Characterization of Tataouines Raw and Activated Clay

Abstract

This study deals with the mineralogical and thermal analysis of red clay taken from the south of Tunisia (Tataouine area) which will be used in industrial and environmental fields. In that purpose the study had recourse to several quantitative and qualitative research instruments: chemical analysis, mineralogical study and thermal analysis. The analyses were carried out by different methods such as: (i) X-ray diffraction (XRD), (ii) infrared spectroscopy (IR), (iii) thermogravimetric analysis (TGA), (iv) differential thermal analysis (DTA) and (v) cation exchange capacity (CEC). The data collected from these techniques show that illite and kaolinite are the major clay phases. The accessory minerals detected in powdered rock is calcite.The raw clay has undergone an acid activation using the sulfuric acid. The acid activation of south of Tunisia clay increase the specific surface area by adsorption of methylene blue from 117 m 2 /g to 163 m 2 /g. The experimental investigation is performed in accordance with the methodology of the factorial design of experiments. The different factors or parameters used in this methodology are: the temperature (T), the contact time (t), the liquid/solid ratio (R), and the acid concentration (C). The optimal conditions, obtained by the statistically designed experiments, for the best results of methylene blue adsorption were: 60 °C, a contact time of 1.5 h, a liquid/solid ratio of 7 and acid concentration of 20%. These parameters are applied in the preparation of the sample used in characterization study. The effect of the reaction conditions on the solid structure is investigated by comparison with the raw clay sample.

Decolorization of soybean oil by acid‐activated Ca‐Bentonite (EL Gnater, Central Tunisia)

“…This indicates the release of Al 3+ , Mg 2+ and Fe 3+ cations from the octahedral sheets. The obtained results accord well with those in the previous studies 27–47 and confirm the chemical found analyses.…”

“…The infrared analyses of the untreated and activated clays are illustrated in Figure 5 to evaluate the influence of the acid treatments on clay material. As can be seen from the spectra of untreated clay (A) the adsorption bands at 3637.61 and 915.1 cm −1 attributed to stretching vibrations Al‐Al‐OH and deformation vibration Al‐OH‐Al, respectively, indicate that this clay is dioctahedral 45,46 . The bands at 840.16 cm −1 , 872 cm −1 can correspond to Al‐Mg‐OH and Al‐Fe‐OH.…”

“…A) the adsorption bands at 3637.61 and 915.1 cm À1 attributed to stretching vibrations Al-Al-OH and deformation vibration Al-OH-Al, respectively, indicate that this clay is dioctahedral 45,46. The bands at 840.16 cm À1 , 872 cm À1 can correspond to Al-Mg-OH and Al-Fe-OH.The intensity of these bands decreased gradually with the concentration of the used acid, namely 1.5, 3 and 4.5 N, in the activation of AA1, AA2 and AA3, respectively.…”

RSM optimization studies for cadmium ions adsorption onto pristine and acid-modified kaolinite clay

“…Due to acid activation, the pH decreased from 8.5 to 3.8. The results indicate the AMKC would be good enough to eliminate metal ions at pH > 3.8 [ 54 ]. A basic idea, samples develop positive charge when the pH of substance is lesser than the pH pzc .…”

Adsorption of Orange G Dye on Hydrophobic Activated Bentonite from Aqueous Solution

“…Some exchangeable cations were replaced during the activation by H + from sulfuric acid and by CTA + from cetyltrimethyl ammonium. In order to balance the negatively charged clay surfaces, the latter attract exchangeable positive ions contained in the solutions [38]. The CEC was reduced by pH treatment [39], and elements can also be released from the octahedral sheet [40].…”