Enhanced sorption of Cu2+ from sulfate solutions onto modified electric arc furnace slag

Abstract

Pristine electric arc furnace slag (EAFS) as well as EAFS modified by alkali activation i.e. alkali activated slag (AAS) have found a novel application as adsorbents used in Cu2+ removal from sulfate solutions. The adsorption tests were carried in batch conditions and results have shown that alkali activation of EAFS enhances the Cu2+ adsorption. The adsorption process was found to follow a pseudo second-order kinetic model and occurs via formation of posnjakite (Cu-4(SO4)(OH)(6)center dot H2O) on the surface of both, EAFS and AAS. Enhanced adsorption properties of AAS, compared to EAFS, are attributed to a more porous structure, larger specific surface area and an increased number of surface groups involved in the binding of Cu2+.