Adsorption of ions of heavy metals in aqueous solutions utilizing montmorillonite

Abstract

The adsorption process is an alternative treatment method used to remove heavy metals of industrials effluents. In the present paper, the sorption processes of the metals nickel (II), copper (II) and lead (II) in aqueous solutions, utilizing montmorillonite like substrates, including adsorption isotherms of single metal solutions were studied. According to X ray diffraction the principal constituent of montmorillonite is the quartz (SiO2) that in the surface area create the most likely group Si-OH. This group is probably going to absorb the cations of the solutions. On the other hand, the dissociated group (-S-O) is a weak Lewis acid because of the polarization, and the chemisorption process in this case is not favorable. The Langmuir adsorption model, in all cases, was found to present the highest regression values (R2), and therefore the best fit. The mineral showed the ability to take up the tested heavy metals in order Ni (II) > Pb (II) > Cu (II), and this could be related to the valence and the hydration radius (IR) of the cations. According to the presented results in this paper the montmorillonite can be used for removal a considerable amount of heavy metals present in aqueous effluent.