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Dimethyl sulfide photocatalytic degradation in a light-emitting-diode continuous reactor / Zimeng Wang in Industrial & engineering chemistry research, Vol. 50 N° 13 (Juillet 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 7977-7984 Titre : Dimethyl sulfide photocatalytic degradation in a light-emitting-diode continuous reactor : kinetic and mechanistic study Type de document : texte imprimé Auteurs : Zimeng Wang, Auteur ; Jing Liu, Auteur ; Yuancan Dai, Auteur Année de publication : 2011 Article en page(s) : pp. 7977-7984 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics  Reactor  Photochemical  degradation Résumé : This study investigated the feasibility, kinetics, and reaction pathways of the photocatalytic degradation of dimethyl sulfide (DMS) in a light-emitting-diode- (LED-) based continuous reactor. Four types of LEDs, with peak wavelengths at 365, 375, 385, and 402 nm, were used for comparison. The data were fitted with the Langmuir- Hinshelwood kinetic model, in which the rate constants for 365- and 375-nm LEDs were significantly larger than those for the 385- and 402-nm LEDs. The effect of wavelength on the reaction rate followed the TiO2 absorption spectrum. The effect of radiation intensity agreed with a nonlinear power law and was attributed to the TiO2 absorption of photon energy. For the 365- and 375-nm LEDs, the transition of the exponent values from first-order to one-half-order was estimated to occur at 0.5-1.0 mW·cm-2, whereas the 385- and 402-nm LEDs did not show a transition at this intensity. Dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO2), dimethyl disulfide (DMDS), methanethiol (MT), methanesulfonic acid (MSA), and sulfate were identified as the reaction products by gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), and ion chromatography (IC). A plausible reaction mechanism is proposed for DMS photocatalytic degradation based on the reaction products detected and possible intermediates formed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24332121 [article] Dimethyl sulfide photocatalytic degradation in a light-emitting-diode continuous reactor : kinetic and mechanistic study [texte imprimé] / Zimeng Wang, Auteur ; Jing Liu, Auteur ; Yuancan Dai, Auteur . - 2011 . - pp. 7977-7984. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 7977-7984 Mots-clés : Kinetics  Reactor  Photochemical  degradation Résumé : This study investigated the feasibility, kinetics, and reaction pathways of the photocatalytic degradation of dimethyl sulfide (DMS) in a light-emitting-diode- (LED-) based continuous reactor. Four types of LEDs, with peak wavelengths at 365, 375, 385, and 402 nm, were used for comparison. The data were fitted with the Langmuir- Hinshelwood kinetic model, in which the rate constants for 365- and 375-nm LEDs were significantly larger than those for the 385- and 402-nm LEDs. The effect of wavelength on the reaction rate followed the TiO2 absorption spectrum. The effect of radiation intensity agreed with a nonlinear power law and was attributed to the TiO2 absorption of photon energy. For the 365- and 375-nm LEDs, the transition of the exponent values from first-order to one-half-order was estimated to occur at 0.5-1.0 mW·cm-2, whereas the 385- and 402-nm LEDs did not show a transition at this intensity. Dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO2), dimethyl disulfide (DMDS), methanethiol (MT), methanesulfonic acid (MSA), and sulfate were identified as the reaction products by gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), and ion chromatography (IC). A plausible reaction mechanism is proposed for DMS photocatalytic degradation based on the reaction products detected and possible intermediates formed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24332121

Study of glutamate-modified cellulose beads for Cr(III) adsorption by response surface methodology / Jing Liu in Industrial & engineering chemistry research, Vol. 50 N° 18 (Septembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp 10784–10791 Titre : Study of glutamate-modified cellulose beads for Cr(III) adsorption by response surface methodology Type de document : texte imprimé Auteurs : Jing Liu, Auteur ; Min Yan, Auteur ; Yong-Kui Zhang, Auteur Année de publication : 2011 Article en page(s) : pp 10784–10791 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Cellulose  ionic  liquid  Adsorption Résumé : A cellulose-based adsorbent was prepared from a cellulose–ionic liquid solution by emulsification followed by modification with glutamic acid for Cr(III) adsorption from aqueous solution. Response surface methodology (RSM) coupled with central composite design (CCD) was employed to optimize the adsorption process to ensure high adsorption efficiency. Three independent variables [initial Cr(III) concentration, pH, and adsorbent dose] were coded as x1, x2, and x3 at five levels (−1.68179, −1, 0, 1, −1.68179), and a second-order polynomial regression equation was then derived to predict the responses. The standardized effects of the independent variables and their interactions were tested by preparing a Pareto chart. Analysis of variance (ANOVA) showed that a high coefficient of determination value (R2 = 0.9959) and a satisfactory predicted second-order regression model were achieved in the study. Therefore, the optimum conditions for Cr(III) adsorption were established, and the optimum values of the selected variables were obtained by solving the quadratic regression and by analyzing the response surface contour plots. Under the optimum conditions, four sets of experimental trials for Cr(III) adsorption rate were performed, with results that were very close to the predicted values. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200857n [article] Study of glutamate-modified cellulose beads for Cr(III) adsorption by response surface methodology [texte imprimé] / Jing Liu, Auteur ; Min Yan, Auteur ; Yong-Kui Zhang, Auteur . - 2011 . - pp 10784–10791. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 18 (Septembre 2011) . - pp 10784–10791 Mots-clés : Cellulose  ionic  liquid  Adsorption Résumé : A cellulose-based adsorbent was prepared from a cellulose–ionic liquid solution by emulsification followed by modification with glutamic acid for Cr(III) adsorption from aqueous solution. Response surface methodology (RSM) coupled with central composite design (CCD) was employed to optimize the adsorption process to ensure high adsorption efficiency. Three independent variables [initial Cr(III) concentration, pH, and adsorbent dose] were coded as x1, x2, and x3 at five levels (−1.68179, −1, 0, 1, −1.68179), and a second-order polynomial regression equation was then derived to predict the responses. The standardized effects of the independent variables and their interactions were tested by preparing a Pareto chart. Analysis of variance (ANOVA) showed that a high coefficient of determination value (R2 = 0.9959) and a satisfactory predicted second-order regression model were achieved in the study. Therefore, the optimum conditions for Cr(III) adsorption were established, and the optimum values of the selected variables were obtained by solving the quadratic regression and by analyzing the response surface contour plots. Under the optimum conditions, four sets of experimental trials for Cr(III) adsorption rate were performed, with results that were very close to the predicted values. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200857n