Adsorption of lead from aqueous solution onto coir-pith activated carbon

Abstract

Adsorption of lead (Pb(II)) from aqueous solution using H₂SO₄-activated carbon developed from coir pith (CPAC) was studied. Batch experiments were performed to explain the effect of initial pH (pH ₀), contact time, adsorbent dose, and temperature on adsorption. A pH ₀ of 5.0, a dose of 1 g L⁻¹ for adsorption at a concentration of Pb of 20 mg L⁻¹ were the optimal conditions. The adsorption of lead onto CPAC was found to be a gradual process and the quasi-equilibrium condition reached in 4 h. The adsorption followed pseudo-second-order kinetics and the adsorption equilibrium followed the Temkin isotherm. Thermodynamic parameters such as ΔG ⁰, ΔH ⁰, and ΔS ⁰ were evaluated by applying the Arrhenius and Van’t Hoff equations, and it was found that adsorption of Pb(II) on CPAC was spontaneous and endothermic.

Keywords:

• Adsorption
• Lead
• Pith activated carbon
• Kinetics
• Isotherms
• Thermodynamics