Optimized Catalytic Bleaching Sequences for Eucalyptus Kraft Pulp

Ghazaleh Afsahi*, Estefania Isaza Ferro, Kyösti Ruuttunen, Tapani Vuorinen

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

6 Citations (Scopus)


Contemporary multi-stage bleaching processes partially remove residual lignin and hexenuronic acid from cellulosic pulps. The reactions in the steps could be faster and consume smaller amounts of chemicals. Catalytic bleaching (Hcat), utilizing hypochlorite (H), triethylenediamine (DABCO) and its derivative N-carboxymethyl triethylenediamine (CM-DABCO), is a new discovery that has the potential to improve the chemical and energetic efficiency of bleaching processes in chemical pulp mills, e.g. through reducing the reaction time of the bleaching processes. The objective of this study was to clarify if new kraft pulp bleaching sequences with initial stage of chlorine dioxide (ClO2; D) and an intermediate stage of Hcat could provide fully bleached pulps. The bleaching sequences of the studied eucalyptus pulps include D0E(OP)Hcat(Q)P and HcatZ/DP, which attained a final brightness of 88 and 89% ISO, respectively. HcatZ/DP showed to be the best sequence for the catalytic bleaching of eucalyptus kraft pulps. This study may open new doors to future bleaching of cellulose pulps with fewer towers and decreased use of chemicals.

Original languageEnglish
Pages (from-to)178-186
Number of pages9
JournalJournal of Wood Chemistry and Technology
Issue number3
Publication statusPublished - 4 May 2019
MoE publication typeA1 Journal article-refereed


  • Catalytic bleaching
  • hexenuronic acid
  • lignin
  • tertiary amine


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