Isolation of cellulose and lignin from Acacia crassicarpa and Eucalyptus pellita wood by prehydrolysis soda cooking with 2-methylanthraquinone as a green additive

Wood is widely used as a biorefinery feedstock. Eucalyptus pellita and Acacia crassicarpa, planted in Indonesia, have enormous potential for producing valuable cellulose, hemicellulose, and lignin products. The prehydrolysis process was effective in separating xylo-oligomers from these woods. As an additive to next-stage soda cooking, 2-methylanthraquinone accelerated lignin removal and stabilized cellulose yield. This study clarified the advantages of 2-methylanthraquinone as a green additive compared to that of soluble anthraquinone in the prehydrolysis soda cooking process. Several doses of 2-methylanthraquinone and active alkali were also examined. The results showed that 0.06% 2-methylanthraquinone addition at 17% active alkali significantly decreased the kappa number of the prehydrolysis soda pulp from 19.3 to 9.8. The addition of 2-methylanthraquinone increased the pulp yield and brightness to 41.0 and 45.1%, respectively, compared to that without 2-methylanthraquinone addition (40.2% and 41.7%). A good-quality cellulose was obtained for E. pellita after bleaching, as a dissolving pulp with 95.2% a-cellulose content, 90.4% pulp brightness, 9.8 mPamiddots pulp viscosity, and 0.07% ash content. Owing to 2-methylanthraquinone addition, the weight-average molecular weight of the dissolved lignin decreased from 1950 to 1415 g/mol for A. crassicarpa. Lignin was separated from the soda cooking black liquor in yields of approximately 88.8 and 85.6% based on the wood lignin value for E. pellita and A. crassicarpa, respectively.

Automated summary

Wood from Eucalyptus pellita and Acacia crassicarpa in Indonesia can be used to produce valuable cellulose, hemicellulose, and lignin products through a prehydrolysis process. The addition of 2-methylanthraquinone as an additive in soda cooking improves lignin removal and cellulose yield. The study highlights the advantages of using 2-methylanthraquinone compared to soluble anthraquinone in the prehydrolysis soda cooking process.