Study On Adsorption And Water Resistance Of Activated Carbon Materials

With the improvement and popularization of environmental protection policies such as carbon neutralization and carbon peaking,the efficient and clean utilization of coal has emerged at the historic moment.Carbon-based materials have attracted more attention due to their porous structure,easy preparation and strong adsorption capacity.However,the removed gaseous pollutants often carry water vapor,resulting in the catalyst deactivation efficiency is reduced,although carbon materials with strong adsorption capacity can reduce the effect of water vapor,but the effect of water vapor can not be ignored.Therefore,in this paper,carbon materials through gas phase reaction method,acid-base reaction method to activate,improve the surface characteristics,and HPW further surface water resistance modification,the preparation of carbon materials applied in the field of flue gas denitrification and VOCs removal to detect the water resistance of carbon materials,hydrophilic and hydrophobic characteristics and regeneration effect.The mechanism process and reaction path of H2O on the surface of carbon materials were investigated by using Gaussian software.The main research contents of this paper are as follows:(1)Using gas phase reaction method,CO2 was selected as the active gas component to activate Jundong coal to prepare carbon materials,and acidized and demineralized first.Onestep activation method was used to prepare carbon materials.Compared with no CO2,the coalbased carbon material prepared by CO2 gas component activation shows better performance in surface group,pore structure and other surface structural characteristics.The specific surface area of the former can reach 708.6m2/g,the maximum penetration time of NOx under wet flue gas is 410s,and the penetration time of the latter is only 230 s.(2)The effect of acid and base activation concentration on the hydrophilic and hydrophobic characteristics of carbon surface was investigated by acid and base reaction method.The carbon material was applied in the field of wet flue gas NOx removal and VOCs purification.The mechanism process was analyzed by the characterization method.The specific surface area of sample KOH-2g-AC was 1222.23 m2/g,and the recycling performance was tested by using VOCs as pollutants.(3)Next,the surface hydrophobic reagent is used for surface water resistance modification,and phosphotungstic acid(HPW)is screened out to have a good effect on the surface water resistance modification of carbon materials.The penetration time of the modified carbon materials under wet flue gas is slightly longer than that under dry flue gas.In the adsorption of VOCs,the adsorption effect of 20%-HAC is relatively poor after HPW modification.When the water vapor content was 8%vol,the surface showed better water resistance.(4)Finally,the DFT calculation was carried out using the simulation software(Gaussian)to explore the interaction mechanism between the surface of carbon materials and H2O molecules.By calculating the Gibbs free energy of the interaction process between carbon materials and H2O molecules with the presence of surface groups and single/double active sites,as well as the possible reaction paths at different temperatures,The influence of surface characteristics of carbon material on H2O was analyzed.In summary,based on two different types of carbon materials,this paper uses different activation methods to improve the surface hydrophilicity and hydrophobicity,and uses the surface modification method loaded with heteropolyacid to enhance the water resistance to prepare carbon materials suitable for different environments.The DFT molecular simulation is used to further study the mechanism process and reaction path,which provides certain guiding significance for the preparation and research of water-resistant carbon materials.