A comparative study of ZnO-CuO-Al2O3/SiO2-Al2O3 composite and hybrid catalysts for direct synthesis of dimethyl ether from syngas / Sajo P. Naik in Industrial & engineering chemistry research, Vol. 47 N° 23 (Décembre 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9791–9794 Titre : A comparative study of ZnO-CuO-Al2O3/SiO2-Al2O3 composite and hybrid catalysts for direct synthesis of dimethyl ether from syngas Type de document : texte imprimé Auteurs : Sajo P. Naik, Auteur ; Hao Du, Auteur ; Haijun Wan, Auteur Année de publication : 2009 Article en page(s) : p. 9791–9794 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : Comparative study ZnO−  CuO−  Al2O3/SiO2−  Al2O3 Dimethyl ether Syngas Résumé : Two different strategies for the preparation of active dimethyl ether catalysts are evaluated using CuO−ZnO−Al2O3 and SiO2−Al2O3 as methanol synthesis and methanol dehydration catalysts components, respectively. Composite catalysts are prepared by mixing of the two freshly precipitated catalyst precursors and by coprecipitation methods, whereas hybrid catalysts are prepared by mechanical mixing of the two calcined catalyst components by grinding. Composite catalysts are partially deactivated during the catalyst preparation or calcination stages and therefore exhibit much lower activity, as compared to the hybrid catalysts toward syngas conversions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801437c [article] A comparative study of ZnO-CuO-Al2O3/SiO2-Al2O3 composite and hybrid catalysts for direct synthesis of dimethyl ether from syngas [texte imprimé] / Sajo P. Naik, Auteur ; Hao Du, Auteur ; Haijun Wan, Auteur . - 2009 . - p. 9791–9794. Chemistry engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9791–9794 Mots-clés : Comparative study ZnO−  CuO−  Al2O3/SiO2−  Al2O3 Dimethyl ether Syngas Résumé : Two different strategies for the preparation of active dimethyl ether catalysts are evaluated using CuO−ZnO−Al2O3 and SiO2−Al2O3 as methanol synthesis and methanol dehydration catalysts components, respectively. Composite catalysts are prepared by mixing of the two freshly precipitated catalyst precursors and by coprecipitation methods, whereas hybrid catalysts are prepared by mechanical mixing of the two calcined catalyst components by grinding. Composite catalysts are partially deactivated during the catalyst preparation or calcination stages and therefore exhibit much lower activity, as compared to the hybrid catalysts toward syngas conversions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801437c

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Isopiestic study of the Na2CrO4−H2O system at 353.15 K: prediction of the solubility of Na2CrO4 in aqueous NaOH solutions / Wei Jin in Industrial & engineering chemistry research, Vol. 49 N° 17 (Septembre 1, 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8244–8247 Titre : Isopiestic study of the Na2CrO4−H2O system at 353.15 K: prediction of the solubility of Na2CrO4 in aqueous NaOH solutions Type de document : texte imprimé Auteurs : Wei Jin, Auteur ; Shili Zheng, Auteur ; Hao Du, Auteur Année de publication : 2010 Article en page(s) : pp 8244–8247 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Isopiestic study Aqueous solutions. Résumé : The osmotic coefficients of the Na2CrO4−H2O system at 353.15 K were determined using isopiestic method ranging from 0.05 to 7.683 mol·kg−1. The experimental osmotic coefficients were excellently correlated with Pitzer equation to obtain the interaction parameters, the activity coefficients, and the solubility product for Na2CrO4. Furthermore, the solubility of Na2CrO4 in NaOH solutions at 353.15 K was predicted using binary parameters, and the predicted values agree with the experimental data, demonstrating the Pitzer equation is capable of optimizing the processes for the removal and recovery of sodium chromate in NaOH solutions at high temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1011068 [article] Isopiestic study of the Na2CrO4−H2O system at 353.15 K: prediction of the solubility of Na2CrO4 in aqueous NaOH solutions [texte imprimé] / Wei Jin, Auteur ; Shili Zheng, Auteur ; Hao Du, Auteur . - 2010 . - pp 8244–8247. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 17 (Septembre 1, 2010) . - pp 8244–8247 Mots-clés : Isopiestic study Aqueous solutions. Résumé : The osmotic coefficients of the Na2CrO4−H2O system at 353.15 K were determined using isopiestic method ranging from 0.05 to 7.683 mol·kg−1. The experimental osmotic coefficients were excellently correlated with Pitzer equation to obtain the interaction parameters, the activity coefficients, and the solubility product for Na2CrO4. Furthermore, the solubility of Na2CrO4 in NaOH solutions at 353.15 K was predicted using binary parameters, and the predicted values agree with the experimental data, demonstrating the Pitzer equation is capable of optimizing the processes for the removal and recovery of sodium chromate in NaOH solutions at high temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1011068

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Surface chemistry features in the flotation of KCl / Qinbo Cao in Minerals engineering, Vol. 23 N° 5 (Avril 2010)  

Public ISBD [article]  inMinerals engineering > Vol. 23 N° 5 (Avril 2010) . - pp. 365–373 Titre : Surface chemistry features in the flotation of KCl Type de document : texte imprimé Auteurs : Qinbo Cao, Auteur ; Hao Du, Auteur ; Jan D. Miller, Auteur Année de publication : 2011 Article en page(s) : pp. 365–373 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : KCl flotation Contact angle Adsorption Molecular dynamics simulation Résumé : Despite the successful industrial practice to recover KCl by flotation, the adsorption state of collectors at KCl salt surfaces is still not fully understood. In this paper, the flotation behavior of KCl and NaCl using different collectors and captive bubble contact angle measurements at KCl and NaCl crystal surfaces in their saturated solutions are reported. The influence of collector concentration and collector structure is considered. The results show that both cationic and anionic collectors produce a hydrophobic state at the structure breaking KCl salt surface, with finite contact angle values of between 30° and 60°. In contrast, the contact angle at the structure making NaCl salt surface is zero at all collector concentrations, suggesting that no collector adsorption occurs, a supposition that is supported by results from molecular dynamics simulation (MDS). Further, it appears that the presence of surface defects such as edges and corners promote the adsorption of collectors at the KCl surface, and that the flotation is achieved by bubble attachment at the edges/corners of KCl particles with the formation of aeroflocs. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900288X [article] Surface chemistry features in the flotation of KCl [texte imprimé] / Qinbo Cao, Auteur ; Hao Du, Auteur ; Jan D. Miller, Auteur . - 2011 . - pp. 365–373. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 5 (Avril 2010) . - pp. 365–373 Mots-clés : KCl flotation Contact angle Adsorption Molecular dynamics simulation Résumé : Despite the successful industrial practice to recover KCl by flotation, the adsorption state of collectors at KCl salt surfaces is still not fully understood. In this paper, the flotation behavior of KCl and NaCl using different collectors and captive bubble contact angle measurements at KCl and NaCl crystal surfaces in their saturated solutions are reported. The influence of collector concentration and collector structure is considered. The results show that both cationic and anionic collectors produce a hydrophobic state at the structure breaking KCl salt surface, with finite contact angle values of between 30° and 60°. In contrast, the contact angle at the structure making NaCl salt surface is zero at all collector concentrations, suggesting that no collector adsorption occurs, a supposition that is supported by results from molecular dynamics simulation (MDS). Further, it appears that the presence of surface defects such as edges and corners promote the adsorption of collectors at the KCl surface, and that the flotation is achieved by bubble attachment at the edges/corners of KCl particles with the formation of aeroflocs. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900288X

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