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In this experiment, xylanase was used prior to bleaching. The dosages of xylanase are 0.25; 0,5; 0,75; 1;1,25 kg/ton of chips. The pulps after pretreatment were tested and treated with D0ED1D2 bleaching sequences. The result shoew that xylanase can decreasekappa number as much as 10.33-11.45. The optinum kappa number (10.33) was obtaidned by addition xylanase 0.75 kg/ton of chips. Xylanase also increases increase bleachability of pulp and decrease dirt on pulp, from initial brightness 82.4 % ISO to 83.10 % ISO. While dirt from 9.5 mm2/m was decrease to 7-8 mm2/m2. Xylanase was able to decrease dichloromethane extractive content in bleached pulp as much as 0.06-0.14 point. Xylanase also increases bleaching selectivity, as physical strength of pulp tend to increase. |
