15 mmol/g, 2.45 mmol/g, 2.48 mmol/g, 2.34 mmol/g, 2.54 mmol/g or 1.90 mmol/g.
  • the fluorine-containing gas is aluminum electrolysis fume.
  • the present application uses red mud loaded carbonized plastic to prepare porous carbon materials for adsorbing and treating PFCs in electrolytic aluminum flue gas. Compared with adsorption materials prepared using red mud or waste plastic alone, this has better effects, not only improving the PFCs removal rate, but also reducing the generation of HF and CO2 gases, thus providing a new method for the resource utilization of red mud.
  • porous carbon material prepared in the present application adsorbs PFCs
  • high-concentration PFCs can be obtained through adsorption-desorption, which can reduce the energy consumption of subsequent treatments such as plasma decomposition and thermal catalysis.
  • This application converts waste plastic bottles into carbon materials as carriers, and then loads the metal oxides in red mud It increases the surface area of the material and the selectivity of the gas, alleviating the impact of waste plastics on the environment.
  • the present application utilizes the method of “treating waste with waste”, which not only improves the utilization rate of red mud and plastics, but also reduces process costs and reduces pollution to the environment.
  • FIG1 is a process flow chart of red mud modification to prepare porous carbon materials for treating fluorine-containing gases.
  • the red mud used in the examples of the present application comes from an aluminum company in Wenshan City, Yunnan province.
  • a method for preparing porous carbon materials by modifying red mud and its application in adsorbing and treating fluorine-containing gases, as shown in FIG1 has the following specific steps:
  • Red mud from an aluminum company in Wenshan City, Yunnan province was placed in an oven at 100°C and dried to constant weight, and then ground to pass through a 100-mesh sieve to obtain red mud powder for use; then an appropriate amount of the red mud powder was taken into a beaker, and a citric acid solution was added for acid treatment, wherein the citric acid in the citric acid solution accounted for 1% of the mass of the red mud powder to remove alkali metals and adhesive components in the red mud, and the red mud was placed in a magnetic stirrer and stirred at room temperature for 20 minutes at a speed of 300 rpm, and then filtered and washed with deionized water until the pH was neutral to obtain a red mud slurry for use;
  • step (3) The carbon material obtained in step (2) is added to the red mud slurry in a mass ratio of 1:2 with the red mud powder obtained in step (1) and mixed.
  • the mixture is placed in a magnetic stirrer and stirred at room temperature for 2 h at a rotation speed of 300 rpm.
  • the formed mixture is placed in a vacuum drying oven at 60°C for 12 h to remove moisture.
  • the dried mixture is then placed in a tubular furnace under a N2 atmosphere and heated to 500°C at a heating rate of 5°C/min and calcined for 3 h. After the calcination temperature is cooled to room temperature, a red mud-based porous carbon material is obtained.
  • the red mud-based porous carbon material was placed in a fixed bed reactor and pretreated at 300°C for 2 h under N 2 atmosphere. After cooling to 120°C, a fluorine-containing mixed gas (2% C 2 F 6 , 2% CF 4 , 2% CO 2 , 94% N 2 ) was introduced at a gas flow rate of 200 mL/min. The outlet gas was tested for PFCs using a flue gas analyzer. When the outlet concentration was the same as the inlet concentration and no longer changed, adsorption saturation was achieved. Then the fixed bed reactor was placed in a fixed bed reactor and the adsorption was carried out. The temperature of the reactor was raised to 150°C, and N2 was purged and desorbed for 3 hours.
  • a fluorine-containing mixed gas 2% C 2 F 6 , 2% CF 4 , 2% CO 2 , 94% N 2
  • the desorbed PFCs were detected by a flue gas analyzer.
  • the adsorption amount of PFCs by the carbon material adsorbent was 1.75 mmol/g. It was also found that the desorbed carbon material was still very effective in purifying fluorine-containing gases when used as an adsorption material again.
  • a method for preparing porous carbon materials by modifying red mud and its application in adsorbing and treating fluorine-containing gases the specific steps are as follows:
  • Red mud from an aluminum company in Wenshan City, Yunnan province was placed in an oven at 100°C and dried to constant weight, and then ground to pass through a 100-mesh sieve to obtain red mud powder for use; then an appropriate amount of the red mud powder was taken into a beaker, and a 0.05 mol/L citric acid solution was added for acid treatment, wherein the citric acid in the citric acid solution accounted for 5% of the mass of the red mud powder to remove alkali metals and adhesive components in the red mud, and the red mud was placed in a magnetic stirrer and stirred at room temperature for 20 minutes at a speed of 300 rpm, and then filtered and washed with deionized water until the pH was neutral to obtain a red mud slurry for use;
  • step (3) The carbon material obtained in step (2) is added to the red mud slurry in a mass ratio of 1:2 with the red mud powder obtained in step (1), and the mixture is placed in a magnetic stirrer and stirred at room temperature for 2 h at a rotation speed of 300 rpm. After being fully mixed, the formed mixture is placed in a vacuum drying oven at 60°C for 12 h to remove moisture. The dried mixture is then placed in a tubular furnace under a N2 atmosphere, heated to 500°C at a heating rate of 5°C/min, and calcined for 3 h. After the calcination temperature is cooled to room temperature, a red mud-based porous carbon material is obtained.
  • the red mud-based porous carbon material was placed in a fixed bed reactor and pretreated at 300° C for 2h under N2 atmosphere. After cooling to 120°C, a fluorine-containing mixed gas (2% C2F6 , 2% CF4 , 2% CO2 , 94% N2 ) was introduced at a gas flow rate of 200mL/min for an adsorption experiment.
  • the outlet gas was detected for PFCs using a flue gas analyzer. When the outlet concentration was the same as the inlet concentration and no longer changed, adsorption saturation was reached.
  • the temperature of the fixed bed reactor was then raised to 150°C, and N2 was purged and desorbed for 3h. The desorbed PFCs were detected by the flue gas analyzer.
  • the adsorption amount of PFCs by the carbon material adsorbent was 2.15mmol/g. It was also found that the desorbed carbon material was still very effective as an adsorbent material for purifying fluorine-containing gases.
  • a method for preparing porous carbon materials by modifying red mud and its application in adsorbing and treating fluorine-containing gases the specific steps are as follows:
  • Red mud from an aluminum company in Wenshan City, Yunnan province was placed in an oven and dried at 100°C to constant weight.
  • the red mud powder is ground and passed through a 100-mesh sieve to obtain a red mud powder for use; then an appropriate amount of the red mud powder is taken into a beaker, and a citric acid solution with a concentration of 0.05 mol/L is added for acid treatment, wherein the citric acid in the citric acid solution accounts for 10% of the mass of the red mud powder, and the alkali metal and adhesive components in the red mud are removed, and the red mud is placed in a magnetic stirrer and stirred at room temperature for 20 minutes at a speed of 300 rpm, and then filtered and washed with deionized water until the pH is neutral to obtain a red mud slurry for use;
  • step (3) The carbon material obtained in step (2) is added to the red mud slurry in a mass ratio of 1:2 with the red mud powder obtained in step (1), and the mixture is placed in a magnetic stirrer and stirred at room temperature for 2 h at a rotation speed of 300 rpm. After being fully mixed, the formed mixture is placed in a vacuum drying oven at 60°C for 12 h to remove moisture. The dried mixture is then placed in a tubular furnace under a N2 atmosphere, heated to 500°C at a heating rate of 5°C/min, and calcined for 3 h. After the calcination temperature is cooled to room temperature, a red mud-based porous carbon material is obtained.
  • the red mud-based porous carbon material was placed in a fixed bed reactor and pretreated at 300° C for 2h under N2 atmosphere. After cooling to 120°C, a fluorine-containing mixed gas (2% C2F6 , 2% CF4 , 2% CO2 , 94% N2 ) was introduced at a gas flow rate of 200mL/min for an adsorption experiment.
  • the outlet gas was detected for PFCs using a flue gas analyzer. When the outlet concentration was the same as the inlet concentration and no longer changed, adsorption saturation was reached.
  • the temperature of the fixed bed reactor was then raised to 150°C, and N2 was purged and desorbed for 3h. The desorbed PFCs were detected by the flue gas analyzer. The adsorption amount of PFCs by the carbon material adsorbent was 2.45mmol/g. It was also found that the desorbed carbon material was still very effective as an adsorbent material for purifying fluorine-containing gases.
  • a method for preparing porous carbon materials by modifying red mud and its application in adsorbing and treating fluorine-containing gases the specific steps are as follows:
  • Red mud from an aluminum company in Wenshan City, Yunnan province was placed in an oven at 110° C. and dried to constant weight, and then ground to pass through a 100-mesh sieve to obtain red mud powder for use; then an appropriate amount of the red mud powder was taken into a beaker, and a 0.05 mol/L citric acid solution was added for acid treatment, wherein the citric acid in the citric acid solution accounted for 5% of the mass of the red mud powder to remove alkali metals and adhesive components in the red mud, and the red mud was placed in a magnetic stirrer and stirred at room temperature for 25 minutes at a speed of 400 rpm, and then filtered and washed with deionized water until the pH was neutral to obtain a red mud slurry for use;
  • step (3) The carbon material obtained in step (2) is added to the red mud slurry in a mass ratio of 1:3 to the red mud powder obtained in step (1), and the mixture is placed in a magnetic stirrer and stirred at room temperature for 3 hours at a rotation speed of 400 rpm. After sufficient mixing, the formed mixture is placed in a vacuum drying oven at 70°C for 12 hours to remove moisture. The dried mixture is then placed in a tubular furnace under a N2 atmosphere, and the temperature is increased to 500°C at a heating rate of 5°C/min and calcined for 3 hours. After the calcination temperature is cooled to room temperature, a red mud-based porous carbon material is obtained.
  • the red mud-based porous carbon material was placed in a fixed bed reactor and pretreated at 300° C for 2h under N2 atmosphere. After cooling to 120°C, a fluorine-containing mixed gas (2% C2F6 , 2% CF4 , 2% CO2 , 94% N2 ) was introduced at a gas flow rate of 200mL/min for an adsorption experiment.
  • the outlet gas was detected for PFCs using a flue gas analyzer. When the outlet concentration was the same as the inlet concentration and no longer changed, adsorption saturation was reached.
  • the temperature of the fixed bed reactor was then raised to 150°C, and N2 was purged and desorbed for 3h. The desorbed PFCs were detected by the flue gas analyzer.
  • the adsorption amount of PFCs by the carbon material adsorbent was 2.48mmol/g. It was also found that the desorbed carbon material was still very effective as an adsorbent material for purifying fluorine-containing gases.
  • a method for preparing porous carbon materials by modifying red mud and its application in adsorbing and treating fluorine-containing gases the specific steps are as follows:
  • Red mud from an aluminum company in Wenshan City, Yunnan province was placed in an oven at 110° C. and dried to constant weight, and then ground to pass through a 100-mesh sieve to obtain red mud powder for use; then an appropriate amount of the red mud powder was taken into a beaker, and a 0.05 mol/L citric acid solution was added for acid treatment, wherein the citric acid in the citric acid solution accounted for 5% of the mass of the red mud powder to remove alkali metals and adhesive components in the red mud, and the red mud was placed in a magnetic stirrer and stirred at room temperature for 25 minutes at a speed of 400 rpm, and then filtered and washed with deionized water until the pH was neutral to obtain a red mud slurry for use;
  • step (3) The carbon material obtained in step (2) is added to the red mud slurry in a mass ratio of 1:4 to the red mud powder obtained in step (1), and the mixture is placed in a magnetic stirrer and stirred at room temperature for 3 h at a rotation speed of 400 rpm. After sufficient mixing, the formed mixture is placed in a vacuum drying oven at 70°C for 12 h to remove moisture. The dried mixture is then placed in a tubular furnace under a N2 atmosphere, and the temperature is increased to 500°C at a heating rate of 5°C/min and calcined for 3 h. After the calcination temperature is cooled to room temperature, a red mud-based porous carbon material is obtained.
  • the red mud-based porous carbon material was placed in a fixed bed reactor and pretreated at 300°C for 2 h under N 2 atmosphere. After cooling to 120°C, a fluorine-containing mixed gas (2% C 2 F 6 , 2% CF 4 , 2% CO 2 , 94% N 2 ) was introduced. The rate was 200mL/min, and the adsorption experiment was carried out. The outlet gas was detected for PFCs using a flue gas analyzer. When the outlet concentration was the same as the inlet concentration and no longer changed, the adsorption saturation was reached. Then the temperature of the fixed bed reactor was increased to 150°C, and N2 was purged and desorbed for 3 hours. The desorbed PFCs were detected by the flue gas analyzer. The adsorption amount of PFCs by the carbon material adsorbent was 2.34mmol/g. At the same time, it was found that the desorbed carbon material was still very effective as an adsorption material for purifying fluorine-containing gases
  • a method for preparing porous carbon materials by modifying red mud and its application in adsorbing and treating fluorine-containing gases the specific steps are as follows:
  • Red mud from an aluminum company in Wenshan City, Yunnan province was placed in an oven at 115°C and dried to constant weight, and then ground to pass through a 100-mesh sieve to obtain red mud powder for use; then an appropriate amount of the red mud powder was taken into a beaker, and a citric acid solution with a concentration of 0.05 mol/L was added for acid treatment, wherein the citric acid in the citric acid solution accounted for 5% of the mass of the red mud powder to remove alkali metals and adhesive components in the red mud, and the red mud was placed in a magnetic stirrer and stirred at room temperature for 30 minutes at a speed of 500 rpm, and then filtered and washed with deionized water until the pH was neutral to obtain a red mud slurry for use;
  • step (3) The carbon material obtained in step (2) is added to the red mud slurry in a mass ratio of 1:3 with the red mud powder obtained in step (1) and mixed.
  • the mixture is placed in a magnetic stirrer at room temperature for 4 hours at a rotation speed of 500 rpm. After sufficient mixing, the formed mixture is placed in a vacuum drying oven at 80°C for 12 hours to remove moisture. The dried mixture is then placed in a tubular furnace under a N2 atmosphere and heated to 650°C at a heating rate of 5°C/min and calcined for 3 hours. After the calcination temperature is cooled to room temperature, a red mud-based porous carbon material is obtained.
  • the red mud-based porous carbon material was placed in a fixed bed reactor and pretreated at 300° C for 2h under N2 atmosphere. After cooling to 120°C, a fluorine-containing mixed gas (2% C2F6 , 2% CF4 , 2% CO2 , 94% N2 ) was introduced at a gas flow rate of 200mL/min for an adsorption experiment.
  • the outlet gas was detected for PFCs using a flue gas analyzer. When the outlet concentration was the same as the inlet concentration and no longer changed, adsorption saturation was reached.
  • the temperature of the fixed bed reactor was then raised to 150°C, and N2 was purged and desorbed for 3h. The desorbed PFCs were detected by the flue gas analyzer. The adsorption amount of PFCs by the carbon material adsorbent was 2.54mmol/g. It was also found that the desorbed carbon material was still very effective as an adsorbent material for purifying fluorine-containing gases.
  • a method for preparing porous carbon material by modifying red mud and its application in adsorbing and treating fluorine-containing gas comprising the following steps: The steps are as follows:
  • Red mud from an aluminum company in Wenshan City, Yunnan province was placed in an oven at 115°C and dried to constant weight, and then ground to pass through a 100-mesh sieve to obtain red mud powder for use; then an appropriate amount of the red mud powder was taken into a beaker, and a citric acid solution with a concentration of 0.05 mol/L was added for acid treatment, wherein the citric acid in the citric acid solution accounted for 5% of the mass of the red mud powder to remove alkali metals and adhesive components in the red mud, and the red mud was placed in a magnetic stirrer and stirred at room temperature for 30 minutes at a speed of 500 rpm, and then filtered and washed with deionized water until the pH was neutral to obtain a red mud slurry for use;
  • step (3) The carbon material obtained in step (2) is added to the red mud slurry in a mass ratio of 1:3 with the red mud powder obtained in step (1), and the mixture is placed in a magnetic stirrer and stirred at room temperature for 4 hours at a rotation speed of 500 rpm. After being fully mixed, the formed mixture is placed in a vacuum drying oven at 80°C for 12 hours to remove moisture. The dried mixture is then placed in a tubular furnace under a N2 atmosphere, and the temperature is increased to 800°C at a heating rate of 5°C/min and calcined for 3 hours. After the calcination temperature is cooled to room temperature, a red mud-based porous carbon material is obtained.
  • the red mud-based porous carbon material was placed in a fixed bed reactor and pretreated at 300° C for 2h under N2 atmosphere. After cooling to 120°C, a fluorine-containing mixed gas (2% C2F6 , 2% CF4 , 2% CO2 , 94% N2 ) was introduced at a gas flow rate of 200mL/min for an adsorption experiment.
  • the outlet gas was detected for PFCs using a flue gas analyzer. When the outlet concentration was the same as the inlet concentration and no longer changed, adsorption saturation was reached.
  • the temperature of the fixed bed reactor was then raised to 150°C, and N2 was purged and desorbed for 3h. The desorbed PFCs were detected by the flue gas analyzer. The adsorption amount of PFCs by the carbon material adsorbent was 1.90mmol/g. It was also found that the desorbed carbon material was still very effective as an adsorbent material for purifying fluorine-containing gases.
  • the red mud slurry prepared in Example 6 was filtered and placed in a vacuum drying oven at 80°C for 12h, then placed in a tubular furnace under N2 atmosphere, heated to 600°C at a heating rate of 5°C/min and calcined for 3h to obtain a red mud-based adsorbent, which was placed in a fixed bed reactor and pretreated at 300°C for 2h under N2 atmosphere.
  • a fluorine-containing mixed gas 2% C2F6 , 2% CF4 , 2% CO2 , 94% N2
  • the outlet gas was tested for PFCs using a flue gas analyzer.
  • the carbon material prepared in Example 6 was mixed with KOH with a concentration of 0.05 mol/L in a mass ratio of 1:3. The mixture was placed in a magnetic stirrer and stirred at room temperature for 1 h at a speed of 500 rpm. After being fully mixed, it was placed in a vacuum drying oven at 80°C for 12 h to remove moisture. The dried mixture was then placed in a tubular furnace under N2 atmosphere and heated to 650°C at a heating rate of 5°C/min for 3 h. After the calcination temperature was cooled to room temperature, a porous carbon material was obtained. The material was placed in a fixed bed reactor and pretreated at 300°C for 2 h under N2 atmosphere.
  • a fluorine - containing mixed gas (2% C2F6 , 2% CF4 , 2% CO2 , 94% N2 ) was introduced at a gas flow rate of 200 mL/min to conduct an adsorption experiment.
  • the outlet gas was tested for PFCs using a flue gas analyzer. When the outlet concentration was the same as the inlet concentration and no longer changed, adsorption saturation was reached.
  • the temperature of the fixed bed reactor was then raised to 150°C and N2 was conducted. 2 After purging and desorption for 3 hours, the desorbed PFCs were detected by flue gas analyzer, and the adsorption amount of PFCs by porous carbon material was 1.35mmol/g.
  • Example 1 Example 2, and Example 3, the effect of carbonization temperature on the performance of the adsorbent was considered, and 600°C was determined to be the optimal carbonization temperature of the carbon material; in Example 3, Example 4, and Example 5, the effect of the amount of red mud powder added on the performance of the adsorbent was considered. As the amount of red mud added increased, the adsorption effect of PFCs increased, but the adsorption effects of the carbon material and red mud powder mass ratios of 1:3 and 1:4 were similar, and considering the economic effect, 1:3 was the optimal mass ratio; in Example 4, Example 6, and Example 7, the effect of activation temperature on the performance of the adsorbent was considered.
  • the adsorption effect of PFCs decreased, because too high a temperature would cause the micropore volume and total specific surface area to decrease, which was not conducive to the adsorption of PFCs. Therefore, when the carbonization temperature was 600°C, the mass ratio of carbon material to red mud powder was 1:3, and the activation temperature was 650°C, that is, Example 6, the pore structure of the prepared red mud-based porous carbon adsorbent was richer, and the adsorption effect of PFCs was the best.

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Abstract

本申请公开一种赤泥改性制备多孔碳材料的方法及应用，将赤泥经烘干、研磨、酸浸、洗涤过滤、洗涤得到中性赤泥浆液，将废塑料瓶破碎、碳化后与赤泥浆液混合，并磁力搅拌使其充分混合，形成的赤泥和碳材料混合物经干燥、活化得到多孔碳材料。本申请通过简单的碳化、活化方法，将工业固体废物赤泥和塑料转化为具有吸附性的材料，实现气-固的协同治理，也为赤泥资源化利用提供一种新思路；本申请利用赤泥掺杂碳化塑料制备的多孔碳材料，相比传统吸附剂具有更好的孔隙结构和选择性，并且PFCs经吸附-解吸后可富集成高浓度的气体，具有一定的经济价值，从而实现铝行业内部废物的环保利用，降低环境治理成本，达到减污降碳协同增效的目的。

Description

一种赤泥改性制备多孔碳材料的方法及应用
本申请要求于2023年06月06日提交中国专利局、申请号为CN202310669230.6、发明名称为“一种赤泥改性制备多孔碳材料的方法及应用”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请属于固体废弃物资源化利用技术领域，具体涉及一种赤泥改性制备多孔碳材料的方法及应用。
背景技术
赤泥作为氧化铝生产过程中产生的大宗固体废物，根据氧化铝品质和生产工艺的不同，赤泥可分为拜耳法赤泥、烧结法赤泥和联合法赤泥。赤泥中含有大量的Fe2O3、Al2O3和TiO2等金属氧化物，具有成为有效处理大气污染物材料的潜质。赤泥传统的处理方式主要是堆存，这不仅占用土地资源，而且赤泥中的重金属会通过地表水及雨水淋溶渗入到地下，污染周围土壤，导致土壤盐渍化。同时，赤泥表面的小颗粒也会扩散到空气中，导致大气污染。因此，提高其综合利用率是解决赤泥大量堆积的关键。
塑料作为一种有机聚合物材料，因其使用方便、成本低、轻便、强度高以及耐腐蚀等特性被广泛应用于工业生产和日常生活中。但塑料在使用过程中容易老化、破损，使用寿命较短，并且在自然环境中很难降解，如果将未经处理的废塑料直接排放到环境中会造成白色污染，引发严重的生态危机。目前对于塑料的处理方法主要包括填埋、焚烧和热解，其中填埋虽然是最简单的方法，但需要占用大量的土地资源；而焚烧过程则会产生大量有害气体，如若泄露到空气中将会造成二次污染。
工业废气对环境有着较大的破坏，容易给人们的生活带来极大的不便，在电解铝行业中最大的污染源是电解槽排放的烟气，如粉尘、全氟化碳(PFCs，主要是CF4和C2F6)、CO2等，其中PFCs作为强温室气体，具有较长的寿命和较高的全球变暖潜力，全球变暖潜值是CO2的几千甚至上万倍，当排入到环境中后，容易造成全球变暖，导致冰川融化、海平面上升、土地沙漠化等问题。
目前针对PFCs的减排技术主要是燃烧、裂解、催化和吸附。其中吸附法因其低能耗、低成本、易于管理被认为是捕获PFCs的一种很有前途的技术。在众 多吸附剂中，多孔碳材料因其制备成本低、比表面积大、孔结构发达、化学和机械稳定性好、相对容易再生等优点被广泛使用。虽然在传统制备多孔碳材料的过程中，利用物理或化学的活化方式来处理碳材料可以得到一定量的孔隙结构，但是物理活化需要很高的温度、较长的时间，且活化所得碳材料的比表面积的增加也相对有限，而化学活化后的碳材料需要进行清洗，去除孔道内的活化剂残留物，进一步提高了反应的成本。
目前国内针对赤泥和废塑料在吸附剂方面的处理，主要集中在利用酸碱处理赤泥或活化剂处理废塑料制备吸附剂，这样方式制备的材料不能充分利用其中含有的金属氧化物、比表面积和孔结构，难以实现高效的吸附净化性能，而且很难达到固体废物资源化的处理目标。
发明内容
本申请提供一种赤泥联合塑料改性制备多孔碳材料及吸附处理含氟气体的方法，采用催化活化的方式，利用赤泥中丰富的金属氧化物如Fe2O3与碳材料进行掺杂，然后进行活化，增加碳材料内部微孔的表面活性点，使微孔转变为介孔，从而提高多孔碳吸附剂的吸附效果，达到净化电解铝烟气的作用。
同时为缓解赤泥和塑料利用率低的问题，本申请以赤泥和废塑料瓶为原料，通过简单的碳化和活化，制备的多孔碳吸附剂具有更好的吸附性质，不仅可以去除电解铝烟气中的PFCs，还可以减少赤泥对环境的污染，实现赤泥的资源化利用，同时，实现铝行业内部废物的环保利用，降低环境治理成本，达到减污降碳协同增效的目的。
本申请的技术方案如下：
一种赤泥改性制备多孔碳材料的方法，具体步骤如下：
(1)将在100-115℃烘干至恒重后的赤泥研磨并过100目筛得到赤泥粉末，在所述赤泥粉末中加入浓度为0.05mol/L的柠檬酸溶液，室温下磁力搅拌20-30min，过滤并利用去离子水洗涤直至pH值呈中性，得到中性赤泥浆液；
(2)将收集到的废塑料瓶破碎成小块并进行碳化，得到碳材料；取所述碳材料与中性赤泥浆液进行混合，得到混合物，所述混合为室温下磁力搅拌2-4h；
(3)将所述混合物真空干燥，所得干燥物焙烧活化，冷却至室温后，得到赤泥基多孔碳材料。
优选的，步骤(1)中所述柠檬酸溶液中的柠檬酸占赤泥粉末质量的1-10％。
优选的，步骤(2)中所述废塑料瓶的主要成分为聚乙烯(PE)。
优选的，步骤(2)中所述碳化为：在N2气氛下，以5℃/min的升温速率升温至450-600℃焙烧3h。
优选的，步骤(2)中，所述碳材料与所述赤泥粉末的质量比为1:2-4。
优选的，步骤(1)和步骤(2)中所述磁力搅拌的转速独立为300-500rpm；所述磁力搅拌的设备为磁力搅拌器。
优选的，步骤(3)中所述真空干燥的温度为60-80℃，所述真空干燥的时间为12h。
优选的，步骤(3)中所述焙烧活化为：在N2气氛下，以5℃/min的升温速率升温至500-800℃焙烧3h。
本申请还提供了上述技术方案所述方法制备的赤泥基多孔碳材料吸附处理含氟气体的应用，所述应用为：将所述赤泥基多孔碳材料置于固定床反应器中，在N2气氛下300℃预处理2h，冷却至120℃后通入含氟气体，进行吸附净化，待所述赤泥基多孔碳材料吸附饱和之后，升温至150℃进行解吸附，收集解吸附的气体，解吸附之后的待所述赤泥基多孔碳材料再次作为吸附材料吸附净化含氟气体。
优选的，所述含氟气体包括2％C2F6、2％CF4、2％CO2、94％N2。
优选的，所述含氟气体的流速为200mL/min。
优选的，所述解吸附为N2吹扫脱附；所述解吸附的时间为3h。
优选的，所述赤泥基多孔碳材料对全氟化碳的吸附量为1.75mmol/g、2.15mmol/g、2.45mmol/g、2.48mmol/g、2.34mmol/g、2.54mmol/g或1.90mmol/g。
优选的，所述含氟气体为电解铝烟气。
本申请的有益效果如下：
(1)本申请利用赤泥负载碳化塑料制备多孔碳材料吸附处理电解铝烟气中的PFCs，相比于单独利用赤泥或废塑料制备的吸附材料具有更好效果，不仅可以提高PFCs去除率，还可以减少HF和CO2气体产生，为赤泥资源化利用提供了一种新的方法。
(2)本申请制备的多孔碳材料将PFCs吸附后，通过吸附-解吸可以得到高浓度PFCs，可降低后续处理如等离子体分解、热催化过程的能源消耗。
(3)本申请将废塑料瓶转化为碳材料作为载体，然后负载赤泥中的金属氧化 物，增强了材料的表面积和气体的选择性，缓解了废塑料对环境带来的影响。
(4)本申请利用“以废治废”的方法，不仅提高了赤泥和塑料的利用率，还降低了工艺成本，减少了对环境造成的污染。
附图说明
图1为赤泥改性制备多孔碳材料处理含氟气体的工艺流程图。
具体实施方式
结合以下实施例，对本申请进行进一步的详细说明。应当理解，此处所描述的具体实施例仅用于解释本申请，并不用于限定本申请。实施例中所用试剂或仪器未注明生产厂商者，均可以通过市售购买获得的常规产品。
本申请实施例中使用的赤泥来自云南省文山市某铝业公司。
实施例1
一种赤泥改性制备多孔碳材料的方法及吸附处理含氟气体的应用，如图1所示，具体步骤如下：
(1)将来源于云南省文山市某铝业公司的赤泥置于烘箱中100℃烘干至恒重，并进行研磨过100目筛，得到赤泥粉末备用；然后取适量赤泥粉末于烧杯中，加入柠檬酸溶液进行酸处理，柠檬酸溶液中的柠檬酸占赤泥粉末质量的1％，去除赤泥中的碱金属和粘接性组分，并将其置于磁力搅拌器中室温下搅拌20min，转速为300rpm，然后进行过滤并利用去离子水洗涤直至pH呈中性，得到赤泥浆液备用；
(2)将收集到的成分为聚乙烯的塑料瓶破碎成小块，然后放置在管式炉中，N2气氛下，以5℃/min的升温速率升温至450℃焙烧3h，得到碳材料；
(3)将步骤(2)得到的碳材料按照与步骤(1)得到的赤泥粉末质量比1:2添加到赤泥浆液中进行混合，混合物置于磁力搅拌器中室温下搅拌2h，转速为300rpm，充分混合后将形成的混合物放置在真空干燥箱中60℃干燥12h，去除水分，然后将干燥混合物放置管式炉中N2气氛下，以5℃/min的升温速率升温至500℃焙烧3h，待焙烧温度冷却至室温后，得到赤泥基多孔碳材料。
将赤泥基多孔碳材料置于固定床反应器中，在N2气氛下300℃预处理2h，冷却至120℃后通入含氟混合气体(2％C2F6，2％CF4、2％CO2、94％N2)，气体流速为200mL/min，进行吸附实验，出口气体利用烟气分析仪对PFCs进行检测，当出口浓度和进口浓度相同并不再发生变化时，达到吸附饱和，然后将固定床 反应器的温度升高至150℃，进行N2吹扫脱附3h，脱附后的PFCs经烟气分析仪检测，碳材料吸附剂对PFCs的吸附量为1.75mmol/g，同时发现解吸附后的碳材料再次作为吸附材料净化含氟气体效果依然很好。
实施例2
一种赤泥改性制备多孔碳材料的方法及吸附处理含氟气体的应用，具体步骤如下：
(1)将来源于云南省文山市某铝业公司的赤泥置于烘箱中100℃烘干至恒重，并进行研磨过100目筛，得到赤泥粉末备用；然后取适量赤泥粉末于烧杯中，加入0.05mol/L的柠檬酸溶液进行酸处理，柠檬酸溶液中的柠檬酸占赤泥粉末质量的5％，去除赤泥中的碱金属和粘接性组分，并将其置于磁力搅拌器中室温下搅拌20min，转速为300rpm，然后进行过滤并利用去离子水洗涤直至pH呈中性，得到赤泥浆液备用；
(2)将收集到的成分为聚乙烯的塑料瓶破碎成小块，然后放置在管式炉中N2气氛下，以5℃/min的升温速率升温至525℃焙烧3h，得到碳材料；
(3)将步骤(2)得到的碳材料按照与步骤(1)得到的赤泥粉末质量比1:2添加到赤泥浆液中进行混合，混合物置于磁力搅拌器中室温下搅拌2h，转速为300rpm，充分混合后将形成的混合物放置在真空干燥箱中60℃干燥12h，去除水分，然后将干燥混合物放置管式炉中N2气氛下，以5℃/min的升温速率升温至500℃焙烧3h，待焙烧温度冷却至室温后，得到赤泥基多孔碳材料。
将赤泥基多孔碳材料置于固定床反应器中，在N2气氛下300℃预处理2h，冷却至120℃后通入含氟混合气体(2％C2F6，2％CF4、2％CO2、94％N2)，气体流速为200mL/min，进行吸附实验，出口气体利用烟气分析仪对PFCs进行检测，当出口浓度和进口浓度相同并不再发生变化时，达到吸附饱和，然后将固定床反应器的温度升高至150℃，进行N2吹扫脱附3h，脱附后的PFCs经烟气分析仪检测，碳材料吸附剂对PFCs的吸附量为2.15mmol/g，同时发现解吸附后的碳材料再次作为吸附材料净化含氟气体效果依然很好。
实施例3
一种赤泥改性制备多孔碳材料的方法及吸附处理含氟气体的应用，具体步骤如下：
(1)将来源于云南省文山市某铝业公司的赤泥置于烘箱中100℃烘干至恒重， 并进行研磨过100目筛，得到赤泥粉末备用；然后取适量赤泥粉末于烧杯中，加入浓度为0.05mol/L的柠檬酸溶液进行酸处理，柠檬酸溶液中的柠檬酸占赤泥粉末质量的10％，去除赤泥中的碱金属和粘接性组分，并将其置于磁力搅拌器中室温下搅拌20min，转速为300rpm，然后进行过滤并利用去离子水洗涤直至pH呈中性，得到赤泥浆液备用；
(2)将收集到的成分为聚乙烯的塑料瓶破碎成小块，然后放置在管式炉中N2气氛下，以5℃/min的升温速率升温至600℃焙烧3h，得到碳材料；
(3)将步骤(2)得到的碳材料按照与步骤(1)得到的赤泥粉末质量比1:2添加到赤泥浆液中进行混合，混合物置于磁力搅拌器中室温下搅拌2h，转速为300rpm，充分混合后将形成的混合物放置在真空干燥箱中60℃干燥12h，去除水分，然后将干燥混合物放置管式炉中N2气氛下，以5℃/min的升温速率升温至500℃焙烧3h，待焙烧温度冷却至室温后，得到赤泥基多孔碳材料。
将赤泥基多孔碳材料置于固定床反应器中，在N2气氛下300℃预处理2h，冷却至120℃后通入含氟混合气体(2％C2F6，2％CF4、2％CO2、94％N2)，气体流速为200mL/min，进行吸附实验，出口气体利用烟气分析仪对PFCs进行检测，当出口浓度和进口浓度相同并不再发生变化时，达到吸附饱和，然后将固定床反应器的温度升高至150℃，进行N2吹扫脱附3h，脱附后的PFCs经烟气分析仪检测，碳材料吸附剂对PFCs的吸附量为2.45mmol/g，同时发现解吸附后的碳材料再次作为吸附材料净化含氟气体效果依然很好。
实施例4
一种赤泥改性制备多孔碳材料的方法及吸附处理含氟气体的应用，具体步骤如下：
(1)将来源于云南省文山市某铝业公司的赤泥置于烘箱中110℃烘干至恒重，并进行研磨过100目筛，得到赤泥粉末备用；然后取适量赤泥粉末于烧杯中，加入浓度为0.05mol/L的柠檬酸溶液进行酸处理，柠檬酸溶液中的柠檬酸占赤泥粉末质量的5％，去除赤泥中的碱金属和粘接性组分，并将其置于磁力搅拌器中室温下搅拌25min，转速为400rpm，然后进行过滤并利用去离子水洗涤直至pH呈中性，得到赤泥浆液备用；
(2)将收集到的成分为聚乙烯的塑料瓶破碎成小块，然后放置在管式炉中N2气氛下，以5℃/min的升温速率升温至600℃焙烧3h，得到碳材料；
(3)将步骤(2)得到的碳材料按照与步骤(1)得到的赤泥粉末质量比1:3添加到赤泥浆液中进行混合，混合物置于磁力搅拌器中室温下搅拌3h，转速为400rpm，充分混合后将形成的混合物放置在真空干燥箱中70℃干燥12h，去除水分，然后将干燥混合物放置管式炉中N2气氛下，以5℃/min的升温速率升温至500℃焙烧3h，待焙烧温度冷却至室温后，得到赤泥基多孔碳材料。
将赤泥基多孔碳材料置于固定床反应器中，在N2气氛下300℃预处理2h，冷却至120℃后通入含氟混合气体(2％C2F6，2％CF4、2％CO2、94％N2)，气体流速为200mL/min，进行吸附实验，出口气体利用烟气分析仪对PFCs进行检测，当出口浓度和进口浓度相同并不再发生变化时，达到吸附饱和，然后将固定床反应器的温度升高至150℃，进行N2吹扫脱附3h，脱附后的PFCs经烟气分析仪检测，碳材料吸附剂对PFCs的吸附量为2.48mmol/g，同时发现解吸附后的碳材料再次作为吸附材料净化含氟气体效果依然很好。
实施例5
一种赤泥改性制备多孔碳材料的方法及吸附处理含氟气体的应用，具体步骤如下：
(1)将来源于云南省文山市某铝业公司的赤泥置于烘箱中110℃烘干至恒重，并进行研磨过100目筛，得到赤泥粉末备用；然后取适量赤泥粉末于烧杯中，加入0.05mol/L的柠檬酸溶液进行酸处理，柠檬酸溶液中的柠檬酸占赤泥粉末质量的5％，去除赤泥中的碱金属和粘接性组分，并将其置于磁力搅拌器中室温下搅拌25min，转速为400rpm，然后进行过滤并利用去离子水洗涤直至pH呈中性，得到赤泥浆液备用；
(2)将收集到的成分为聚乙烯的塑料瓶破碎成小块，然后放置在管式炉中N2气氛下，以5℃/min的升温速率升温至600℃焙烧3h，得到碳材料；
(3)将步骤(2)得到的碳材料按照与步骤(1)得到的赤泥粉末质量比1:4添加到赤泥浆液中进行混合，混合物置于磁力搅拌器中室温下搅拌3h，转速为400rpm，充分混合后将形成的混合物放置在真空干燥箱中70℃干燥12h，去除水分，然后将干燥混合物放置管式炉中N2气氛下，以5℃/min的升温速率升温至500℃焙烧3h，待焙烧温度冷却至室温后，得到赤泥基多孔碳材料。
将赤泥基多孔碳材料置于固定床反应器中，在N2气氛下300℃预处理2h，冷却至120℃后通入含氟混合气体(2％C2F6，2％CF4、2％CO2、94％N2)，气体流 速为200mL/min，进行吸附实验，出口气体利用烟气分析仪对PFCs进行检测，当出口浓度和进口浓度相同并不再发生变化时，达到吸附饱和，然后将固定床反应器的温度升高至150℃，进行N2吹扫脱附3h，脱附后的PFCs经烟气分析仪检测，碳材料吸附剂对PFCs的吸附量为2.34mmol/g，同时发现解吸附后的碳材料再次作为吸附材料净化含氟气体效果依然很好。
实施例6
一种赤泥改性制备多孔碳材料的方法及吸附处理含氟气体的应用，具体步骤如下：
(1)将来源于云南省文山市某铝业公司的赤泥置于烘箱中115℃烘干至恒重，并进行研磨过100目筛，得到赤泥粉末备用；然后取适量赤泥粉末于烧杯中，加入浓度为0.05mol/L的柠檬酸溶液进行酸处理，柠檬酸溶液中的柠檬酸占赤泥粉末质量的5％，去除赤泥中的碱金属和粘接性组分，并将其置于磁力搅拌器中室温下搅拌30min，转速为500rpm，然后进行过滤并利用去离子水洗涤直至pH呈中性，得到赤泥浆液备用；
(2)将收集到的成分为聚乙烯的塑料瓶破碎成小块，然后放置在管式炉中N2气氛下，以5℃/min的升温速率升温至600℃焙烧3h，得到碳材料；
(3)将步骤(2)得到的碳材料按照与步骤(1)得到的赤泥粉末质量比1:3添加到赤泥浆液中进行混合，混合物置于磁力搅拌器中室温下4h，转速为500rpm，充分混合后将形成的混合物放置在真空干燥箱中80℃干燥12h，去除水分，然后将干燥混合物放置管式炉中N2气氛下，以5℃/min的升温速率升温至650℃焙烧3h，待焙烧温度冷却至室温后，得到赤泥基多孔碳材料。
将赤泥基多孔碳材料置于固定床反应器中，在N2气氛下300℃预处理2h，冷却至120℃后通入含氟混合气体(2％C2F6，2％CF4、2％CO2、94％N2)，气体流速为200mL/min，进行吸附实验，出口气体利用烟气分析仪对PFCs进行检测，当出口浓度和进口浓度相同并不再发生变化时，达到吸附饱和，然后将固定床反应器的温度升高至150℃，进行N2吹扫脱附3h，脱附后的PFCs经烟气分析仪检测，碳材料吸附剂对PFCs的吸附量为2.54mmol/g，同时发现解吸附后的碳材料再次作为吸附材料净化含氟气体效果依然很好。
实施例7
一种赤泥改性制备多孔碳材料的方法及吸附处理含氟气体的应用，具体步 骤如下：
(1)将来源于云南省文山市某铝业公司的赤泥置于烘箱中115℃烘干至恒重，并进行研磨过100目筛，得到赤泥粉末备用；然后取适量赤泥粉末于烧杯中，加入浓度为0.05mol/L的柠檬酸溶液进行酸处理，柠檬酸溶液中的柠檬酸占赤泥粉末质量的5％，去除赤泥中的碱金属和粘接性组分，并将其置于磁力搅拌器中室温下搅拌30min，转速为500rpm，然后进行过滤并利用去离子水洗涤直至pH呈中性，得到赤泥浆液备用；
(2)将收集到的成分为聚乙烯的塑料瓶破碎成小块，然后放置在管式炉中N2气氛下，以5℃/min的升温速率升温至600℃焙烧3h，得到碳材料；
(3)将步骤(2)得到的碳材料按照与步骤(1)得到的赤泥粉末质量比1:3添加到赤泥浆液中进行混合，混合物置于磁力搅拌器中室温下搅拌4h，转速为500rpm，充分混合后将形成的混合物放置在真空干燥箱中80℃干燥12h，去除水分，然后将干燥混合物放置管式炉中N2气氛下，以5℃/min的升温速率升温至800℃焙烧3h，待焙烧温度冷却至室温后，得到赤泥基多孔碳材料。
将赤泥基多孔碳材料置于固定床反应器中，在N2气氛下300℃预处理2h，冷却至120℃后通入含氟混合气体(2％C2F6，2％CF4、2％CO2、94％N2)，气体流速为200mL/min，进行吸附实验，出口气体利用烟气分析仪对PFCs进行检测，当出口浓度和进口浓度相同并不再发生变化时，达到吸附饱和，然后将固定床反应器的温度升高至150℃，进行N2吹扫脱附3h，脱附后的PFCs经烟气分析仪检测，碳材料吸附剂对PFCs的吸附量为1.90mmol/g，同时发现解吸附后的碳材料再次作为吸附材料净化含氟气体效果依然很好。
对比例1
将实施例6制备得到的赤泥浆液过滤后放置在真空干燥箱中80℃干燥12h，然后放置在管式炉中N2气氛下，以5℃/min的升温速率升温至600℃焙烧3h，得到赤泥基吸附剂，将其置于固定床反应器中，在N2气氛下300℃预处理2h，冷却至120℃后通入含氟混合气体(2％C2F6，2％CF4、2％CO2、94％N2)，气体流速为200mL/min，进行吸附实验，出口气体利用烟气分析仪对PFCs进行检测，当出口浓度和进口浓度相同并不再发生变化时，达到吸附饱和，然后将固定床反应器的温度升高至150℃，进行N2吹扫脱附3h，脱附后的PFCs经烟气分析仪检测，赤泥基吸附剂对PFCs的吸附量为1.12mmol/g。
对比例2
将实施例6制备得到的碳材料与浓度为0.05mol/L的KOH按照质量比1:3进行混合，混合物置于磁力搅拌器中室温下搅拌1h，转速为500rpm，充分混合后放置在真空干燥箱中80℃干燥12h，去除水分，然后将干燥混合物放置管式炉中N2气氛下，以5℃/min的升温速率升温至650℃焙烧3h，待焙烧温度冷却至室温后，得到多孔碳材料，将其置于固定床反应器中，在N2气氛下300℃预处理2h，冷却至120℃后通入含氟混合气体(2％C2F6，2％CF4、2％CO2、94％N2)，气体流速为200mL/min，进行吸附实验，出口气体利用烟气分析仪对PFCs进行检测，当出口浓度和进口浓度相同并不再发生变化时，达到吸附饱和，然后将固定床反应器的温度升高至150℃，进行N2吹扫脱附3h，脱附后的PFCs经烟气分析仪检测，多孔碳材料对PFCs的吸附量为1.35mmol/g。
实施例1、实施例2、实施例3考虑了碳化温度对吸附剂性能的影响，确定了600℃为碳材料最佳的碳化温度；实施例3、实施例4、实施例5考虑了赤泥粉末添加量对吸附剂性能的影响，随着赤泥的添加量增加，PFCs的吸附效果增加，但碳材料与赤泥粉末质量比为1:3和1:4的吸附效果相近，考虑到经济效果即1:3为最佳质量比；实施例4、实施例6、实施例7考虑了活化温度对吸附剂性能的影响，随着温度的升高，PFCs的吸附效果降低，这是由于温度过高会导致微孔体积和总比表面积下降，不利于PFCs的吸附。因此，当碳化温度为600℃、碳材料和赤泥粉末质量比为1:3、活化温度为650℃时即实施例6，所制备得到的赤泥基多孔碳吸附剂的孔隙结构更加丰富，对PFCs的吸附效果最好。
尽管上述实施例对本申请做出了详尽的描述，但它仅仅是本申请一部分实施例而不是全部实施例，人们还可以根据本实施例在不经创造性前提下获得其他实施例，这些实施例都属于本申请保护范围。

Claims (14)

  1. 一种赤泥改性制备多孔碳材料的方法，其特征在于，具体步骤如下：
    (1)将在100-115℃烘干至恒重后的赤泥研磨并过100目筛得到赤泥粉末，在所述赤泥粉末中加入浓度为0.05mol/L的柠檬酸溶液，室温下磁力搅拌20-30min，过滤并利用去离子水洗涤直至pH值呈中性，得到中性赤泥浆液；
    (2)将收集到的废塑料瓶破碎成小块进行碳化，得到碳材料；取所述碳材料与中性赤泥浆液进行混合，得到混合物，所述混合为室温下磁力搅拌2-4h；
    (3)将所述混合物真空干燥，所得干燥物焙烧活化，冷却至室温后，得到赤泥基多孔碳材料。
  2. 根据权利要求1所述的方法，其特征在于，步骤(1)中所述柠檬酸溶液中的柠檬酸占赤泥粉末质量的1-10％。
  3. 根据权利要求1所述的方法，其特征在于，步骤(2)中所述废塑料瓶的主要成分为聚乙烯。
  4. 根据权利要求1所述的方法，其特征在于，步骤(2)中所述碳化为：在N2气氛下，以5℃/min的升温速率升温至450-600℃焙烧3h。
  5. 根据权利要求1所述的方法，其特征在于，步骤(2)中，所述碳材料与所述赤泥粉末的质量比为1:2-4。
  6. 根据权利要求1所述的方法，其特征在于，步骤(1)和步骤(2)中所述磁力搅拌的转速独立为300-500rpm。
  7. 根据权利要求1所述的方法，其特征在于，步骤(3)中所述真空干燥的温度为60-80℃，所述真空干燥的时间为12h。
  8. 根据权利要求1所述的方法，其特征在于，步骤(3)中所述焙烧活化为：在N2气氛下，以5℃/min的升温速率升温至500-800℃焙烧3h。
  9. 权利要求1～8任一项所述方法制备的赤泥基多孔碳材料吸附处理含氟气体的应用，所述应用为：将所述赤泥基多孔碳材料置于固定床反应器中，在N2气氛下300℃预处理2h，冷却至120℃后通入含氟气体，进行吸附净化，待所述赤泥基多孔碳材料吸附饱和之后，升温至150℃进行解吸附，收集解吸附的气体，解吸附之后的所述赤泥基多孔碳材料再次作为吸附材料吸附净化含氟气体。
  10. 根据权利要求9所述的应用，其特征在于，所述含氟气体包括2％C2F6、2％CF4、2％CO2、94％N2。
  11. 根据权利要求9或10所述的应用，其特征在于，所述含氟气体的流速 为200mL/min。
  12. 根据权利要求9所述的应用，其特征在于，所述解吸附为N2吹扫脱附；所述解吸附的时间为3h。
  13. 根据权利要求9所述的应用，其特征在于，所述赤泥基多孔碳材料对全氟化碳的吸附量为1.75mmol/g、2.15mmol/g、2.45mmol/g、2.48mmol/g、2.34mmol/g、2.54mmol/g或1.90mmol/g。
  14. 根据权利要求9所述的应用，其特征在于，所述含氟气体为电解铝烟气。
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CN108543517A (zh) * 2018-04-24 2018-09-18 中国科学院过程工程研究所 一种赤泥的资源化回收方法及其产品和用途
CN109772265A (zh) * 2019-03-27 2019-05-21 安徽工业大学 一种用于烟气脱硫脱硝的烧结法赤泥改性活性炭及其制备方法
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CN113277600A (zh) * 2020-02-20 2021-08-20 中国科学院大连化学物理研究所 赤泥粒子电极及其制备方法、应用
CN112915966A (zh) * 2021-01-28 2021-06-08 东北大学 一种聚苯胺基活性炭的制备方法及其应用
CN114288812A (zh) * 2021-11-30 2022-04-08 浙江大学 一种分离含氟电子特气的方法
CN116654928A (zh) * 2023-06-06 2023-08-29 昆明理工大学 一种赤泥改性制备多孔碳材料的方法及应用

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