Synthèse de MWNT dans un réacteur continu incliné rotatif à lit mobile par procédé CCVD

Conference (2012, October)

Optimized deposition of TiO2 thin films produced by a non-aqueous sol–gel method and quantification of their photocatalytic activity

Conference (2012, August)

Optimized deposition of TiO2 thin films produced by a non-aqueous sol-gel method and quantification of their photocatalytic activity

in Chemical Engineering Journal (2012), 195-196

TiO2 thin films have been produced by a dip-coating process using a non-aqueous sol-gel method. This study investigated the influence of the operating variables such as nature of the substrate, sol ... [more ▼]

TiO2 thin films have been produced by a dip-coating process using a non-aqueous sol-gel method. This study investigated the influence of the operating variables such as nature of the substrate, sol concentration, withdrawing speed of the dip-coater and number of layers on the physico-chemical properties of the films using XRD, GIXRD, UV-Vis spectroscopy, profilometry, spectroscopic ellipsometry and SEM. Photocatalytic activity of the films was evaluated by following the degradation of methylene blue under artificial UV light at 25°C. The performances of the catalysts were compared through the reaction rate constants determined using an apparent first-order kinetic model adjusted on the experimental data. This study showed that the photocatalytic activity and the reaction rate constant depend on the film thickness through the synthesis and dipping variable, with an optimum thickness of 80 nm being observed. An optimized transparent film exhibiting a high adhesion, a well crystallized TiO2-anatase phase, a good photocatalytic activity and a reaction rate constant k equal to 0.126 h-1 was obtained using a simple process. The specific photocatalytic activity of this film was higher to the one measured for TiO2 powders in previous works. [less ▲]

Large-scale synthesis of multi-walled carbon nanotubes in a continuous inclined mobile-bed rotating reactor by the catalytic chemical vapour deposition process using methane as carbon source

in Chemical Engineering Journal (2012)

Multi-walled carbon nanotubes (CNTs) were produced in a continuous inclined mobile-bed rotating reactor by the catalytic chemical vapour deposition of methane on a bimetallic Ni-Mo/MgO catalyst whose ... [more ▼]

Multi-walled carbon nanotubes (CNTs) were produced in a continuous inclined mobile-bed rotating reactor by the catalytic chemical vapour deposition of methane on a bimetallic Ni-Mo/MgO catalyst whose activity remains constant in the course of time. Measurements performed on the continuous reactor were validated to ensure that the installation worked correctly and that measurements were precise enough. The performance of the reactor was simulated using a model based on the chemical reactor engineering approach. Hypotheses of the model were verified, and a kinetic study was performed to obtain a kinetic rate expression and to determine the catalytic activity as a function of time. The purity level of produced CNTs depends on the desired properties of the product, so the operating conditions are linked to the purity level that is required. A minimal purity level corresponds to high carbon production, and a maximal purity level corresponds to high specific productivity. It was shown that operating conditions had to be fixed to reach a given specific productivity or a given carbon production, and the optimized operating conditions leading to those two opposite purity level objectives were established. [less ▲]

Modelling of a continuous rotary reactor for carbon nanotube synthesis by catalytic chemical vapour deposition

Conference (2011, November)

Optimized deposition of photocatalytic TiO2 thin films produced by a non-aqueous sol-gel method

Poster (2011, September)

Kinetic study of double-walled carbon nanotube synthesis by catalytic chemical vapour deposition over an Fe-Mo/MgO catalyst using methane as the carbon source

in Chemical Engineering Journal (2011), 175

Experimental procedure and statistical data treatment for the kinetic study of selective hydrodechlorination of 1,2-dichloroethane into ethylene over a Pd-Ag sol–gel catalyst

in Chemical Engineering Journal (2011), 173(3), 801-812

The kinetics of selective hydrodechlorination of 1,2-dichloroethane into ethylene over a Pd- Ag/SiO2 catalyst was studied using an a priori experimental design with five independent variables—temperature ... [more ▼]

The kinetics of selective hydrodechlorination of 1,2-dichloroethane into ethylene over a Pd- Ag/SiO2 catalyst was studied using an a priori experimental design with five independent variables—temperature and partial pressures of 1,2-dichloroethane, hydrogen, ethylene and hydrogen chloride. A Langmuir–Hinshelwood model including two types of active site and the 1,2-dichloroethane adsorption as the rate-determining step was found to fit correctly with experimental data, according to the analysis of variance and the analysis of pondered residuals. The study allowed for catalytic deactivation. The rigorous experimental and statistical approach followed to carry out such a kinetic study is explained in detail. [less ▲]

Ethylene partial pressure, carbon nanotube production and catalytic deactivation profiles through a continuous rotary reactor for carbon nanotube synthesis by the CCVD method

Conference (2009, August)

Modeling of a continuous rotary reactor for carbon nanotube synthesis by catalytic chemical vapor deposition

in AIChE Journal (2009), 55

The modeling of carbon nanotube production by the CCVD process in a continuous rotary reactor with mobile bed was performed according to a rigorous chemical reaction engineering approach. The geometric ... [more ▼]

The modeling of carbon nanotube production by the CCVD process in a continuous rotary reactor with mobile bed was performed according to a rigorous chemical reaction engineering approach. The geometric, hydrodynamic, physical and physicochemical factors governing the process were analyzed in order to establish the reactor equations. While the study of the hydrodynamic factor suggests a co-current plug-flow approximation, the physical factor mainly deals with the phenomena of transport and the transfer of mass, which can be neglected. Concerning the physicochemical factor, the modeling is based on knowledge of the expression of the initial reaction rate, and takes into account catalytic deactivation as a function of time, according to a sigmoid decreasing law. The reactor modeling allows obtaining the evolution of partial pressure, carbon nanotube production and catalytic deactivation along the reactor for given initial operating conditions. The comparison between experimental and calculated production highlights a very good fit of data. (c) 2009 American Institute of Chemical lEngineers AIChE J, 55: 675-686, 2009 [less ▲]