| Spherical porous carbon has the advantages of excellent specific surface area,good stability,unique morphology and easily adjustable geometric dimensions,and have been widely used in energy and environment engineering.Spherical porous carbon prepared by traditional methods often has uneven particle size,poor monodispersity,and uncontrollable morphology.The droplet-based microfluidics technology provides a new solution to the problems of low regularity and repeatability in common preparation methods for spherical materials.The comparison and analysis of liquid-liquid two-phase flow in different channels show that the coaxial microchannel has more practical advantages in preparing monodisperse droplets.A convenient and universal coaxial microfluidic device was developed,which only composed of commercial parts.Based on this design,a theoretical relation for stable generation of monodisperse droplets was established and proved to be reasonable by experiments.The limits of flow rates were obtained,and spherical precursors of porous carbon with uniform size were efficiently prepared.Based on the results of thermogravimetric analysis(TG),the carbonization process of the precursor was determined.The effects of different activation processes on the specific surface area,pore size distribution and other parameters of the material were investigated experimentally.The spherical porous carbon with higher specific surface area(1837m2/g)and high microporous ratio {Vmicro/Vtotal=83.8%)was obtained by KOH activation.Dynamic CO2 adsorption experiments on prepared spherical porous carbon in a fixed bed were conducted.The adsorption effect and effective utilization of adsorbents were evaluated under different intake volume flow rates and adsorption pressures.In addition,by comparing the adsorption effects of the adsorbents after different regeneration time,the optimal regeneration time of the adsorbent prepared in our study was determined to be 15 minutes. |
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