Removal of heavy metals via adsorption on activated carbon synthesized from solid wastes

The huge quantity of date pits as solid waste byproduct in Saudi Arabia pose a problem as they are difficult to biodegrade. The potential of using date pits as a cheap precursor to prepare activated carbons was investigated. Steam as well as zinc chloride activated carbons were prepared from dates pit. The textural properties, including surface area, mean pore radius and total pore volume, were determined from the adsorption of nitrogen at 77 K. FT-IR spectroscopy and base neutralization capacity were used to determine the surface groups. The adsorption of Cu2+, Pb2+ and Cd2+ was studied in equilibrium method. FT-IR investigation of un-activated carbons identified phenolic, lactonic, -O-H, quinonic and carboxylate groups. For steam and zinc chloride activated carbons, some of the adsorption bands either disappeared or become less predominant, depending on the acidic or basic nature of the surface. The measurements of BNC indicated that steam activated carbons were predominately basic, while zinc chloride activated carbons exhibited acidic nature. Physical and chemical activation increase the porosity and thereby develop a higher surface area. The adsorption of Cu2+, Pb2+ and Cd2+ followed the order Pb2+ > Cu2+ > Cd2+. Zinc chloride activated carbons had a higher adsorption power compared with steam activated carbons. The adsorption behavior was affected by the textural and chemistry of the surface.