Activated hydrogen peroxide decolorization of a model azo dye-colored pulp

Research output: Contribution to journalArticleScientificpeer-review

Researchers

  • Elsa Walger
  • Camille Rivollier
  • Nathalie Marlin
  • Gérard Mortha

Research units

  • Universite Grenoble Alpes
  • CNRS
  • LGP2

Abstract

Recovered fibers are reused for manufacturing bright paper after deinking and fiber decolorization. This second process generally starts with an alkaline hydrogen peroxide (H2O2) stage, referred to as P. However, the color-stripping effect of P is often limited due to the low reactivity of H2O2 on the azo groups of dyes. The purpose of this study was to improve the removal of these azo dyes by H2O2. A bleached kraft pulp was dyed with a model azo dye and submitted to activated H2O2 bleaching. Phenanthroline and copper(II)-phenanthroline (Cu-Phen) served as activating compounds. The color-stripping trials were carried out at weak or conventional alkaline pH. The results were mainly evaluated in terms of dye removal index and degree of polymerization of cellulose. The theoretical composition of Cu-Phen in the bleaching conditions was calculated by means of the geochemical software PHREEQC. The results show that Cu-Phen was able to activate H2O2 color stripping, although it was accompanied by additional cellulose degradation. Moreover, the color stripping was more effective under alkaline conditions, in which case CuPhen(OH)2 would be present. Two hypotheses are proposed to explain this activated decolorization: a free radical mechanism and the influence of CuPhen(OH)2 as an activating species.

Details

Original languageEnglish
Pages (from-to)677-683
Number of pages7
JournalHolzforschung
Volume69
Issue number6
Publication statusPublished - 2015
MoE publication typeA1 Journal article-refereed

    Research areas

  • Azo dye, Copper(II)-phenanthroline complex, Decolorization, Dyed pulp, Hydrogen peroxide, pH, PHREEQC software, Speciation simulation

ID: 12209538