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SCIENTIFIC PAPER |
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Cerig |
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Last update : August 25, 2014 |
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New conditions of use of ozone for cellulosic pulp bleaching - Development of a green bleaching sequence
Nouvelles conditions d'utilisation de l'ozone dans le blanchiment des pâtes cellulosiques.
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Frédéric Pouyet |
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PhD thesis defended on March 21, 2014 Thèse soutenue le 21 mars 2014 |
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In order to obtain white paper, the brown kraft pulp obtained from wood after a chemical treatment has to be bleached. Several chemical reagents can be used, including the efficient chlorinated agents. However, the use of those chlorinated agents leads to the generation of toxic compounds, among other issues. Other reagents such as ozone and peroxide can be used to partially or fully replace them, but the way they react with pulp components was not fully understood and they seemed to inevitably lead to a degradation of the end product.
The aim of this thesis was to design a greener bleaching sequence, giving high quality pulps without the use of chlorinated reagents. This was achieved thanks to a better understanding of the chemical reactions involved in the bleaching of pulp, and more specifically through a better apprehension of the possible reactions of ozone.
Dans les applications papetières, pour fabriquer du papier de haute blancheur, la pâte brune obtenue à partir du bois doit être blanchie. Ce blanchiment est réalisable grâce à des produits chlorés. Or, la toxicité de ces derniers provoque de multiples problèmes notamment en termes d’impact sur l’environnement. Des alternatives existent, impliquant l’utilisation de l’ozone et du peroxyde d’hydrogène, mais elles provoquent des dégradations de la pâte.
Le but de cette thèse était d’élaborer des séquences de blanchiment non-chlorées aboutissant à un produit final de haute qualité. Cet objectif a été atteint grâce notamment à des avancées quant à la compréhension des modes d’action de l’ozone sur les composants des pâtes, plus particulièrement sur les composés insaturés.
Thesis prepared under the supervision of:
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