Improving Optical Properties of Soda Bagasse Pulp Utilizing Complementary Bleaching with Sodium Hydrosulfite

Soda bagasse pulp was bleached, using sodium hypochlorite and sodium hydrosulfite sequence or vice
versa (reverse sequence). The optical behavior of the bleached pulps was investigated through optical
and thermal accelerated aging of the handsheets. Some characteristics such as brightness (R) ,
lightness (L *), yellowness (b*) and greenness (a*) factors as well as absorption and scattering
coefficients of light before and after aging were assessed.
Also, in this study, the effect of consistency (percent) of pulp and Fe2
+ ion and a chelating agent
(EDTA) on yellowing of paper was determined. The results indicate that application of a reductive
bleaching stage after oxidative treatment of the pulp will cause more brightness stability as compared
to the reverse sequence.