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Organic-inorganic hybrid membranes / Mahadevappa Y. Kariduraganavar in Industrial & engineering chemistry research, Vol. 48 N° 8 (Avril 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 8 (Avril 2009) . - pp. 4002–4013 Titre : Organic-inorganic hybrid membranes : solving the trade-off phenomenon between permeation flux and selectivity in pervaporation Type de document : texte imprimé Auteurs : Mahadevappa Y. Kariduraganavar, Auteur ; Jolly G. Varghese, Auteur ; Santosh K. Choudhari, Auteur Année de publication : 2009 Article en page(s) : pp. 4002–4013 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Organic−inorganic  hybrid  membranes  Chitosan  TiO2  Fourier  transform  infrared  spectroscopy  Scanning  electron  microscopy  Thermogravimetric  analysis Résumé : To solve the trade-off phenomenon existing between permeation flux and selectivity of membranes in pervaporation, organic−inorganic hybrid membranes composed of chitosan and TiO2 were prepared using a solution technique. The resulting hybrid membranes were characterized by Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Compared to pure chitosan membrane, the hybrid membranes exhibited high thermal stability and low crystallinity. These membranes were tested for their ability to separate water−isopropanol mixtures by pervaporation in the temperature range of 30−50 °C. The experimental results demonstrated that both flux and selectivity increased simultaneously with increasing TiO2 content in the membrane. The permeation flux of pure chitosan membrane increased dramatically from 3.06 to 12.17 × 10−2 kg/(m2 h) when 40 mass % of TiO2 was incorporated, and correspondingly its separation factor increased from 509 to 94 984 at 30 °C for 5 mass % of water in the feed. The total flux and flux of water were found to be almost overlapping particularly for hybrid membranes, suggesting that these membranes could be used effectively to break the azeotropic point of water−isopropanol mixtures. From the temperature dependent diffusion and permeation values, the Arrhenius activation parameters were estimated. The activation energy values obtained for water permeation (Epw) were significantly lower than those of isopropanol permeation (EpIPA), suggesting that the developed membranes have higher separation efficiency for water−isopropanol systems. The negative heat of sorption (ΔHS) values were observed in all the membranes, indicating that Langmuir’s mode of sorption is predominant. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8016626 [article] Organic-inorganic hybrid membranes : solving the trade-off phenomenon between permeation flux and selectivity in pervaporation [texte imprimé] / Mahadevappa Y. Kariduraganavar, Auteur ; Jolly G. Varghese, Auteur ; Santosh K. Choudhari, Auteur . - 2009 . - pp. 4002–4013. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 8 (Avril 2009) . - pp. 4002–4013 Mots-clés : Organic−inorganic  hybrid  membranes  Chitosan  TiO2  Fourier  transform  infrared  spectroscopy  Scanning  electron  microscopy  Thermogravimetric  analysis Résumé : To solve the trade-off phenomenon existing between permeation flux and selectivity of membranes in pervaporation, organic−inorganic hybrid membranes composed of chitosan and TiO2 were prepared using a solution technique. The resulting hybrid membranes were characterized by Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Compared to pure chitosan membrane, the hybrid membranes exhibited high thermal stability and low crystallinity. These membranes were tested for their ability to separate water−isopropanol mixtures by pervaporation in the temperature range of 30−50 °C. The experimental results demonstrated that both flux and selectivity increased simultaneously with increasing TiO2 content in the membrane. The permeation flux of pure chitosan membrane increased dramatically from 3.06 to 12.17 × 10−2 kg/(m2 h) when 40 mass % of TiO2 was incorporated, and correspondingly its separation factor increased from 509 to 94 984 at 30 °C for 5 mass % of water in the feed. The total flux and flux of water were found to be almost overlapping particularly for hybrid membranes, suggesting that these membranes could be used effectively to break the azeotropic point of water−isopropanol mixtures. From the temperature dependent diffusion and permeation values, the Arrhenius activation parameters were estimated. The activation energy values obtained for water permeation (Epw) were significantly lower than those of isopropanol permeation (EpIPA), suggesting that the developed membranes have higher separation efficiency for water−isopropanol systems. The negative heat of sorption (ΔHS) values were observed in all the membranes, indicating that Langmuir’s mode of sorption is predominant. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8016626