Utilization of agricultural waste to produce valuable products has opened opportunities in Egypt to
minimize serious public health risks from exposure to dangerous fumes that come from burning the
agricultural wastes in open fields. In this study, activated carbon produced locally from cotton stalks
was examined for the removal of target heavy metal contaminants from water and wastewater.
Adsorption studies conducted in completely mixed batch reactors showed the ability of the produced
activated carbon to remove heavy metals; namely lead, cadmium and copper; from aqueous solutions
in a pH range below that of precipitation and with high uptake capacity after an equilibrium reaction
time of 72 hours. The surface titration experiment indicated a negative surface charge of the produced
activated carbon in solution at pH as low as 6, meaning that electrostatic attraction of the divalent
heavy metals can occur below the pH required for precipitation. The highest adsorption capacity was
for lead, followed by copper and then cadmium. Multicomponent metal adsorption experiments
indicated a competition for the available surface sites. Adsorption capacities in the mixture were
reduced from their single-solute values for all metals.