An effective metal controller used for enhancing cellulose protection in oxygen delignification

Due to the detrimental effects induced by transition metals on oxygen delignification, it is necessary to explore effective cellulose protector for improving the oxygen delignification efficiency. In this work, chitosan/tripolyphosphate microspheres (C/TPP) with different size were prepared and introduced for alleviating the transition metal ions effects on cellulose degradation. The results showed that both size and amount of C/TPP had a significant effect on cellulose degradation but negligible influence on lignin; C/TPP with suitable amount and smaller size was favored for cellulose protection and thus selectivity improvement. C/TPP is found to be comparable to MgSO4 and more outstanding for the pulps with extra metals; in this case, C/TPP leads only a marginal impairment in lignin degradation and removal, but provides a significant improvement for cellulose viscosity. Moreover, C/TPP is substantially more effective when is used in a combination with MgSO4.