The enhanced selectivity of oxygen delignification of kraft pine wood pulps: The effects of pentosane-based cherry and guar gum additions

Abstract

The objective of this study was to decrease the adverse effects of radicals created in the reaction medium by adding cherry gum or guar gum, which are sugar-based polymers, into the oxygen delignification (OD) solution used in the bleaching process of pine wood pulp produced by the kraft process. In order to enhance the dissolution of lignin, peroxide was introduced into the oxygen delignification solution, resulting in the formation of a more intensive oxidative environment. The impact of each gum addition on cellulose and hemicelluloses during oxidation processes was assessed by determining pulp viscosity, kappa number, and yield values. The addition of 2% cherry gum to the OD pulp resulted in a 2.1% increase in the removal of residual lignin and a 1.9% increase in viscosity compared to the pulp without cherry gum. Similar results were also achieved in the examination of OD pulps reinforced with guar gum. The study revealed that using cherry gum and peroxide-reinforced OD pulps resulted in the lightest-colored pulps. It was observed that additions of both gums increased the strength of the pulp except for the tearing index.