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Adsorption of aqueous Cr(VI) by novel fibrous adsorbent with amino and quaternary ammonium groups / Jing Wang in Industrial & engineering chemistry research, Vol. 51 N° 42 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 42 (Octobre 2012) . - pp. 13655-13662 Titre : Adsorption of aqueous Cr(VI) by novel fibrous adsorbent with amino and quaternary ammonium groups Type de document : texte imprimé Auteurs : Jing Wang, Auteur ; Liang Zhao, Auteur ; Wenjie Duan, Auteur Année de publication : 2012 Article en page(s) : pp. 13655-13662 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Adsorption Résumé : A novel fibrous adsorbent functionalized with both amino and quaternary ammonium groups (QAPAN) was prepared through a simple two-step route (i.e., amination followed by quaternization reactions) for removing aqueous Cr(VI) through batch and column experiments. As compared with traditional adsorbents, the QAPAN had an extremely fast adsorption kinetic (equilibrium achieved within 10 min) and an exceptionally high adsorption capacity (Qm = 248 mg/g). The QAPAN worked well even in strong basic conditions, and ionic strength and coexisting anions had minor inhibitory effects on the adsorption. Besides, the QAPAN could be repeatedly used for Cr(VI) adsorption with no obvious decrease of uptake after regeneration with 0.1 mol/L NaOH. By analyzing FTIR and XPS spectra, an electrostatic interaction mechanism between Cr(VI) oxyanions and the surface amino and quaternary ammonium groups was proposed. Findings of the current study provided a novel material and technology for treatment of Cr(VI) contaminated waters. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26508190 [article] Adsorption of aqueous Cr(VI) by novel fibrous adsorbent with amino and quaternary ammonium groups [texte imprimé] / Jing Wang, Auteur ; Liang Zhao, Auteur ; Wenjie Duan, Auteur . - 2012 . - pp. 13655-13662. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 42 (Octobre 2012) . - pp. 13655-13662 Mots-clés : Adsorption Résumé : A novel fibrous adsorbent functionalized with both amino and quaternary ammonium groups (QAPAN) was prepared through a simple two-step route (i.e., amination followed by quaternization reactions) for removing aqueous Cr(VI) through batch and column experiments. As compared with traditional adsorbents, the QAPAN had an extremely fast adsorption kinetic (equilibrium achieved within 10 min) and an exceptionally high adsorption capacity (Qm = 248 mg/g). The QAPAN worked well even in strong basic conditions, and ionic strength and coexisting anions had minor inhibitory effects on the adsorption. Besides, the QAPAN could be repeatedly used for Cr(VI) adsorption with no obvious decrease of uptake after regeneration with 0.1 mol/L NaOH. By analyzing FTIR and XPS spectra, an electrostatic interaction mechanism between Cr(VI) oxyanions and the surface amino and quaternary ammonium groups was proposed. Findings of the current study provided a novel material and technology for treatment of Cr(VI) contaminated waters. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26508190

Helical crystal assemblies in nonracemic chiral liquid crystalline polymers / Jing Wang in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11936–11947 Titre : Helical crystal assemblies in nonracemic chiral liquid crystalline polymers : where chemistry and physics meet Type de document : texte imprimé Auteurs : Jing Wang, Auteur ; Christopher Y. Li, Auteur ; Shi Jin, Auteur Année de publication : 2011 Article en page(s) : pp. 11936–11947 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Liquid  Crystalline  Polymers Résumé : Chirality transfer (or amplification) in soft materials is an important topic for understanding how chiral assemblies develop from the atomic level to macroscopic objects. This is an interdisciplinary area which is critically associated with the evolution from asymmetric chemistry to asymmetric physics, and, more specifically, in biomaterials, liquid crystals, and polymers. In this review, we discuss our recent studies on the conditions for chirality transfer across different length scales. We observed that the formation of helical structures in different length scales is a typical process in chirality transfer. This is illustrated by a series of nonracemic chiral main-chain liquid crystalline (LC) polyesters, PETs(R*-n). The polymers contained a different number of methylene units in the chain backbone (from 7 to 11). All of the PETs(R*-n) macroscopically exhibited an LC chiral smectic C (SC*) phase, a chiral smectic A (SA*) phase, and a twist grain boundary smectic A (TGBA*) phase with increasing temperature. The atomic chiral centers caused the helical conformation, and then, helical lamellar crystals were found in these polymers. The crystal structures were determined by X-ray diffraction and electron diffraction techniques. Dark field transmission electron microscopic images revealed that the molecular orientation in these helical crystals is double twisted. Our systematic studies showed that chirality transfer from one length scale to another is neither automatic, nor necessary, and it critically depends upon the packing scheme of the chiral building blocks on each length scale. It was particularly surprising that in this series of polyesters, the odd−even effect exists across many length scales. This includes not only thermodynamic properties such as the SC*, the SA*, and the TGBA* LC phase transition temperatures, but also the helical crystal handedness. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100248r#afn1 [article] Helical crystal assemblies in nonracemic chiral liquid crystalline polymers : where chemistry and physics meet [texte imprimé] / Jing Wang, Auteur ; Christopher Y. Li, Auteur ; Shi Jin, Auteur . - 2011 . - pp. 11936–11947. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11936–11947 Mots-clés : Liquid  Crystalline  Polymers Résumé : Chirality transfer (or amplification) in soft materials is an important topic for understanding how chiral assemblies develop from the atomic level to macroscopic objects. This is an interdisciplinary area which is critically associated with the evolution from asymmetric chemistry to asymmetric physics, and, more specifically, in biomaterials, liquid crystals, and polymers. In this review, we discuss our recent studies on the conditions for chirality transfer across different length scales. We observed that the formation of helical structures in different length scales is a typical process in chirality transfer. This is illustrated by a series of nonracemic chiral main-chain liquid crystalline (LC) polyesters, PETs(R*-n). The polymers contained a different number of methylene units in the chain backbone (from 7 to 11). All of the PETs(R*-n) macroscopically exhibited an LC chiral smectic C (SC*) phase, a chiral smectic A (SA*) phase, and a twist grain boundary smectic A (TGBA*) phase with increasing temperature. The atomic chiral centers caused the helical conformation, and then, helical lamellar crystals were found in these polymers. The crystal structures were determined by X-ray diffraction and electron diffraction techniques. Dark field transmission electron microscopic images revealed that the molecular orientation in these helical crystals is double twisted. Our systematic studies showed that chirality transfer from one length scale to another is neither automatic, nor necessary, and it critically depends upon the packing scheme of the chiral building blocks on each length scale. It was particularly surprising that in this series of polyesters, the odd−even effect exists across many length scales. This includes not only thermodynamic properties such as the SC*, the SA*, and the TGBA* LC phase transition temperatures, but also the helical crystal handedness. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100248r#afn1

PH-sensitive magnetic ion exchanger for protein separation / Liangrong Yang in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009)

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 944–950 Titre : PH-sensitive magnetic ion exchanger for protein separation Type de document : texte imprimé Auteurs : Liangrong Yang, Auteur ; Chen, Guo, Auteur ; Shu Chen, Auteur ; Feng Wang, Auteur ; Jing Wang, Auteur ; Zhentao An, Auteur Année de publication : 2009 Article en page(s) : p. 944–950 Note générale : chimical engineering Langues : Anglais (eng) Mots-clés : pH-sensitive Résumé : A pH-sensitive magnetic ion exchanger was synthesized by binding carboxymethylated chitosan (CMCH) covalently on the surface of Fe3O4 nanoparticles. The diameter for magnetic particles observed at 25 °C was 15 nm. The ion exchanger was superparamagnetic with a saturation magnetization of 64.21 emu/g and an isoelectric point (pI) of 5.75. In a model system, the laccase adsorption capacity reached equilibrium within 15 min (pH 5). The adsorption process followed the Langmuir adsorption isotherm, and the maximum equilibrium adsorption capacity was calculated to be 198.81 mg/g. The laccase can be completely desorbed at pH 8. About 97% laccase can be effectively desorbed from the surface of particles within 15 min. Moreover, the specific activity of the laccase remained constant during the adsorption and desorption process. Finally, the pH-sensitive magnetic ion exchanger was used for separation of laccase directly from culture supernatant, and nearly pure laccase was isolated by a single step with an activity recovery rate of 63%. [article] PH-sensitive magnetic ion exchanger for protein separation [texte imprimé] / Liangrong Yang, Auteur ; Chen, Guo, Auteur ; Shu Chen, Auteur ; Feng Wang, Auteur ; Jing Wang, Auteur ; Zhentao An, Auteur . - 2009 . - p. 944–950. chimical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 944–950 Mots-clés : pH-sensitive Résumé : A pH-sensitive magnetic ion exchanger was synthesized by binding carboxymethylated chitosan (CMCH) covalently on the surface of Fe3O4 nanoparticles. The diameter for magnetic particles observed at 25 °C was 15 nm. The ion exchanger was superparamagnetic with a saturation magnetization of 64.21 emu/g and an isoelectric point (pI) of 5.75. In a model system, the laccase adsorption capacity reached equilibrium within 15 min (pH 5). The adsorption process followed the Langmuir adsorption isotherm, and the maximum equilibrium adsorption capacity was calculated to be 198.81 mg/g. The laccase can be completely desorbed at pH 8. About 97% laccase can be effectively desorbed from the surface of particles within 15 min. Moreover, the specific activity of the laccase remained constant during the adsorption and desorption process. Finally, the pH-sensitive magnetic ion exchanger was used for separation of laccase directly from culture supernatant, and nearly pure laccase was isolated by a single step with an activity recovery rate of 63%.

Strategies for the design of hydrophilic microspheres with controlled size and microstructure / Huanhuan Qu in Industrial & engineering chemistry research, Vol. 47 N°17 (Septembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°17 (Septembre 2008) . - p. 6399–6404 Titre : Strategies for the design of hydrophilic microspheres with controlled size and microstructure Type de document : texte imprimé Auteurs : Huanhuan Qu, Auteur ; Fangling Gong, Auteur ; Jing Wang, Auteur Année de publication : 2008 Article en page(s) : p. 6399–6404 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Hydrophilic  microspheres  Membrane  emulsification  Droplets  swelling  method  PHEMA  microspheres Résumé : Synthesizing hydrophilic microspheres is a subject of great interest for a variety of applications. However, there is difficulty in the control of the microspheresʼ size. In this study, the combination of membrane emulsification and droplets swelling method is utilized to prepare poly(2-hydroxyethylmethacrylate) (PHEMA) microspheres, a kind of hydrophilic material. The former is used to prepare monodisperse seed droplets, which include hydrophobic monomer (ethylenedimethacrylate, EDMA) and some assistant agents, whereas the latter is used for the absorption of hydrophilic monomer (HEMA). After a polymerization process, PHEMA microspheres with desired size can be obtained. It is found that large membrane pore size or high swelling ratio tended to increase the final particle size. At the same time, smaller particle size is got at higher EDMA concentration in the seed droplets. In addition, microstructure of the microspheres is also controlled by using this method. Nonporous, porous, nonporous/porous half-moon, or macroporous microspheres can be obtained easily by changing the total oil composition in swollen droplets. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800094a [article] Strategies for the design of hydrophilic microspheres with controlled size and microstructure [texte imprimé] / Huanhuan Qu, Auteur ; Fangling Gong, Auteur ; Jing Wang, Auteur . - 2008 . - p. 6399–6404. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°17 (Septembre 2008) . - p. 6399–6404 Mots-clés : Hydrophilic  microspheres  Membrane  emulsification  Droplets  swelling  method  PHEMA  microspheres Résumé : Synthesizing hydrophilic microspheres is a subject of great interest for a variety of applications. However, there is difficulty in the control of the microspheresʼ size. In this study, the combination of membrane emulsification and droplets swelling method is utilized to prepare poly(2-hydroxyethylmethacrylate) (PHEMA) microspheres, a kind of hydrophilic material. The former is used to prepare monodisperse seed droplets, which include hydrophobic monomer (ethylenedimethacrylate, EDMA) and some assistant agents, whereas the latter is used for the absorption of hydrophilic monomer (HEMA). After a polymerization process, PHEMA microspheres with desired size can be obtained. It is found that large membrane pore size or high swelling ratio tended to increase the final particle size. At the same time, smaller particle size is got at higher EDMA concentration in the seed droplets. In addition, microstructure of the microspheres is also controlled by using this method. Nonporous, porous, nonporous/porous half-moon, or macroporous microspheres can be obtained easily by changing the total oil composition in swollen droplets. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800094a

Strategies to achieve a uniform cell structure with a high void fraction in advanced structural foam molding / John W. S. Lee in Industrial & engineering chemistry research, Vol. 47 N° 23 (Décembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9457–9464 Titre : Strategies to achieve a uniform cell structure with a high void fraction in advanced structural foam molding Type de document : texte imprimé Auteurs : John W. S. Lee, Auteur ; Jing Wang, Auteur ; Jae D. Yoon, Auteur Année de publication : 2009 Article en page(s) : p. 9457–9464 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : Achieve  a  uniform  cell  structure  High  void  Structural  foam  molding Résumé : Structural foams offer numerous advantages over their solid counterparts, including greater geometrical accuracy, the absence of sink marks on the final product’s surface, lower weight (and, by extension, the need for less material), and a higher stiffness-to-weight ratio. The possibility of achieving a suitable void fraction in structural foams using conventional structural foam molding methods, however, has been of limited success; these methods allow for little control and typically yield large voids and a nonuniform cell structure. This article reports on our use of an advanced structural foam molding machine to achieve a uniform cell structure with a high void fraction. We studied the following processing parameters: injection flow rate, blowing agent content, and melt temperature. The pressure profile inside the mold cavity under various processing conditions was also investigated to elucidate cell nucleation and growth behaviors. By optimizing all processing conditions, we achieved a uniform cell structure and a very high void fraction (over 40%). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0707016 [article] Strategies to achieve a uniform cell structure with a high void fraction in advanced structural foam molding [texte imprimé] / John W. S. Lee, Auteur ; Jing Wang, Auteur ; Jae D. Yoon, Auteur . - 2009 . - p. 9457–9464. Chemistry engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9457–9464 Mots-clés : Achieve  a  uniform  cell  structure  High  void  Structural  foam  molding Résumé : Structural foams offer numerous advantages over their solid counterparts, including greater geometrical accuracy, the absence of sink marks on the final product’s surface, lower weight (and, by extension, the need for less material), and a higher stiffness-to-weight ratio. The possibility of achieving a suitable void fraction in structural foams using conventional structural foam molding methods, however, has been of limited success; these methods allow for little control and typically yield large voids and a nonuniform cell structure. This article reports on our use of an advanced structural foam molding machine to achieve a uniform cell structure with a high void fraction. We studied the following processing parameters: injection flow rate, blowing agent content, and melt temperature. The pressure profile inside the mold cavity under various processing conditions was also investigated to elucidate cell nucleation and growth behaviors. By optimizing all processing conditions, we achieved a uniform cell structure and a very high void fraction (over 40%). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0707016

Ultrasonic irradiation enhanced cell nucleation in microcellular poly (lactic Acid) / Jing Wang in Industrial & engineering chemistry research, Vol. 50 N° 24 (Décembre 2011) 

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