Biobleaching of Pulp with Dioxygen in the Laccase-Mediator System. Part 1. Kinetics of Delignification
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Mikhail Balakshin
Summary
Kinetics of pine kraft-AQ pulp delignification with the laccase-mediator system (LMS) and the effects of variable factors on the delignification were studied. The delignification was conducted in acetate buffer solution at pH 4.5 and at 40°C under atmospheric pressure. Only a part of the residual lignin could be removed in one-stage processes. Kinetics of kappa number reduction follows a pseudo-second order rate law with pulp consistency of 10 %, mediator charge of 0.1 mmole HOBT/g pulp and laccase charage of 10 U Coriolus laccase/g pulp. Kinetics of dioxygen uptake follows a pseudo-first order rate law up to first 8 hours of the reaction and a pseudo-zero order rate law at the reaction time of 8–24 hours. The amounts of dioxygen consumed per removal of one C9-unit equivalent of residual lignin is rather high, 1.5–2.5 mole, and increases with increasing reaction time. Experimental data show that side reactions between the Laccase-Mediator System and products of oxidative degradation of lignin strongly inhibit the delignification either by chemical or physical means or both. Removal of the degraded lignin fragments by alkaline extraction effectively restores the delignification of pulp with LMS. A four-stage process consisting of consecutive treatment of pulp with dioxygen-laccase-HOBT (LMS) followed by alkaline extraction (E), (LMS-E)4, decreased kappa number of a pine kraft-AQ pulp from 21.8 to less than 5. On the basis of the kinetic data, the mechanism of the pulp delignification with LMS is discussed.
Copyright © 2000 by Walter de Gruyter GmbH & Co. KG
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- Electron Paramagnetic Resonance Spectroscopic (EPR) Study of Copper Amine Treated Southern Pine in Wood Preservation
- Comparative Studies of Hemicelluloses Solubilized during the Treatments of Maize Stems with Peroxymonosulfuric Acid, Peroxyformic Acid, Peracetic Acid, and Hydrogen Peroxide. Part 1. Yield and Chemical Characterization
- Homolytic Scission of Interunitary Bonds in Lignin Induced by Ultrasonic Irradiation of MWL Dissolved in Dimethylsulfoxide
- Eucalyptus globulus Kraft Pulp Residual Lignins. Part 1. Effects of Extraction Methods upon Lignin Structure
- Lignin Behavior During the Autocatalyzed Methanol Pulping of Eucalyptus globulus Changes in Molecular Weight and Functionality
- Lignin Degradation in Oxygen Delignification Catalysed by [PMo7V5O40]8- Polyanion. Part I. Study on Wood Lignin
- Biobleaching of Pulp with Dioxygen in the Laccase-Mediator System. Part 1. Kinetics of Delignification
- Degradation of Model Compounds for Cellulose and Lignocellulosic Pulp during Ozonation in Aqueous Solution
- Application of a Catalyst in Peroxide Bleaching of Eucalyptus Kraft Pulp
- Kinetic Study on Delignification of Kraft-AQ Pine Pulp with Hydrogen Peroxide Catalyzed by Mn(IV)-Me4DTNE
- An Analysis of Rolling Shear of Spruce Wood by the Iosipescu Method
- An Investigation of the Crack Tendency on Wood Surfaces After Different Machining Operations
- Microfibril Angle Determination of Rattan Fibers and its Influence on the Properties of the Cane
- Effects of Element Size and Orientation in the Production of High Strength Resin Impregnated Wood Based Materials
- Literature Reports
Articles in the same Issue
- Dielectrically Observed Consequences of Microbial Treatment of Wood and Bamboo
- Adsorption of Cr(VI) from Dichromate Solutions onto Black Locust Leaves
- Electron Paramagnetic Resonance Spectroscopic (EPR) Study of Copper Amine Treated Southern Pine in Wood Preservation
- Comparative Studies of Hemicelluloses Solubilized during the Treatments of Maize Stems with Peroxymonosulfuric Acid, Peroxyformic Acid, Peracetic Acid, and Hydrogen Peroxide. Part 1. Yield and Chemical Characterization
- Homolytic Scission of Interunitary Bonds in Lignin Induced by Ultrasonic Irradiation of MWL Dissolved in Dimethylsulfoxide
- Eucalyptus globulus Kraft Pulp Residual Lignins. Part 1. Effects of Extraction Methods upon Lignin Structure
- Lignin Behavior During the Autocatalyzed Methanol Pulping of Eucalyptus globulus Changes in Molecular Weight and Functionality
- Lignin Degradation in Oxygen Delignification Catalysed by [PMo7V5O40]8- Polyanion. Part I. Study on Wood Lignin
- Biobleaching of Pulp with Dioxygen in the Laccase-Mediator System. Part 1. Kinetics of Delignification
- Degradation of Model Compounds for Cellulose and Lignocellulosic Pulp during Ozonation in Aqueous Solution
- Application of a Catalyst in Peroxide Bleaching of Eucalyptus Kraft Pulp
- Kinetic Study on Delignification of Kraft-AQ Pine Pulp with Hydrogen Peroxide Catalyzed by Mn(IV)-Me4DTNE
- An Analysis of Rolling Shear of Spruce Wood by the Iosipescu Method
- An Investigation of the Crack Tendency on Wood Surfaces After Different Machining Operations
- Microfibril Angle Determination of Rattan Fibers and its Influence on the Properties of the Cane
- Effects of Element Size and Orientation in the Production of High Strength Resin Impregnated Wood Based Materials
- Literature Reports
