This paper describes the adsorption of Cu2+ and Fe2+ ions, common heavy metals found in industrial wastewater, by a fly ash-based geopolymer in batch adsorption experiments. Kinetics studies showed that the adsorption of each ion followed a pseudo-second order reaction. Moreover, adsorption isotherm of Cu2+ and Fe2+ ions followed the Langmuir model. Monolayer adsorption capacities were approximately 53.76 mg/g for Cu2+ ion and 52.63 mg/g for Fe2+ ion, respectively.
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