Physicochemical characterization of edible clays and release of trace elements

The mineralogical composition of seven edible clays from West Africa (Ivory Coast, Guinea and Senegal) was determined by X-ray diffraction, thermal (DTA, TGA and DSC) and chemical (ICP-MS and ICP-OES) analyses and measurement of specific surface areas and density. The major compounds were kaolinite, illite, muscovite, quartz and feldspars. Electrochemical analysis of clay suspensions by voltamperometry (SnO 2:F) yielded no results at 6.5 < pH < 7 and pH ≈ 8.3. However, ionic species transfer was revealed at pH ≈ 1.8 by an anodic peak. The analysis by X-ray diffraction of the metal cation layers which were deposited on the blades (SnO 2:F), showed the presence of mineral elements having therapeutic implications such as Fe and Zn.