This study aims to determine the influence of concentration of potassium hydroxide (KOH) on the adsorption of Pb2+ and Cu2+ metal ions in industrial used water. The activated carbon was prepared from pineapple crown waste. Pineapple crown was pre-carbonized at 180oC for 1 hours. Chemical activation was done using KOH with variations in concentrations of 2, 3, and 4 M. The samples were irradiateā¦