Adsorption of Pb(II) Ions from Aqueous Solutions by Pyrolusite-modifiedActivated Carbon Prepared from Sewage Sludge

摘要

In this study, activated carbons were prepared from sewage sludgeby chemical activation, and modified with pyrolusite as a catalyst duringactivation and carbonization. The influence of the addition of the mineral on theproperties of the produced activated carbons was evaluated. The modifiedactivated carbons exhibited BET surface areas which were 11.31% higher thanordinary sludge-based activated carbons and had larger pore volumes. The resultsof adsorption experiments showed that the pyrolusite-added adsorbentsperformed better towards the removal of Pb(II) ions than those without pyrolusiteaddition. At an initial pH of 5.4 for the Pb(II) ion solution, addition of thepyrolusite-added activated carbon led to the effective removal of Pb(II) ions withan adsorption capacity of ca. 70 mg/g. The adsorption capacity towards Pb(II) ionremoval also increased with increasing contact time and adsorbent dosage.Compared to adsorbents derived from various other materials, the pyrolusite-modified adsorbent had a relatively high Pb(II) ion adsorption capacity.Adsorption isotherm and kinetics studies showed that the adsorption of Pb(II)ions onto the pyrolusite-modified adsorbent was well fitted by the Langmuirisotherm and could be described by the pseudo-second-order kinetic model.