Environment-Friendly Non-Sulfur Cooking and Totally Chlorine-Free Bleaching for Preparation of Sugarcane Bagasse Cellulose

This study focuses on improving the quality of dissolving pulp (DP) from sugarcane bagasse (SB) prepared by a non-sulfur cooking method and totally chlorine-free (TCF) bleaching sequences. First, the effects of prehydrolysis and soda-anthraquinone (AQ) cooking conditions on brightness and viscosity were studied. Second, a novel five-stage TCF bleaching sequence, which employs oxygen (O) bleaching, peroxymonosulfuric acid (P-sa) treatment and alkali extraction with hydrogen peroxide (E-p) in the sequence O-P-sa-E-p-P-sa-E-p was applied to SB pulps. The maximum brightness and viscosity of unbleached pulp were 46.3% ISO and 34.1 cP, respectively, whereas after the final bleaching stage, the maximum qualities (brightness: 89.1% ISO, viscosity: 6.4 cP, glucan content: 95.7%, and ash content: 0.12%) met the standard requirements. For comparison, the effects of TCF bleaching on oil palm empty fruit bunch pulp were investigated. The proposed TCF bleaching shows a potential as a bleaching method to produce high-quality DP from SB.