Documents disponibles écrits par cet auteur

Separation of CO2 from light gas mixtures using ion-exchanged silicoaluminophosphate nanoporous sorbents / Milton E. Rivera-Ramos in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5602–5610 Titre : Separation of CO2 from light gas mixtures using ion-exchanged silicoaluminophosphate nanoporous sorbents Type de document : texte imprimé Auteurs : Milton E. Rivera-Ramos, Auteur ; Gerardo J. Ruiz-Mercado, Auteur ; Arturo J. Hernandez-Maldonado, Auteur Année de publication : 2008 Article en page(s) : p. 5602–5610 Note générale : Bibliogr. p. 5609-5610 Langues : Anglais (eng) Mots-clés : Light  gas  mixtures;  Adsorption  equilibria;  Ion-quadrupole  interactions Résumé : Na+-SAPO-34 sorbents were ion-exchanged with several individual metal cations to study their effect on the adsorption of similar size light gases. Measurements of pure component adsorption equilibria, with emphasis on CO2, were performed at different temperatures (273−348 K) and pressures (<1 atm). Adsorption isotherms for CO2 in Mn+-SAPO-34 materials displayed a nonlinear behavior and did not follow the typical pore-filling mechanism. In general, the overall adsorption performance of the exchanged materials increased as follows: Ce3+ < Ti3+ < Mg2+ < Ca2+ < Ag+ < Na+ < Sr2+. The strontium exchanged materials excelled at low-pressure ranges, exhibiting very sharp isotherm slopes at all temperatures. For example, the Sr2+-SAPO-34 sorbents were capable of removing as much as 2.8 wt % at a CO2 partial pressure of 10−3 atm and room temperature. Isosteric heat of adsorption data confirmed that the Sr2+ species were responsible for the surface strong interaction, and therefore it is plausible to state that cations were occupying exposed sites (SII′) in the material Chabazite cages. In addition, all divalent cations were found to interact more with the sorbate when compared to the other charged species. Adsorption isotherms for trivalent exchanged cations (Ce3+, Ti3+), on the other hand, showed what appears to be partial blockage of pore windows (occupancy of SIII), resulting in very low adsorption capacities. The surface interactions were analyzed according to electrostatic and nonspecific contributions. Due to strong ion−quadrupole interactions, all the sorbent materials exhibited higher affinity for CO2 over the other gases tested (i.e., CH4, H2, N2, and O2). Mathematical modeling to estimate binary component adsorption performance during vacuum pressure adsorption (VPSA) corroborated that Sr2+-SAPO-34 sorbents are by far the best option for CO2 removal from CH4 mixtures, especially at low concentrations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071309v [article] Separation of CO2 from light gas mixtures using ion-exchanged silicoaluminophosphate nanoporous sorbents [texte imprimé] / Milton E. Rivera-Ramos, Auteur ; Gerardo J. Ruiz-Mercado, Auteur ; Arturo J. Hernandez-Maldonado, Auteur . - 2008 . - p. 5602–5610. Bibliogr. p. 5609-5610 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5602–5610 Mots-clés : Light  gas  mixtures;  Adsorption  equilibria;  Ion-quadrupole  interactions Résumé : Na+-SAPO-34 sorbents were ion-exchanged with several individual metal cations to study their effect on the adsorption of similar size light gases. Measurements of pure component adsorption equilibria, with emphasis on CO2, were performed at different temperatures (273−348 K) and pressures (<1 atm). Adsorption isotherms for CO2 in Mn+-SAPO-34 materials displayed a nonlinear behavior and did not follow the typical pore-filling mechanism. In general, the overall adsorption performance of the exchanged materials increased as follows: Ce3+ < Ti3+ < Mg2+ < Ca2+ < Ag+ < Na+ < Sr2+. The strontium exchanged materials excelled at low-pressure ranges, exhibiting very sharp isotherm slopes at all temperatures. For example, the Sr2+-SAPO-34 sorbents were capable of removing as much as 2.8 wt % at a CO2 partial pressure of 10−3 atm and room temperature. Isosteric heat of adsorption data confirmed that the Sr2+ species were responsible for the surface strong interaction, and therefore it is plausible to state that cations were occupying exposed sites (SII′) in the material Chabazite cages. In addition, all divalent cations were found to interact more with the sorbate when compared to the other charged species. Adsorption isotherms for trivalent exchanged cations (Ce3+, Ti3+), on the other hand, showed what appears to be partial blockage of pore windows (occupancy of SIII), resulting in very low adsorption capacities. The surface interactions were analyzed according to electrostatic and nonspecific contributions. Due to strong ion−quadrupole interactions, all the sorbent materials exhibited higher affinity for CO2 over the other gases tested (i.e., CH4, H2, N2, and O2). Mathematical modeling to estimate binary component adsorption performance during vacuum pressure adsorption (VPSA) corroborated that Sr2+-SAPO-34 sorbents are by far the best option for CO2 removal from CH4 mixtures, especially at low concentrations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071309v

Sr2+–SAPO-34 prepared via coupled partial detemplation and solid state ion exchange / Ana G. Arevalo-Hidalgo in Industrial & engineering chemistry research, Vol. 50 N° 17 (Septembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 17 (Septembre 2011) . - pp. 10259-10269 Titre : Sr2+–SAPO-34 prepared via coupled partial detemplation and solid state ion exchange : effect on textural properties and carbon dioxide adsorption Type de document : texte imprimé Auteurs : Ana G. Arevalo-Hidalgo, Auteur ; Noelia E. Almodovar-Arbelo, Auteur ; Arturo J. Hernandez-Maldonado, Auteur Année de publication : 2011 Article en page(s) : pp. 10259-10269 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adsorption  Carbon  dioxide  Ion  exchange Résumé : Sr2+-SAPO-34 materials were prepared via solid-state ion exchange (SSIE) to improve their CO2 adsorptive properties, particularly at low partial pressure, and study the effect of the ion exchange treatments on the structural and textural properties of the materials. In the past, these materials have been prepared with traditional liquid-state ion exchange (LSIE) methods yielding a strontium(II) content of about one cation per unit cell, well below the theoretical maximum and probably due to aqueous phase equilibrium constraints. Characterization of the SSIE materials included coupled thermal gravimetric analyses/Fourier transform infrared spectroscopy (TGA/FT-IR), X-ray diffraction (XRD), energy-dispersive analysis by X-rays (EDAX), surface area, and pure component CO2 equilibrium adsorption. Coupled TGA/FT-IR studies were used for the selection of the SSIE temperature for both NH4+-SAPO-34 and as-synthesized Na+-SAPO-34 starting materials. In general, the results indicated that temperatures well above the Tammann point are necessary to achieve acceptable strontium(II) loadings via SSIE while minimizing the loss of effective surface area due to pore dogging with unexchanged SrCl2. Furthermore, in situ partial detemplation (PD) of the as-synthesized material during SSIE avoided the formation of excess proton (acid) sites and allowed further loading of strontium(II) onto sites suitable for interaction with CO2. In order to increase the strontium(II) loading per unit cell, a combined PD/SSIE/LSIE strategy was used to remove some of the remaining tenacious sodium(I) cations remaining after SSIE. This approach resulted in materials with a loading of nearly two strontium cations per unit cell and, as a result, improved the overall CO2 adsorption performance of the materials in a remarkable fashion. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24483670 [article] Sr2+–SAPO-34 prepared via coupled partial detemplation and solid state ion exchange : effect on textural properties and carbon dioxide adsorption [texte imprimé] / Ana G. Arevalo-Hidalgo, Auteur ; Noelia E. Almodovar-Arbelo, Auteur ; Arturo J. Hernandez-Maldonado, Auteur . - 2011 . - pp. 10259-10269. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 17 (Septembre 2011) . - pp. 10259-10269 Mots-clés : Adsorption  Carbon  dioxide  Ion  exchange Résumé : Sr2+-SAPO-34 materials were prepared via solid-state ion exchange (SSIE) to improve their CO2 adsorptive properties, particularly at low partial pressure, and study the effect of the ion exchange treatments on the structural and textural properties of the materials. In the past, these materials have been prepared with traditional liquid-state ion exchange (LSIE) methods yielding a strontium(II) content of about one cation per unit cell, well below the theoretical maximum and probably due to aqueous phase equilibrium constraints. Characterization of the SSIE materials included coupled thermal gravimetric analyses/Fourier transform infrared spectroscopy (TGA/FT-IR), X-ray diffraction (XRD), energy-dispersive analysis by X-rays (EDAX), surface area, and pure component CO2 equilibrium adsorption. Coupled TGA/FT-IR studies were used for the selection of the SSIE temperature for both NH4+-SAPO-34 and as-synthesized Na+-SAPO-34 starting materials. In general, the results indicated that temperatures well above the Tammann point are necessary to achieve acceptable strontium(II) loadings via SSIE while minimizing the loss of effective surface area due to pore dogging with unexchanged SrCl2. Furthermore, in situ partial detemplation (PD) of the as-synthesized material during SSIE avoided the formation of excess proton (acid) sites and allowed further loading of strontium(II) onto sites suitable for interaction with CO2. In order to increase the strontium(II) loading per unit cell, a combined PD/SSIE/LSIE strategy was used to remove some of the remaining tenacious sodium(I) cations remaining after SSIE. This approach resulted in materials with a loading of nearly two strontium cations per unit cell and, as a result, improved the overall CO2 adsorption performance of the materials in a remarkable fashion. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24483670