Study on improving bleaching performance of mechanical-route eucalyptus pulp by ultrasonic pretreatment
XIE Cun-xin1, DENG Yong-jun2, JIAO Jian1, HAN Shan-ming2, LIANG Long1, TIAN Qing-wen1, FANG Gui-gan1
1. National Engineering Laboratory for Biomass Chemical Utilization, State Forestry Administration's Key and Open Laboratory for Forest Chemical Engineering, Jiangsu Provincial Key Laboratory for Biomass Energy and Material, Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry, Nanjing 210042, China; 2. Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, China
Abstract: The influences of ultrasonic power,ultrasonic irritation time and pulp concentration for ultrasound pretreatment on pulp whiteness and physical properties are examined through using mechanical-route eucalyptus pulp as research object.The optimal process conditions for bleaching pulp assisted by ultrasonic pretreatment are investigated by comparing the change trends of the whiteness of pulp and the residual content of hydrogen peroxide after pulp bleaching under different ultrasonic processes.The experimental results show that the whiteness of pulp can be increased by 1.7% ISO and the residual content of hydrogen peroxide rises by 1.4% when the power and frequency of ultrasonic is 585 W and 22.5 Hz respectively,the pulp concentration is 2% and pretreatment lasts for 30min,which translating to a significant improvement of bleaching performance.In addition,the accessibility of the liquid and the effects of impregnation and penetration are enhanced due to cavitation of fibers by ultrasonic pretreatment.