Preparation of activated carbon from Guhanshan coal and its effect on methane adsorption thermodynamics at different temperatures

In this study, activated carbon was prepared using KOH activated anthracite Guhanshan (GHS) for CH4 adsorption. The influencing factors of carbon to alkali ratio, activation temperature, pickling time, and pickling temperature were considered comprehensively. Results show that the elemental O content of the pre-oxidized sample was increased by 44.6%. As an activator, KOH would generate more micropores on the coal matrix, the maximum specific surface area was 3136.80 m2/g. With the increase of KOH, the affinity of methane on the surface of activated carbon decreases by an average of 57%. However, the adsorption capacity of activated carbon on methane gases would be increased greatly, and the fitting result of the L-F equation shows that the maximum adsorption capacity is 19.31 mmol/g. Based on present results, the optimal preparation conditions seem to be 1:5 carbon to alkali ratio at 700 °C activation temperature and 3 h pickling with 5% hydrochloric acid at 60 °C.