4 résultat(s) recherche sur le tag 'Désorption'

Désorption thermoprogrammée (DTP) in L'ACTUALITE CHIMIQUE, N° 314 (12/2007)  

[article]  inL'ACTUALITE CHIMIQUE > N° 314 (12/2007) . - p. 51-52 Titre : Désorption thermoprogrammée (DTP) Type de document : texte imprimé Année de publication : 2007 Article en page(s) : p. 51-52 Note générale : Bibliogr. Langues : Français (fre) Catégories : Catalyse hétérogène Tags : Désorption  température  programmée  Spectoscopie  TPD  TPS Index. décimale : 540 Chimie et sciences connexes En ligne : https://www.lactualitechimique.org/Fiche-catalyse-no-50-Desorption-thermoprogram [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3870 [article]

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Adsorption and desorption of ionic surfactants / T. Pusic in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 47, N° 3/2010 (24/05/2010)

[article]  inTENSIDE, SURFACTANTS, DETERGENTS > Vol. 47, N° 3/2010 (24/05/2010) . - p. 173-178 Titre : Adsorption and desorption of ionic surfactants Type de document : texte imprimé Auteurs : T. Pusic, Auteur ; A. M. Grancaric, Auteur ; A. Tarbuk, Auteur ; O. Sauperl, Auteur ; I. Soljacic, Auteur Année de publication : 2010 Article en page(s) : p. 173-178 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Surfactants  Adsorption  Désorption  Fibre  'Potentiel  électrocinétique''Valeur  de  rétention  d'eau'  WRV Index. décimale : 668.1 Agents tensioactifs : savons, détergents Résumé : Surfactants as organic compounds are widely used in the processes of textile finishing and care with regard to different variations and specific hydrophilic/hydrophobic character. Specific behaviour of these compounds is partly based on the adsorption process. In this study the adsorption and desorption of ionic surfactants have been studied upon the influence of fibre composition and surfactant ionogenity as well as variation of hydrophobic chain length and hydrophilic group in the molecule. Textile fibres were characterized through electrokinetic potential, sorption characteristics and swelling capacity expressed by moisture regain and water retention value (WRV). Different types of cationic and anionic surfactants were adsorbed on cotton, wool, polyester and polypropylene fibres at 20°C during 60 minutes. The quantity of adsorbed surfactants on textile fibres was determined by potentiometric titration. The textile fibres were centrifuged afterwards and the amount of surfactants was determined in the centrifugate, respectively. Drying followed at 60°C. The desorption of surfactants was performed at 20°C during 30 minutes. The results showed a correlation between amount of adsorbed, desorbed and residual surfactants and swelling capacity expressed through WRV. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9468 [article]

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A fluorescence study on dissolution of polymeric glasses prepared in various molecular weights / Önder Pekcan in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 75, N° 944 (09/2003)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 75, N° 944 (09/2003) . - p. 55-63 Titre : A fluorescence study on dissolution of polymeric glasses prepared in various molecular weights Type de document : texte imprimé Auteurs : Önder Pekcan, Auteur ; Saziye Ugur, Auteur Année de publication : 2003 Article en page(s) : p. 55-63 Note générale : Bibiogr. Langues : Américain (ame) Tags : Cinétique  Polymère  vitreux  Gel  colloïdal  Polymérisation  masse  Désorption  Relation  moléculaire  propriété  Méthode  mesure  Dissolution  Gonflement  Fluorescence  Extinction  luminescence  radicalaire  Polyméthacrylate  méthyle Index. décimale : 667.9 Revêtements et enduits Résumé : Polymethyl methacrylate (PMMA) discs in various molecular weights, Mw, were prepared by free-radical polymerization of methyl methacrylate (MMA). Pyrene (P) was introduced during polymerization as a fluorescence probe to monitor the gelation and dissolution processes in chloroform vapor and solvent, respectively. In-situ steady state fluorescence (SSF) experiments were performed to monitor vapor uptake and chain desorption processes. Direct illumination of PMMA discs were performed to excite the P molecules embedded inside the PMMA glass. Variation in P intensity, I, was monitored during the swelling of the PMMA material exposed to chloroform vapor. It was observed that PMMA film swells like a crosslinked polymeric gel at early times by obeying the Li-Tanaka equation. Swelling time constants, tc, of PMMA discs were measured and found to have a strong correlation with the molecular weight, of PMMA. In a separate experiment, when the PMMA discs were in chloroform, desorption of PMMA chains from glass discs was monitored by observing the change of pyrene fluorescence intensity. A diffusion model with a moving boundary was employed to quantify the fluorescence data observed from dissolving PMMA discs made at various molecular weights. It was observed that desorption coefficient, D, decreased by increasing Mw by obeying the D»Mw–1 law. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5573 [article]

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Removal of crystal violet from water by adsorbent prepared from turkish coffee residue in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 49, N° 2 (03-04/2012)

[article]  inTENSIDE, SURFACTANTS, DETERGENTS > Vol. 49, N° 2 (03-04/2012) . - p. 107-113 Titre : Removal of crystal violet from water by adsorbent prepared from turkish coffee residue Type de document : texte imprimé Année de publication : 2012 Article en page(s) : p. 107-113 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Surfactants Tags : Adsorption  'Résidue  café  turque'  Désorption  'Crystal  violet Index. décimale : 668.1 Agents tensioactifs : savons, détergents Résumé : Carbon prepared from Turkish coffee residue was used to remove crystal violet dye from aqueous solutions. The adsorbent was characterized by surface analyzer, infra red (IR) spectroscopy, Boehm titration and mass titration. Adsorption was studied as a function of pH, dye concentration and contact time. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to describe the kinetic data. The adsorption of crystal violet dye on prepared adsorbent followed pseudo second order kinetic model rather than pseudo first order kinetic model. The adsorption equilibrium data were analyzed using the Langmuir, Freundlich and Temkin isotherms model. The pH of the solution affects the adsorption capacity of the adsorbent. An increase in the adsorption capacity of the dye was observed with increase in pH. However, this was up to pH 6.5. The increase was insignificant from pH 6.5 to 10. The desorption experiments showed the possibility of regeneration of the adsorbent. Equilibrium was attained within 4 hour for 30 mg L–1 of dye concentration, while for 25 mg L1 and 15 mg L–1 it was less than 4 hour. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=13902 [article]

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