Chemical reactions in chlorine dioxide stages of pulp bleaching

Kolar, Jana; Lindgren, B.; Pettersson, B.

doi:10.1007/bf00369129

Cited by 71 publications

(52 citation statements)

References 4 publications

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“…The HOCl reacts very rapidly with the pulp. Once the HOCl is consumed, no more AOX is generated (Kolar et al 1983;Ni et al 1992;Hart and Hsieh 1993;Ni et al 1994;. Thus, it can be seen that the formation of AOX during the chlorine dioxide bleaching of bagasse pulp was a very fast process.…”

Section: Aox Formation and Mechanism Model Developmentmentioning

confidence: 99%

Kinetics of AOX Formation in Chlorine Dioxide Bleaching of Bagasse Pulp

et al. 2014

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In this paper, a kinetic model of the first chlorine dioxide bleaching stage (D0) in an elemental chlorine-free (ECF) bleaching sequence is presented for bagasse pulps. The model is based on the rate of adsorbable organic halogen (AOX) formation. The effects of the chlorine dioxide dosage, the sulfuric acid dosage, and the reaction temperature on the AOX content of wastewater are examined. The reaction of AOX formation could be divided into two periods. A large amount of AOX was formed rapidly within the first 10 min. Ten minutes later, the AOX formation rate significantly decreased. The kinetics could be expressed as: 4 ] is the dosage of sulfuric acid (kg/odt). The fit of the experiment results obtained for different temperatures, initial chlorine dioxide dosages, initial sulfuric acid dosages, and AOX content were very good, revealing the ability of the model to predict typical mill operating conditions.

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Section: Aox Formation and Mechanism Model Developmentmentioning

confidence: 99%

Kinetics of AOX Formation in Chlorine Dioxide Bleaching of Bagasse Pulp

et al. 2014

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“…This Iow degree of chlorine Substitution is expected since chlorine dioxide should result exclusively in oxidation reactions. Any Substitution reaction giving rise to organically bound chlorine should be attributed to elemental chlorine and/or hypochlorous acid (Gierer 1982;Kolar et al 1983). …”

Section: Elemental Compositionmentioning

confidence: 99%

Characterization of the High Molecular Mass Chlorinated Matter in Spent Bleach Liquors (SBL). Part II. Acidic SBL

Österberg¹,

Lindström²

1985

Holzforschung

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“…These intermediates may react with some pulp components, but chlorine dioxide itself reacts mainly with lignin and not with cellulose (Vuorinen et al 2007). It has been observed that one equivalent of HOCl is formed when two equivalents of ClO 2 are consumed in lignin oxidation (Kolar et al 1983;Vuorinen et al 2005). In addition, it is known that under acidic conditions HOCl is able to oxidize carbohydrates (Craik 1924;Churganova and Lopyrev 1980;Röhr-ling et al 2002;Zhou et al 2008) and to introduce new carbonyl groups in pulp Chirat and Chapelle 1999).…”

Section: Introductionmentioning

confidence: 96%

“…In chlorine dioxide bleaching of pulp, several intermediates are formed from chlorine dioxide, such as chlorate (ClO 3 -), chlorite (ClO 2 -), elemental chlorine (Cl 2 ) and hypochlorous acid (HOCl) (Kolar et al 1983;Dence and Reeve 1996). These intermediates may react with some pulp components, but chlorine dioxide itself reacts mainly with lignin and not with cellulose (Vuorinen et al 2007).…”

Section: Introductionmentioning

confidence: 98%

Brightness reversion of eucalyptus kraft pulp: Effect of carbonyl groups generated by hypochlorous acid oxidation

Zhou¹,

Jääskeläinen²,

Adorjan³

et al. 2011

Holzforschung

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The impact of hypochlorous acid (HOCl) treatment on a fully bleached eucalyptus kraft pulp was studied with respect to the final brightness as well as the brightness reversion under humid ageing conditions. The carbonyl contents in the pulps were determined by the CCOA method where carbazole-9-carboxylic acid w2-(2-aminooxethoxy)-ethoxyx amide (CCOA) was applied as the carbonyl-selective fluorescence label. The molecular weight distribution of cellulose and hemicelluloses was analyzed as well. The amount of carbonyl groups in pulp was observed to increase significantly after the HOCl treatment, and the carbonyl distribution in pulp to shift towards the low molecular weight fraction. Plotting the carbonyl content against the post color number (PCN) of the pulps revealed a linear correlation. Additionally, the effect of the hemicellulose content was investigated, and alkaline extraction was applied to partially remove the hemicelluloses in pulp. These hemicellulose-poor samples showed a lower reactivity with hypochlorous acid and less brightness reversion at equal carbonyl content.

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Chemical reactions in chlorine dioxide stages of pulp bleaching

Cited by 71 publications

References 4 publications

Kinetics of AOX Formation in Chlorine Dioxide Bleaching of Bagasse Pulp

Kinetics of AOX Formation in Chlorine Dioxide Bleaching of Bagasse Pulp

Characterization of the High Molecular Mass Chlorinated Matter in Spent Bleach Liquors (SBL). Part II. Acidic SBL

Brightness reversion of eucalyptus kraft pulp: Effect of carbonyl groups generated by hypochlorous acid oxidation

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