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Biomimetic synthesis of magnetic composite particles for laccase immobilization / Xiaobing Zheng in Industrial & engineering chemistry research, Vol. 51 N° 30 (Août 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 30 (Août 2012) . - pp. 10140–10146 Titre : Biomimetic synthesis of magnetic composite particles for laccase immobilization Type de document : texte imprimé Auteurs : Xiaobing Zheng, Auteur ; Qi Wang, Auteur ; Yanjun Jiang, Auteur Année de publication : 2012 Article en page(s) : pp. 10140–10146 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Biomimetic  Magnetic  composite Résumé : Magnetic silica composite particles were prepared by using the biosilicification reaction, in which Fe3O4 nanoparticles were entrapped in a silica matrix. The composite particles were functionalized with 3-aminopropyltriethoxysilane (APTES). These functionalized magnetic composite particles were used to immobilize a kind of valuable bulky industrial enzyme (laccase). The incorporation of magnetic nanoparticles greatly facilitates the manipulation of the immobilized biocatalyst, since it can be easily and quickly recovered from the reaction system by the simple application of an external magnetic field. The effects of immobilization conditions were optimized and the activity of the immobilized laccase was investigated. The results showed that the highest specific activity of immobilized laccase reached to 224 U and the activity recovery was 83.9%. Compared with free laccase, the thermal, pH, operational and storage stabilities of the immobilized laccase were improved significantly. The catalytic activity of the immobilized laccase was also demonstrated by the degradation of two phenolic substances (i.e., 2,4-dichlorophenol and 4-chlorophenol). It was found that the removal rates of 2,4-dichlorophenol and 4-chlorophenol were 80.9% and 64.2% in about 12 h, respectively. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3000908 [article] Biomimetic synthesis of magnetic composite particles for laccase immobilization [texte imprimé] / Xiaobing Zheng, Auteur ; Qi Wang, Auteur ; Yanjun Jiang, Auteur . - 2012 . - pp. 10140–10146. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 30 (Août 2012) . - pp. 10140–10146 Mots-clés : Biomimetic  Magnetic  composite Résumé : Magnetic silica composite particles were prepared by using the biosilicification reaction, in which Fe3O4 nanoparticles were entrapped in a silica matrix. The composite particles were functionalized with 3-aminopropyltriethoxysilane (APTES). These functionalized magnetic composite particles were used to immobilize a kind of valuable bulky industrial enzyme (laccase). The incorporation of magnetic nanoparticles greatly facilitates the manipulation of the immobilized biocatalyst, since it can be easily and quickly recovered from the reaction system by the simple application of an external magnetic field. The effects of immobilization conditions were optimized and the activity of the immobilized laccase was investigated. The results showed that the highest specific activity of immobilized laccase reached to 224 U and the activity recovery was 83.9%. Compared with free laccase, the thermal, pH, operational and storage stabilities of the immobilized laccase were improved significantly. The catalytic activity of the immobilized laccase was also demonstrated by the degradation of two phenolic substances (i.e., 2,4-dichlorophenol and 4-chlorophenol). It was found that the removal rates of 2,4-dichlorophenol and 4-chlorophenol were 80.9% and 64.2% in about 12 h, respectively. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3000908

Fenton and Fenton-like reaction followed by hydroxide precipitation in the removal of Ni(II) from NiEDTA wastewater / Fenglian Fu in Chemical engineering journal, Vol. 155 N° 3 (Decembre 2009) 

Public ISBD [article]  in Chemical engineering journal > Vol. 155 N° 3 (Decembre 2009) . - pp. 769-774 Titre : Fenton and Fenton-like reaction followed by hydroxide precipitation in the removal of Ni(II) from NiEDTA wastewater : a comparative study Type de document : texte imprimé Auteurs : Fenglian Fu, Auteur ; Qi Wang, Auteur ; Bing Tang, Auteur Année de publication : 2010 Article en page(s) : pp. 769-774 Note générale : Génie Chimique Langues : Anglais (eng) Mots-clés : NiEDTA  wastewater  FR-HP  process  Fenton  reaction  Fenton-like  reaction Index. décimale : 660 Résumé : It is difficult to remove Ni(II) from NiEDTA wastewater by many conventional processes. A new method for removing Ni(II) from NiEDTA wastewater by Fenton and Fenton-like reaction followed by hydroxide precipitation presents an important breakthrough. This treatment process is referred to as Fenton/Fenton-like reaction-hydroxide precipitation (FR-HP) process. This study investigated the use of FR-HP process for the removal of Ni(II) from NiEDTA complex wastewater. The removal efficiency of Ni(II) by FR-HP process was investigated and the kinetics of the two processes was studied. Results indicated that the removal efficiency was strongly dependent on the initial concentration of Fe2+ or Fe3+ and H2O2, initial and precipitation pH and temperature. Both FR-HP processes can effectively remove Ni(II). At optimal operation conditions, the removal efficiency of Ni(II) were 92.8% and 94.7% for Fenton and Fenton-like systems after 60 min, respectively. FR-HP process seems to be an economically and environmentally friendly process to remove the metal from metal–EDTA wastewater. Hopefully, FR-HP process will promote the development of metal–EDTA treatment technology. DEWEY : 660 ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFJ-4X908Y5-3&_user=6 [...] [article] Fenton and Fenton-like reaction followed by hydroxide precipitation in the removal of Ni(II) from NiEDTA wastewater : a comparative study [texte imprimé] / Fenglian Fu, Auteur ; Qi Wang, Auteur ; Bing Tang, Auteur . - 2010 . - pp. 769-774. Génie Chimique Langues : Anglais (eng) in Chemical engineering journal > Vol. 155 N° 3 (Decembre 2009) . - pp. 769-774 Mots-clés : NiEDTA  wastewater  FR-HP  process  Fenton  reaction  Fenton-like  reaction Index. décimale : 660 Résumé : It is difficult to remove Ni(II) from NiEDTA wastewater by many conventional processes. A new method for removing Ni(II) from NiEDTA wastewater by Fenton and Fenton-like reaction followed by hydroxide precipitation presents an important breakthrough. This treatment process is referred to as Fenton/Fenton-like reaction-hydroxide precipitation (FR-HP) process. This study investigated the use of FR-HP process for the removal of Ni(II) from NiEDTA complex wastewater. The removal efficiency of Ni(II) by FR-HP process was investigated and the kinetics of the two processes was studied. Results indicated that the removal efficiency was strongly dependent on the initial concentration of Fe2+ or Fe3+ and H2O2, initial and precipitation pH and temperature. Both FR-HP processes can effectively remove Ni(II). At optimal operation conditions, the removal efficiency of Ni(II) were 92.8% and 94.7% for Fenton and Fenton-like systems after 60 min, respectively. FR-HP process seems to be an economically and environmentally friendly process to remove the metal from metal–EDTA wastewater. Hopefully, FR-HP process will promote the development of metal–EDTA treatment technology. DEWEY : 660 ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFJ-4X908Y5-3&_user=6 [...]

Removal of cobalt from aqueous solution by magnetic multiwalled carbon nanotube/iron oxide composites / Qi Wang in Chemical engineering journal, Vol. 174 N° 1 (Octobre 2011) 

Public ISBD [article]  in Chemical engineering journal > Vol. 174 N° 1 (Octobre 2011) . - pp.126–133 Titre : Removal of cobalt from aqueous solution by magnetic multiwalled carbon nanotube/iron oxide composites Type de document : texte imprimé Auteurs : Qi Wang, Auteur ; Jiaxing Li, Auteur ; Changlun Chen, Auteur Année de publication : 2012 Article en page(s) : pp.126–133 Note générale : Génie chimique Langues : Anglais (eng) Mots-clés : Co(II)  Magnetic  MWCNT/IO  composites  Humic  substances  Removal Résumé : The effects of contact time, pH, ionic strength, foreign ions, temperature, humic substances (HSs), and the addition sequences of Co(II)/HSs on Co(II) sorption on magneticmultiwalled carbon nanotube/iron oxide composites (magnetic MWCNT/IO composites) were investigated under ambient conditions. The results indicated that Co(II) sorption on the magnetic MWCNT/IO composites increased with increasing pH. The ionic strength and foreign ion dependent of Co(II) sorption suggested that ion exchange and outer-sphere surface complexation were the main sorption mechanism at low pH, whereas the ionic strength and foreign ion independent of Co(II) sorption at high pH values indicated that inner-sphere surface complexation was predominant sorption mechanism. The Langmuir model fitted Co(II) sorption isotherms better than the Freundlich model. The thermodynamic data calculated from the temperature dependent sorption isotherms suggested that Co(II) sorption on the magnetic MWCNT/IO composites was a spontaneous and endothermic process. The removal of Co(II) by the magnetic MWCNT/IO composites was affected evidently by the presence of HSs and by the addition sequences of Co(II)/HSs. This study highlights the interactions between Co(II) and HSs to determine the mutual effects of inorganic and organic matters on the removal of metal ions in environmental pollution management. ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science/article/pii/S1385894711010175 [article] Removal of cobalt from aqueous solution by magnetic multiwalled carbon nanotube/iron oxide composites [texte imprimé] / Qi Wang, Auteur ; Jiaxing Li, Auteur ; Changlun Chen, Auteur . - 2012 . - pp.126–133. Génie chimique Langues : Anglais (eng) in Chemical engineering journal > Vol. 174 N° 1 (Octobre 2011) . - pp.126–133 Mots-clés : Co(II)  Magnetic  MWCNT/IO  composites  Humic  substances  Removal Résumé : The effects of contact time, pH, ionic strength, foreign ions, temperature, humic substances (HSs), and the addition sequences of Co(II)/HSs on Co(II) sorption on magneticmultiwalled carbon nanotube/iron oxide composites (magnetic MWCNT/IO composites) were investigated under ambient conditions. The results indicated that Co(II) sorption on the magnetic MWCNT/IO composites increased with increasing pH. The ionic strength and foreign ion dependent of Co(II) sorption suggested that ion exchange and outer-sphere surface complexation were the main sorption mechanism at low pH, whereas the ionic strength and foreign ion independent of Co(II) sorption at high pH values indicated that inner-sphere surface complexation was predominant sorption mechanism. The Langmuir model fitted Co(II) sorption isotherms better than the Freundlich model. The thermodynamic data calculated from the temperature dependent sorption isotherms suggested that Co(II) sorption on the magnetic MWCNT/IO composites was a spontaneous and endothermic process. The removal of Co(II) by the magnetic MWCNT/IO composites was affected evidently by the presence of HSs and by the addition sequences of Co(II)/HSs. This study highlights the interactions between Co(II) and HSs to determine the mutual effects of inorganic and organic matters on the removal of metal ions in environmental pollution management. ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science/article/pii/S1385894711010175