The Ca(II) concentration increased in solution as the amount of metal ions increased;
this was occurred due to themetal sorption onto biosorbent.
The Ca(II)concentration was 10 mg/L when the seashell powder was in25 mL deionized water, 20 mg/L in 25 mL of 20 mg/L Pb(II) solution, and 30 mg/L in 25 mL of 100 mg/L of Pb(II) solution.