摘要

The acid hydrogen peroxide system has been evaluated in more detail in the presence of a coarse Norway spruce thermomechanical pulp (TMP). The effects of parameters on the reactions involved were determined, such as pH, retention time, pulp consistency, type of iron catalyst, and the amount of dissolved organic material. Residual hydrogen peroxide, chemical oxygen demand, dissolved iron, and total fiber charge were quantified and the hydroxyl radical activity was monitored. The results showed that a catalyst of free ferrous ions (Fe2+) gave more reactions with the lignocellulosic material than ferric ions (Fe3+) chelated with EDTA. Furthermore, there were somewhat more reactions with the TMP when there was less dissolved organic material in the liquid phase from the start. Hydroxyl radicals were detected in all cases, but the level differed depending on the conditions used. It is likely that the iron must bind with the TMP or be in close proximity for the hydroxyl radicals to react with the pulp.

  • 出版日期2013-12-1