Purification of a Brazilian Smectite Clay

Abstract:

In this work, a commercial Brazilian clay (BUN Bentonit União Nordeste), was purified by three different processes. Impurities and iron oxides limit the use of the Brazilian clays in applications such as filler for nanocomposites. The first purification method refers to the separation of the colloidal fraction of the clay, to remove the remaining larger than clay-size impurities. The second step involves the removal of iron oxide or hydroxide (dithionite-citrate-bicarbonate method). Finally, hydrogen peroxide was used to remove from the clay the organic residues. The clays were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), and had their particle size distribution measured (laser scattering). The clays were treated with a quaternary ammonium salt, to investigate the modification in its cationic exchange capacity. XRD results showed that the structure of the clay was not significantly modified with the removal of iron, and that there was incorporation of the organic salt into the interlayer space. Approximately 30wt.% of the iron ion content was removed (XRF).

• Periodical: Materials Science Forum (Volumes 727-728)
• Pages: 929-934
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.727-728.929
• Online since: August 2012
• Authors: Pedro Garcia Lins, Ticiane Sanches Valera, Nicole Raymonde Demarquette
• Keywords: Brazilian Smectite Clay, Purification Methods

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