Study On Photocatalysis Bleaching Technology And Mechanisms Of Bamboo Kraft Pulp

There are abundant bamboo resources in China. Developing the bamboo pulp industrialization according with the local conditions, what is an available way to solve the shortage of fiber material for papermaking. Due to conventional bleaching technology with chlorine containing agents bring severe pollution on environment, especially bleaching effluent, it is necessary to look for a new environment friendly bleaching technology for bamboo pulp, and it is beneficial to promote bamboo pulp industrialization. Furthermore, it is significant to the sustainable development of Chinese paper-making industry.In this study, a series of pulp photocatalysis bleaching reactors were designed and made firstly. In those reactors, mercury lamp with a quartz glass cooler, as a ultraviolet light resource, was immerged into the reactor, photocatalysis bleaching of the bamboo kraft pulp were operated at atmospheric pressure in these reacrors. First of all, the technology and influence factor of photocatalysis bleaching were studied, and compared with conventional bleaching technology, which contained chlorine agents were performed. The results showed that there were many of difference between photocatalysis bleaching with conventional bleaching methods. There were several key effects during photocatalysis bleaching for pulp: irradiation mode was the first key effect, photocatalysis bleaching accorded with Grotthus-Drapper Law in photochemistry; oxygen was another key effect, delignification and improving brightness could not keep on without oxygen in system; alkaline condition was very important and had a directly effect on bleaching time, modest alkaline condition was helpful to obtain high brightness with a good pulp viscosity, but too much alkali dosage would lead to badly degradation of carbohydrate and big loss in pulp viscosity. Moreover, temperature had less effect on result of photocatalysis bleaching than conventional bleaching, even at a lower temperature(13 ℃ ), 81%(ISO) brightness could be obtained after 8 hours photo-bleaching, the brightness would improve with higher temperature. Pulp photocatalysis bleaching had a special and macroscopical "Reactor Dimension Effect" when the light source and other parameters were invariant, the bigger dimension of reactor, the thicker pulp layer, the lower brightness was obtained. At constant light resource condition, the more consistency increasing, the lower brightness was obtained, the less content of lignin...