Adsorptive removal of manganese (II) from aqueous solution using graphene oxide: A kinetics and thermodynamics study

Abstract

An excess amount of manganese is known to affect neurological toxicity. This study focused on adsorptive removal of Mn(II) using graphene oxide, which was carried out under optimum conditions after varying some experimental effects including pH, an incubation time and an initial concentration. It was demonstrated that Mn(II) adsorption follows both Langmuir and Freundlich isotherms. The maximum adsorption capacity for Mn(II) removal from an aqueous solution was 41.67 mg/g at pH 5 and their adsorption state was completed within 30 min. The adsorption kinetics was in accordance with pseudo second-order kinetic model. In thermodynamics diversion, changes in free energy, enthalpy and entropy were also studied. Overall, the adsorption process was exothermic and spontaneous in nature.