气体对涡流空化降解壳聚糖的影响

Influents of gas on degradation of chitosan with swirling cavitation

为降低壳聚糖的分子量,提高其应用范围,利用涡流强化降解壳聚糖,考察在涡流空化过程中壳聚糖溶液浓度、溶液p H、反应温度、出口压力、反应时间、通气方式等因素对强化壳聚糖空化降解的影响,同时对比空气、氧气、氮气对空化效应的影响。结果表明:不同的反应条件下,在涡流空化过程中通入空气均能强化壳聚糖降解,且氧气的强化作用大于空气,而通入氮气则抑制壳聚糖的降解。在壳聚糖浓度为3g/L、p H为4.4时、反应温度60℃、压力0.3 MPa、空化时间为3 h的条件下,相比于未通气的涡流空化降解,通入空气、氧气使壳聚糖黏度下降率分别提高了15.92%,9.10%,而通入氮气则使黏度下降率降低了9.89%。因此,空气、氧气的加入可有效提高壳聚糖的降解率,这为壳聚糖的开发与应用提供了理论依据。

In the present work,degradation of chitosan with swirling cavitation was investigated to strengthen the effect of degradation,reduce the molecular weight of chitosan and expand the range of application.Different operating parameters such as initial concentration,initial p H,solution temperature,outlet pressure,treatment time and the method of ventilate was investigate on the degradation of chitosan.And different gas such as air,oxygen and nitrogen was used to compare the effect of gas on the effect of cavitation.The results show that： Air has an obvious influence on the degradation of chitosan on the different reaction condition,and the influence of oxygen is better than that of air,but nitrogen is inhibiting the degradation of chitosan.The experiment was performed under the following conditions： a solution concentration of 3 g / L,p H 4.4,a temperature of 60 ℃,a pressure of 0.3 MPa and a treatment time of 3 h,compared with degradation of chitosan in the condition of no-gas swirling cavitation,the aeration of air,oxygen make the intrinsic viscosity reduction rate of chitosan increased by 15.92% and 9.1%.But the aeration of nitrogen make the intrinsic viscosity reduction rate decreased by 9.89%.Therefore,the addition of air and oxygen can improve the degradation rate of chitosan effectively.This study will provide a useful theoretical basis for the development and application of chitosan.