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

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1600
Author(s):  
Letian Qi ◽  
Jinke Liu ◽  
Jianmin Peng ◽  
Guihua Yang ◽  
Fengfeng Li ◽  
...  

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.

2017 ◽  
Vol 20 (4) ◽  
pp. 945-950 ◽  
Author(s):  
Giovani Boaventura Bacarin ◽  
Flávio Camargo Cabrera ◽  
Marcelo Rodrigues da Silva ◽  
Aldo Eloizo Job

Cellulose ◽  
2014 ◽  
Vol 21 (5) ◽  
pp. 3655-3666 ◽  
Author(s):  
Annariikka Roselli ◽  
Michael Hummel ◽  
Alireza Monshizadeh ◽  
Thaddeus Maloney ◽  
Herbert Sixta

Holzforschung ◽  
2015 ◽  
Vol 69 (8) ◽  
pp. 933-942 ◽  
Author(s):  
Hui-Chao Hu ◽  
Xin-Sheng Chai ◽  
Chun-Yun Zhang ◽  
Li-Min Fu ◽  
Donald Barnes ◽  
...  

Abstract This paper reports on the formation of methanol (MeOH) during conventional oxygen delignification (OD) of four typical alkaline pulps, namely, southern pine kraft pulp (SP-KP), wheat straw soda pulp (WS-SP), and eucalyptus kraft pulp (E-KP) with κ numbers (KN) of 32.8 and 16.9 (E-KP32.8 and E-KP16.9). Based on the mass transfer effect of MeOH and a proposed demethoxylation reaction pathway of lignin, two kinds of kinetic models were proposed to predict MeOH formation. The results show that the two-stage pseudo kinetic model with a first-order rate equation is adequate, which was further modified to a first-order kinetic model by means of which MeOH formation during OD of the pulps can be effectively predicted. Finally, the single set of kinetic parameters for the WS-SP, E-KP32.8, and E-KP16.9 pulps was calculated. The proposed kinetic model is considered as a valuable tool for the prediction and control of MeOH formation during OD of various alkaline pulps.


Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 788
Author(s):  
Beibei Zhang ◽  
Lu Zhang ◽  
Yulong Zhang ◽  
Chao Liu ◽  
Jiexiang Xia ◽  
...  

In this work, a simple chemical precipitation method was employed to prepare spherical-like Ag3PO4 material (IL-Ag3PO4) with exposed {111} facet in the presence of reactive ionic liquid 1-butyl-3-methylimidazole dihydrogen phosphate ([Omim]H2PO4). The crystal structure, microstructure, optical properties, and visible-light photocatalytic performance of as-prepared materials were studied in detail. The addition of ionic liquids played a crucial role in forming spherical-like morphology of IL-Ag3PO4 sample. Compared with traditional Ag3PO4 material, the intensity ratio of {222}/{200} facets in XRD pattern of IL-Ag3PO4 was significantly enhanced, indicating the main {111} facets exposed on the surface of IL-Ag3PO4 sample. The presence of exposed {111} facet was advantageous for facilitating the charge carrier transfer and separation. The light-harvesting capacity of IL-Ag3PO4 was larger than that of Ag3PO4. The photocatalytic activity of samples was evaluated by degrading rhodamine B (RhB) and p-chlorophenol (4-CP) under visible light. The photodegradation efficiencies of IL-Ag3PO4 were 1.94 and 2.45 times higher than that of Ag3PO4 for RhB and 4-CP removal, respectively, attributing to a synergy from the exposed {111} facet and enhanced photoabsorption. Based on active species capturing experiments, holes (h+), and superoxide radical (•O2−) were the main active species for visible-light-driven RhB photodegradation. This study will provide a promising prospect for designing and synthesizing ionic liquid-assisted photocatalysts with a high efficiency.


Sign in / Sign up

Export Citation Format

Share Document