Kinetic on Microwave-assisted Delignification of Wheat Straw by Caustic Soda Solution

Under the condition of atmospheric pressure and different microwave radiation power, cooking experiment were conducted. Pulp yield and lignin content was increasing along with the microwave power growing, pH value under 400W was the highest. Then the mechanisms and kinetics of NaOH pulping of wheat straw were studied. The process condition was set as follows: microwave radiation power was 400 W, NaOH solution content was 1%, solid-liquid ratio was1:10, and the microwave heating temperature was from 50  ℃ to 95 ℃, the time was from 10 mins to 45 mins. The result shows that the rate of delignification reaction was 1.3 order with respect to residual lignin and 0.21 order with respect to [OH-]. The activation energies of the delignification was 25.4 kJ/mol.