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Ben Hamouda S.,Laboratoire Of Traitement Des Eaux Naturelles | Nguyen Q.T.,University of Rouen | Langevin D.,University of Rouen | Roudesli S.,University of Monastir
Comptes Rendus Chimie | Year: 2010

Poly(vinylalcohol) (PVA)/poly(ethyleneimine) (PEI)/poly(ethyleneglycol) (PEG) blend membranes were prepared by solution casting followed by solvent evaporation. The effects of the blend polymer composition on the membrane structure and CO2/N2 permeation characteristics were investigated. IR spectroscopy evidenced strong hydrogen bonding interactions between amorphous PVA and PEI, and weaker interactions between PVA and PEG. DSC studies showed that PVA crystallization was partially inhibited by the interactions between amorphous PVA and PEI blend, in which PEG separated into nodules. The CO2 permeability decreased with an increase in CO2 partial pressure in feed gas, while the N2 permeability remained constant. This result indicated that only CO2 was transported by the facilitated transport mechanism. The CO2 and N2 permeabilities increased monotonically with the PEI content in the blend membranes, whereas the ideal selectivity of CO2 to N2 transport showed a maximum. When CO2 is humidified, its permeability through the blend membranes is much higher than that of dry CO2, but the change in permeability due to the presence of humidity is reversible. © 2009 Académie des sciences. Source


Hamouda S.B.,Laboratoire Of Traitement Des Eaux Naturelles | Boubakri A.,Laboratoire Of Traitement Des Eaux Naturelles | Nguyen Q.T.,University of Rouen | Amor M.B.,Laboratoire Of Traitement Des Eaux Naturelles
High Performance Polymers | Year: 2011

Hydrophobic dense membrane PEBAX were prepared, and their suitability for a water pervaporation process was studied. The effects of the following parameters on the water flux were determined as operating conditions [brine inlet temperature (28-54°C) and NaCl concentration in the feed brine (0-3.5 mol L-1)]. A water flux of 1.3-7 g m-2 h-1 was obtained using this type of membranes. It was found that, for our application, the optimal specifications for our membrane is a thickness of 100 ?m and an operating temperature of 50°C that allow us to have a water flux of 7 g m-2 h-1 in the permeate side. These data are required for the manufacturing of a novel desalination system based on this type of dense membranes. © The Author(s) 2011. Source


Turki T.,Laboratoire Of Traitement Des Eaux Naturelles | Ben Hamouda S.,Laboratoire Of Traitement Des Eaux Naturelles | Hamdi R.,Laboratoire Of Traitement Des Eaux Naturelles | Ben Amor M.,Laboratoire Of Traitement Des Eaux Naturelles
Desalination and Water Treatment | Year: 2012

Ion-exchange technology was studied to remove nitrates using PUROLITE A 520E. Predicting the rate at which adsorption takes place for a given system is probably the single most important factor for adsorber design, with adsorbate residence time and ultimately the reactor dimensions controlled by the system's kinetics. A fixed volume stirred tank reactor was used to study the kinetics of adsorption in a single-component system. Results of the intraparticle diffusion and the film diffusion models show that the film diffusion was the main rate-limiting step at high concentrations of nitrates. Process parameters including the rate of agitation, pH, and initial concentrations of nitrates were examined and the obtained data were modeled using three kinetic models including the pseudo-first-order equation, secondorder equation, and intraparticular diffusion model. The best fit of experimental adsorption data was obtained by means of the pseudo-second-order models. Equilibrium data were fitted to the Freundlich, Langmuir, and Dubinin-Radushkevich isotherm equations, and the equilibrium data were found to be well represented by the Langmuir isotherm equation. The thermodynamic constants of adsorption phenomena, ΔH0 and ΔS0 were found to be - 14.88 kJ/mol and 1.08 J/mol in the range 300-343 K respectively. The negative values of the Gibbs free energy ΔG0 demonstrate the spontaneous nature of adsorption of nitrates onto PUROLITE A 520E. © 2012 Desalination Publications. All rights reserved. Source


Ben Moussa S.,Laboratoire Of Traitement Des Eaux Naturelles | Tlili M.M.,Laboratoire Of Traitement Des Eaux Naturelles | Batis N.,Unite de Recherche sur les Nanomateriaux et Leurs Applications | Amor M.B.,Laboratoire Of Traitement Des Eaux Naturelles
Crystal Research and Technology | Year: 2011

The present study explores struvite precipitation by degassing method under different temperature (14.5-35 °C). It is shown that an increase of temperature does not affect the nucleation kinetics but strongly influences the growth rate and the efficiency of the phosphate removal. This was attributed to the effect of temperature on the struvite solubility and then the reached supersaturation coefficient. It was also shown, by using degassing method, that the determined solubility constant (pK s) values of struvite, at 14.5, 20, 25 and 35 °C are 13.00, 12.82, 12.63 and 13.20, respectively, are close to those presented in the literature. The results show that temperature influences the kinetics of precipitation. First-order kinetics were found to be sufficient to describe the rate data. The rates decreased with increasing temperature and the apparent rate constants for the reaction were determined. Arrhenius plots yielded a relatively apparent high activation energy E a = 31.0 kJ·mol -1. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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