Removal of Lead (II) Ions from Aqueous Solution Using Eggplant Peels Activated Charcoal

Abstract

The eggplant peel activated charcoal (EPPAC) was investigated as an adsorbent for the removal of lead II ions from aqueous solution. Three methods were tested for the production of eggplant peel activated charcoal (EPPAC) from eggplant peel charcoal (EPPC), yielding three different products; EPPAC-1, EPPAC-2, and EPPAC-3. The difference among the three methods lies in the primary physical mixing of the EPPC with the activating agent (potassium hydroxide) before heating the mixture in a furnace for activation. The removal efficiency of lead II ions by the three adsorbents was 57.7%, 70.0%, and 60.0% for EPPAC-1, EPPAC-2, and EPPPAC-3, respectively. The optimized activation parameters for EPPAC-2 were: activation time 2 hours, activation temperature 700°C, and activation ratio 1:2 (EPPAC: KOH). Scanning electron microscopy (SEM) revealed that EPPAC-2 has the most porous structure. The surface area of EPPAC-2 was measured to be 739 m²/g. Adsorption kinetics of lead (II) is best described by the pseudo-second-order kinetic model with second order rate constant of 1.70 × 10⁻³ g/mg.h at room temperature. The adsorption of lead on EPPAC-2 is found to follow the Langmuir isotherm with a maximum adsorption capacity of 1.4 × 10² mg/g.

Keywords:

• eggplant peel
• activated charcoal
• adsorption
• isotherm
• low cost adsorbent
• wastewater treatment
• heavy metals