Preparation And Characterization Of Micro-Mesoporous Carbon And The Dynamic Adsorption Performance For Toluene Gas

The serious harm of volatile organic compounds(VOCs)to the ecological environment and human health has attracted worldwide attention.Fossil fuel combustion,petrochemicals,paints,coatings,pesticides,plastics and other industrial processes have caused a large portion of man-made VOC emissions.Due to the cost-effectiveness,simplicity and low energy consumption,adsorption is considered to be one technology of the effective VOC emission reduction,and adsorbent is the core of adsorption technology.In view of the problems for traditional micro-porous carbon materials,such as high adsorption resistance and easy clogging,this thesis aims at the development of high-performance adsorbents and dynamic adsorption performance of target pollutant toluene gas.The research contents are as follows:First,the mesoporous carbon(OMC)material was prepared by the soft template method,and characterized by SEM,TEM,small angle XRD,nitrogen adsorption and desorption analysis,elemental analysis,etc.The characterization shows that the prepared OMC has mesoscopically ordered and uniformly arranged pores structure.The pore size distribution is concentrated in the range of 3.5-5nm,the BET specific surface area is 1343m2 g-1,and the total pore volume is 1.237cm3 g-1.Chemical activation was used to enrich the pore structure of OMC,and the activation process conditions were optimized from the aspects of activator screening,activation temperature,and alkali-carbon ratio,combined with dynamic adsorption experiments and characterization.It is concluded that the activated sample has a hierarchical micro-mesoporous structure,and the KOH-activated OMC product has the largest toluene dynamic adsorption capacity when the activation temperature is 800? and the KOH/OMC mass ratio is 3:1.Secondly,the dynamic adsorption performance of toluene under the optimal process conditions KOMC-3-800 was studied.Under the condition that other factors remain unchanged,the testing conditions,such as the initial concentration of toluene,the adsorption temperature and the gas flow rate,were sequentially changed,and the influence of the testing conditions on the adsorption performance was analyzed by the dynamic adsorption breakthrough curve and the calculation of the saturated adsorption amount.The dynamic adsorption model Yoon-Nelson model and Thomas model were used to linearly fit the adsorption experiment data under different conditions,and the linear fitting degree is more than 93%,which can accurately predict the adsorption time and the saturated adsorption amount.Regeneration and recycling research of KOMC-3-800,the regenerated KOMC-3-800 still keeps good recycling efficiency.After 5 absorption and desorption cycles,the adsorption efficiency still keep high level,indicating that KOMC-3 has good adsorption performance and structural stability.Thus KOMC-3-800 has definitely practical application potential in toluene gas adsorption.