Characterization and electrokinetic properties of montmorillonite

Abstract

The determination of surface properties of montmorillonite clay is an important criterion for establishment of its adsorption ability against anionic and cationic species from wastewaters. In this study, electrokinetic surface properties of montmorillonite were investigated using the microelectrophoresis technique. The zeta-potential (zeta) analysis of the montmorillonite was done by streaming potential measurements as a function of salt concentration and equilibrium pH of solution. It was found that the zeta potential of the clay particles was negative for monovalent cations (KCl, LiCl, NaCl) added to solution phase. Divalent cations (CaCl2, Ca(NO3)(2), Pb(NO3)(2)) could provide a neutral charge at just maximum concentrations. In addition, montmorillonite had a negative charge even at pH 2 and only trivalent cations (Fe(NO3)(3), FeCl3) provided positive surface charge at just maximum concentration. The characterization of the montmorillonite was performed by using XRD, XRF, FTER, SEM imaging, and N-2-BET analyses. The determined porous structure and strong negative surface charge of the montmorillonite showed that this clay would be used effectively in removal of cationic species from waters.