کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9616771 | 48922 | 2005 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Oxygen bleaching of kraft pulp with polyoxometalates and laccase applying a novel multi-stage process
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
کاتالیزور
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
A series of manganese substituted polyoxotungstates, [SiW11MnIII(H2O)O39]5â and [PW11MnIII(H2O)O39]4â, and [SiW11VVO40]5â were applied as catalysts for the oxygen delignification of unbleached eucalypt kraft pulp with laccase of Trametes versicolor. Unlike to modest results obtained in the Laccase-Mediator System (LMS) at 45-60 °C (lignin oxidation and catalyst re-oxidation occurred at the same stage), a sustainable delignification with removal of about 50% of residual lignin was achieved with [SiW11MnIII(H2O)O39]5â and [SiW11VVO40]5â when the kraft pulp treatment was carried out with polyoxometalate at 110 °C (lignin oxidation stage) and with laccase at 45 °C (catalyst re-oxidation stage) in separate stages. The use of [PW11MnIII(H2O)O39]4â in this multi-stage process was limited by the low re-oxidation rate with laccase. The best selectivity on the pulp delignification was found with polyoxoanion [SiW11MnIII(H2O)O39]5â, whereas [SiW11VVO40]5â was the most effective in the oxidative delignification. The influence of process factors on the POMs re-oxidation, such as the amount of laccase, oxygen pressure and temperature is discussed. UV-vis and 51V NMR studies indicated that POMs maintained stable after redox turnovers during the pulp delignification.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Catalysis B: Enzymatic - Volume 33, Issues 3â6, 1 June 2005, Pages 57-64
Journal: Journal of Molecular Catalysis B: Enzymatic - Volume 33, Issues 3â6, 1 June 2005, Pages 57-64
نویسندگان
Jose A.F. Gamelas, Ana P.M. Tavares, Dmitry V. Evtuguin, Ana M.B. Xavier,