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Chemically modified chicken feather as sorbent for removing toxic chromium(VI) ions / Ping Sun in Industrial & engineering chemistry research, Vol. 48 N° 14 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6882–6889 Titre : Chemically modified chicken feather as sorbent for removing toxic chromium(VI) ions Type de document : texte imprimé Auteurs : Ping Sun, Auteur ; Zhao-Tie Liu, Auteur ; Zhong-Wen Liu, Auteur Année de publication : 2009 Article en page(s) : pp. 6882–6889 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Chromium(VI)  ions  Chicken  feathers Résumé : To improve the sorption capacity of Cr(VI) ions, chicken feathers (CFs) were chemically treated by several methods: (1) To clarify the changes in the structure and morphology of CFs, CFs were treated with aqueous NaOH solutions of varying concentrations. The results suggest that reactions occur on the surface rather than in the interior of the CFs and that keratin fragments exfoliate from the CF surface layer by layer and then dissolve in aqueous solution. (2) Keratin fragments could be rejoined to the CF surface by cross-linking with epichlorohydrin (Epi) through a series of ring-opening, recyclization, and ring-opening reactions of Epi in aqueous NaOH solution, and Epi-modified CF (EpiCF) was obtained. (3) CFs were functionalized with ethylenediamine (EA) in aqueous NaOH solution by cross-linking with Epi (EAEpiCF). The structure and properties of chemically treated CFs were investigated by FT-IR spectroscopy, XRD, SEM, elemental analysis, and water contact-angle measurements. CFs treated with NaOH were found to be similar in structure and properties to each other and exhibited a relatively low sorption capacity for removal of Cr(VI) ions from water, but a higher capacity than raw CFs. EpiCF exhibited an excellent capacity for adsorbing relatively low concentrations (10 ppm) of Cr(VI) ions but a low sorption capacity for Cu(II) ions in water. EAEpiCF was found to be hydrophilic and to exhibit 90% efficiency for removing Cr(VI) ions in the concentration range of 10−80 ppm but to have a low sorption capacity for Cu(II) in water. Equilibrium sorption isotherms for the raw and chemically treated CFs fit the Freundlich and Dubinin−Radushkevich (D−R) isotherm models; however, the Langmuir model was not able to describe the sorption behavior. The values of the free sorption energy (E) were calculated. The E values of NaOH-treated CFs were found to be similar to each other and much larger than that of raw CFs for the sorption of Cr(VI), and the sorption processes were found to be physical. The process of EpiCF adsorbing Cr(VI) ions from water is chemisorption, and that for Cu(II) ions is physisorption. The free sorption energy of EAEpiCF sorption of Cr(VI) ions was close to 8 kJ·mol−1 (7.274 kJ·mol−1), so that chemical interactions might exist between EAEpiCF and Cr(VI), whereas for Cu(II), the sorption process is physical adsorption. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900106h [article] Chemically modified chicken feather as sorbent for removing toxic chromium(VI) ions [texte imprimé] / Ping Sun, Auteur ; Zhao-Tie Liu, Auteur ; Zhong-Wen Liu, Auteur . - 2009 . - pp. 6882–6889. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6882–6889 Mots-clés : Chromium(VI)  ions  Chicken  feathers Résumé : To improve the sorption capacity of Cr(VI) ions, chicken feathers (CFs) were chemically treated by several methods: (1) To clarify the changes in the structure and morphology of CFs, CFs were treated with aqueous NaOH solutions of varying concentrations. The results suggest that reactions occur on the surface rather than in the interior of the CFs and that keratin fragments exfoliate from the CF surface layer by layer and then dissolve in aqueous solution. (2) Keratin fragments could be rejoined to the CF surface by cross-linking with epichlorohydrin (Epi) through a series of ring-opening, recyclization, and ring-opening reactions of Epi in aqueous NaOH solution, and Epi-modified CF (EpiCF) was obtained. (3) CFs were functionalized with ethylenediamine (EA) in aqueous NaOH solution by cross-linking with Epi (EAEpiCF). The structure and properties of chemically treated CFs were investigated by FT-IR spectroscopy, XRD, SEM, elemental analysis, and water contact-angle measurements. CFs treated with NaOH were found to be similar in structure and properties to each other and exhibited a relatively low sorption capacity for removal of Cr(VI) ions from water, but a higher capacity than raw CFs. EpiCF exhibited an excellent capacity for adsorbing relatively low concentrations (10 ppm) of Cr(VI) ions but a low sorption capacity for Cu(II) ions in water. EAEpiCF was found to be hydrophilic and to exhibit 90% efficiency for removing Cr(VI) ions in the concentration range of 10−80 ppm but to have a low sorption capacity for Cu(II) in water. Equilibrium sorption isotherms for the raw and chemically treated CFs fit the Freundlich and Dubinin−Radushkevich (D−R) isotherm models; however, the Langmuir model was not able to describe the sorption behavior. The values of the free sorption energy (E) were calculated. The E values of NaOH-treated CFs were found to be similar to each other and much larger than that of raw CFs for the sorption of Cr(VI), and the sorption processes were found to be physical. The process of EpiCF adsorbing Cr(VI) ions from water is chemisorption, and that for Cu(II) ions is physisorption. The free sorption energy of EAEpiCF sorption of Cr(VI) ions was close to 8 kJ·mol−1 (7.274 kJ·mol−1), so that chemical interactions might exist between EAEpiCF and Cr(VI), whereas for Cu(II), the sorption process is physical adsorption. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900106h

Co / pillared clay bifunctional catalyst for controlling the product distribution of fischer − tropsch synthesis / Qing-Qing Hao in Industrial & engineering chemistry research, Vol. 49 N° 19 (Octobre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 19 (Octobre 2010) . - pp. 9004–9011 Titre : Co / pillared clay bifunctional catalyst for controlling the product distribution of fischer − tropsch synthesis Type de document : texte imprimé Auteurs : Qing-Qing Hao, Auteur ; Guang-Wei Wang, Auteur ; Zhao-Tie Liu, Auteur Année de publication : 2010 Article en page(s) : pp. 9004–9011 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Pillared  clays  Catalyst Résumé : Pillared interlayer clays (PILCs) were synthesized by pillaring montmorillonite with SiO2, Al2O3, and ZrO2, and Co-supported PILCs were prepared by the impregnation method. For comparison, Co/SiO2 and Co-supported montmorillonite treated with dilute HNO3 (acid-clay) were also prepared. The materials were characterized by XRD, H2-TPR, NH3-TPD, O2 titration, and N2 adsorption−desorption. The Co-supported catalysts were comparatively investigated for Fischer−Tropsch (FT) synthesis in a fixed-bed reactor under the conditions of 1 MPa, 508 K, H2/CO = 2, and W/F = 5.02 g·h·mol−1. The results indicate that the activities of the catalysts (i.e., CO conversions) increase in the order of Co/Na-Clay Co/Si-PILC ≈ Co/acid-clay ≈ Co/Al-PILC < Co/Zr-PILC ≈ Co/SiO2. Moreover, Co/PILCs can effectively narrow the product distribution of FT synthesis showing significantly increased C5−C12 selectivity and much decreased C21+ selectivity. The results are well explained based on the acidic properties of the PILCs together with the textural properties, pore size distributions, and reduction behaviors of the catalysts. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101163w [article] Co / pillared clay bifunctional catalyst for controlling the product distribution of fischer − tropsch synthesis [texte imprimé] / Qing-Qing Hao, Auteur ; Guang-Wei Wang, Auteur ; Zhao-Tie Liu, Auteur . - 2010 . - pp. 9004–9011. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 19 (Octobre 2010) . - pp. 9004–9011 Mots-clés : Pillared  clays  Catalyst Résumé : Pillared interlayer clays (PILCs) were synthesized by pillaring montmorillonite with SiO2, Al2O3, and ZrO2, and Co-supported PILCs were prepared by the impregnation method. For comparison, Co/SiO2 and Co-supported montmorillonite treated with dilute HNO3 (acid-clay) were also prepared. The materials were characterized by XRD, H2-TPR, NH3-TPD, O2 titration, and N2 adsorption−desorption. The Co-supported catalysts were comparatively investigated for Fischer−Tropsch (FT) synthesis in a fixed-bed reactor under the conditions of 1 MPa, 508 K, H2/CO = 2, and W/F = 5.02 g·h·mol−1. The results indicate that the activities of the catalysts (i.e., CO conversions) increase in the order of Co/Na-Clay Co/Si-PILC ≈ Co/acid-clay ≈ Co/Al-PILC < Co/Zr-PILC ≈ Co/SiO2. Moreover, Co/PILCs can effectively narrow the product distribution of FT synthesis showing significantly increased C5−C12 selectivity and much decreased C21+ selectivity. The results are well explained based on the acidic properties of the PILCs together with the textural properties, pore size distributions, and reduction behaviors of the catalysts. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101163w