Comparison of the porosity evaluation results based on immersion calorimetry and gravimetric sorption measurements, for activated chars from a high volatile bituminous coal

The porous structure of chars from a high volatile bituminous coal from mine Pumarabule in Spain, initial and preoxidized, then steam activated, was characterized by carbon dioxide and benzene adsorption measurements, as well as by immersion calorimetry; molecular probes with increasing critical dimensions were used. The influence of preoxidation of the coal on the values of parameters describing the pore size distribution, with particular attention to micropores, evaluated according to each of the applied methods, is discussed.