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

摘要

Adsorption of lead (Pb(Ⅱ)) from aqueous solution using H_2SO_4-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 gL~(-1) for adsorption at a concentration of Pb of 20 mgL~(-1) were the optimal conditions. The adsorption of lead onto CPAC was found to be a gradual process and the quasi-equilib-rium 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.