The influence of transition metal ions on the oxidation of kraft pulp using hydrogen peroxide under mildly acidic conditions
Journal article, 2023

Oxidation of kraft pulp using hydrogen peroxide under mild acidic conditions can be applied in order to obtain new functionality of the fibres, in the form of carbonyl groups. The hydrogen peroxide concentration must, however, be higher than consumed by the oxidation reactions meaning that the liquid must be recirculated to fully utilize the hydrogen peroxide. This paper investigates the consequences of recirculation of the oxidation liquor. It was found that recirculation results in an accumulation of ions of transition metals (copper, iron and manganese) in the oxidation liquor. The transition metal ions are known for catalytic decomposition of hydrogen peroxide, producing radicals which may react with carbohydrates, forming carbonyl groups as well as causing carbohydrate degradation. This was confirmed through the recirculation of oxidation liquor as well as through controlled addition of transition metals. At high transition metal ion concentration the reactions were fast and a severe degradation of carbohydrates was observed, accompanied by a rapid hydrogen peroxide consumption. The consequence of this, in an industrial context, is that the concentration of metal ions must be carefully controlled in order to add functionality to the cellulose without causing excessive degradation of carbohydrates or consumption of hydrogen peroxide.

hydrogen peroxide

oxidation

carbohydrate degradation

kraft pulp

hydrogen peroxide decomposition

Author

Axel Martinsson

Chalmers, Chemistry and Chemical Engineering, Chemical Technology

Merima Hasani

Chalmers, Chemistry and Chemical Engineering, Chemical Technology

Hans Theliander

Chalmers, Chemistry and Chemical Engineering, Chemical Technology

Published in

Holzforschung

0018-3830 (ISSN) 1437-434X (eISSN)

Vol. 77Issue 5p. 318-325

Categorizing

Subject Categories

Polymer Technologies

Other Chemical Engineering

Organic Chemistry

Identifiers

DOI

10.1515/hf-2022-0184

More information

Latest update

3/7/2024 9