Methane Adsorption in Microporous Carbon Adsorbent LCN Obtained by Thermochemical Synthesis from Lignocellulose

Resumo

A microporous carbon adsorbent labeled as LCN was prepared by thermochemical synthesis from lignocellulose, and methane adsorption on it was studied within the temperature range from 303 to 333 K and at pressures up to 40 MPa. The total pore volume was determined to be 0.68 cm³/g. The maximum values of methane adsorption of ~14.5 mmol/g (23.2 wt %) were obtained at the temperature of 303 K and the pressure of 40 MPa. The calculated differential molar isosteric heat of methane adsorption is, on average, ~12–13 kJ/mol. Methane adsorption on LCN was calculated with the use of the Dubinin–Radushkevich and Dubinin–Astakhov equations, as well as the linearity of adsorption isosteres. It was shown that the Dubinin–Radushkevich and fundamental regularities of the theory of volume filling of micropores provide the best description of experimental data using only the standard structural and energy characteristics of the adsorbent.