Résumé
The present work aims to study the effect of sulfuric acid and sodium hydroxid on two types of natural clays from two regions of Cameroon. Kaolinite clay from Wak and a montmorillonite clay from Maroua were activated using three concentration of sulfuric acid and sodium hydroxide respectively. The effect of the H2SO4 and NaOH activation on the composition, structure and surface properties of the different clay minerals were investigated in this study by using elemental chemical analysis, X-Ray Diffractometry, IR Spectroscopy and gas adsorption-desorption measurement. The chemical compositions of the raw clays and activated clays at different acid and alkali concentrations were analysed to investigate the extent of cations dissolution and exchange. Cation Exchange Capacity (CEC) was found to decrease with increase in acid and alkali concentration. Increasing concentration of sulfuric acid from 0.5M to 2M induce the increasing of BET specific surface area of the montmorillonite and kaolinite clays, while alkali treatment of the same clays induce contrary effect. The specific surface increased from 79m2/g to 99m2/g for untreated montmorillonite and montmorillonite treated with H2SO4 2 M respectively. Acid treatment leads to severe mineral crystal structure alteration which is shown characteristic peaks lowering on the patterns, indicating a decrease in the regularity of the mineral structure of studies clays.