Abstract

This study is made to prove the efficiency of the activated carbon (AC) of Lebanese Cymbopogon citratus in the adsorption of lead (Pb(II))
from aqueous medium. The adsorption was found to be dependent on initial metal ion concentration, pH of the solution, temperature,
contact time and adsorbent dose. The maximum adsorption capacity was found for the concentration of 450 mg L-1
, pH 4, temperature 25
o
C, contact time 2 h, and adsorbent dose 1g. The equilibrium adsorption was better described by Freundlich isotherm model rather than
Langmuir model. The kinetic data were better represented by the pseudo-second-order than the pseudo-first-order kinetic model.
Thermodynamic studies showed that the process was exothermic and spontaneous. The results of this study reveal that the activated carbon
(AC) of Lebanese Cymbopogon citratus is a very effective and environmentally friendly adsorbent, with low cost for Pb(II) removal.

Key words: Activated carbon, adsorption, isotherm, kinetic, thermodynamic.