Application And Mechanism Of Xylanase Boosting Bleaching In Bamboo Pulp

With the quick development of paper industry,our country has rarely lacked for the material used in paper. The exploitation and application of material could be propitious to make up the lack for paper material .Bamboo is a fine fibre for paper. Paper industry make grave pollution to env-ironment.Biobleaching can cut down dosage and improve bleachability of unbleached pulp so that reduce the environment pollution. In this thesis, technological process and mechanism of xylanase boosting bleaching are studied.The main conclusion are as the follows.The optimum condition of xylanase Pulpzyme HC is 70 ℃ by tem-perature,PH value 6.5,1 hour by time,dosage of xylanase 0.04% and chel-ated dosage 0.5%.The effects of xylanase pretreatment before oxygen bleaching and CEH bleaching show that the pretreatment could decrease the Kappanumber and increase the bightness of pulp, but also improve comprehensive strength of pulp and decrease dosage.The results of UV(ultraviolet spectra) show that the waste liquid after xylanase treating with bamboo unbleached pulp embody lignin, which indicate xylanase could degrad hemicellulose of LCC and make it easier for dissolved lignin.The results of GPC(gel permeation chromatograhy)show that unbleached pulp after xylanase pretreatment have bigger molecules of lignin and carbohydrate. The results indicate that xylanase could dissolve the xylan of LCC in residual lignin and degrade lignin.SEM(scanning electron microscopy) observes fibre surface configuration of xylanase pretreatment pulp. The result show that fibre surface have more small opening, which was propitious to dissolve residual lignin.FTIR spectra analysis shows that with xylanase pretreatment, the a-bsorption intensity assign to the aromatic ring and occuring colour compounds vibration gradually decreas, even vanish, which improv the brightness of pulp.