| With the development of economy in our country, the huge demand for paper and paper products increases promptly. The limited forestry resources resulted in a severe shortage of wood pulp. Besides, the raw material structure and the level of technical equipment resuled in the pollution of paper industy more seriously, which restricted the development of china’s paper industry. Moreover, China is one of the bamboo rich countries in the world and stands in the first place in amount of bamboo resources, the fiber and chemical composition of bamboo are fit for pulping. In order to make up the shortage of the wood pulp raw material, reduce the envirometal pollution of pulping and papermaking and promote the reasonable development of China’s paper industry, utilizing the abundant bamboo resources in our country and adopting TCF bleavhing process will provide technical support and throretical foundation of green bleaching.This paper adopts the homemade highly efficient ozone bleaching reactor to systematicly explore the ozone bleaching of kraft bamboo pulp. Designing single factor experiment and exploring the effect of pulp concentration, charge of ozone, ozone concentration and p H value on ozone bleaching of sulfate bamboo pulp. Through in-depth study of various bleaching factors, It is concluded that the best bleaching condition at room temperature: pulp concisistency of 35% or so, ozone consistency of 10%, the reaction time of 2.5 min. Through the above conditions, we can get good bleaching effect. The pulp brightness was 68.5% ISO, viscosity was 758 m L·g-1, kappa value was 3.3. On the basis, to study the protective effect of different kinds of additive on carbohydrates, M fertilizer can obviously improve the selectivity of ozone bleaching, improve the Brightness of bleaching pulp and reduce the loss of the Viscosity. Under the condition of M additives was 0.3%, compared with the ozone bleaching without the use of additives, the pulp brighness increased by 3.6%ISO,Viscosity increased 50 m L·g-1,Selective raised 0.8.After the design of single factor experiment, hydrogen peroxide bleaching after ozone bleaching kraft bamboo pulp, test shows that The brighness of the result pulp bleaching was 88.5% ISO, viscosity was 705 m L·g-1 under the condition of H2O2 dosage 2.0 % with the temperature 90℃ for 120 min. On the basis of the combination of response surface analysis, we can get the optimum process conditions of hydrogen peroxide blesching: The brighness of the result pulp bleaching was 88.6% ISO, viscosity was 706 m L·g-1 under the condition of H2O2 dosage 2.0 % with the temperature 90℃ for 115 min.Through the above analysis of oxygen bleaching agent bleaching effect and research, explored the sulfate bamboo pulp TCF bleaching process based on ozone bleaching, studied the bleaching effect and physical properties of ozone bleaching and combination bleaching. Test shows that combination bleaching not only can improve the brighness of pulp, but also can resolve the problem of viscosity loss in the process of bleaching. Tensile index, tear inde, burst index and folding number of pulp after TCF bleaching process was 61.5 N·m2·g-1, 10.24 m N·m2·g-1, 5.18Kpa·m2·g-1, 83 times.After the study of sulfate bamboo pulp TCF bleaching process, Microscope and scanning electron microscopy(SEM) were used before and after ozone bleaching process to observe fiber morphological changes under the condition of ozone bleaching. The results showed that most of the fibers became shorter and thinner. The phenomenons of broom, bur and tear on fiber surface were showed. FTIR and X-ray diffraction were used in studying the mechanism of ozone bleaching. Results indicated that the benzene were damaged and hydroxylated to increase the possibility of ozone contacting with the lignin. And Carbonyl on the benzene ring was damaged to improve pulp brighness. The degree of crystallinity before and after ozone bleaching was 41.6% and 38.4% respectively. When adding M additives, the diffraction peak before and after ozone bleaching didn’t change much, and reduction in strength og pulp was little. Test showes that the degradation of carbohydrates after ozone bleaching was less effected. Keywords: Kraft bamboo pulp; Ozone bleaching; Response surface analysis; Viscosity... |
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