Lead Adsorption onto Various Solid Surfaces

Abstract

Adsorption is becoming an important method in water and wastewater treatment technology at low concentrations. Pb 2+ adsorption at low concentration onto various solid surfaces using either nano metal oxide of MnO 2 , or granulated activated carbon (GAC) or agricultural by-products such as tea leaves and coffee residue are considered promising. In this adsorption study the measurements were conducted by equilibrating Lead solutions at different concentrations range 19 - 291 μmol·L -1 with various adsorbent suspensions in the concentration range 0.388 - 8.738 g·L -1 . Comparing all the adsorption capacities calculated using Langmuir equation Pb 2+ adsorption by MnO 2 shows the highest adsorption capacity with the estimated Γ m = 528.0 μmol·g –1 at a fixed equilibrium constant K = 0.0119 L·μmoL -1 . In addition, the Pb 2+ adsorption by coffee residue is subject to a particle concentration effect in which the adsorption density decreases as the concentration of solid adsorbent C s is increased. The Pb 2+ adsorption by tea leaves, MnO 2 and GAC shows less dependency to the concentration of solid adsorbent C s , especially at lower metal ion concentrations. In the particular case of Pb 2+ adsorption on MnO 2 there appears to be no dependence on C s .