Back to Search Start Over

The Dual Effect of Ionic Liquid Pretreatment on the Eucalyptus Kraft Pulp during Oxygen Delignification Process

Authors :
Letian Qi
Jinke Liu
Jianmin Peng
Guihua Yang
Fengfeng Li
Yu Xue
Jiachuan Chen
Source :
Polymers, Vol 13, Iss 10, p 1600 (2021)
Publication Year :
2021
Publisher :
MDPI AG, 2021.

Abstract

Oxygen delignification presents high efficiency but causes damage to cellulose, therefore leading to an undesired loss in pulp strength. The effect of ionic liquid pretreatment of [BMIM][HSO4] and [TEA][HSO4] on oxygen delignification of the eucalyptus kraft pulp was investigated at 10% IL loading and 10% pulp consistency, after which composition analysis, pulp and fiber characterizations, and the mechanism of lignin degradation were carried out. A possible dual effect of enhancing delignification and protecting fibers from oxidation damage occurred simultaneously. The proposed [TEA][HSO4] pretreatment facilitated lignin removal in oxygen delignification and provided fibers with improved DP, fiber length and width, and curl index, resulting in the enhanced physical strength of pulp. Particularly, its folding endurance improved by 110%. An unusual brightness reduction was identified, followed by detailed characterization on the pulps and extracted lignin with FTIR, UV, XPS, and HSQC. It was proposed that [TEA][HSO4] catalyzed the cleavage of β-O-4 bonds in lignin during the oxygen delignification, with the formation of Hibbert’s ketones and quinonoid compounds. The decomposed lignin dissolved and migrated to the fiber surface, where they facilitated the access of the oxidation agent and protected the fiber framework from oxidation damage. Therefore, it was concluded that ionic liquid pretreatment has a dual effect on oxygen delignification.

Details

Language :
English
ISSN :
20734360
Volume :
13
Issue :
10
Database :
Directory of Open Access Journals
Journal :
Polymers
Publication Type :
Academic Journal
Accession number :
edsdoj.3eb5ab675ef3442da5ac9f4aede9ceb9
Document Type :
article
Full Text :
https://doi.org/10.3390/polym13101600