Fe^2＋-H2O2体系降解壳聚糖

Degradation of Chitosan by Fe^(2+)-H_2O_2 System

Fe2+-H2O2体系能够有效地降解壳聚糖,反应介质的pH值、反应时间、反应温度、Fe2+浓度及H2O2浓度等实验因素对壳聚糖的降解效果都有程度不同的影响,其中以反应介质的pH值和H2O2浓度对降解反应的影响为最大。在pH值为3~5时Fe2+-H2O2体系降解壳聚糖的活性最高。适当增大H2O2的用量可以增大壳聚糖的降解程度,但当其用量增大至一定程度后,壳聚糖降解产物分子量的下降趋势明显变缓。合理的Fe2+-H2O2体系降解壳聚糖的实验条件为:介质pH值3~5;温度,室温;时间60~90min;壳聚糖:H2O2:Fe2+=240:12~24:1~2(摩尔比)。

Chitosan can be effectively degraded by Fe^2＋-H2O2 system. The degradation was affected by pH, reaction time, reaction temperature, concentration of Fe^2＋ and concentration of H2O2 , at different degree. Among them, pH and concentration of H2O2 were the most important to the degradation of chitosan. Fe^2＋ -H2O2 system possessed maximum activity at pH 3-5. The molecular weight of the degraded chitosan reduced as the concentration of H2O2 increased, but the var/ation became less as the concentration of H2O2 increased. The suitable experimental conditions of degrading chitosan by Fe^2＋-H2O2 as follows：pH 3-5,room temperature,60-90 min,chitosan：H2O2 ：Fe^2＋ =240：12-24：1-2 （mole ratio）.