A study of adsorption of cadmium, copper and lead by two clays from Burkina Faso

Abstract : Water pollution caused by natural and anthropogenic causes become a major problem for many countries around the world in trying to find adequate and accessible means of treating polluted water. For more than a decade, research is focused on local adsorbent materials such as clays. It is in this dynamic that two clays extracted in Burkina Faso and referenced KORO and SIT were used to evaluate their capacities to reduce the content of heavy metals in aqueous solutions simulating waste water. The monitoring of the removal processes uses electrochemical characterizations, as voltammetry, evidencing a removal degree of heavy metals exceeding 90%. Characterizations of the process were also obtained by X-ray diffraction, Infrared Spectroscopy and Scanning Electron Microscopy. It is shown that the removal process occurs through the formation of clay-heavy metals complexes with both KORO and SIT. The three major mechanisms that were evidenced are complexation, ion-exchange and precipitation.