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Catalytic hydrogenation of corn stalk to ethylene glycol and 1,2-propylene glycol / Jifeng Pang in Industrial & engineering chemistry research, Vol. 50 N° 11 (Juin 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 11 (Juin 2011) . - pp 6601–6608 Titre : Catalytic hydrogenation of corn stalk to ethylene glycol and 1,2-propylene glycol Type de document : texte imprimé Auteurs : Jifeng Pang, Auteur ; Mingyuan Zheng, Auteur ; Aiqin Wang, Auteur Année de publication : 2011 Article en page(s) : pp 6601–6608 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalytic  Hydrogenation  lignocellulosic  biomass Résumé : The use of whole lignocellulosic biomass as the feedstock for cellulose conversion is of great significance for large-scale, low-cost biomass conversion to biofuel and other useful chemicals. We recently achieved the direct conversion of cellulose (pure microcrystalline cellulose) into ethylene glycol at high yields over tungsten carbide catalysts. Here, corn stalk, an agricultural residue available in large quantities, was used as a lignocellulosic feedstock for conversion over nickel-promoted tungsten carbide catalysts under hydrothermal conditions and a hydrogen atmosphere. Nine different pretreatment methods were employed to convert the raw corn stalk to cellulosic feedstock with different chemical components and structures before the catalytic reaction. We found that corn stalks pretreated with 1,4-butanediol, NaOH, H2O2, and ammonia produced much higher yields of ethylene glycol (EG) and 1,2-propylene glycol (1,2-PG) compared to raw corn stalks, whereas pretreatments with ethanol solution, hot water, hot limewater, and supercritical CO2 just slightly improved the EG and 1,2-PG yields and corn stalk conversion. The hemicellulose in the corn stalk can be effectively converted to EG and 1,2-PG without hindering the cellulose conversion. In contrast, the lignin was resistant to degradation in the reaction and also inhibited EG and 1,2-PG production. The crystallinity of cellulose did not appear to have notable influence on the EG and 1,2-PG production. In view of the environmental benignity and low cost, pretreatment with ammonia and/or diluted H2O2 solution might be a practical method for corn stalk conversion, after which the derived cellulosic feedstock is readily converted into EG and 1,2-PG at an overall yield of 48% in the reaction. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102505y [article] Catalytic hydrogenation of corn stalk to ethylene glycol and 1,2-propylene glycol [texte imprimé] / Jifeng Pang, Auteur ; Mingyuan Zheng, Auteur ; Aiqin Wang, Auteur . - 2011 . - pp 6601–6608. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 11 (Juin 2011) . - pp 6601–6608 Mots-clés : Catalytic  Hydrogenation  lignocellulosic  biomass Résumé : The use of whole lignocellulosic biomass as the feedstock for cellulose conversion is of great significance for large-scale, low-cost biomass conversion to biofuel and other useful chemicals. We recently achieved the direct conversion of cellulose (pure microcrystalline cellulose) into ethylene glycol at high yields over tungsten carbide catalysts. Here, corn stalk, an agricultural residue available in large quantities, was used as a lignocellulosic feedstock for conversion over nickel-promoted tungsten carbide catalysts under hydrothermal conditions and a hydrogen atmosphere. Nine different pretreatment methods were employed to convert the raw corn stalk to cellulosic feedstock with different chemical components and structures before the catalytic reaction. We found that corn stalks pretreated with 1,4-butanediol, NaOH, H2O2, and ammonia produced much higher yields of ethylene glycol (EG) and 1,2-propylene glycol (1,2-PG) compared to raw corn stalks, whereas pretreatments with ethanol solution, hot water, hot limewater, and supercritical CO2 just slightly improved the EG and 1,2-PG yields and corn stalk conversion. The hemicellulose in the corn stalk can be effectively converted to EG and 1,2-PG without hindering the cellulose conversion. In contrast, the lignin was resistant to degradation in the reaction and also inhibited EG and 1,2-PG production. The crystallinity of cellulose did not appear to have notable influence on the EG and 1,2-PG production. In view of the environmental benignity and low cost, pretreatment with ammonia and/or diluted H2O2 solution might be a practical method for corn stalk conversion, after which the derived cellulosic feedstock is readily converted into EG and 1,2-PG at an overall yield of 48% in the reaction. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102505y

Kapok fiber oriented polyaniline for removal of sulfonated dyes / Yian 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. 10079-10087 Titre : Kapok fiber oriented polyaniline for removal of sulfonated dyes Type de document : texte imprimé Auteurs : Yian Zheng, Auteur ; Yi Liu, Auteur ; Aiqin Wang, Auteur Année de publication : 2012 Article en page(s) : pp. 10079-10087 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dyes Résumé : In the present work, kapok fiber oriented polyaniline (KF-O-PAN) was prepared via a facile polymerization of aniline on the surface of KF and optimized using response surface methodology based on a central composite design. Adsorption characteristics of KF-O-PAN were examined using three sulfonated dyes, that is, Congo Red (CR), Orange II (OG-II), and Orange G (OG-G), as the model adsorbates. The effects of contact time, pH, initial dye concentration, and poly(vinyl alcohol) sizing on the amount of dye adsorbed were investigated using a batch experiment. The amount of dye adsorbed in different water bodies including distilled water, tap water, well water, and lake water was compared to study further the influence of ionic strength. The results indicate that the adsorption equilibrium can be achieved within 4 h, and the monolayer adsorption capacity calculated from the Langmuir equation is 40.82, 188.7, and 192.3 mg/g for CR, OG-II, and OG-G, respectively. KF-O-PAN shows a higher amount of dye adsorbed despite the influences of ionic strength when pH < 8 except for CR, The higher desorption efficiency using NaOH solution and multiple adsorption-desorption cycles suggests the potential of KF-O-PAN for efficient removal of sulfonated dyes from aqueous solution. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26201422 [article] Kapok fiber oriented polyaniline for removal of sulfonated dyes [texte imprimé] / Yian Zheng, Auteur ; Yi Liu, Auteur ; Aiqin Wang, Auteur . - 2012 . - pp. 10079-10087. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 30 (Août 2012) . - pp. 10079-10087 Mots-clés : Dyes Résumé : In the present work, kapok fiber oriented polyaniline (KF-O-PAN) was prepared via a facile polymerization of aniline on the surface of KF and optimized using response surface methodology based on a central composite design. Adsorption characteristics of KF-O-PAN were examined using three sulfonated dyes, that is, Congo Red (CR), Orange II (OG-II), and Orange G (OG-G), as the model adsorbates. The effects of contact time, pH, initial dye concentration, and poly(vinyl alcohol) sizing on the amount of dye adsorbed were investigated using a batch experiment. The amount of dye adsorbed in different water bodies including distilled water, tap water, well water, and lake water was compared to study further the influence of ionic strength. The results indicate that the adsorption equilibrium can be achieved within 4 h, and the monolayer adsorption capacity calculated from the Langmuir equation is 40.82, 188.7, and 192.3 mg/g for CR, OG-II, and OG-G, respectively. KF-O-PAN shows a higher amount of dye adsorbed despite the influences of ionic strength when pH < 8 except for CR, The higher desorption efficiency using NaOH solution and multiple adsorption-desorption cycles suggests the potential of KF-O-PAN for efficient removal of sulfonated dyes from aqueous solution. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26201422

Microwave-assisted preparation and hydrazine decomposition properties of nanostructured tungsten carbides on carbon nanotubes / Changhai Liang in Industrial & engineering chemistry research, Vol. 48 N° 6 (Mars 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 6 (Mars 2009) . - pp. 3244–3248 Titre : Microwave-assisted preparation and hydrazine decomposition properties of nanostructured tungsten carbides on carbon nanotubes Type de document : texte imprimé Auteurs : Changhai Liang, Auteur ; Ling Ding, Auteur ; Aiqin Wang, Auteur Année de publication : 2009 Article en page(s) : pp. 3244–3248 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Carbon  nanotubes  Microwave  organic  chemical  vapor  deposition  Fluidized  bed  reactor Résumé : Nearly monodispersed nanostructured tungsten carbide particles on carbon nanotubes (CNTs) have successfully been synthesized by microwave-assisted metal−organic chemical vapor deposition (MOCVD) at atmospheric pressure in a fluidized bed reactor. The results show that the tungsten carbide particles with 2−5 nm on CNTs can be formed several minutes and the particle sizes increase with the increase of microwave irradiation time. The preoxidation of CNTs is not necessary in the microwave-assisted MOCVD. The resulting materials are active catalysts for hydrazine decomposition and exhibit high selectivity to hydrogen, indicating that nanostructured tungsten carbides on CNTs is an inexpensive and promising alternative to the noble-metal catalysts for hydrazine decomposition. The microwave-assisted MOCVD is of great potential in the controlled synthesis of supported catalytic materials. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801591x [article] Microwave-assisted preparation and hydrazine decomposition properties of nanostructured tungsten carbides on carbon nanotubes [texte imprimé] / Changhai Liang, Auteur ; Ling Ding, Auteur ; Aiqin Wang, Auteur . - 2009 . - pp. 3244–3248. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 6 (Mars 2009) . - pp. 3244–3248 Mots-clés : Carbon  nanotubes  Microwave  organic  chemical  vapor  deposition  Fluidized  bed  reactor Résumé : Nearly monodispersed nanostructured tungsten carbide particles on carbon nanotubes (CNTs) have successfully been synthesized by microwave-assisted metal−organic chemical vapor deposition (MOCVD) at atmospheric pressure in a fluidized bed reactor. The results show that the tungsten carbide particles with 2−5 nm on CNTs can be formed several minutes and the particle sizes increase with the increase of microwave irradiation time. The preoxidation of CNTs is not necessary in the microwave-assisted MOCVD. The resulting materials are active catalysts for hydrazine decomposition and exhibit high selectivity to hydrogen, indicating that nanostructured tungsten carbides on CNTs is an inexpensive and promising alternative to the noble-metal catalysts for hydrazine decomposition. The microwave-assisted MOCVD is of great potential in the controlled synthesis of supported catalytic materials. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801591x

Preparation and ammonium adsorption properties of biotite - based hydrogel composites / Yian Zheng in Industrial & engineering chemistry research, Vol. 49 N° 13 (Juillet 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6034-6041 Titre : Preparation and ammonium adsorption properties of biotite - based hydrogel composites Type de document : texte imprimé Auteurs : Yian Zheng, Auteur ; Aiqin Wang, Auteur Année de publication : 2010 Article en page(s) : pp. 6034-6041 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Composite  material  Adsorption  Preparation Résumé : We present here a simple and effective strategy to obtain a series of hydrogel composites using biotite (BT particles and poly(acrylic acid) (PAA) as the inorganic and organic components, respectively. These hydroge composites were prepared at room temperature via a self-induced redox system based on ammonium persulfate and Fe(II) arisen from iron-rich BT. After NaOH activation, as-prepared hydrogel composites were used as the adsorbents to remove ammonium (NH4+) from its aqueous solution. The effects of preparation and adsorption conditions on NH4+ removal were investigated. The results show that the adsorption of NH4+ onto as-prepared PAA/BT (30%) is complete within 15 min, with the equilibrium adsorption capacity of 32.87 mg N/g at an initial NH4+ concentration of 100 mg N/L. In addition, the reusability of as-preparec PAA/BT for NH4+ removal was evaluated and the adsorption mechanism of NH4+ onto as-prepared hydroge composite was proposed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974421 [article] Preparation and ammonium adsorption properties of biotite - based hydrogel composites [texte imprimé] / Yian Zheng, Auteur ; Aiqin Wang, Auteur . - 2010 . - pp. 6034-6041. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 13 (Juillet 2010) . - pp. 6034-6041 Mots-clés : Composite  material  Adsorption  Preparation Résumé : We present here a simple and effective strategy to obtain a series of hydrogel composites using biotite (BT particles and poly(acrylic acid) (PAA) as the inorganic and organic components, respectively. These hydroge composites were prepared at room temperature via a self-induced redox system based on ammonium persulfate and Fe(II) arisen from iron-rich BT. After NaOH activation, as-prepared hydrogel composites were used as the adsorbents to remove ammonium (NH4+) from its aqueous solution. The effects of preparation and adsorption conditions on NH4+ removal were investigated. The results show that the adsorption of NH4+ onto as-prepared PAA/BT (30%) is complete within 15 min, with the equilibrium adsorption capacity of 32.87 mg N/g at an initial NH4+ concentration of 100 mg N/L. In addition, the reusability of as-preparec PAA/BT for NH4+ removal was evaluated and the adsorption mechanism of NH4+ onto as-prepared hydroge composite was proposed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22974421