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32 results on '"Bergaoui, Latifa"'

1. Interaction of ammonium with birnessite: Evidence of a chemical and structural transformation in alkaline aqueous medium

Author

Boumaiza, Hella, Coustel, Romain, Despas, Christelle, Ruby, Christian, and Bergaoui, Latifa

Subjects
Condensed Matter - Materials Science
Abstract

The ammonium cation interaction with Na-birnessite in aqueous alkaline medium was studied. Solution and solid analysis give evidence that birnessite is not only acting as a cationic exchanger toward NH4+. The surface analysis performed by XPS showed that N1s spectra are characterized by the existence of two different environments: one assignable to an interlayer NH4+ and the second to a chemisorbed N-species. Structural and chemical transformations were observed on birnessite with nitrogen mass balance deficit. The monitoring of NH4 +, Na+, Mn2+, NO3- and NO2- and solid changes (average oxidation state of Mn, cation exchange capacity, solid nitrogen content and symmetry evolution identified by XRD and FTIR) indicate unambiguously that NH4+ reacts chemically with the birnessite.

Published
2022

2. Conditions for the formation of pure birnessite during the oxidation of Mn(II) cations in aqueous alkaline medium

Author

Boumaiza, Hella, Coustel, Romain, Medjahdi, Ghouti, Ruby, Christian, and Bergaoui, Latifa

Subjects
Condensed Matter - Materials Science
Abstract

Birnessite was synthetized through redox reaction by mixing MnO4-, Mn2+ and OH- solutions. The Mn(VII): Mn(II) ratio of 0.33 was chosen and three methods were used consisting in a quick mixing under vigorous stirring of two of the three reagents and then on the dropwise addition of the third one. The obtained solids were characterized by XRD, FTIR and XPS spectroscopies. Their average oxidation states were determined from ICP and CEC measurements while their surface properties were investigated by XPS. This study provides an increased understanding of the importance of dissolved oxygen in the formation of birnessite and hausmannite and shows the ways to obtain pure birnessite. The role of counter-ion ie. Na+ or K+ was also examined.

Published
2022
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23. A comparative study of the acidity toward the aqueous phase and adsorptive properties of Al13-pillared montmorillonite and Al13-pillared saponite

Author

Bergaoui, Latifa, Mrad, Ihsen, Lambert, Jean-Francois, and Ghorbel, Abdelhamid

Subjects
Clay -- Analysis, Soil absorption and adsorption -- Analysis, Cadmium -- Analysis, Copper -- Analysis, Chemicals, plastics and rubber industries
Abstract

The selectivity of an Al13-pillared saponite and an Al13-pillared montmorillonite for Cd2+ and Cu2+ adsorption was investigated. Pillared clays adsorb more cadmium and copper than classic aluminum hydroxides which is because of a higher density of surface aluminum groups. A number of differences in behavior were seen between pillared montmorillonite and pillared saponite. Pillared montmorillonite is more acidic, which is correlated with a more advanced degree of structural modification of the pillars on calcination.

Published
1999

25. Optimization of Hydrothermal and Diluted Acid Pretreatments of Tunisian Luffa cylindrica (L.) Fibers for 2G Bioethanol Production through the Cubic Central Composite Experimental Design CCD: Response Surface Methodology

Author

Zaafouri, Kaouther, primary, Ziadi, Manel, additional, Ben Hassen-Trabelsi, Aida, additional, Mekni, Sabrine, additional, Aïssi, Balkiss, additional, Alaya, Marwen, additional, Bergaoui, Latifa, additional, and Hamdi, Moktar, additional

Published
2017
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32. Silane layers on silicon surfaces: mechanism of interaction, stability, and influence on protein adsorption.

Author

Aissaoui N, Bergaoui L, Landoulsi J, Lambert JF, and Boujday S

Subjects
Adsorption, Microscopy, Atomic Force, Surface Properties, Proteins chemistry, Silanes chemistry
Abstract

In this work the mechanism of (3-aminopropyl)triethoxysilane (APTES) interaction with silicon surfaces is investigated at the molecular level. We studied the influence of experimental parameters such as time, temperature, and concentration on the quality of the APTES layer in terms of chemical properties, morphology, and stability in aqueous medium. This was achieved using a highly sensitive IR mode recently developed, grazing angle attenuated total reflection (GA-ATR). This technique provides structural information on the formed APTES layer. The topography of this layer was investigated by atomic force microscopy in aqueous medium. The hydrophilicity was also studied using contact angle measurement. Combining these techniques enables discussion of the mechanism of silane grafting. Considerable differences were observed depending on the reaction temperature, room temperature or 90 °C. The data suggest the presence of two adsorption sites with different affinities on the oxidized silicon layer. This also allows the optimal parameters to be established to obtain an ordered and stable silane layer. The adsorption of proteins on the APTES layer was achieved and monitored using in situ quartz crystal microbalance with dissipation monitoring and ex situ GA-ATR analyses.

Published
2012
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