The role of copper ions in hydrogen peroxide bleaching: Their origin, removal, and effect on pulp quality
authors Loureiro, PEG; Duarte, S; Evtuguin, DV; Carvalho, MGVS
nationality International
journal TAPPI JOURNAL
keywords KRAFT PULP; CHELATION PRIOR; ACID TREATMENT; EQUILIBRIA; STABILITY; SYSTEMS; HISTORY
abstract This study puts particular emphasis on the role of copper ions in the performance of hydrogen peroxide bleaching (P-stage). Owing to their variable levels across the bleaching line due to washing filtrates, bleaching reagents, and equipment corrosion, these ions can play a major role in hydrogen peroxide decomposition and be detrimental to polysaccharide integrity. In this study, a Cu-contaminated D-0(EOP)D-1 prebleached pulp was subjected to an acidic washing (A-stage) or chelation (Q-stage) before the alkaline P-stage. The objective was to understand the isolated and combined role of copper ions in peroxide bleaching performance. By applying an experimental design, it was possible to identify the main effects of the pretreatment variables on the extent of metals removal and performance of the P-stage. The acid treatment was unsuccessful in terms of complete copper removal, magnesium preservation, and control of hydrogen peroxide consumption in the following P-stage. Increasing reaction temperature and time of the acidic A-stage improved the brightness stability of the D-0(EOP)D(1)AP bleached pulp. The optimum conditions for chelation pretreatment to maximize the brightness gains obtained in the subsequent P-stage with the lowest peroxide consumption were 0.4% diethylenetriaminepentaacetic acid (DTPA), 80 degrees C, and 4.5 pH.
publisher TECH ASSOC PULP PAPER IND INC
issn 0734-1415
year published 2012
volume 11
issue 7
beginning page 37
ending page 46
web of science category Materials Science, Paper & Wood
subject category Materials Science
unique article identifier WOS:000306851600005
  ciceco authors
  impact metrics
journal analysis (jcr 2017):
journal impact factor 0.516
5 year journal impact factor 0.611
category normalized journal impact factor percentile 35.714
altmetrics (social interaction):



 


Sponsors

1suponsers_list_ciceco.jpg