In present study, xylanase and laccase were produced in a cost-effective manner up to 10 kg substrate level and evaluated in elemental chlorine free bleaching of Eucalyptus kraft pulp. Compared to the pulp pre-bleached with xylanase (15%) or laccase (25%) individually, the ClO2 savings were higher with sequential treatment of xylanase followed by laccase (35%) at laboratory scale. The sequentia...

Rice straw was cooked with three levels of alkali content (12, 14 and 16%) in cooking liquor by soda-organosolv (ethanol, diethylene glycol, dimethyl formamide) process. The effect of alkali addition on yield, kappa number, brightness and viscosity of organosolv unbleached pulps was studied. The TCF bleachability of these organosolv pulps and kraft pulp was carried out using a simple three stag...

The influence of operating variables [viz: temperature 55-85°C, process time 30-120 min, pH 9-11,peraceticacid concentration 0.5-3.5% oven dried pulp (o.d.p.)., and sodium perborate concentration 1-5% o.d.p.] on the bleached pulp characteristics [viz: viscosity (VI), brightness (BR), kappa number (KN)], and resulting paper sheets properties [viz: breaking length (BL), stretch (ST), tear (TI), a...

The screened Eucalyptus camendulensis chips were cooked in the laboratory at various alkalinities (14, 16, 18 and 20 per cent) and sulphidity (20, 30 and 40 per cent). Due to the variation in chemical charge, the pulp yield was found to be different. The average pulp yield was 50.6 per cent after washing and the final yield was obtained 40 per cent, which followed the normal kraft yield trend. ...

Ozone is a non-chlorine bleaching agent that can reduce pollution in the pulp bleaching stage. In this work the ozone bleaching of eucalyptus kraft pulp was performed as part of a kinetics study to explain factors affecting the properties of bleached pulp. The bleaching efficiency was closely related to the rates of mass transfer and self-decomposition, as well as the intensity of ozonation. Fo...

The adsorption of cellulases onto fibers may be one of the most important factors affecting the enzymatic reaction between cellulases and fibers. This study investigated the adsorption kinetics involved, using isothermal adsorption equations. Cellulose binding domains (CBDs) were isolated from a commercial cellulase, and their role in the adsorption and enzymatic reaction was evaluated. Approxi...

Sodium hydroxide (NaOH) has been used as an alkali source in conventional hydrogen peroxide bleaching. In the present work, partial and total replacement of NaOH with magnesium hydroxide (Mg(OH)2) as the alkali source for hydrogen peroxide bleaching of deinked pulp was studied. The bleached pulp was studied with respect to brightness, post color (P.C.) number, and mechanical properties (i.e., t...

This article is based on a n extensive report with the same title and available from the Univenity oj Toronto Puljo &Paper Centre. referred to as pulp) used in the manufacture of a variety of paper products. The chemicals assessed in this report include chlorination derivatives of 10 compounds (oleic acid, linoleic acid, stearic acid, beta-sitosterol, stigmasterol, prenols, squalene, phenol, ca...

This study evaluated the histological changes in dental pulp after nightguard vital bleaching with 10% carbamide peroxide gel. Fifteen patients between 12 and 26 years of age with caries-free first premolars scheduled for orthodontic extraction were treated with 10% Opalescence (Ultradent Products, Inc). Tooth #5 had four days of bleaching, tooth #12 was treated for two weeks, tooth #21 was ble...