A preliminary examination of the adsorption characteristics of Pb(II) ions using sulphurised activated carbon prepared from bagasse pith

Abstract

Bagasse pith, a sugar industry waste, has been converted into sulphurised activated carbon by carbonisation at 200°C under N₂ for 2h, followed by steam activation in presence of SO₂ and H₂S at 400°C for 2h. The adsorption characteristics of Pb(II) ions on activated carbon have been examined from aqueous solutions using batch technique. The effect of agitation

period, initial concentration of sorbate, <i>p</i>H, ionic strength, temperature and particle size of the adsorbent has been studied to optimise the conditions for maximum removal of Pb(II) ions. The maximum removal takes place in the <i>p</i>H range of 4.0-8.0.With an initial concentration of Pb(II) at 50 mg/L at 30°C and <i>p</i>H 6.0, its removal has been found to be 99.8%. The process of uptake is governed by a pseudo-second-order kinetics. Kinetic parameters as a function of initial concentration and temperature have been calculated. Decrease in ionic strength and increase in temperature of the solution has been found to improve the uptake of Pb(II). Studies show that the adsorption decreases with an increase in particle size of the adsorbent. Sorption data of Pb(II) in the concentration range 50-1000 mg/L have been correlated with Langmuir isotherm model. Sulphurised activated carbon had adsorption capacities for Pb(II) from 200.08 mg/g at 30°C to 243.93 mg/g at 60°C, which is much higher than the values for the adsorbent materials reported in the literature. The adsorbent has been satisfactorily used for the removal of Pb(II) from synthetic wastewaters. The adsorbed Pb(II) ions are completely recovered with 0.2 M HCl.