Documents disponibles écrits par cet auteur

Adsorption – desorption of Cd(II) and Pb(II) on Ca - montmorillonite / Yan Li in Industrial & engineering chemistry research, Vol. 51 N° 18 (Mai 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 18 (Mai 2012) . - pp. 6520-6528 Titre : Adsorption – desorption of Cd(II) and Pb(II) on Ca - montmorillonite Type de document : texte imprimé Auteurs : Yan Li, Auteur ; Ji-de Wang, Auteur ; Xiao-jun Wang, Auteur Année de publication : 2012 Article en page(s) : pp. 6520-6528 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Montmorillonite  Desorption  Adsorption Résumé : The adsorption and desorption of Cd(II) and Pb(II) on Ca-montmorillonite have been investigated. The maximum removal efficiency of Cd(II) reaches 98% at the initial concentration of 50.00 mg L―1, while it is about 70% for Pb(II) at the initial concentration of 58.79 mg L―1. Experimental results indicate that adsorption reactions of Cd(II) and Pb(II) on Ca-montmorillonite agree well with second-order kinetics and the Langmuir isotherm model. Cd(II) and Pb(II) on Ca-montmorillonite are successfully desorbed by NaCl solution of high concentration. Data shows that desorption efficiencies are mainly influenced by the concentration of NaCl and temperature. The optimum desorption concentrations of NaCl for Cd(II) and Pb(ll) are 1 mol L―1 and 3 mol L―1, respectively, where the adsorption efficiencies can reach 93% and 83%. The results of 4-time consecutive adsorption-desorption show that the method of desorption by NaCl solution is efficient and practical. Samples before and after adsorption or desorption have been characterized by X-ray diffraction, which are consistent with the results mentioned above. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25867303 [article] Adsorption – desorption of Cd(II) and Pb(II) on Ca - montmorillonite [texte imprimé] / Yan Li, Auteur ; Ji-de Wang, Auteur ; Xiao-jun Wang, Auteur . - 2012 . - pp. 6520-6528. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 18 (Mai 2012) . - pp. 6520-6528 Mots-clés : Montmorillonite  Desorption  Adsorption Résumé : The adsorption and desorption of Cd(II) and Pb(II) on Ca-montmorillonite have been investigated. The maximum removal efficiency of Cd(II) reaches 98% at the initial concentration of 50.00 mg L―1, while it is about 70% for Pb(II) at the initial concentration of 58.79 mg L―1. Experimental results indicate that adsorption reactions of Cd(II) and Pb(II) on Ca-montmorillonite agree well with second-order kinetics and the Langmuir isotherm model. Cd(II) and Pb(II) on Ca-montmorillonite are successfully desorbed by NaCl solution of high concentration. Data shows that desorption efficiencies are mainly influenced by the concentration of NaCl and temperature. The optimum desorption concentrations of NaCl for Cd(II) and Pb(ll) are 1 mol L―1 and 3 mol L―1, respectively, where the adsorption efficiencies can reach 93% and 83%. The results of 4-time consecutive adsorption-desorption show that the method of desorption by NaCl solution is efficient and practical. Samples before and after adsorption or desorption have been characterized by X-ray diffraction, which are consistent with the results mentioned above. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25867303

Microstructures and shape memory characteristics of dual-phase Co–Ni–Ga high-temperature shape memory alloys / Yan Li in Acta materialia, Vol. 58 N° 10 (Juin 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 10 (Juin 2010) . - pp. 3655–3663 Titre : Microstructures and shape memory characteristics of dual-phase Co–Ni–Ga high-temperature shape memory alloys Type de document : texte imprimé Auteurs : Yan Li, Auteur ; Yan Xin, Auteur ; Liang Chai, Auteur Année de publication : 2011 Article en page(s) : pp. 3655–3663 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Co–Ni–Ga  Dual  phases  Shape  memory  alloys  Martensitic  phase  transformation  Fracture Résumé : The influence of microstructure on mechanical properties and shape memory characteristics of Co–Ni–Ga high-temperature shape memory alloys were investigated in this study. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were employed to detect the microstructures. We found that these alloys were composed of dual phases, a non-modulated tetragonal L10 martensite and a face-centered cubic (fcc) γ phase. The martensite was twinned and well self-accommodated. The γ phase was a Co-based solid solution with 30% lower hardness than martensite. Although the fracture mode was intergranular, the strength and plasticity of the alloys increased markedly with the increasing volume fraction of the γ phase. The presence of the γ phase in grain boundaries rather than in the martensite is favorable to shape memory recovery. This was revealed by the maximum shape recovery strain over 5.0% that was obtained in the Co46Ni25Ga29 alloy, with the γ phase formed mainly in grain boundaries. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410001461 [article] Microstructures and shape memory characteristics of dual-phase Co–Ni–Ga high-temperature shape memory alloys [texte imprimé] / Yan Li, Auteur ; Yan Xin, Auteur ; Liang Chai, Auteur . - 2011 . - pp. 3655–3663. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 10 (Juin 2010) . - pp. 3655–3663 Mots-clés : Co–Ni–Ga  Dual  phases  Shape  memory  alloys  Martensitic  phase  transformation  Fracture Résumé : The influence of microstructure on mechanical properties and shape memory characteristics of Co–Ni–Ga high-temperature shape memory alloys were investigated in this study. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were employed to detect the microstructures. We found that these alloys were composed of dual phases, a non-modulated tetragonal L10 martensite and a face-centered cubic (fcc) γ phase. The martensite was twinned and well self-accommodated. The γ phase was a Co-based solid solution with 30% lower hardness than martensite. Although the fracture mode was intergranular, the strength and plasticity of the alloys increased markedly with the increasing volume fraction of the γ phase. The presence of the γ phase in grain boundaries rather than in the martensite is favorable to shape memory recovery. This was revealed by the maximum shape recovery strain over 5.0% that was obtained in the Co46Ni25Ga29 alloy, with the γ phase formed mainly in grain boundaries. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410001461

Prediction of vapor-liquid equilibrium at high pressure using a new excess free energy mixing rule coupled with the original UNIFAC method and the SRK equation of state / Zhen-hua Chen in Industrial & engineering chemistry research, Vol. 48 N° 14 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6836–6845 Titre : Prediction of vapor-liquid equilibrium at high pressure using a new excess free energy mixing rule coupled with the original UNIFAC method and the SRK equation of state Type de document : texte imprimé Auteurs : Zhen-hua Chen, Auteur ; Zhen Yao, Auteur ; Yan Li, Auteur Année de publication : 2009 Article en page(s) : pp. 6836–6845 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Low-pressure  mixing  rule  UNIFAC  method  Soave-Redlich-Kwong  equation  EoS/GE  predictive  model Résumé : A new excess free energy mixing rule that employs a low-pressure reference state is proposed in this work. This new low-pressure mixing rule (LPMR), coupled with the original UNIFAC method and the Soave−Redlich−Kwong (SRK) equation of state (EoS), leads to an improved EoS/GE predictive model (LPMR−SRK model) that was applied to the high-pressure vapor−liquid phase equilibria of various systems including symmetric and asymmetric systems of n-alkanes with different gases (C2H6, C3H8, CO2, H2) and polar systems. The results are compared with those of other EoS/GE predictive models, such as the predictive Soave−Redlich−Kwong (PSRK), Chen-modified PSRK (MPSRK), volume-translated Peng−Robinson group contribution equation of state (VTPR), and linear combination of the Vidal and Michelsen rules (LCVM) models. It is demonstrated that LPMR−SRK method gives similar accuracy as the PSRK approach for symmetric or slightly asymmetric systems and gives better results than the MPSRK, VTPR, and LCVM models. For highly asymmetric nonpolar systems, the results indicate that the LPMR−SRK method has an accuracy similar to or slightly better than that of the MPSRK and VTPR models and gives a much better performance than the PSRK model. Furthermore, the LPMR−SRK approach is competitive with or better than the LCVM approach, except for some CO2/heavy alkane systems. In addition, although it is slightly inferior to the PSRK and LCVM approaches, the LPMR−SRK method can still provide satisfactory descriptions of polar systems that are more accurate than those of the MPSRK and VTPR models. Moreover, three ternary and one quaternary systems can also be predicted successfully by the LPMR−SRK method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900111h [article] Prediction of vapor-liquid equilibrium at high pressure using a new excess free energy mixing rule coupled with the original UNIFAC method and the SRK equation of state [texte imprimé] / Zhen-hua Chen, Auteur ; Zhen Yao, Auteur ; Yan Li, Auteur . - 2009 . - pp. 6836–6845. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6836–6845 Mots-clés : Low-pressure  mixing  rule  UNIFAC  method  Soave-Redlich-Kwong  equation  EoS/GE  predictive  model Résumé : A new excess free energy mixing rule that employs a low-pressure reference state is proposed in this work. This new low-pressure mixing rule (LPMR), coupled with the original UNIFAC method and the Soave−Redlich−Kwong (SRK) equation of state (EoS), leads to an improved EoS/GE predictive model (LPMR−SRK model) that was applied to the high-pressure vapor−liquid phase equilibria of various systems including symmetric and asymmetric systems of n-alkanes with different gases (C2H6, C3H8, CO2, H2) and polar systems. The results are compared with those of other EoS/GE predictive models, such as the predictive Soave−Redlich−Kwong (PSRK), Chen-modified PSRK (MPSRK), volume-translated Peng−Robinson group contribution equation of state (VTPR), and linear combination of the Vidal and Michelsen rules (LCVM) models. It is demonstrated that LPMR−SRK method gives similar accuracy as the PSRK approach for symmetric or slightly asymmetric systems and gives better results than the MPSRK, VTPR, and LCVM models. For highly asymmetric nonpolar systems, the results indicate that the LPMR−SRK method has an accuracy similar to or slightly better than that of the MPSRK and VTPR models and gives a much better performance than the PSRK model. Furthermore, the LPMR−SRK approach is competitive with or better than the LCVM approach, except for some CO2/heavy alkane systems. In addition, although it is slightly inferior to the PSRK and LCVM approaches, the LPMR−SRK method can still provide satisfactory descriptions of polar systems that are more accurate than those of the MPSRK and VTPR models. Moreover, three ternary and one quaternary systems can also be predicted successfully by the LPMR−SRK method. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900111h

Utilizing polystyrene microspheres as confined space to help TiO2 nanocrystals formation with assistance of supercritical CO2 / Aping Niu in Industrial & engineering chemistry research, Vol. 48 N° 15 (Août 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 15 (Août 2009) . - pp. 7103–7109 Titre : Utilizing polystyrene microspheres as confined space to help TiO2 nanocrystals formation with assistance of supercritical CO2 Type de document : texte imprimé Auteurs : Aping Niu, Auteur ; Yan Li, Auteur ; Jiafu Chen, Auteur Année de publication : 2009 Article en page(s) : pp. 7103–7109 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Titania  nanocrystals  Tetrabutyl  titanate  Polystyrene  microspheres Résumé : Titania nanocrystals were prepared by a particular way: first, supercritical CO2 (SC CO2) carried precursor tetrabutyl titanate (TBT) into the confined space of polystyrene (PS) microspheres; second, hydrolysis of TBT was controlled by the confined space of PS microspheres, which had a restraining effect on the hydrolysis rate of TBT; finally, TiO2 nanocrystals were obtained by calcining PS@TiO2 composite microspheres. The products obtained after hydrolysis and calcination, that is, PS@TiO2 composite microspheres and the finally obtained TiO2 nanocrystals, were characterized by transmission electron microscope and scanning electron microscope, respectively. Further high-resolution transmission electron microscopy and X-ray diffraction (XRD) indicated that the obtained TiO2 nanocrystals had fine crystalline structure. Additionally, the XRD pattern verified the presence of anatase and rutile in TiO2. The nucleation mechanism of TiO2 nanocrystals in the confined space of PS microspheres was also proposed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900204y [article] Utilizing polystyrene microspheres as confined space to help TiO2 nanocrystals formation with assistance of supercritical CO2 [texte imprimé] / Aping Niu, Auteur ; Yan Li, Auteur ; Jiafu Chen, Auteur . - 2009 . - pp. 7103–7109. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 15 (Août 2009) . - pp. 7103–7109 Mots-clés : Titania  nanocrystals  Tetrabutyl  titanate  Polystyrene  microspheres Résumé : Titania nanocrystals were prepared by a particular way: first, supercritical CO2 (SC CO2) carried precursor tetrabutyl titanate (TBT) into the confined space of polystyrene (PS) microspheres; second, hydrolysis of TBT was controlled by the confined space of PS microspheres, which had a restraining effect on the hydrolysis rate of TBT; finally, TiO2 nanocrystals were obtained by calcining PS@TiO2 composite microspheres. The products obtained after hydrolysis and calcination, that is, PS@TiO2 composite microspheres and the finally obtained TiO2 nanocrystals, were characterized by transmission electron microscope and scanning electron microscope, respectively. Further high-resolution transmission electron microscopy and X-ray diffraction (XRD) indicated that the obtained TiO2 nanocrystals had fine crystalline structure. Additionally, the XRD pattern verified the presence of anatase and rutile in TiO2. The nucleation mechanism of TiO2 nanocrystals in the confined space of PS microspheres was also proposed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900204y