Ty. Tsai et al., FORMATION OF POLYCHLORINATED PHENOLIC-COMPOUNDS DURING HIGH CHLORINE DIOXIDE SUBSTITUTION BLEACHING .1. LABORATORY INVESTIGATION, Tappi journal, 77(8), 1994, pp. 149-157
The amount of pollutants (AOX, chlorinated phenols, COD, color) genera
ted during kraft pulp bleaching decreases with decreasing kappa factor
, unbleached pulp kappa number, and increasing level of chlorine dioxi
de substitution. At 100% chlorine dioxide substitution, the formation
of polychlorinated phenolic compounds is at or below the detection lim
it and essentially independent of the kappa number of the unbleached p
ulp and, therefore, of the use of extended or oxygen delignification.
In fact, oxygen delignification may actually increase the concentratio
n of catechols and guaiacols and, therefore, the concentration of thei
r chlorinated derivatives.