Papers by Author: Brahim Djellouli

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Authors: Salah Bahah, Saci Nacef, Derradji Chebli, Brahim Djellouli, Abdallah Bouguettoucha
Abstract: In order to search the correlation between textural properties and geometrical heterogeneity in clays, as characterized by the surface fractal dimension, we used, three different cationic clays; namely Kaolin of Hamam Dbagh, Montmorillonite (Mt) of Maghnia and a sample prepared from Sodium Montmorillonte (Na-Mt)) and three different synthetic anionic clays, ZnAlCO3, MgAlCO3 at a molar ratio equal to three (R=3), and NiAlCO3 with different molar ratios (R=2, R=3 and R= 4). This DS parameter was evaluated from nitrogen (N2) analysis gas. the fractal Frenkel-Halsey-Hill (FHH) (DS) models was used to estimate the surface fractal dimensions at two ranges of relative pressure, the first between 0.08 and 0.22, which were found Ds to be 2.59, 2.53 and 2.68 from Kaolin, Montmorillonite and Sodium Montmorillonte clays respectively and 2.33, 2.61, 2.53, 2.56 and 2.56 for ZnAlCO3 and MgAlCO3, NiAlCO3 (2, 3 and 4) respectively, and other at medium relative pressure, which there was an excellent linear adjustment for F-H-H equation within the range between 0.37 and 0.82, which were found Ds to be 2.77, 2.64 and 2.82 for Kaolinite, Montmorillonite and Sodium Montmorillonte clays respectively, and 2.68, 2.64, 2.40, 2.60, 2.47 for ZnAlCO3, MgAlCO3, NiAlCO3 (2, 3 and 4) respectively. SEM Characterization confirmed the heterogeneous distribution of the particles and the BET analysis confirmed the fractal nature of the surface of these materials. The zeta potential of the sample which is most used as an indicator of dispersion stability, show a proportionality between increases of zeta potential with increase of dimension fractal (DS), for the same type of clays ( (NiAlCO3) with (R=2, 3 and 4) and Mt, Na-Mt). Key words: Anionic clays; Cationic clays; Fractal dimension; geometrical heterogeneity; Frenkel-Halsey-Hill model.
Authors: Dalila Smail, Brahim Djellouli, Ali Ourari
Abstract: This paper presents preliminary results of modified Montmorillonite samples and the surface treatment with hydrochloric acid were investigated. The modification of this Montmorillonite surface, negatively charged and exchanged by organic cations such as alkylammoniums (Trimethylexadecyl C16 and Trimethyloctadecyl C18), yields a modified Montmorillonite (MMt). The resulting organo-mineral material acquires an organophilic character which could be used in several applications. The organically modified MMts were prepared by an ion exchange process in which sodium ions were replaced by alkylammonium ions. This material, used in the present work, is an Algerain montmorillonite obtained from MAGHNIA (West Algeria). Octadecyltrimethylammonium and hexadecyltrimethylammonium chlorides, utilized here as surfactants activators to organophilize the Montmorillonite. The microstructure of this modified Montmorillonite was characterized by XRD-diffraction with which the effects of the intercalation associated to the conformation of the long hydrocarbon chain were investigated. The results obtained showed that the amounts of hydrochloric acid added to these modified materials affect considerably the conformation of the intercalated surfactants. Their physical characteristics were determined by infrared spectrophotometer (FT-IR) and their chemical modification revealed that their thermal properties have been advantageously improved.
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