Please use this identifier to cite or link to this item: http://hdl.handle.net/10316/10520
Title: Selectivity Studies of Oxygen and Chlorine Dioxide in the Pre-Delignification Stages of a Hardwood Pulp Bleaching Plant
Authors: Barroca, Maria J. M. C. 
Marques, Pedro J. T. S. 
Seco, Isabel M. 
Castro, José Almiro A. M. 
Issue Date: 28-Nov-2001
Publisher: American Chemical Society
Citation: Industrial & Engineering Chemistry Research. 40:24 (2001) 5680-5685
Abstract: This work is concerned with the role of oxygen on the selectivity of chlorine dioxide in the pre-delignification stage of a E. globulus pulp bleaching plant. Its main purpose is to study the selectivity of chlorine dioxide when applied to an oxygen pre-delignified hardwood kraft pulp and to compare it to that of a conventional pre-delignification with chlorine dioxide (D). The intrinsic viscosity and kappa number were used to follow the polysaccharides degradation and the delignification rates. In an oxygen stage (O), the selectivity varies with the degree of delignification. In the initial fast phase of reaction it exhibits values similar to those of chlorine dioxide in a conventional pre-delignification stage (D), although it diminishes drastically in the second, slow phase of reaction. On the other hand, chlorine dioxide in a conventional pre-delignification stage (D) is a very selective agent and its selectivity remains practically constant along the process. Moreover, it's shown that it is independent of the initial viscosity and kappa number of pulp. However, when chlorine dioxide is applied to a previously oxygen delignified pulp, its selectivity decreases gradually with the extent of delignification in the preceding oxygen stage. The experiments suggest that the global selectivity of an OD sequence with Eucalyptus globulus kraft pulp can be improved if the delignification with oxygen is limited to the fast phase of reaction, which corresponds to the first 5−10 min of reaction.
URI: http://hdl.handle.net/10316/10520
ISSN: 0888-5885
DOI: 10.1021/ie0103613
Rights: openAccess
Appears in Collections:FCTUC Eng.Química - Artigos em Revistas Internacionais

Files in This Item:
File Description SizeFormat
Selectivity Studies of Oxygen and Chlorine Dioxide.pdf83.69 kBAdobe PDFView/Open
Show full item record

SCOPUSTM   
Citations

12
checked on Feb 18, 2020

WEB OF SCIENCETM
Citations 10

8
checked on Apr 2, 2022

Page view(s) 50

451
checked on Aug 11, 2022

Download(s) 10

1,382
checked on Aug 11, 2022

Google ScholarTM

Check

Altmetric

Altmetric


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.