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Adsorption of lignocelluloses dissolved in prehydrolysis liquor of kraft - based dissolving pulp process on oxidized activated carbons / Xin Liu in Industrial & engineering chemistry research, Vol. 50 N° 20 (Octobre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 20 (Octobre 2011) . - pp. 11706–11711 Titre : Adsorption of lignocelluloses dissolved in prehydrolysis liquor of kraft - based dissolving pulp process on oxidized activated carbons Type de document : texte imprimé Auteurs : Xin Liu, Auteur ; Pedram Fatehi, Auteur ; Yonghao Ni, Auteur Année de publication : 2011 Article en page(s) : pp. 11706–11711 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adsorption  Lignocelluloses Résumé : The prehydrolysis stage is essential in producing high-purity cellulose from the kraft-based process and is effective in removing hemicelluloses from wood chips. To convert hemicelluloses and other dissolved materials of the prehydrolysis liquor (PHL) into value-added products, they must first be recovered from the PHL. In this work, we investigated the use of activated carbon (AC) to adsorb such materials from the PHL. The adsorption of hemicelluloses on unmodified AC was significantly higher in neutral than acidic environment. To improve the adsorption performance of AC, the AC was oxidized with H2O2 or H2SO4. The H2O2- and H2SO4-modified ACs prepared under milder conditions had higher capacities than those prepared under stronger conditions for adsorbing hemicelluloses, lignin, and furfural. Additionally, the modifications increased the adsorption rate of dissolved materials on the AC, especially that of hemicelluloses. Oxidized activated carbon is a promising adsorbent for lignocellulosic materials of the PHL that can be employed in biorefinery processes conducted during the kraft-based dissolved pulp production process DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201036q [article] Adsorption of lignocelluloses dissolved in prehydrolysis liquor of kraft - based dissolving pulp process on oxidized activated carbons [texte imprimé] / Xin Liu, Auteur ; Pedram Fatehi, Auteur ; Yonghao Ni, Auteur . - 2011 . - pp. 11706–11711. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 20 (Octobre 2011) . - pp. 11706–11711 Mots-clés : Adsorption  Lignocelluloses Résumé : The prehydrolysis stage is essential in producing high-purity cellulose from the kraft-based process and is effective in removing hemicelluloses from wood chips. To convert hemicelluloses and other dissolved materials of the prehydrolysis liquor (PHL) into value-added products, they must first be recovered from the PHL. In this work, we investigated the use of activated carbon (AC) to adsorb such materials from the PHL. The adsorption of hemicelluloses on unmodified AC was significantly higher in neutral than acidic environment. To improve the adsorption performance of AC, the AC was oxidized with H2O2 or H2SO4. The H2O2- and H2SO4-modified ACs prepared under milder conditions had higher capacities than those prepared under stronger conditions for adsorbing hemicelluloses, lignin, and furfural. Additionally, the modifications increased the adsorption rate of dissolved materials on the AC, especially that of hemicelluloses. Oxidized activated carbon is a promising adsorbent for lignocellulosic materials of the PHL that can be employed in biorefinery processes conducted during the kraft-based dissolved pulp production process DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201036q

Cationic alkoxylated amine surfactant as a debonding agent for papers made of sulfite-bleached fibers / Pedram Fatehi 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. 749–754 Titre : Cationic alkoxylated amine surfactant as a debonding agent for papers made of sulfite-bleached fibers Type de document : texte imprimé Auteurs : Pedram Fatehi, Auteur ; Kevin C. Outhouse, Auteur ; Huining Xiao, Auteur Année de publication : 2009 Article en page(s) : p. 749–754 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Sulfite-Bleached  --  Papers  Made Résumé : Today, there is a steadily increasing demand for the application of surfactants as debonding agents in tissue manufacturing. The work presented herein focused on evaluating the debonding ability of cationic alkoxylated amine surfactant on unrefined and refined fibers. The results showed that, as the dosage of the surfactant was increased to 10 mg/g on unrefined pulps, the adsorption of the surfactant on the fibers increased to 5 mg/g, and the tensile and burst indices of the papers made of the modified fibers decreased by as much as 12.6% and 14.9%, respectively. Also, the roughness, strain, and moisture content of the papers were enhanced, whereas the apparent density was reduced. Furthermore, the tear index of the papers increased upon the application of surfactant (10 mg/g) at the expense of reductions in tensile and burst indices, as well as the apparent density at any pressure applied in wet pressing. Also, as the pressure was increased, the surfactant impacted the fiber bonding more significantly. On the other hand, the application of surfactant (10 mg/g) somewhat increased the light scattering coefficient of the papers, regardless of the refining load. Furthermore, the adsorption of the surfactant on refined fibers increased with increasing refining load. However, the influence of the surfactant on the tear, tensile, and burst indices and the apparent density was impaired with increasing refining load. Also, the zero-span tensile index and brightness of the papers varied negligibly upon surfactant application. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800929p [article] Cationic alkoxylated amine surfactant as a debonding agent for papers made of sulfite-bleached fibers [texte imprimé] / Pedram Fatehi, Auteur ; Kevin C. Outhouse, Auteur ; Huining Xiao, Auteur . - 2009 . - p. 749–754. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 749–754 Mots-clés : Sulfite-Bleached  --  Papers  Made Résumé : Today, there is a steadily increasing demand for the application of surfactants as debonding agents in tissue manufacturing. The work presented herein focused on evaluating the debonding ability of cationic alkoxylated amine surfactant on unrefined and refined fibers. The results showed that, as the dosage of the surfactant was increased to 10 mg/g on unrefined pulps, the adsorption of the surfactant on the fibers increased to 5 mg/g, and the tensile and burst indices of the papers made of the modified fibers decreased by as much as 12.6% and 14.9%, respectively. Also, the roughness, strain, and moisture content of the papers were enhanced, whereas the apparent density was reduced. Furthermore, the tear index of the papers increased upon the application of surfactant (10 mg/g) at the expense of reductions in tensile and burst indices, as well as the apparent density at any pressure applied in wet pressing. Also, as the pressure was increased, the surfactant impacted the fiber bonding more significantly. On the other hand, the application of surfactant (10 mg/g) somewhat increased the light scattering coefficient of the papers, regardless of the refining load. Furthermore, the adsorption of the surfactant on refined fibers increased with increasing refining load. However, the influence of the surfactant on the tear, tensile, and burst indices and the apparent density was impaired with increasing refining load. Also, the zero-span tensile index and brightness of the papers varied negligibly upon surfactant application. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800929p

Debonding performance of various cationic surfactants on networks made of bleached kraft fibers / Pedram Fatehi in Industrial & engineering chemistry research, Vol. 49 N° 22 (Novembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 22 (Novembre 2010) . - pp.11402–11407 Titre : Debonding performance of various cationic surfactants on networks made of bleached kraft fibers Type de document : texte imprimé Auteurs : Pedram Fatehi, Auteur ; Kevin C. Outhouse, Auteur ; Huining Xiao, Auteur Année de publication : 2011 Article en page(s) : pp.11402–11407 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Cationic  Fibers Résumé : Debonding agents are applied in the paper industry for various purposes, for example, to increase the softness of tissue paper. In this work, the debonding capacities of three cationic aliphatic ammonium surfactants and one alkoxylated amine surfactant on kraft fibers were determined. The results showed that the adsorption of the alkoxylated amine surfactant (AAS) was higher than that of others on the fibers, but a cationic cetyltrimethyl ammonium surfactant (cetyltrimethyl ammonium bromide, CAB) was the most effective debonding agent, probably because of its relatively long hydrophobic chain. By applying CAB at levels of up to 20 mg/g, the tensile and burst indices were reduced by 37% and 41%, respectively. By applying AAS at levels of up to 20 mg/g, the tensile and burst indices of the networks were reduced by 18.6%, and 14.2%, respectively. The tear index of the fiber networks negligibly changed upon application of AAS, but increased by 19% upon application of CAB. The strain of the fiber networks prior to rupturing increased upon application of AAS, whereas it decreased upon application of CAB, which implies that the surfactants have different debonding mechanisms. The debonding efficiency of CAB was independent of both the refining revolutions and basis weights of the fiber networks. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101442p [article] Debonding performance of various cationic surfactants on networks made of bleached kraft fibers [texte imprimé] / Pedram Fatehi, Auteur ; Kevin C. Outhouse, Auteur ; Huining Xiao, Auteur . - 2011 . - pp.11402–11407. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 22 (Novembre 2010) . - pp.11402–11407 Mots-clés : Cationic  Fibers Résumé : Debonding agents are applied in the paper industry for various purposes, for example, to increase the softness of tissue paper. In this work, the debonding capacities of three cationic aliphatic ammonium surfactants and one alkoxylated amine surfactant on kraft fibers were determined. The results showed that the adsorption of the alkoxylated amine surfactant (AAS) was higher than that of others on the fibers, but a cationic cetyltrimethyl ammonium surfactant (cetyltrimethyl ammonium bromide, CAB) was the most effective debonding agent, probably because of its relatively long hydrophobic chain. By applying CAB at levels of up to 20 mg/g, the tensile and burst indices were reduced by 37% and 41%, respectively. By applying AAS at levels of up to 20 mg/g, the tensile and burst indices of the networks were reduced by 18.6%, and 14.2%, respectively. The tear index of the fiber networks negligibly changed upon application of AAS, but increased by 19% upon application of CAB. The strain of the fiber networks prior to rupturing increased upon application of AAS, whereas it decreased upon application of CAB, which implies that the surfactants have different debonding mechanisms. The debonding efficiency of CAB was independent of both the refining revolutions and basis weights of the fiber networks. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101442p

Influence of Soda−Air−AQ Pulping of Straw on Silica Precipitation, Paper Strength, and Performance of CPVA as a Dry Strength Additive / Pedram Fatehi in Industrial & engineering chemistry research, Vol. 48 N° 23 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10190–10195 Titre : Influence of Soda−Air−AQ Pulping of Straw on Silica Precipitation, Paper Strength, and Performance of CPVA as a Dry Strength Additive Type de document : texte imprimé Auteurs : Pedram Fatehi, Auteur ; Ahmet Tutus, Auteur ; Yonghao Ni, Auteur Année de publication : 2010 Article en page(s) : pp. 10190–10195 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Influence--Soda−Air−AQ--Pulping--Straw--Silica--Precipitation--Paper  Strength--Performance--CPVA--Strength  Additive Résumé : In this study, the impact of soda−air−anthraquinone (AQ) pulping conditions on delignification and silica precipitation onto pulp fibers and paper sheets was studied. The results showed that the yield and silica precipitation slightly increased upon application of AQ in soda−air pulping. Scanning electron microscopy (SEM) and elemental analysis confirmed the deposition of silica-related particles on fibers and on paper sheets for both soda−air and soda−air−AQ pulping. Furthermore, increasing the cooking temperature had a stronger impact on delignification and silica deposition than did increasing the cooking time for soda−air−AQ pulping. In another set of experiments, the influence of cationic poly(vinyl alcohol) (CPVA) with two different molecular weights on improving the strength properties of straw pulps produced under various soda−air−AQ pulping conditions was studied. The adsorption of CPVA onto straw pulp and its effect on silica retention for paper sheets were comprehensively investigated. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901273m [article] Influence of Soda−Air−AQ Pulping of Straw on Silica Precipitation, Paper Strength, and Performance of CPVA as a Dry Strength Additive [texte imprimé] / Pedram Fatehi, Auteur ; Ahmet Tutus, Auteur ; Yonghao Ni, Auteur . - 2010 . - pp. 10190–10195. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10190–10195 Mots-clés : Influence--Soda−Air−AQ--Pulping--Straw--Silica--Precipitation--Paper  Strength--Performance--CPVA--Strength  Additive Résumé : In this study, the impact of soda−air−anthraquinone (AQ) pulping conditions on delignification and silica precipitation onto pulp fibers and paper sheets was studied. The results showed that the yield and silica precipitation slightly increased upon application of AQ in soda−air pulping. Scanning electron microscopy (SEM) and elemental analysis confirmed the deposition of silica-related particles on fibers and on paper sheets for both soda−air and soda−air−AQ pulping. Furthermore, increasing the cooking temperature had a stronger impact on delignification and silica deposition than did increasing the cooking time for soda−air−AQ pulping. In another set of experiments, the influence of cationic poly(vinyl alcohol) (CPVA) with two different molecular weights on improving the strength properties of straw pulps produced under various soda−air−AQ pulping conditions was studied. The adsorption of CPVA onto straw pulp and its effect on silica retention for paper sheets were comprehensively investigated. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901273m

Lime treatment of prehydrolysis liquor from the kraft - based dissolving pulp production process / Jing Shen in Industrial & engineering chemistry research, Vol. 51 N° 2 (Janvier 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 2 (Janvier 2012) . - pp. 662–667 Titre : Lime treatment of prehydrolysis liquor from the kraft - based dissolving pulp production process Type de document : texte imprimé Auteurs : Jing Shen, Auteur ; Pedram Fatehi, Auteur ; Pendar Soleimani, Auteur Année de publication : 2012 Article en page(s) : pp. 662–667 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Prehydrolysis  liquor Résumé : In this study, the concept of using lime for the treatment of industrially produced prehydrolysis liquor (PHL) of kraft-based dissolving pulp production process was tested, and its effect on the concentrations of acetic acid, furfural, UV lignin, and hemicelluloses was explored. Lime treatment resulted in a significant increase in the acetic acid concentration due to alkaline hydrolysis of the acetyl groups bound to the dissolved hemicelluloses in PHL, and the degradation of sugars. At relatively high lime dosages (e.g., above 1.7%), furfural was completely eliminated, while the lignin concentration decreased by 20–25%. The hemicelluloses concentration can be significantly decreased due to the alkaline oxidative degradation. However, when performed in the absence of oxygen/air by bubbling carbon dioxide to the lime/PHL system, the degradation of hemicelluloses was effectively minimized. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2019195 [article] Lime treatment of prehydrolysis liquor from the kraft - based dissolving pulp production process [texte imprimé] / Jing Shen, Auteur ; Pedram Fatehi, Auteur ; Pendar Soleimani, Auteur . - 2012 . - pp. 662–667. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 2 (Janvier 2012) . - pp. 662–667 Mots-clés : Prehydrolysis  liquor Résumé : In this study, the concept of using lime for the treatment of industrially produced prehydrolysis liquor (PHL) of kraft-based dissolving pulp production process was tested, and its effect on the concentrations of acetic acid, furfural, UV lignin, and hemicelluloses was explored. Lime treatment resulted in a significant increase in the acetic acid concentration due to alkaline hydrolysis of the acetyl groups bound to the dissolved hemicelluloses in PHL, and the degradation of sugars. At relatively high lime dosages (e.g., above 1.7%), furfural was completely eliminated, while the lignin concentration decreased by 20–25%. The hemicelluloses concentration can be significantly decreased due to the alkaline oxidative degradation. However, when performed in the absence of oxygen/air by bubbling carbon dioxide to the lime/PHL system, the degradation of hemicelluloses was effectively minimized. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2019195

Optimizing the poly ethylene oxide flocculation process for isolating lignin of prehydrolysis liquor of a kraft - based dissolving pulp production process / Haiqiang Shi in Industrial & engineering chemistry research, Vol. 51 N° 14 (Avril 2012) 

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Treatment of fractionated fibers with various cationic-modified poly(vinyl alcohols) and Its iImpact on paper properties / Pedram Fatehi in Industrial & engineering chemistry research, Vol. 48 N° 23 (Décembre 2009) 

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