Kinetic Calculation of Sorption of Ethyl Alcohol on Carbon Materials

The kinetics of ethanol sorption on activated petroleum coke with specific surface area 1218 m²/g and hydroanthracite (4.87 m²/g) has been studied. The limiting stage of sorption for hydroanthracite is external diffusion; the diffusion coefficient at 293 K is 5.87 × 10^–10 m²/s; the thickness of the diffusion layer is 169 µm. For highly porous activated petroleum coke, the limiting stage changes as the sorption process progresses. In the first 5 min of the process, the sorption rate is determined by external mass transfer, then in the period from 5 to 15 min, both external and internal diffusion make a significant contribution to the overall rate of the process; from 15 min until equilibrium is reached, the main contribution to the process rate is made by internal diffusion. The coefficients of external diffusion in the area from 5 to 15 min and internal diffusion in the area from 15 min until equilibrium is reached are 5.87 × 10^–10 and 2.89 × 10^–11 m²/s. The activation energy for hydroanthracite is 20.03 ± 5.31 kJ/mol, for activated petroleum coke in the first section it is 18.68 ± 3.25, while in the second section it is 78.71 ± 34.19 kJ/mol.