Abstract
In this study, activated carbon was synthesized from durian peel and used for the removal of lead (II) ions from water. The
activated carbon was produced with physical activation method using CO2 as the activating agent at 900 oC. Prior to the
activation process, durian peel was carbonized under either nitrogen atmospheric or vacuum pyrolysis in order to compare the
properties of the synthesized activated carbons. Suitable adsorption kinetics and isotherm models for the lead (II) removal in a
batch system were evaluated. The experimental data were analyzed based on five adsorption kinetics models (pseudo-first-order,
pseudo-second-order, Elovich, intraparticle diffusion and liquid film diffusion models) in order to determine the best fit model
for the adsorption of lead (II) ions on durian peel-derived activated carbons. Langmuir and Freundlich adsorption isotherms were
applied to the experimental data at equilibrium. Characterization of the synthesized activated carbon included N2 adsorption,
FTIR, iodine number and methylene blue adsorption. The results showed that the activated carbon synthesized under vacuum
pyrolysis had greater BET surface area, pore volume and lead (II) adsorption capacity than that synthesized under nitrogen
atmospheric pyrolysis. The adsorption kinetics followed the pseudo-second-order model, suggesting chemisorption as the rate
controlling step. Langmuir adsorption isotherm better fitted to the experimental data than Freundlich adsorption isotherm. Durian
peel-derived activated carbon is a useful adsorbent to remove lead (II) ions from water since durian peel is abundant and locally
acquired with no cost.