During the first 30 min, adsorption rate of both materials was
extremely high, comprising approximately 95% of the total adsorption.
Then, the rate began to drop toward a steady state, with insignificant
levels of adsorption. The two adsorption materials reached
steady state for the same type of metal ion simultaneously, but
achieved steady state at different times for different metal ions.
As observed in the adsorption curve, the rapid adsorption of lead
in the first twenty minutes, and the rapid adsorption of copper in
the first thirty minutes, may be due to physical adsorption or ion
adsorption on the surface of the algae powder