Surfactant reinforced oxygen delignification

Oxygen delignification is widely applied in TCF bleaching to meet stringent environmental regulation worldwide. In order to improve oxygen delignification efficiency, four surfactants were selected and applied to oxygen delignification. It was found that anionic surfactant and non-ionic-anionic complex surfactant could efficiently improve the delignification when anionic surfactant dosage was 1%, the delignification rate increased from 28.7% to 51.5% and brightness increased 8.83% ISO without significantly affecting the viscosity of oxygen delignified pulp. But the cationic surfactant had negative effect on the delignification. The SEM observation showed that the surfactant could improve the fibers swelling, softening and splitting of the oxygen delignified pulp. The high brightness (+80% ISO) and good strength TCF bleached pulp was obtained with the surfactant reinforced oxygen delignification combined with enzyme and H2O2 bleaching.