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Biogenic silver nanoparticles by cacumen platycladi extract / Jiale Huang in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9095-9106 Titre : Biogenic silver nanoparticles by cacumen platycladi extract : synthesis, formation mechanism, and antibacterial activity Type de document : texte imprimé Auteurs : Jiale Huang, Auteur ; Guowu Zhan, Auteur ; Bingyun Zheng, Auteur Année de publication : 2011 Article en page(s) : pp. 9095-9106 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Formation  mechanism  Extract  Nanoparticle  Biogenic  factor Résumé : Biosynthesis of Ag nanoparticles (AgNPs) by Cacumen Platycladi extract was investigated. The AgNPs were characterized by ultraviolet-visible absorption spectroscopy (UV-vis), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and X-ray diffraction (XRD). The results showed that increasing the initial AgNO3 concentration at 30 or 60 °C increased the mean size and widened the size distribution of the AgNPs leading to red shift and broadening of the Surface Plasmon Resonance absorption. The conversion of silver ions was determined by atomic absorption spectroscopy (AAS) and to discuss the bioreductive mechanism, the reducing sugar, flavonoid, saccharide, protein contents in the extract, and the antioxidant activity were measured using 3,5-dinitrosalicylic acid colorimetric; Coomassie brilliant blue; phenol-sulfuric acid; rutin-based spectrophotometry method; and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assay methods. The results showed that the reducing sugars and flavonoids were mainly responsible for the bioreduction of the silver ions and their reductive capability promoted at 90 °C, leading to the formation of AgNPs (18.4 ± 4.6 nm) with narrow size distribution. Finally, the antibacterial activity of the AgNPs against E. coli and S. aureus was assessed to determine their potential applications in silver-loaded antibacterial materials. This work provides useful technical parameters for industrialization ofthe biosynthetic technique and further antibacterial application of the AgNPs. Furthermore, the elucidation of bioreductive mechanism of silver ions by measuring the change of the biomolecular concentrations in plant extract exemplifies understanding the formation mechanism of such biogenic AgNPs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395857 [article] Biogenic silver nanoparticles by cacumen platycladi extract : synthesis, formation mechanism, and antibacterial activity [texte imprimé] / Jiale Huang, Auteur ; Guowu Zhan, Auteur ; Bingyun Zheng, Auteur . - 2011 . - pp. 9095-9106. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9095-9106 Mots-clés : Formation  mechanism  Extract  Nanoparticle  Biogenic  factor Résumé : Biosynthesis of Ag nanoparticles (AgNPs) by Cacumen Platycladi extract was investigated. The AgNPs were characterized by ultraviolet-visible absorption spectroscopy (UV-vis), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and X-ray diffraction (XRD). The results showed that increasing the initial AgNO3 concentration at 30 or 60 °C increased the mean size and widened the size distribution of the AgNPs leading to red shift and broadening of the Surface Plasmon Resonance absorption. The conversion of silver ions was determined by atomic absorption spectroscopy (AAS) and to discuss the bioreductive mechanism, the reducing sugar, flavonoid, saccharide, protein contents in the extract, and the antioxidant activity were measured using 3,5-dinitrosalicylic acid colorimetric; Coomassie brilliant blue; phenol-sulfuric acid; rutin-based spectrophotometry method; and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assay methods. The results showed that the reducing sugars and flavonoids were mainly responsible for the bioreduction of the silver ions and their reductive capability promoted at 90 °C, leading to the formation of AgNPs (18.4 ± 4.6 nm) with narrow size distribution. Finally, the antibacterial activity of the AgNPs against E. coli and S. aureus was assessed to determine their potential applications in silver-loaded antibacterial materials. This work provides useful technical parameters for industrialization ofthe biosynthetic technique and further antibacterial application of the AgNPs. Furthermore, the elucidation of bioreductive mechanism of silver ions by measuring the change of the biomolecular concentrations in plant extract exemplifies understanding the formation mechanism of such biogenic AgNPs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395857

Synthesis of gold nanoplates with bioreducing agent using syringe pumps / Guowu Zhan in Industrial & engineering chemistry research, Vol. 51 N° 48 (Décembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 48 (Décembre 2012) . - pp. 15753-15762 Titre : Synthesis of gold nanoplates with bioreducing agent using syringe pumps : A kinetic control Type de document : texte imprimé Auteurs : Guowu Zhan, Auteur ; Lanting Ke, Auteur ; Qingbiao Li, Auteur Année de publication : 2013 Article en page(s) : pp. 15753-15762 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Kinetics  Pump Résumé : Anisotropic Au nanoplates are particularly important owing to their unusual properties. Herein, we describe a plant-mediated bioreduction method to increase the yield of Au nanoplates and shorten the reaction time through a kinetically manipulated procedure. More specifically, the reduction rate was controlled by modulating experimental factors such as the addition mode and rate of the feed solutions, the temperature, and the pH based on a syringe-pumps apparatus. The dimensions of the obtained Au nanoplates were measured using TEM and AFM. The single-crystalline structure was demonstrated by HRTEM, SAED, and XRD. The results of XPS, FTIR, and TG analyses indicated strong affinity of the biomolecules binding to the Au nanoplate facets. In particular, the nanoplate films exhibited strong surface plasmon absorbance in the near-infrared range of 700―3000 nm, vital for optical applications. Furthermore, we propose a mechanism for this formation following the time-resolved studies. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26710612 [article] Synthesis of gold nanoplates with bioreducing agent using syringe pumps : A kinetic control [texte imprimé] / Guowu Zhan, Auteur ; Lanting Ke, Auteur ; Qingbiao Li, Auteur . - 2013 . - pp. 15753-15762. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 48 (Décembre 2012) . - pp. 15753-15762 Mots-clés : Kinetics  Pump Résumé : Anisotropic Au nanoplates are particularly important owing to their unusual properties. Herein, we describe a plant-mediated bioreduction method to increase the yield of Au nanoplates and shorten the reaction time through a kinetically manipulated procedure. More specifically, the reduction rate was controlled by modulating experimental factors such as the addition mode and rate of the feed solutions, the temperature, and the pH based on a syringe-pumps apparatus. The dimensions of the obtained Au nanoplates were measured using TEM and AFM. The single-crystalline structure was demonstrated by HRTEM, SAED, and XRD. The results of XPS, FTIR, and TG analyses indicated strong affinity of the biomolecules binding to the Au nanoplate facets. In particular, the nanoplate films exhibited strong surface plasmon absorbance in the near-infrared range of 700―3000 nm, vital for optical applications. Furthermore, we propose a mechanism for this formation following the time-resolved studies. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26710612

Vapor-phase propylene epoxidation with H2/O2 over bioreduction Au/TS-1 catalysts / Guowu Zhan in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - 9019-9026 Titre : Vapor-phase propylene epoxidation with H2/O2 over bioreduction Au/TS-1 catalysts : synthesis, characterization, and optimization Type de document : texte imprimé Auteurs : Guowu Zhan, Auteur ; Mingming Du, Auteur ; Daohua Sun, Auteur Année de publication : 2011 Article en page(s) : 9019-9026 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimization  Catalyst  Bioremediation  Epoxidation Résumé : Au/TS-1 catalysts could be prepared by immobilizing the biosynthesized Au sol on TS-1 supports. A variety of techniques, such as N2 physisorption, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectorscopy, UV-visible diffuse reflectance, and thermogravimetric analysis, were employed to characterize both the supports and the bioreduction catalysts. The influence of various parameters (Si/Ti molar ratio, Au loading, immobilization pH, reaction temperature, and space velocity) on the catalytic performance in vapor phase propylene epoxidation with H2/O2 was systematically analyzed. parameter optimization results manifested that the optimum catalytic activity and stability of bioreduction Au/TS-1 catalysts were obtained of 573 optimum operation conditions of Si/Ti molar ratio Furthermore, of were also made to pH of 2, reaction temperature of 573 K, and space velocity of 4000-8000 mL gcat-1 h-1. Furthermore, efforts were also made to clarify the plausible reaction routes over the bioreduction catalysts. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395848 [article] Vapor-phase propylene epoxidation with H2/O2 over bioreduction Au/TS-1 catalysts : synthesis, characterization, and optimization [texte imprimé] / Guowu Zhan, Auteur ; Mingming Du, Auteur ; Daohua Sun, Auteur . - 2011 . - 9019-9026. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - 9019-9026 Mots-clés : Optimization  Catalyst  Bioremediation  Epoxidation Résumé : Au/TS-1 catalysts could be prepared by immobilizing the biosynthesized Au sol on TS-1 supports. A variety of techniques, such as N2 physisorption, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectorscopy, UV-visible diffuse reflectance, and thermogravimetric analysis, were employed to characterize both the supports and the bioreduction catalysts. The influence of various parameters (Si/Ti molar ratio, Au loading, immobilization pH, reaction temperature, and space velocity) on the catalytic performance in vapor phase propylene epoxidation with H2/O2 was systematically analyzed. parameter optimization results manifested that the optimum catalytic activity and stability of bioreduction Au/TS-1 catalysts were obtained of 573 optimum operation conditions of Si/Ti molar ratio Furthermore, of were also made to pH of 2, reaction temperature of 573 K, and space velocity of 4000-8000 mL gcat-1 h-1. Furthermore, efforts were also made to clarify the plausible reaction routes over the bioreduction catalysts. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395848