渗透汽化膜行为研究(Ⅰ)——壳聚糖膜的分离性能与溶解吸附平衡的关系

Study on the pervaporation membrane behavior(Ⅰ)——relationship between separation characteristics and sorption equilibrium of chitosan membrane

讨论了渗透汽化膜的渗透行为.以乙醇—水混合溶液为进料,在全浓度范围内,分别测定了4张不同硫酸交联程度的壳聚糖膜的渗透汽化性能及平衡溶解吸附性能.结果表明,硫酸交联增强了水的渗透,抑制了醇的渗透,从而使膜分离性能明显改善.膜对水及乙醇的透量与膜对水及乙醇的溶胀度之间存在明显的对应关系.在引入溶解吸附分离系数α_s 和扩散蒸发分离系数α_(DV)后计算表明,膜的分离性能主要取决于水和乙醇在膜界面上的溶解分配平衡.

The permeation behavior of pervaporation membrane was discussed in this pa- per.Water-ethanol mixture was used as feed,the pervaporation and sorption characteristics of chitosan membranes with different H_2SO_4 crosslinking degrees were measured in the whole feed composition range.The results showed that the crosslinking enhanced the permeation of water and hindered ethanol from permeating.Therefore the separation characteristics were improved.The flux of water and ethanol had corresponding relationship to the swelling de- gree of water and ethanol.Introducing sorption separation factor α_s and diffusion—evapora- tion separation factor α_(DV),calculations showed that the separation characteristics of mem- brane were mainly determined by the sorption equilibrium of water and ethanol at the up- stream side of membrane.