Integrating fiber fractionation and deep eutectic solvent treatment to upgrade a bamboo kraft pulp into a cellulose acetate-grade dissolving pulp

• Published in: Separation and purification technology Vol. 345; p. 127358
• Main Authors: Tian, Chaochao, Duan, Chao, Meng, Zixuan, Wen, Yijian, Feng, Xiaomeng, Xie, Zengyin, Xie, Zhanghong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-10-2024
• Subjects: Bamboo fiber; Cellulose acetate; DES treatment; Dissolving pulp; Fiber fractionation; Bamboo fiber; Cellulose acetate; Dissolving pulp; DES treatment; Fiber fractionation
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2024.127358

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•An integrated process of fiber fractionation and DES treatment is proposed for bamboo pulp upgradation.•Fiber fractionation separates the parenchyma cells to improve fiber homogeneity.•DES treatment facilitates the fiber swelling and hemicellulose removal.•The upgraded acetate-grade bamboo dissolving pulp has a high reactivity and acetylation.
The production of high purity cellulose and its derivates from bamboo is appealing to agroforestry industry in China. However, the inhomogeneity and recalcitrance of bamboo pulp hinder its purification, rendering a poor reactivity and an inferior quality. In this study, we propose an integrated process, involving fiber fractionation (FF) and deep eutectic solvent treatment (DES), for overcoming the nonuniformity and low reactivity of the bamboo kraft pulp (BKP) as to develop it into a high-quality cellulose acetate (CA)-grade dissolving pulp. Results show that the fiber fractionation can develop two more uniform fiber fractions, namely the short-fiber (SF, parenchyma cells and fines) and the long-fiber (LF, bamboo fibers). Thanks to the fiber fractionation, the LF has a higher fiber accessibility, thus facilitating the mass transfer and reaction efficiency during the DES (ChCl-OA) treatment. Moreover, the DES treatment further improves the properties of LF in terms of purity (from 88.9 % to 95.1 %) and reactivity (from 43.0 % to 94.6 %). As a result, the regular BKP fiber can be upgraded to the CA-grade with a high substitution of 2.87 and a yield of 50.1 %.