Use of zeolites in stabilising alkaline peroxide solutions and their application in the bleaching of a TMP pulp

Abstract

Silicate-based chemistry is a common industrial practice to improve peroxide bleaching, however, the transition metal ion-induced peroxide decomposition is still inevitable. In this study, we investigated the potential to further decrease the peroxide decomposition by adding zeolites to the silicate-based peroxide system. The peroxide decomposition results showed that the combined effect of zeolites and sodium silicate is more effective than sodium silicate alone in decreasing the manganese-induced peroxide decomposition. Two types of zeolites, X and Y, were studied. The bleaching experiments showed that an improved peroxide bleaching performance was obtained by adding Y-zeolites to the conventional peroxide process.La chimieà base de silicates est une pratique industrielle commune visantà améliorer le blanchiment au peroxyde; cependant, la décomposition du peroxyde par les ions de métaux de transition reste inévitable. Dans cetteétude, nous avonsétudié le potentiel d'une réduction supplémentaire de la décomposition du peroxyde en ajoutant des zéolites au système de peroxydeà base de silicates. Les résultats de la décomposition du peroxyde ont démontré que l'effet combiné des zéolites et du silicate de sodium est plus efficace que le silicate de sodium employé seul pour la réduction de la décomposition du peroxyde par le manganèse. Deux types de zéolites, X et Y, ontétéétudiés. Les expériences de blanchiment ont démontré qu'on a obtenu un rendement accru de blanchiment au peroxyde en ajoutant des zéolites-Y au processus de peroxyde traditionnel.

Improving the hydrogen peroxide bleaching efficiency of aspen chemithermomechanical pulp by using chitosan

“…At the end of the bleaching process, the bleaching liquor was sampled, and the residual hydrogen peroxide content was determined by the iodometric method (Wekesa & Ni, 2011). The residual hydrogen peroxide content was expressed as the percentage of the residual hydrogen peroxide to the original amount of hydrogen peroxide added.…”

“…Hydrogen peroxide was decomposed according to previously described methods (Wekesa & Ni, 2011). The decomposition experiments were carried out in a thermostatic water bath at 80 • C using hydrogen peroxide solutions with an initial concentration of 2%.…”