Commercial bleached kraft pulps were treated by ozone. Changes in the total halogen and ethanol extractable organic halogen of these pulps as well as brightness, viscosity and the water retention value were investigated during the ozone treatment.The effects of the ozone treatment on the total halogen and ethanol extractable organic halogen of the waste paper were also studied using toner-printed copy paper. The ozone treatments of the chlorine-bleached pulps and the waste copy paper were

more »

... d out at a 4 % (or 30%) pulp consistency and at lot for 5,10 and 20 min.. respectively. The total halogen and the ethanol extractable organic halogen of the chlorine-bleached pulps were much higher than those of the elemental chlorine-free pulps. The ozone treatment substantially reduced both the total halogen and the ethanol extractable organic halogen of the chlorine-bleached pulps. The ozone-treated pulps from the waste copy paper resulted in a lower total halogen compared with the usual deinked pulp. The hardwood bleached pulp with a lower brightness showed some increase in brightness after the ozone treatment. Although the pulp viscosity significantly decreased during the ozone treatment. the strength properties of the handsheet from the ozone-treated pulps were slightly changed.