Trivalent Chromium removal from Aqueous solution using Raw Natural Mixed Clay from Burkina Faso

• Acid-base properties of the raw mixed clay TOU from Burkina Faso, were study as well as the potential of the sample, in removing of chromium(III). The interactions of chromium(III) cation with the natural mixed clay minerals were examined using extended X-ray absorption fine structure (EXAFS) spectroscopy. Chemical elementary composition study of the mixed clay revealed presence of silicon, Aluminum and iron as mains elements. Qualitative mineralogical characterization of the clay by X-ray diffraction, point out quartz and 7 Å halloysite as the dominating component in the sample. pHpzc of the clays, as determined by potentiometric titrations, was 8.21. Cr3+ adsorption on clay started at pH below pHpzc indicating inner-sphere complexes formation. More than 95% of chromium(III) is achieved at pH greater than 7. Chromium(III) forms a tetramer hydrolysis complex on the mineral surface with Cr-O bond and Cr···Cr distances of 2.487, 3.087 and 3.636 Å, respectively, which is indicative of a chain structure with edge sharing CrO6 octahedra.

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NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Multidisciplinär geovetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Geosciences, Multidisciplinary (hsv//eng)

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