The system was heated to the desired temperature at
a rate of 5°C min
-1
, held at that desired temperature
for 60 min, and cooled with nitrogen overnight. The
carbon materials obtained in the experiments were
refluxed in a concentrated hydrochloric acid
solution to remove impurities and reduce the
amount of ash content. Then, they were washed
several times with hot distilled water, and finally
with cold distilled water until chloride ions were not
detected. The washed activated carbon samples were
dried in an oven at 103°C for 24h. Specific surface
areas and pore volumes of the activated carbons
were measured by N2 adsorption