膜蒸馏法浓缩中药提取液过程膜污染机理类型的确定

The mechanism of fouling resistance in the treatment of traditional Chinese medicine by membrane distillation technology

用聚偏氟乙烯中空纤维疏水膜对中药提取液进行直接接触式膜蒸馏,测定了不同封装分率和料液流量下的跨膜通量。应用膜污染机理中的4种过滤模型分别对实验数据进行线性拟合,结果发现滤饼过滤模型的拟合程度最好。这说明在所研究的过程中膜污染物基本没有进入膜孔,为时短暂的膜孔堵塞也可以忽略,膜表面上滤饼层增厚是导致跨膜通量下降的最直接原因。

A hollow fiber hydrophobic membrane （PVDF） has been employed to treat traditional Chinese medicine （TCM） by direct contact membrane distillation. The membrane flux was measured with different parameters such as feed flow rate and packing density of the membrane module. Four filtration models of fouling mechanisms were used to analyze the experimental results. It was found that the experimentally observed flux decline for constant feed concentration agreed best with the cake filtration model. This indicates that the membrane fouling in the experiments was mainly caused by foulant deposition and cake growth, with almost no foulants entering into the membrane pores and reducing the size of the path for mass transfer through the membrane.