蔗渣浆酶促漂白预处理对纤维形态性质和污染物发生的影响

采用Pulpzyme HC木聚糖酶对蔗渣纸浆进行酶促漂白处理。试验结果表明，酶处理的最佳纸浆浓度为5％，处理时间为60min．酶用量为1．0IU／g。酶处理后纸浆的得率下降不多．强度略有升高，但纸浆白度增加。试验结果还表明，酶处理对纸浆纤维不具有破坏性。对酶处理后纸浆的扫描电镜观察说明，随酶处理时间和酶用量的增加，蔗渣中木聚糖的溶出量加大。酶处理使木聚糖降解溶出，使木质素充分暴露出来，有利于后续漂白剂与之反应．同时可减少后续化学漂白剂的使用量，从而减少有毒氯化有机污染物的产生。随处理时间增长和酶用量增加，处理液中CODcr，和BOD5呈上升趋势。酶用量超过1．5IU／g后．BOD5增长较缓慢，表明酶的作用对纤维表面生物可降解成分的溶出较彻底。

Effect of enzyme-aided bleaching of bagasse pulp on fiber morphology and pollutant generation

Bagasse pulp was bleached using xylanase\|Pulpzyme HC. Experimental results showed that, the optimal concentration of bagasse pulp was 5%, optimal treatment time and dose of enzyme was 60 min and 1.0 IU/g respectively. Pulp recovery decreased slightly, strength of pulp increased while the brightness improved substantially after pretreatment with enzyme. Enzyme\|aided bleaching has not resulted in harming to bagasse fiber. SEM observation indicated that, with treatment time and dose of enzyme increasing, more xylan was stripped. Bleaching with xylanase pretreatment resulted in more lignin exposing to the bleacher, which helped to cut down the usage of bleacher. After the enzyme\|aided bleaching, the degraded xylan turned to organic pollutants. The generated COD\-\{Cr\} and BOD increased with the time of treatment and the dose of enzyme. The BOD value increased slightly when the enzyme dose reached 1.5 IU/g, which demonstrated that the biodegradable contents on the surface of the pulp fiber have almost stripped completely.