Molecular Simulation of Adsorption of Hydrogen by Activated Carbon at Low Temperature and Low Pressure
Compared with traditional methods,the low-temperature adsorption method for treating H2 in laser ex-haust offers various advantages,such as compact size,light mass,low operating costs,and minimal vibration noise.The key challenge involves developing high-performance H2 adsorbents under low-temperature and low-pressure conditions.A porous activated carbon model was constructed using graphite slices,and the grand canonical Monte Carlo(GCMC)simulation was employed to investigate H2 adsorption behavior within this material.By examin-ing the influence of various factors,the study aimed to enhance H2 adsorption capacity.The pcff force field was used for calculations,with the Lennard-Jones 12-6 potential accounting for van der Waals interactions.The H2 adsorption isotherms and BET parameters computed using the model were then compared with experimental data,validating the accuracy of the model and force field.Subsequently,the effects of graphite slice scale,porous activated carbon den-sity,and adsorption temperature on H2 adsorption were explored.Results indicated that the graphite slice scale con-siderably affects H2 adsorption,with models constructed from 1-ring slices exhibiting the poorest performance and those from 19-ring showing the best performance.The adsorption performance ranking across both single and mixed graphite models was as follows:19-ring＞37-ring＞7-ring＞1-ring.Within the established model density range of 0.5-1.3 g/cm3,an optimal density of 1.1 g/cm3 was identified,which yielded the maximum H2 adsorption capacity.Surface area and pore size distribution jointly influenced the adsorption performance.The temperature had a substan-tial effect on low-temperature H2 adsorption,with adsorption decreasing by 19.1%and 36.8%as the temperature in-creased by 5 K and 10 K,respectively.Therefore,enhancing heat dissipation during the adsorption process and op-timizing the adsorption bed structure can increase H2 adsorption.
activated carbonadsorptionMonte Carlo simulationhydrogenlow temperature and low pressure
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