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Importance of cellulosic fines relative to the dewatering rates of fiber suspensions / Hao Chen in Industrial & engineering chemistry research, Vol. 48 N° 20 (Octobre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9106–9112 Titre : Importance of cellulosic fines relative to the dewatering rates of fiber suspensions Type de document : texte imprimé Auteurs : Hao Chen, Auteur ; Andrew Park, Auteur ; John A. Heitmann, Auteur Année de publication : 2010 Article en page(s) : pp. 9106–9112 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Cellulosic  fines  Fiber  suspensions Résumé : When cellulosic fines are present in significant amounts, they can have a dominant influence on dewatering. Pulp suspensions drain rapidly if the fines have been removed. In this study, the dependency of gravity dewatering rates on the level and properties of cellulosic fine matter was quantified. Bleached hardwood kraft pulp was used as a source of primary fines (collected before refining) and secondary fines (collected after refining of fines-free fiber suspensions). Fractions of fine matter also were obtained from chemithermomechanical (CTMP) pulp. Size distributions of these fines were characterized using a laser diffraction method. Results were explainable by a mechanism in which unattached fines are able to move relative to adjacent fibers during the dewatering and consolidation of a mat of fibers. Due to such movement, fines end up in locations where they plug drainage channels in the mat. The contribution of the fines to dewatering increased in inverse proportion to particle size and with increasing surface area, as calculated from the light scattering analysis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006613 [article] Importance of cellulosic fines relative to the dewatering rates of fiber suspensions [texte imprimé] / Hao Chen, Auteur ; Andrew Park, Auteur ; John A. Heitmann, Auteur . - 2010 . - pp. 9106–9112. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 20 (Octobre 2009) . - pp. 9106–9112 Mots-clés : Cellulosic  fines  Fiber  suspensions Résumé : When cellulosic fines are present in significant amounts, they can have a dominant influence on dewatering. Pulp suspensions drain rapidly if the fines have been removed. In this study, the dependency of gravity dewatering rates on the level and properties of cellulosic fine matter was quantified. Bleached hardwood kraft pulp was used as a source of primary fines (collected before refining) and secondary fines (collected after refining of fines-free fiber suspensions). Fractions of fine matter also were obtained from chemithermomechanical (CTMP) pulp. Size distributions of these fines were characterized using a laser diffraction method. Results were explainable by a mechanism in which unattached fines are able to move relative to adjacent fibers during the dewatering and consolidation of a mat of fibers. Due to such movement, fines end up in locations where they plug drainage channels in the mat. The contribution of the fines to dewatering increased in inverse proportion to particle size and with increasing surface area, as calculated from the light scattering analysis. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9006613

Monitoring cellulase protein adsorption and recovery using SDS-PAGE / Gang Hu in Industrial & engineering chemistry research, Vol. 49 N° 18 (Septembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8333–8338 Titre : Monitoring cellulase protein adsorption and recovery using SDS-PAGE Type de document : texte imprimé Auteurs : Gang Hu, Auteur ; John A. Heitmann, Auteur ; Orlando J. Rojas, Auteur Année de publication : 2010 Article en page(s) : pp. 8333–8338 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Microcrystalline  celluloses Résumé : Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was employed to study the sorption behaviors of cellulases on microcrystalline celluloses and hardwood pulp. The adsorption and recovery of cellulases from Aspergillus niger and Trichoderma reesei were investigated at 25 °C. Cellulase recovery was conducted by rinsing adsorbed enzymes with sodium acetate buffer, Milli-Q water, and sodium hydroxide solution. The initial, equilibrium, and recovered enzymes were analyzed using SDS-PAGE gels. Gels were scanned and analyzed using ImagePro software. The molecular weights of cellulase proteins were determined using a protein marker having seven known proteins. The cellulase system from Trichoderma reesei had a higher adsorption on all substrates studied than the cellulase system from Aspergillius niger, and higher pH favored desorption from the substrates studied. Experimental results also demonstrated that adsorption and desorption amounts determined by SDS-PAGE were proportional to protein concentrations in their crude mixtures. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100731b [article] Monitoring cellulase protein adsorption and recovery using SDS-PAGE [texte imprimé] / Gang Hu, Auteur ; John A. Heitmann, Auteur ; Orlando J. Rojas, Auteur . - 2010 . - pp. 8333–8338. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8333–8338 Mots-clés : Microcrystalline  celluloses Résumé : Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was employed to study the sorption behaviors of cellulases on microcrystalline celluloses and hardwood pulp. The adsorption and recovery of cellulases from Aspergillus niger and Trichoderma reesei were investigated at 25 °C. Cellulase recovery was conducted by rinsing adsorbed enzymes with sodium acetate buffer, Milli-Q water, and sodium hydroxide solution. The initial, equilibrium, and recovered enzymes were analyzed using SDS-PAGE gels. Gels were scanned and analyzed using ImagePro software. The molecular weights of cellulase proteins were determined using a protein marker having seven known proteins. The cellulase system from Trichoderma reesei had a higher adsorption on all substrates studied than the cellulase system from Aspergillius niger, and higher pH favored desorption from the substrates studied. Experimental results also demonstrated that adsorption and desorption amounts determined by SDS-PAGE were proportional to protein concentrations in their crude mixtures. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100731b