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Manufacture of high-performance rice-straw fiberboards / Sören Halvarsson in Industrial & engineering chemistry research, Vol. 49 N° 3 (Fevrier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 3 (Fevrier 2010) . - pp. 1428–1435 Titre : Manufacture of high-performance rice-straw fiberboards Type de document : texte imprimé Auteurs : Sören Halvarsson, Auteur ; Håkan Edlund, Auteur ; Magnus Norgren, Auteur Année de publication : 2010 Article en page(s) : pp. 1428–1435 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Manufacture--High-Performance--Rice-Straw--Fiberboards Résumé : Rice straw, a waste agriculture material grown and harvested in Willows, CA, was used as a raw material in the production of thin medium- and high-density fiberboards (MDFs and HDFs). The rice straw was cleaned, size-reduced, and soaked in water before being refined. Defibration was performed in a pressurized pilot-plant single-disk refiner, OHP 20”. The fiber production capacity reached a level of 63 kg/h, and the proper fiber quality for MDF/HDF production was established. Analysis of the produced fiber showed an average fiber length of approximately 0.9 mm, an average fiber width of 31 μm, a shive weight of below 24%, and a dust content of less than 30%. Production of fiberboards was performed by addition of 3%, 4%, and 5% methylene diphenyl diisocyanate (MDI). The flexural properties, internal bond strength, and thickness swelling of the produced fiberboards were evaluated according to ASTM methods. The finished fiberboards based on rice straw and MDI resin showed excellent properties. The internal bond (IB) reached levels of 2.6 MPa, and the modulus of rupture (MOR) and modulus of elasticity (MOE) showed levels comparable to those of wood-based fiberboards and were acceptable according to the requirements of medium-density fiberboard (MDF) for interior applications (American National Standards Institute, ANSI A208.2-2002). The water-repelling properties of the 3-mm rice-straw fiberboards were encouraging; the thickness swelling (TS) was in the range of 15−30%. Two different methods to avoid adhesion between the press plates and the resinated fiber material during hot pressing were investigated: protective paper sheets were placed between the fiber mat and press plates, or a press-release agent was sprayed on steel plates that were then placed in the press before pressing. Satisfactory results were obtained with both methods, and no adhesion was observed between the fiberboard and the steel plates. The method of using press-release agent during pressing had no notable negative effects on the fiberboard properties. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901272q [article] Manufacture of high-performance rice-straw fiberboards [texte imprimé] / Sören Halvarsson, Auteur ; Håkan Edlund, Auteur ; Magnus Norgren, Auteur . - 2010 . - pp. 1428–1435. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 3 (Fevrier 2010) . - pp. 1428–1435 Mots-clés : Manufacture--High-Performance--Rice-Straw--Fiberboards Résumé : Rice straw, a waste agriculture material grown and harvested in Willows, CA, was used as a raw material in the production of thin medium- and high-density fiberboards (MDFs and HDFs). The rice straw was cleaned, size-reduced, and soaked in water before being refined. Defibration was performed in a pressurized pilot-plant single-disk refiner, OHP 20”. The fiber production capacity reached a level of 63 kg/h, and the proper fiber quality for MDF/HDF production was established. Analysis of the produced fiber showed an average fiber length of approximately 0.9 mm, an average fiber width of 31 μm, a shive weight of below 24%, and a dust content of less than 30%. Production of fiberboards was performed by addition of 3%, 4%, and 5% methylene diphenyl diisocyanate (MDI). The flexural properties, internal bond strength, and thickness swelling of the produced fiberboards were evaluated according to ASTM methods. The finished fiberboards based on rice straw and MDI resin showed excellent properties. The internal bond (IB) reached levels of 2.6 MPa, and the modulus of rupture (MOR) and modulus of elasticity (MOE) showed levels comparable to those of wood-based fiberboards and were acceptable according to the requirements of medium-density fiberboard (MDF) for interior applications (American National Standards Institute, ANSI A208.2-2002). The water-repelling properties of the 3-mm rice-straw fiberboards were encouraging; the thickness swelling (TS) was in the range of 15−30%. Two different methods to avoid adhesion between the press plates and the resinated fiber material during hot pressing were investigated: protective paper sheets were placed between the fiber mat and press plates, or a press-release agent was sprayed on steel plates that were then placed in the press before pressing. Satisfactory results were obtained with both methods, and no adhesion was observed between the fiberboard and the steel plates. The method of using press-release agent during pressing had no notable negative effects on the fiberboard properties. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901272q

Removal of lignin from wastewater generated by mechanical pulping using activated charcoal and fly ash / Kerstin I. Andersson in Industrial & engineering chemistry research, Vol. 50 N° 13 (Juillet 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) Titre : Removal of lignin from wastewater generated by mechanical pulping using activated charcoal and fly ash : adsorption isotherms and thermodynamics Type de document : texte imprimé Auteurs : Kerstin I. Andersson, Auteur ; Marie Eriksson, Auteur ; Magnus Norgren, Auteur Année de publication : 2011 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Wastewater  generated  Adsorption  Isotherms Résumé : Lignin-related material found in wastewater from thermomechanical pulping resists conventional biological treatment, entailing the use of advanced removal methods. In this work, the use of adsorption for removing lignin-related material was investigated. Activated charcoal and fly ash were used to study the adsorption behavior of lignin and to determine the adsorption capacities of these two adsorbents. Experimental data were fitted to various isotherm equations to find the best description of the sorption systems, and the corresponding thermodynamic parameters were calculated. Fly ash exhibited good sorption properties, although its sorption capacity was inferior to that of activated charcoal. Both the Freundlich and Langmuir equations provided reasonable models of the sorption processes, and the thermodynamic parameters indicated that sorption onto activated charcoal is endothermic, whereas sorption onto fly ash appears to be exothermic. Fly ash is a low-cost material that is often available on-site and offers an interesting alternative to high-cost advanced wastewater treatment systems for removing recalcitrant organic materials. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200378s [article] Removal of lignin from wastewater generated by mechanical pulping using activated charcoal and fly ash : adsorption isotherms and thermodynamics [texte imprimé] / Kerstin I. Andersson, Auteur ; Marie Eriksson, Auteur ; Magnus Norgren, Auteur . - 2011. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) Mots-clés : Wastewater  generated  Adsorption  Isotherms Résumé : Lignin-related material found in wastewater from thermomechanical pulping resists conventional biological treatment, entailing the use of advanced removal methods. In this work, the use of adsorption for removing lignin-related material was investigated. Activated charcoal and fly ash were used to study the adsorption behavior of lignin and to determine the adsorption capacities of these two adsorbents. Experimental data were fitted to various isotherm equations to find the best description of the sorption systems, and the corresponding thermodynamic parameters were calculated. Fly ash exhibited good sorption properties, although its sorption capacity was inferior to that of activated charcoal. Both the Freundlich and Langmuir equations provided reasonable models of the sorption processes, and the thermodynamic parameters indicated that sorption onto activated charcoal is endothermic, whereas sorption onto fly ash appears to be exothermic. Fly ash is a low-cost material that is often available on-site and offers an interesting alternative to high-cost advanced wastewater treatment systems for removing recalcitrant organic materials. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200378s

Removal of lignin from wastewater generated by mechanical pulping using activated charcoal and fly ash / Kerstin I. Andersson in Industrial & engineering chemistry research, Vol. 50 N° 13 (Juillet 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 7733-7739 Titre : Removal of lignin from wastewater generated by mechanical pulping using activated charcoal and fly ash : adsorption kinetics Type de document : texte imprimé Auteurs : Kerstin I. Andersson, Auteur ; Marie Eriksson, Auteur ; Magnus Norgren, Auteur Année de publication : 2011 Article en page(s) : pp. 7733-7739 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics  Adsorption  Fly  ash  Mechanical  pulping  Waste  water Résumé : The possible application of adsorption for the removal of lignin-related material found in wastewater generated by mechanical pulping was investigated. Activated charcoal and fly ash were used as adsorbents in batch experiments. The lignin-related material exhibited properties well-suited for adsorption onto both adsorbents, although the sorption capacity of activated charcoal exceeds that of fly ash. The experimental data were fitted to pseudo-first- and pseudo-second-order rate kinetic expressions, and an attempt was made to find the rate-limiting step involved in the adsorption processes. The results showed that lignin adsorption onto both activated charcoal and fly ash follows pseudo-second-order rate kinetics and that both boundary-layer diffusion and intraparticle diffusion are likely involved in the rate-limiting mechanisms. Adsorption is an interesting option in advanced wastewater treatment, and fly ash appears to be a suitable low-cost adsorbent for recalcitrant organic pollutants. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24332094 [article] Removal of lignin from wastewater generated by mechanical pulping using activated charcoal and fly ash : adsorption kinetics [texte imprimé] / Kerstin I. Andersson, Auteur ; Marie Eriksson, Auteur ; Magnus Norgren, Auteur . - 2011 . - pp. 7733-7739. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 7733-7739 Mots-clés : Kinetics  Adsorption  Fly  ash  Mechanical  pulping  Waste  water Résumé : The possible application of adsorption for the removal of lignin-related material found in wastewater generated by mechanical pulping was investigated. Activated charcoal and fly ash were used as adsorbents in batch experiments. The lignin-related material exhibited properties well-suited for adsorption onto both adsorbents, although the sorption capacity of activated charcoal exceeds that of fly ash. The experimental data were fitted to pseudo-first- and pseudo-second-order rate kinetic expressions, and an attempt was made to find the rate-limiting step involved in the adsorption processes. The results showed that lignin adsorption onto both activated charcoal and fly ash follows pseudo-second-order rate kinetics and that both boundary-layer diffusion and intraparticle diffusion are likely involved in the rate-limiting mechanisms. Adsorption is an interesting option in advanced wastewater treatment, and fly ash appears to be a suitable low-cost adsorbent for recalcitrant organic pollutants. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24332094

Sulfate and surfactants as boosters of kraft lignin precipitation / Magnus Norgren in Industrial & engineering chemistry research, Vol. 48 N° 10 (Mai 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5098–5104 Titre : Sulfate and surfactants as boosters of kraft lignin precipitation Type de document : texte imprimé Auteurs : Magnus Norgren, Auteur ; Sofia Mackin, Auteur Année de publication : 2009 Article en page(s) : pp. 5098–5104 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Salts  Surfactants  Kraft  lignin  precipitation Résumé : In the spirit of the biorefinery concept, an increasing interest in further utilization of technical lignins outside the pulp mills has arisen. In this context optimization of the precipitation process to increase the yield of the lignin recovered is of great importance. The objectives of this investigation have been to study how specific salts and surfactants affect kraft lignin yield during precipitation and washing. From the results it was seen that additions of sodium sulfate increased the yield of precipitation at elevated temperatures at much lower concentrations than sodium chloride. Earlier studies of the effect of monovalent salts on kraft lignin stability have shown that specific ions either increase or decrease the formation of precipitates during kraft lignin aggregation. Thus, the presented results in this study further strengthen this dependency concerning divalent anions. Regarding the role of surfactants as precipitation enhancers, cationic surfactants gave rise to fast aggregation and relatively high yields. This was found mainly due to attractive electrostatic interactions between the cationic surfactant headgroup and the oppositely charged groups on the kraft lignin macromolecules, introducing an increased degree of hydrophobicity of the lignin and thus a decreased stability. The nonionic surfactants tested affected the system very differently. In some cases the aggregation was fast and the aggregates became relatively large before settling, whereas some surfactants induced the formation of relatively dense precipitates that settled rapidly. Concerning kraft lignin precipitate washing, calcium chloride at concentrations in the millimolar region decreased the lignin losses dramatically. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900141s [article] Sulfate and surfactants as boosters of kraft lignin precipitation [texte imprimé] / Magnus Norgren, Auteur ; Sofia Mackin, Auteur . - 2009 . - pp. 5098–5104. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 10 (Mai 2009) . - pp. 5098–5104 Mots-clés : Salts  Surfactants  Kraft  lignin  precipitation Résumé : In the spirit of the biorefinery concept, an increasing interest in further utilization of technical lignins outside the pulp mills has arisen. In this context optimization of the precipitation process to increase the yield of the lignin recovered is of great importance. The objectives of this investigation have been to study how specific salts and surfactants affect kraft lignin yield during precipitation and washing. From the results it was seen that additions of sodium sulfate increased the yield of precipitation at elevated temperatures at much lower concentrations than sodium chloride. Earlier studies of the effect of monovalent salts on kraft lignin stability have shown that specific ions either increase or decrease the formation of precipitates during kraft lignin aggregation. Thus, the presented results in this study further strengthen this dependency concerning divalent anions. Regarding the role of surfactants as precipitation enhancers, cationic surfactants gave rise to fast aggregation and relatively high yields. This was found mainly due to attractive electrostatic interactions between the cationic surfactant headgroup and the oppositely charged groups on the kraft lignin macromolecules, introducing an increased degree of hydrophobicity of the lignin and thus a decreased stability. The nonionic surfactants tested affected the system very differently. In some cases the aggregation was fast and the aggregates became relatively large before settling, whereas some surfactants induced the formation of relatively dense precipitates that settled rapidly. Concerning kraft lignin precipitate washing, calcium chloride at concentrations in the millimolar region decreased the lignin losses dramatically. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900141s