for an initial copper concentration of 100 mg/L, the kinetics
of copper removal from aqueous solution by dried sunflower
leaves presents a shape characterized by a strong increase of
the amount of copper sorbed during the first minutes of contact
solution–sunflower leaves, follow-up of a slow increase until to
reach a state of equilibrium. As an approximation, the removal
of copper ions can be said to take place in two distinct steps:
a relatively fast one followed by a slower one. The necessary
time to reach this equilibrium is about 5 h and an increase of
removal time to 24 h does not show notable effects. At equilibrium,
the amount of copper sorbed by dried sunflower leaves is
about 34.60 mg/g (0.54 mmol/g) corresponding to a removal of
about 73% of initial copper solution.