Abstract
Industrial oxygen-delignified birch kraft pulp was bleached with
alkaline hydrogen peroxide (P stage) after acid (A stage) or chelation (Q
stage) pretreatments to remove detrimental metal residues. Pulp brightness
correlated clearly with the manganese (Mn) content of the incoming pulp
irrespective of the method used for the metal removal. Pulp viscosity after
peroxide stage was not significantly affected by the Mn content, whereas the
preceding A stage was detrimental to it. Some typical lignin degradation
products, together with 2-furan carboxylic acid, were abundant in the peroxide
stage filtrates after incomplete pretreatment. 2-furan carboxylic acid is
easy to detect due to its UV activity, thus providing a potent marker compound
for peroxide stage performance. Part of the 2-furan carboxylic acid in the P
stage was explained as direct carry-over from the preceeding A and Q stages,
but its content increased in the P stage possibly due to further reactions of
some transient species remaining in the pulp after the pretreatment.
| Original language | English |
|---|---|
| Pages (from-to) | 82-91 |
| Journal | O Papel |
| Volume | 68 |
| Issue number | 2 |
| Publication status | Published - 2007 |
| MoE publication type | A1 Journal article-refereed |
Keywords
- Brightness
- capillary electrophoresis
- chelation
- hydrogen peroxide
- metal