Inspection of Fig. 5a–d showed two different characteristics
for Co(II) and Cu(II) metal ions adsorption. In case of Co(II)
metal ions, it is clear that the adsorption in the first stage occurred in
fast step. That leads to saturation of the adsorbent surface, and then
the rate of adsorption decreases considerably. The third step
occurred at longer timewith very small rate. The gradual decrease in
the adsorption capacity of the adsorbent at the third stage indicates
the desorption of Co(II) ions to themedium. Desorption of Co(II) ions
indicates the weak bond between the adsorbent and the metal ions.
That behavior is inverted in case of Cu(II) ions adsorption