Degradation of Lignin Induced by Microwave Treatment of Straw Pulp

摘要

Microwave-induced bleaching of straw pulp was carried out in a sequence consisting of sodium hypochlorite (H)and hydrogen peroxide(P).The effects of the microwave power,bleaching time and the consumption of sodium hypochlorite and hydrogen peroxide on the main physical properties of bleached pulp were investigated.The resultsshowed that the maximum brightness was achieved when the chemical consumption,the microwave power,and bleaching time were 8%,320W,and 2 minutes respectively for the H stage,and 1.5%,320W,1.5 minutes,respectively for the P stage.Under these conditions it was possible to achieve brightness of higher than 80% ISO,as well as better brightness stability and pulp viscosity.A shortened bleaching time meant energy saving.Therefore microwave-induced bleaching could be an energy saving bleaching technology.The physical and surface properties of pulp fibers were investigated.The results showed that bleaching by microwave inducement could produce pulp with higher viscosity and reduced micro-fibers and fiber damage.The SEM and AFM of the bleached pulps from the control and microwave induced process support the advantages of the microwave-induced bleaching technology.