Further Understanding on the Cationic Demand of Dissolved Substances During Peroxide Bleaching of a Spruce TMP

摘要

Two issues were investigated regarding the cationic demand generated during peroxide bleaching of a spruce TMP. The kinetic study showed that the cationic demand was formed in a rapid process, with the vast majority formed at the very beginning of the reactions. The amount of cationic demand from the conventional peroxide bleaching (the P process) was compared with that from the modified peroxide bleaching process (the P_M process). A second aspect of this investigation was on the contribution of oxidized and dissolved lignin to the cationic demand formed. Experimental evidence supports the conclusion that the oxidized and dissolved lignin is an important source of the cationic demand. A methodology was developed to estimate the contribution of each of the dissolved organic components to the total cationic demand formed during peroxide bleaching of mechanical pulp.