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Alila S.,University of Sfax | Aloulou F.,Center National Of Recherche En Science Des Materiaux Cnrsm | Thielemans W.,University of Nottingham | Boufi S.,University of Sfax
Industrial Crops and Products | Year: 2011

Chemically modified starch nanocrystals were used as adsorbents for the removal of aromatic organic compounds from water. The nanocrystals were chemically modified by grafting with stearate moieties which enhanced the adsorption capacity of the nanometric substrate. Their adsorption capacity ranged between 150 and 900μmolg -1 of modified nanoparticles and the adsorption isotherms could be described accurately by the Langmuir model. The adsorption kinetics followed a two-step process with first pure adsorption of the aromatic compounds onto the surface of the nanoparticles followed by a diffusion of the compounds into the layer of surface chains grafted onto the nanoparticles. Furthermore, the feasibility of using these nanoparticles in continuous flow mode processes was confirmed using a fixed bed column setup. The fixed bed column could also be regenerated by washing with ethanol and was found not to exhibit any loss in adsorption capacity over multiples adsorption-desorption cycles. © 2010 Elsevier B.V.


Jabou K.,Laboratoire Of Chimie Des Materiaux Et Catalyse | Kochkar H.,Center National Of Recherche En Science Des Materiaux Cnrsm | Berhault G.,CNRS Research on Catalysis and Environment in Lyon | Ghorbel A.,Laboratoire Of Chimie Des Materiaux Et Catalyse
Studies in Surface Science and Catalysis | Year: 2010

Palladium nanoparticles (NPs) with well-controlled morphologies (cubes, rods, icosahedra) and with preferential crystallographic planes were prepared through a seed-mediated colloidal approach. Pd NPs were then impregnated onto high surface area hydrogenotitanate nanotubes before being evaluated in the selective hydrogenation of a α,β-unsaturated aldehyde, i.e. cinnamaldehyde. Their preferential exposition of crystallographic planes (mainly (100) and (111) sites) offers the unique ability to determine the influence of the structure-sensitivity of this selective hydrogenation reaction in real experimental conditions. Results show that the selectivity to saturated alcohol increases with increasing proportion of Pd(111) sites. © 2010 Elsevier B.V. All rights reserved.


Turki A.,Tunis el Manar University | Kochkar H.,Center National Of Recherche En Science Des Materiaux Cnrsm | Berhault G.,CNRS Research on Catalysis and Environment in Lyon | Ghorbel A.,Tunis el Manar University
Studies in Surface Science and Catalysis | Year: 2010

Pd- and Fe/Pd-HNT were elaborated by successive ionic exchange and wet impregnation at room temperature of hydrogenotitanate nanotubes (HNT) nanomaterials. Hydrogen peroxide was generated in situ via reaction of oxygen and formic acid (FA) over Fe/Pd-HNT catalysts. A high p-hydroxybenzoic acid (p-HBz) mineralization was achieved (52%) using Fe/Pd-HNT/FA/O 2/UV system compared to the simulated reaction using Fe/Pd-HNT/H 2O 2/UV system (34%). The rate of hydrogen peroxide formation over Pd-HNT catalyst, during in situ generation, probably plays a key role in controlling the kinetics of the p-HBz degradation. © 2010 Elsevier B.V. All rights reserved.

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