Removal of Lead and Cadmium from Aqueous Solution Using Activated Carbons from Desert Dates and Shea Nut Shells.

Abstract

Shells of Balanitesaegyptiaca (desert date) and Vitellariaparadoxa (shea nut) activated with 1.00 mol/dm3H2SO4and their blends were investigated for the removal of Pb and Cd from aqueous solution. Effects of operational parameters, such as contact time, pH, initial metal ion concentration and temperature were investigated. The adsorption process was found to be dependent on all the factors investigated. The optimum pH for the removal of Pb was 6, while Cd was found to be 8. Optimum contact time for Pb and Cd was 90 min. Highest removal of Pb and Cd was 70 and 65%, respectively. The adsorptive capacity of all the adsorbent used was in the order AC2>AC4>AC3>AC1. Experimental data tested fitted better into the Freundlich isotherm compared to the Langmuir isotherm. Adsorption kinetic of the process was best described by pseudo-second order model. Thermodynamic investigations showed that the process was spontaneous, feasible, and endothermic and proceed with increasing randomness.