This study aimed to evaluate the effect of residual lignin content and nature on the efficiency and selectivity of ozone bleaching of conventional (kraft) and oxygen delignified (kraft-O) pulps. Ozone bleaching efficiency was found to be enhanced by increasing pulp residual lignin content. Ozone treatment is more selective for kraft-O pulps, but for a given type of pulp (kraft or kraft-O), ozone bleaching selectivity increases with increasing pulp lignin content. Ozone bleaching efficiency increases with increasing pulp lignin phenolic hydroxyl content whereas selectivity is negatively affected by these structures.
Bleaching; ozone; pulp e residual lignin
