The majority of the ACs prepared in this research was basically
microporous, because more than 90% of the total pore volume was
included within this range. This statement is confirmed by
analyzing the pore size distribution with the BJH theory. Fig. 2
shows also the BJH pore size distribution for the AC derived from
eucalyptus wood with ZnCl2, H3PO4 and KOH at different
impregnation ratios. It can be seen that the pore size distribution
of the AC samples are similar and more narrowly distributed and
mainly composed of micropores. It is good to mention that
adsorbent pores are classified as micropore (diameter < 2 nm),
mesopore (2 < diameter < 50 nm) and macropore (diameter > 50 nm) [18,38].