POLYOXOMETALATE-CATALYZED OXYGEN DELIGNIFICATION PROCESS: KINETIC STUDIES, DELIGNIFICATION SEQUENCES AND REUSE OF HPA-5-MnII AQUEOUS SOLUTION
authors Gaspar, AR; Gamelas, JAF; Evtuguin, DV; Neto, CP
nationality International
journal CHEMICAL ENGINEERING COMMUNICATIONS
author keywords Bleaching sequence; Catalysis; Kinetics; Oxygen delignification; Polyoxometalates; Selectivity
keywords ENVIRONMENTALLY BENIGN TECHNOLOGY; HEXENURONIC ACID GROUPS; KRAFT PULP; MODEL COMPOUNDS; OXIDATION; WATER; ECF
abstract Kinetic studies on the use of Mn-assisted molybdovanadophosphate polyoxoanion (HPA-5-MnII) as catalyst for the aerobic delignification of Eucalyptus globulus kraft pulps were performed. The delignification as measured by the decrease of kappa number corrected to the lignin content in pulp followed pseudo-first-order reaction kinetics with a rate constant of 4.010-3min-1, while carbon dioxide production followed pseudo-zero-order kinetics with a rate constant of 0.031gKg-1min-1. Aqueous delignification filtrate containing the polyoxometalate (POM) HPA-5-MnII could be used in 16 multiple delignification cycles without showing significant changes in the kappa number of the delignified pulps and presenting only slight decreases in their intrinsic viscosity. Delignification sequence including a conventional alkaline-oxygen delignification stage followed by a POM stage generated a kappa number decrease of 76% while intrinsic viscosity had a drop of only 23%.
publisher TAYLOR & FRANCIS INC
issn 0098-6445
year published 2009
volume 196
issue 7
beginning page 801
ending page 811
digital object identifier (doi) 10.1080/00986440802589883
web of science category Engineering, Chemical
subject category Engineering
unique article identifier WOS:000264136400003
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journal analysis (jcr 2019):
journal impact factor 1.802
5 year journal impact factor 1.742
category normalized journal impact factor percentile 43.007
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