Physico-chemical activation of South African bentonite clay and impact on metal adsorption capacity

Abstract

The aim of the project is to investigate the influence of physico-chemical activation on the metal adsorption capacities of natural bentonite clay from the North West Province of South Africa. The clay has been characterized using XRF and XRD analysis, in order to determine the mineralogical and elemental composition of the clay. The following activation techniques have been investigated to determine the influence they have on the adsorption capacities of the clay: acid activation, heat treatment, time of treatment, type of acid and concentrations of the acids. The kinetic and isotherm models have been used to determine the adsorption behaviour of the activated and non-activated clays. The clay adsorption capacity for the removal of Co(II) was improved after chemical treatment, but the adsorption capacity for the removal of Pb(II) was decreased after activation. The FTIR analysis has shown that the binding group mainly involved in the removal of metals is -CO. This study informs on the suitable activation technique for the improvement of the adsorption capacity of the typical clay from the North West Province of South Africa