The Dual Effect of Ionic Liquid Pretreatment on the Eucalyptus Kraft Pulp during Oxygen Delignification Process
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][HSO<sub>4</sub>] and [TEA][HSO<sub>4</sub>] on oxygen delignification of the eucalyptus k...
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doaj-3eb5ab675ef3442da5ac9f4aede9ceb92021-06-01T00:08:48ZengMDPI AGPolymers2073-43602021-05-01131600160010.3390/polym13101600The Dual Effect of Ionic Liquid Pretreatment on the Eucalyptus Kraft Pulp during Oxygen Delignification ProcessLetian Qi0Jinke Liu1Jianmin Peng2Guihua Yang3Fengfeng Li4Yu Xue5Jiachuan Chen6State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, ChinaState Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, ChinaState Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, ChinaState Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, ChinaState Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, ChinaState Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, ChinaState Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, ChinaOxygen 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][HSO<sub>4</sub>] and [TEA][HSO<sub>4</sub>] 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][HSO<sub>4</sub>] 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][HSO<sub>4</sub>] 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.https://www.mdpi.com/2073-4360/13/10/1600ionic liquidpretreatmentoxygen delignificationfiber protection |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Letian Qi Jinke Liu Jianmin Peng Guihua Yang Fengfeng Li Yu Xue Jiachuan Chen |
spellingShingle |
Letian Qi Jinke Liu Jianmin Peng Guihua Yang Fengfeng Li Yu Xue Jiachuan Chen The Dual Effect of Ionic Liquid Pretreatment on the Eucalyptus Kraft Pulp during Oxygen Delignification Process Polymers ionic liquid pretreatment oxygen delignification fiber protection |
author_facet |
Letian Qi Jinke Liu Jianmin Peng Guihua Yang Fengfeng Li Yu Xue Jiachuan Chen |
author_sort |
Letian Qi |
title |
The Dual Effect of Ionic Liquid Pretreatment on the Eucalyptus Kraft Pulp during Oxygen Delignification Process |
title_short |
The Dual Effect of Ionic Liquid Pretreatment on the Eucalyptus Kraft Pulp during Oxygen Delignification Process |
title_full |
The Dual Effect of Ionic Liquid Pretreatment on the Eucalyptus Kraft Pulp during Oxygen Delignification Process |
title_fullStr |
The Dual Effect of Ionic Liquid Pretreatment on the Eucalyptus Kraft Pulp during Oxygen Delignification Process |
title_full_unstemmed |
The Dual Effect of Ionic Liquid Pretreatment on the Eucalyptus Kraft Pulp during Oxygen Delignification Process |
title_sort |
dual effect of ionic liquid pretreatment on the eucalyptus kraft pulp during oxygen delignification process |
publisher |
MDPI AG |
series |
Polymers |
issn |
2073-4360 |
publishDate |
2021-05-01 |
description |
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][HSO<sub>4</sub>] and [TEA][HSO<sub>4</sub>] 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][HSO<sub>4</sub>] 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][HSO<sub>4</sub>] 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. |
topic |
ionic liquid pretreatment oxygen delignification fiber protection |
url |
https://www.mdpi.com/2073-4360/13/10/1600 |
work_keys_str_mv |
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