Abstract: Laccase being catalyzer, the degradation mechanism of 2,4-Dichlorophenol, 4-Chlorophenol and 2-Chlorophenol is studied. The effects of reaction time, pH, temperature, concentration of chlorophenols and laccase on the removal of chlorophenols are discussed in detail, as well as the optimum reaction condition. The results indicate that reactivity of 2,4-DCP is better than that of other two chlorophenols under laccase catalyzing, with a degradation rate of 94% in 10 h， then 2-CP, 75% and 4-CP 69% in 10 h. The suitable pH for laccase to degrade chlorophenols is around 5.5. The removal of chlorophenols increases with increase of laccase concentration and temperature, but effects of increase of concentration of chlorophenols on the removal of chlorophenol are different. The reaction of degradation 2,4-DCP catalyzed by laccase followed the first-order reaction and the reaction activation energy is about 44.8 kJ·mol^-1. In addition, laccase is immobilized by using crosslinked chitosan with glutaraldehyde.The activity of immobilized laccase is lower than that of free laccase, but the stability is increased significantly. The immobilized laccase is used to degrade 2,4-DCP repeatedly in 6 days, and the degradation rate in 6 h is more than 60% throughout.

Key words: chlorophenol, laccase, catalytical degradation, immobilized enzyme

摘要： 采用漆酶为催化剂，研究2,4－二氯酚、4－氯酚和2－氯酚的催化降解机理，探讨了反应时间、pH值、反应温度、氯酚浓度以及漆酶浓度对其降解效果的影响和最适降解条件。结果表明，漆酶催化氧化2,4－二氯酚的能力最强，其降解率10h内达到94%，4－氯酚为75%，2－氯酚为69%。2,4－二氯酚发生反应的最适pH值在5.2～6.0之间，4－氯酚在5.5附近，2－氯酚在4.5～5.5之间。漆酶对氯酚的降解率随着漆酶浓度、反应温度的升高而增大，但随着氯酚浓度的升高，不同氯酚的变化趋势并不相同。漆酶降解2,4－二氯酚的反应属于一级反应，反应活化能约为44.8 kJ·mol^-1。另外，利用戊二醛交联壳聚糖制成载体来固定化漆酶，固定化漆酶的活性虽低于自由漆酶，但稳定性明显增强，连续6d用其降解2,4－二氯酚，6h降解率始终在60%以上。

关键词: 氯酚, 漆酶, 催化降解, 酶固定化