Taed Activated The H <sub> 2 </ Sub> O <sub> 2 </ Sub> For Pulp Bleaching

In this thesis, we studied the activation of tetraacetylethylenediamine(TAED) to H2O2 bleaching process of kraft bamboo pulp and bagasse pulp, and the deligninfication mechanism. Including the study of the activation of TAED to the H2O2 bleaching of kraft bamboo pulp and alkali bagasse pulp, reducing chlorine bleaching of CEH bleaching, combination of. activated H2O2 bleaching with oxygen bleaching, and the study of UV and IR spectra analysis of residual lignin. The main conclusion are as the follows.The additive of TAED to the H2O2 bleaching can upgrade the brightness of the kraft bamboo pulp, from 32.6%ISO to 53.4%ISO, 13.2%ISO higher than using H2O2 alone which can reach 40.2%ISO. Using H2O2 alone, the brightness of the bagasse pulp can reach 56.2%ISO, which can reach 70.1%ISO after using TAED. The optimal conditions in this bleaching experiment of soda bagasse pulp are as follows: TAED: H2O2 (mol ratio) =0.55, 3%H2O2, retention time 50 minutes, temperature 55 $, pulp dense 12%, 3%Na2SiO3%, 0.05%MgSO4.Combining the traditional CEH bleaching with the activated H2O2 by TAED can achieve a preferable bleaching effect than the traditional CEH bleaching, which can make the brightness of pulp upgrade 8.3%ISO, 2.5%ISO higher than the combining H2O2 with traditional CEH bleaching, the viscosity drops 19 ml/g. The total chlorine in the traditional CEH bleaching is 5%, the total residual chlorine is 0.8591 g/1. While in the CEPTAEDH sequence, l%H2O2(mol ratio: H2O2/TAED=2), total chlorine is only 3%. The residual chlorine is 0.5473 g/1, reduce 39.29%.By TAED activates H2O2 bleaching, intensified oxygen bleaching can improve the oxygen bleaching capability. It can upgrade the pulp brightness by 3.8%ISO, but lower than using H2O2 to intensify oxygen bleaching alone, which can upgrade 6.5%ISO. A preferable AOP_TAED sequence is used to improve the oxygen bleaching capability, it can upgrade 12.8%ISO than AO sequence, KMnO4 value reduce 1.84, viscosity reduce 241 ml/g. Though the AOO sequence can make the brightness ofpulp reach 78.4%ISO, but the viscosity reduce to 707 ml/g, 465 ml/g less than the AO sequence, fibers are damnified seriously.UV spectra analysis of the residual lignin shows, H2O2 bleaching destroys the structure of the benzene a little, H2O2 bleaching activated by TAED destroys the structure of the benzene more better, the use of TAED in IOi can intensify the delignin ability of H2O2. IR spectra analysis of the residual lignin shows, using H2O2z alone in pulp bleaching can't destroy the benzene and the hydroxybenzene, while the hydroxybenzene disappears when the TAED is ued, maybe this is why the brightness of pulp can be improved.The result of the research show: TAED is an excellent FbC bleaching activator, it can upgrade the brightness of pulp, remain the viscosity of pulp; Combining the traditional CEH bleaching with the activated HiC by TAED, which can reach a good bleaching effect, the dose of the chlorine and hypochlorite is reduced, so the residual chlorine reduces too; With TAED activates FCh bleaching, the effect of intensifying oxygen is not evident, while the AOPjAED sequence can reach a good bleaching effect, which is a feasible bleaching process.