Natural Botanic Fiber Bleaching with H2O2/TAED System

Natural botanic fiber, the CTMP pulp fiber of Populus nigra, was bleached in a sequence incorporating TAED (tetra-acetyl-ethylenediamine) with hydrogen peroxide as a bleach activator. This is technology has been used successfully by the textile industry; now we are studying its application to the pulp and paper industry. This paper was conducted to optimize the H2O2/TAED bleaching process and compare the bleaching results with traditional H2O2 bleaching. The following primary process variables were evaluated: H2O2 dosage, the ratio of NaOH to H2O2, TAED dosage, bleaching time and temperature. Compared with the peroxide bleaching, the H2O2/TAED system can be carried out at lower temperature (55-70 degrees C) and shorter time (60 min). The suitable mole ratio of TAED to H2O2 was 0. 1 similar to 0.3. The best bleaching results, which can get 27.8 brightness gain, was achieved with the following one stage bleaching conditions:55 degrees C, 60min, 15% pulp concentration, 6% H2O2 dosage and 4% NaOH dosage, the mole ratio of TAED to H2O2 was 0. 1. A multi-stage bleaching, which was initialed by a H2O2/TAED bleaching stage and then followed by a H2O2 stage bleaching, could get 33.2 brightness gains. Results showed that the use of TAED in the peroxide offers a mean to improve the pulp brightness significantly at a short time cycle and relative low temperature, which indicated the reduction of energy and production cost.