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Adsorption of organic compounds in vapor, liquid, and aqueous solution phases on hydrophobic aerogels / Ding Wang in Industrial & engineering chemistry research, Vol. 50 N° 21 (Novembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 21 (Novembre 2011) . - pp. 12177–12185 Titre : Adsorption of organic compounds in vapor, liquid, and aqueous solution phases on hydrophobic aerogels Type de document : texte imprimé Auteurs : Ding Wang, Auteur ; Elisabeth McLaughlin, Auteur ; Robert Pfeffer, Auteur Année de publication : 2011 Article en page(s) : pp. 12177–12185 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : kinetics  Adsorption  Organic  compounds  Aqueous  Solution Résumé : The kinetics and equilibrium capacity for adsorption of six volatile organic compounds (VOCs) in the vapor, pure liquid, and aqueous solution phases on commercially available hydrophobic silica aerogel granules (Cabot Nanogel) were studied at room temperature. Very different rates of adsorption were observed depending on whether the vapor, liquid, or solution phases were used. Adsorption of vapor is very slow due to the extremely low thermal conductivity of the aerogel. Effects of heat of adsorption are minimal for the liquid and solution phases, and the faster adsorption rates observed in these two cases are controlled by the mass transport of the organic compounds, either by capillary flow for the adsorption of liquids, or by vapor diffusion/adsorption for the adsorption of the organic compounds from water solutions. The equilibrium adsorption capacities of the aerogel were measured and compared to other sorbents for similar VOCs for the three different phases. The adsorption capacity of the commercial aerogel from the vapor phase studied in this work is higher than that of two other hydrophobic aerogels that were synthesized in the laboratory using supercritical drying, and much higher than that of two commercial sorbents (silica gel and activated carbon). The volumetric sorption capacities of all of the organic liquids studied on Nanogel are all around 16 mL/g. The equilibrium adsorption capacities of the six VOCs from aqueous solution increase in the following order: benzene < trichloroethylene < toluene < chlorobenzene < p-xylene and o-xylene. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201301n [article] Adsorption of organic compounds in vapor, liquid, and aqueous solution phases on hydrophobic aerogels [texte imprimé] / Ding Wang, Auteur ; Elisabeth McLaughlin, Auteur ; Robert Pfeffer, Auteur . - 2011 . - pp. 12177–12185. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 21 (Novembre 2011) . - pp. 12177–12185 Mots-clés : kinetics  Adsorption  Organic  compounds  Aqueous  Solution Résumé : The kinetics and equilibrium capacity for adsorption of six volatile organic compounds (VOCs) in the vapor, pure liquid, and aqueous solution phases on commercially available hydrophobic silica aerogel granules (Cabot Nanogel) were studied at room temperature. Very different rates of adsorption were observed depending on whether the vapor, liquid, or solution phases were used. Adsorption of vapor is very slow due to the extremely low thermal conductivity of the aerogel. Effects of heat of adsorption are minimal for the liquid and solution phases, and the faster adsorption rates observed in these two cases are controlled by the mass transport of the organic compounds, either by capillary flow for the adsorption of liquids, or by vapor diffusion/adsorption for the adsorption of the organic compounds from water solutions. The equilibrium adsorption capacities of the aerogel were measured and compared to other sorbents for similar VOCs for the three different phases. The adsorption capacity of the commercial aerogel from the vapor phase studied in this work is higher than that of two other hydrophobic aerogels that were synthesized in the laboratory using supercritical drying, and much higher than that of two commercial sorbents (silica gel and activated carbon). The volumetric sorption capacities of all of the organic liquids studied on Nanogel are all around 16 mL/g. The equilibrium adsorption capacities of the six VOCs from aqueous solution increase in the following order: benzene < trichloroethylene < toluene < chlorobenzene < p-xylene and o-xylene. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201301n

In situ measurements of gas fluidized nanoagglomerates / Jose A. Quevedo in Industrial & engineering chemistry research, Vol. 49 N° 11 (Juin 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 11 (Juin 2010) . - pp. 5263–5269 Titre : In situ measurements of gas fluidized nanoagglomerates Type de document : texte imprimé Auteurs : Jose A. Quevedo, Auteur ; Robert Pfeffer, Auteur Année de publication : 2010 Article en page(s) : pp. 5263–5269 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Gas  Fluidized Résumé : The size of fluidized agglomerates of nanoparticles was successfully measured in situ in conventional and microjet assisted gas fluidized beds by using Lasentec Focused Beam Reflectance Method (FBRM) and Particle Vision Measurement (PVM) probes. In situ particle size distributions and agglomerate images of Aerosil R974 and Aerosil 90 nanopowders were obtained. This was achieved by reducing the electrostatic charge in the fluidized bed by bubbling the gas through an alcohol−water solution before entering the bed. Failure to remove electrostatic charges resulted in blocking of the probe lenses and blurred images or spiky size distributions. The agglomerate size distributions show that Aerosil R974 agglomerates (APF-type nanopowder) are smaller and less dense than Aerosil 90 agglomerates (ABF-type nanopowder). These observations match their respective fluidization behavior and confirm that the APF−ABF classification is dependent on the size and density of the agglomerates. The application of the microjet assisting method results in a further reduction in the mean size and density of the agglomerates and explains the higher quality of fluidization and larger bed expansion observed with the microjet. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9015446 [article] In situ measurements of gas fluidized nanoagglomerates [texte imprimé] / Jose A. Quevedo, Auteur ; Robert Pfeffer, Auteur . - 2010 . - pp. 5263–5269. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 11 (Juin 2010) . - pp. 5263–5269 Mots-clés : Gas  Fluidized Résumé : The size of fluidized agglomerates of nanoparticles was successfully measured in situ in conventional and microjet assisted gas fluidized beds by using Lasentec Focused Beam Reflectance Method (FBRM) and Particle Vision Measurement (PVM) probes. In situ particle size distributions and agglomerate images of Aerosil R974 and Aerosil 90 nanopowders were obtained. This was achieved by reducing the electrostatic charge in the fluidized bed by bubbling the gas through an alcohol−water solution before entering the bed. Failure to remove electrostatic charges resulted in blocking of the probe lenses and blurred images or spiky size distributions. The agglomerate size distributions show that Aerosil R974 agglomerates (APF-type nanopowder) are smaller and less dense than Aerosil 90 agglomerates (ABF-type nanopowder). These observations match their respective fluidization behavior and confirm that the APF−ABF classification is dependent on the size and density of the agglomerates. The application of the microjet assisting method results in a further reduction in the mean size and density of the agglomerates and explains the higher quality of fluidization and larger bed expansion observed with the microjet. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9015446

Removal of oil from water by inverse fluidization of aerogels / Jose A. Quevedo in Industrial & engineering chemistry research, Vol. 48 N°1 (Janvier 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°1 (Janvier 2009) . - p. 191-201 Titre : Removal of oil from water by inverse fluidization of aerogels Type de document : texte imprimé Auteurs : Jose A. Quevedo, Editeur scientifique ; Gaurav Patel, Editeur scientifique ; Robert Pfeffer, Editeur scientifique Année de publication : 2009 Article en page(s) : p. 191-201 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Removal  of  oil  water  Hydrophobic  aerogel  (Nanogel) Résumé : Surface-treated hydrophobic aerogel (Nanogel) granules of sizes between 500 and 850 μm, 1.7 and 2.3 mm, and 0.5 and 2.3 mm are fluidized by a downward flow of oil-contaminated water in an inverse fluidization mode. Aerogel particles are nanostructured, extremely light and porous, have a very large surface area per unit mass, and are sufficiently robust to be fluidized. Their hydrophobic surface gives them a strong affinity for oil and other organic compounds, with the exclusion of water. These desirable properties make them an ideal sorbent or filter media for the removal of oil from wastewater. The hydrodynamic characteristics of inverse fluidized beds of aerogel granules of different size ranges were studied by measuring the pressure drop and bed expansion as a function of superficial velocity. The oil removal efficiency and capacity of the aerogel granules in the inverse fluidized bed were found to depend mainly on the size of the granules, the initial height of the bed (amount of powder used), the void fraction, and the fluid velocity. Among the advantages of the process are the extremely low energy consumption (low pressure drop) during oil removal and the large absorption capacity. Oil concentrations of about 2000 mg/L in water could be reduced to less than 10 mg/L by the inverse fluidization process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800022e [article] Removal of oil from water by inverse fluidization of aerogels [texte imprimé] / Jose A. Quevedo, Editeur scientifique ; Gaurav Patel, Editeur scientifique ; Robert Pfeffer, Editeur scientifique . - 2009 . - p. 191-201. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°1 (Janvier 2009) . - p. 191-201 Mots-clés : Removal  of  oil  water  Hydrophobic  aerogel  (Nanogel) Résumé : Surface-treated hydrophobic aerogel (Nanogel) granules of sizes between 500 and 850 μm, 1.7 and 2.3 mm, and 0.5 and 2.3 mm are fluidized by a downward flow of oil-contaminated water in an inverse fluidization mode. Aerogel particles are nanostructured, extremely light and porous, have a very large surface area per unit mass, and are sufficiently robust to be fluidized. Their hydrophobic surface gives them a strong affinity for oil and other organic compounds, with the exclusion of water. These desirable properties make them an ideal sorbent or filter media for the removal of oil from wastewater. The hydrodynamic characteristics of inverse fluidized beds of aerogel granules of different size ranges were studied by measuring the pressure drop and bed expansion as a function of superficial velocity. The oil removal efficiency and capacity of the aerogel granules in the inverse fluidized bed were found to depend mainly on the size of the granules, the initial height of the bed (amount of powder used), the void fraction, and the fluid velocity. Among the advantages of the process are the extremely low energy consumption (low pressure drop) during oil removal and the large absorption capacity. Oil concentrations of about 2000 mg/L in water could be reduced to less than 10 mg/L by the inverse fluidization process. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800022e