Influence of pH and ionic strength on Cd, Cu and Pb removal from water by adsorption in Na-bentonite

GLATSTEIN, DANIEL A.; FRANCISCA, FRANCO M.

APPLIED CLAY SCIENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 118 p. 61 - 67

0169-1317

This article presents a study on cadmium, copper and lead removal by means of adsorption in a natural Nabentonite. Influence of pH and ionic strength on clay fabric and its role on cation removal are analyzed by means of Zeta potential and sedimentation tests. Batch adsorption and kinetics testswere carried out to quantify the adsorption capacity of the bentonite at monospecies and ultispecies conditions,where ion competitionwas analyzed. Experimental results showthat ionic strength strongly affects clay structure and cadmiumremoval, but has little influence on lead and copper removal. Adsorption kineticswas fast in all cases, which was mostly related to reaction kinetics than to diffusion kinetics. Cadmium adsorption can be explained by linear adsorption models, while copper, lead and the multispecies tests showed good agreement with both the linear and Freundlich models within the tested concentration range. The results confirmthat tested Na-bentonite possesses a high capacity for the removal of Cd, Cu and Pb.