Per Acetic Acid Bleaching of Ground Pulp

Enzymatic Bleaching of Wood Pulp

The dark colour of kraft pulp after the wood chips have been heated at high temperature with NaOH solution is caused by lignin (a complex phenolic polymer) still attached to the cellulose fibres. Traditionally this pulp is treated with chlorine to bleach the pulp to make it suitable for paper making. Unfortunately this leads to the formation of some potentially toxic chlorophenolic compounds of...

Pulp reaction to vital bleaching.

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...

Greater Pulp Yields per Acre per Year

Enzymes Improve Ecf Bleaching of Pulp

The delignification efficiency of different laccase enzymes was examined on the eucalyptus Kraft pulp. The laccase enzyme from Trametes versicolor showing the highest delignification efficiency was selected and used in the elemental chlorine-free bleaching sequence for improving the pulp bleachability. An appreciable reduction in chlorine dioxide consumption was also obtained. Further reduction...

Use of Enzymes in Deinked Pulp Bleaching

To comply with government’s environmental policies and to satisfy the requests of the consumers, recycling of waste paper is essential for reducing the consumption of virgin fibers in pulp and paper industry. However, the poor optical properties of recycled fibers restrict their use in value-added papers. Enzymes, such as lipase and laccase, represent an interesting alternative. The detachment ...