Physico-chemical and mineralogical characterization

of a Moroccan bentonite (Trebia) and determination

of its nature and its chemical structure


A. Er-ramly*, A. Ider

Laboratoire de procédés et de l'exploitation des ressources naturelles, l'Environnement et les matériaux,

Département de Chimie Appliquée et Environnement.

L'équipe de développement, la structure et les propriétés des matériaux,
Faculté des Sciences et Techniques de Settat BP 577, Université Hassan 1er - Maroc

* Corresponding author: E-mail:

Received: 18 May 2011; revised version accepted: 28 August 2011



This study concerns the results of Physicochemical and mineralogical characterization of a Moroccan bentonite (bentonite Trebia) and determination of its nature and its chemical structure. Several techniques were used; in particular X-ray diffraction (XRD), scanning electron microscopy coupled with EDX microanalysis (SEM-EDX), differential thermal and gravimetric analyses (DTA-TGA) and finally infrared Fourier transform (FTIR) and X-ray fluorescence (XRF). The bentonite fine fraction (< 2 µm in size), was characterized by BET method for specific surface area, and a cation- exchange capacity.

The X-ray diffraction analysis supplemented by gravimetric analysis showed that Trebia bentonite is  primarily smectite (63 wt %) with the presence of feldspar (30 wt%), magnetite (5 wt%) and an amorphous iron oxide in the form of scales (2 wt%). It has a specific surface area by using surface area analyzer and N2 gas was used as adsorbate under atmosphere of 37 m²/g, and a cation- exchange capacity (CEC) of 89 meq/100g. in sheets of smectite saturated with K allows to highlight the heterogeneity of charge and they are closed and their presence reduces the CEC, the structural formula calculated for bentonite has shown that the beidellite has a high charge density and has a rich iron. SEM-EDX, X-ray, chemical analysis and Infrared spectroscopy demonstrated that this beideliite contains iron Fe3 + in the octahedral sheet. The origin of the charge sheets is tetrahedral (Si3.6 Al0.33) with total charge 0.48 from which 0.33 (68.7%) occurring in tetrahedral sheet, the beidellitic character of the smectite is present (more than 50%) with a phase rich in iron.

Keywords:  XRD; (DTA-TGA); (SEM-EDX); FTIR; FX; Bentonite Trebia; Beidellite, Morocco.

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