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.
|Publication status||Published - 2007|
|MoE publication type||A1 Journal article-refereed|
- capillary electrophoresis
- hydrogen peroxide