Effect of Two-step Thermal Treatments on Peroxide Bleachability of Thermomechanical Pulp

Seo, Jin-Ho; Kim, Hyoung-Jin; Ahn, Chi-Deuck

doi:10.15376/biores.10.4.7752-7762

Cited by 1 publication

(1 citation statement)

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“…The color of the chemimechanical pulp has been mainly attributed to the chromophoric structures of lignin (He et al 2004;Seo et al 2015). During peroxide bleaching, the initial chromophoric structures of lignin are eliminated by bleaching chemicals, but new chromophores are simultaneously generated (Maria et al 1997;Leary and Giampaolo 1998).…”

Section: Introductionmentioning

confidence: 99%

Bleachability improvement of eucalypt mechanical pulps using hydrogen peroxide in ethanol-water media

Fang

Liang

Deng

et al. 2020

BioRes

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Alkaline darkening has a negative effect on chemimechanical pulps produced from various eucalypt chips. For instance, the pulp’s brightness has been found to drop rapidly when alkali addition exceeds its optimum amount. Therefore, to compare the effects of different media on brightness gain, eucalypt mechanical pulps were bleached using a typical peroxide bleaching sequence in a water medium and in an ethanol-water (E/W) medium. Various pulp brightness levels and changes of residue chemicals in the spent bleaching liquors were investigated. Compared to water medium, the net brightness gain notably increased when using the E/W medium at the same chemical dosages. The rate of pulp brightness loss caused by increasing alkali dosage dropped in the E/W medium. Analyses based on ultraviolet-visible diffuse reflectance spectra of bleached pulps, as well as gel permeation chromatography and pyrolysis-gas chromatography-mass spectrometry spectra of the residues in the spent bleaching liquors, indicated that the contributions to brightness improvement from ethanol-water media could be explained by the selective dissolution and removal of phenolic- or guaiacyl-structured lignin fragments that result in the formation of chromophoric groups under alkaline conditions.

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Section: Introductionmentioning

confidence: 99%