Removal of copper from water samples by sorption onto powdered limestone

Abstract

The present paper describes the results of a study concerning Cu(II) removal from aqueous systems by batch adsorption experiments, using fine powdered Limestone (LS) as an effective sorbent, which is widespread and cheap. The parameters (i.e., initial solution pH, sorbent and copper concentrations, stirring times and temperature) influencing the sorption process, in addition to the effect of some foreign ions, were investigated. The results obtained showed that the sorption of Cu²⁺ ions onto LS is exothermic and spontaneous in nature, and followed first-order kinetics. The adsorption data were well described by Langmuir, Freundlich, Dubinin-Radushkevich (D-R) adsorption models over the concentration range studied. Under the optimum experimental conditions employed, the removal of ca. 100% of Cu²⁺ ions was attained. The procedure was successfully applied to the removal of copper from aqueous and different natural water samples. The adsorption mechanism is also suggested.