The aim of this work was to synthesis highly amorphous geopolymer from waste coal fly ash, to be used as
an adsorbent for lead Pb(II) removal from aqueous wastewater. The effect of various parameters including
geopolymer dosage, initial concentration, contact time, pH and temperature on lead adsorption were
investigated. The major components of the used ash in the current study were SiO2, Al2O3 and Fe2O3
representing 91.53 wt% of its mass. It was found that the synthesized geopolymer has higher removal
capacity for lead ions when compared with that of raw coal fly ash. The removal efficiency increases with
increasing geopolymer dosage, contact time, temperature, and the decrease of Pb2+ initial concentration.
The optimum removal efficiency was obtained at pH 5. Adsorption isotherm study indicated that Langmuir
isotherm model is the best fit for the experimental data than Freundlich model. It was found also
that the adsorption process is endothermic and more favorable at higher temperatures.