2.1.2. Pretreatment of adsorbent
The cotton stalk activated carbon was boiled and washed three
times in distilled water and dried at 105 ◦C for 24 h before being
used as adsorbent. The pore structures of the activated carbon were
investigated by using a computer controlled automated porosimeter
(Micromeritics ASAP-2020, America). Nitrogen was used as the
cold bath (77 K) and classical adsorption models BET theory was
used. The porous structural parameters used in this paper were
taken from BJH data. The pH at the point of zero charge (pHpzc)
of cotton stalk activated carbon was determined by batch equilibrium
method described by Babic . The elemental analysis of
the activated carbon was obtained from a CHN-O-Rapid Elemental
Analytical Instrument (Elementer, Germany)