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CN-122010113-A - Gas separation-based ultra-microporous activated carbon and preparation method thereof

CN122010113ACN 122010113 ACN122010113 ACN 122010113ACN-122010113-A

Abstract

The invention discloses a gas separation-based ultra-microporous activated carbon and a preparation method thereof, which belong to the technical field of ultra-microporous activated carbon, wherein biomass raw materials and polymer raw materials are used as carbon sources, a biomass-polymer composite carbon skeleton with developed pore channels and stable structure is constructed after co-pyrolysis, molecular sieve materials are grown on the surface of the biomass-polymer composite carbon skeleton to form a continuous integrated composite adsorption system, calcium ions are further introduced through ion exchange, the electric field environment and the adsorption energy level in the pore channels of a molecular sieve are further regulated and controlled, the selective adsorption capacity for carbon dioxide molecules is enhanced, the prepared ultra-microporous activated carbon has the high specific surface area of the activated carbon and the separation selectivity of the molecular sieve, the problem that adsorption heat release concentration in the traditional layered filling structure leads to thermal failure of active adsorption sites of the molecular sieve is effectively avoided, and the ultra-microporous activated carbon has excellent gas separation performance in complex gas systems such as coal-fired flue gas.

Inventors

  • DAI RUXIN
  • ZHANG WUJING
  • LI JIA
  • ZHU ZHAOSHUAI

Assignees

  • 江苏乾汇和环保再生有限公司

Dates

Publication Date
20260512
Application Date
20260209

Claims (10)

  1. 1. The preparation method of the ultra-microporous activated carbon based on gas separation is characterized by comprising the following steps of: blending a biomass raw material and a polymer raw material, carrying out pyrolysis carbonization to construct a basic carbon skeleton to obtain a biomass-polymer carbonized material, and then carrying out high-temperature chemical etching activation on the carbonized material by using potassium hydroxide to obtain activated porous activated carbon; Adding an aluminum source and a silicon source into a strong alkaline reaction environment constructed by sodium hydroxide to perform hydrolysis and polycondensation reaction to obtain molecular sieve precursor sol, and then introducing activated porous activated carbon into a molecular sieve precursor sol system to perform in-situ hydrothermal crystallization to obtain a molecular sieve loaded activated carbon matrix; And thirdly, placing the molecular sieve loaded activated carbon matrix and the calcium nitrate solution in deionized water for liquid phase ion exchange reaction, and directionally replacing sodium ions in a molecular sieve framework by utilizing calcium ions to obtain the gas separation-based ultra-microporous activated carbon.
  2. 2. The method for preparing the gas separation-based ultra-microporous activated carbon according to claim 1, wherein the dosage ratio of the molecular sieve loaded activated carbon matrix, the calcium nitrate solution and the deionized water in the step three is 100-200g:800-1000mL:600-800mL.
  3. 3. The method for preparing the ultra-microporous activated carbon based on gas separation according to claim 1, wherein the molecular sieve-loaded activated carbon matrix in the second step is prepared by the following steps: placing molecular sieve precursor sol and activated porous activated carbon into a reaction kettle, stirring for 20-40 minutes at 25-35 ℃, fixing the reaction kettle into a homogeneous phase reactor for reaction for 6-8 hours, filtering, washing, and vacuum drying to constant weight to obtain a molecular sieve loaded activated carbon matrix.
  4. 4. The method for preparing the gas separation-based ultra-microporous activated carbon according to claim 3, wherein the mass ratio of the molecular sieve precursor sol to the activated porous activated carbon is 40-60:200-300.
  5. 5. The method for preparing the gas separation-based ultra-microporous activated carbon according to claim 4, wherein the molecular sieve precursor sol is prepared by the following steps: And (3) placing sodium hydroxide, sodium aluminate and deionized water into a reaction kettle, stirring for 10-20 minutes at 25-35 ℃, adding sodium silicate nonahydrate, and continuously reacting for 1-2 hours at the same temperature to obtain molecular sieve precursor sol.
  6. 6. The method for preparing the gas separation-based ultra-microporous activated carbon according to claim 5, wherein the dosage ratio of sodium hydroxide, sodium aluminate, sodium silicate nonahydrate and deionized water is 10-20g:12-25g:40-60g:200-300mL.
  7. 7. The method for preparing a gas separation-based ultra-microporous activated carbon according to claim 1, wherein the activated porous activated carbon in the first step is prepared by: Placing biomass-polymer carbonized material, potassium hydroxide and deionized water into a reaction kettle, stirring for 6-8h at 25-35 ℃, vacuum drying the reaction liquid to constant weight at 100-120 ℃, placing the dried material into a tubular furnace under the protection of nitrogen atmosphere, heating to 700-800 ℃ at the heating rate of 5 ℃ per minute, calcining at constant temperature for 1-2h, adding 1mol/L hydrochloric acid to adjust the pH value to 7, filtering, washing, vacuum drying to constant weight, and screening to obtain the activated porous activated carbon.
  8. 8. The method for preparing the gas separation-based ultra-microporous activated carbon according to claim 1, wherein the mass ratio of the biomass-polymer carbonized material to the potassium hydroxide to the deionized water is 300-400:600-800:600-800.
  9. 9. The method for preparing the gas separation-based ultra-microporous activated carbon according to claim 8, wherein the biomass-polymer carbonized material is prepared by the following steps: Placing the biomass raw material and the polymer raw material into a high-speed pulverizer for pulverizing treatment, screening with a 60-100 mesh screen, collecting materials, grinding and mixing for 10-30min, placing the mixed materials into a tube furnace under the protection of nitrogen atmosphere, heating to 500-600 ℃ at a heating rate of 8 ℃ per min, calcining at a constant temperature for 1-2h, collecting and grinding the products to obtain biomass-polymer carbonized materials; The mass ratio of the biomass raw material to the polymer raw material is 600-800:300-400.
  10. 10. A gas separation-based ultra microporous activated carbon prepared by the method for preparing a gas separation-based ultra microporous activated carbon according to any one of claims 1 to 9.

Description

Gas separation-based ultra-microporous activated carbon and preparation method thereof Technical Field The invention belongs to the technical field of ultra-microporous activated carbon, and particularly relates to ultra-microporous activated carbon based on gas separation and a preparation method thereof. Background Because of the air combustion-supporting technology, the discharged flue gas of coal-fired power plants presents the composition characteristics of high inert nitrogen and low carbon dioxide concentration, carbon dioxide is continuously accumulated as main greenhouse gas to aggravate global warming and ecological unbalance, and the carbon dioxide is required to be captured and separated from a large amount of nitrogen, and in the current industrial adsorption separation field, the zeolite molecular sieve is widely applied to the gas separation technology because of the developed macroporous network and excellent hydrodynamic property of the activated carbon, and because of the strong affinity and high selectivity of the zeolite molecular sieve to the carbon dioxide, the zeolite molecular sieve is often regarded as two core substrates for constructing an efficient adsorption system. However, the method is limited by the performance bottleneck of a single material, and a sectional filling mode of an active carbon layer and a molecular sieve layer is generally adopted, namely, gas is firstly subjected to coarse separation through the active carbon layer and then enters the molecular sieve layer to be subjected to fine separation, however, when high-flow-rate carbon dioxide gas passes through the active carbon layer at the front end, a large amount of adsorption heat is released due to rapid progress of an adsorption process, so that the air flow temperature is rapidly increased, the heated high-temperature air flow directly impacts the molecular sieve layer at the rear end, the capture capacity of active sites in the molecular sieve on carbon dioxide is obviously inhibited by heat energy, and the due separation efficiency of the active carbon and the molecular sieve cannot be exerted, so that the utilization rate of the active carbon and the molecular sieve is low, and the integral separation effect is poor. Therefore, under the application scene of capturing the carbon in the coal-fired flue gas, how to break through the technical bottleneck of thermal failure of the active chemical adsorption sites of the molecular sieve caused by interstage thermal interference in the traditional layered filling process, and construct the active carbon composite material capable of maintaining good separation performance under the adsorption exothermic working condition, which becomes a key technical problem to be solved in the field. Disclosure of Invention The invention aims to provide a gas separation-based ultra-microporous active carbon and a preparation method thereof, which improve the adsorption and separation efficiency through the cooperative regulation and control of an active carbon carrier and a molecular sieve pore structure so as to meet the requirements of separation performance stability and practical application reliability under a complex gas system. The aim of the invention can be achieved by the following technical scheme: a gas separation-based ultra-microporous activated carbon is prepared by the following steps: Blending a biomass carbon material and a plastic carbon material, performing pyrolysis carbonization to construct a basic carbon skeleton to obtain a biomass-polymer carbonized material, and performing high-temperature chemical etching activation on the carbonized material by using potassium hydroxide to obtain activated porous activated carbon. Adding an aluminum source and a silicon source into a strong alkaline reaction environment constructed by sodium hydroxide to perform hydrolysis and polycondensation reaction to obtain molecular sieve precursor sol, and then introducing activated porous activated carbon into a molecular sieve precursor sol system to perform in-situ hydrothermal crystallization to obtain a molecular sieve loaded activated carbon matrix. And thirdly, placing the molecular sieve loaded activated carbon matrix and the calcium nitrate solution in deionized water for liquid phase ion exchange reaction, and directionally replacing sodium ions in a molecular sieve framework by utilizing calcium ions to obtain the gas separation-based ultra-microporous activated carbon. Further, the dosage ratio of the molecular sieve loaded activated carbon matrix, the calcium nitrate solution and the deionized water is 100-200g:800-1000mL:600-800mL. Further, the preparation process of the molecular sieve loaded activated carbon matrix comprises the following steps: placing molecular sieve precursor sol and activated porous activated carbon into a reaction kettle, stirring for 20-40 minutes at 25-35 ℃, fixing the reaction kettle into a homogeneous phase reactor for reaction for 6