THE CHANGE OF KINETICS RATE OF EXCITATION PURITY IN OZONIZATION OF OXYGEN DELIGNIFIED HARDWOOD KRAFT PULP

The absence of detailed kinetic description of excitation purity of the ozonization of oxygen delignified hardwood kraft pulp in the literature was the reason to become interested in this topic. To fulfil the goals, the ozone delignification was studied at various conditions. Influence of pH in the range 0.3; 2.6; 3.9; 8.8 and 9.6 and the temperature of 20 and 40 degrees C in ozonization process were studied according to excitation purity and its rate. The conditions of ozone bleaching process were: Oxygen flow rate 7.5 ml O-2.s(-1) (27 1 O-2.h(-1)), the consistency of the pulp 30 % and ozone production of 56 mg O-3.l(-1) O-2. It was found that temperature and pH affected the progress rate constants of excitation purity at the ozonization process. The most constant rate of excitation purity was observed at pH in acid range (pH = 2.6) and at temperature 20 degrees C. The greatest decline of excitation purity was achieved at acidic pH range (0.3 and 2.6) in the ozone consumption 0.62-0.95 % O-3 on o.d. pulp at temperature 40 degrees C. We found out that dominant wavelength is 578.93 +/- 0.07 nm and is independent on temperature, pH and time of ozonization.