亲疏水性溶解性有机物对聚偏氟乙烯超滤膜污染行为

Fouling behaviour of hydrophilic and hydrophobic organic matters in PVDF ultrafiltration membrane

选用模拟亲疏水性有机物及实际二级处理水中的亲疏水性有机物,分别进行了聚偏氟乙烯(PVDF)超滤膜污染实验。并测定了不同污染物与膜及污染物间的作用力,分析亲/疏水性有机物对PVDF超滤膜的污染行为。结果表明,膜-污染物及污染物间相互作用力是控制膜污染行为的主导因素。亲水性有机物与PVDF超滤膜之间的相互亲和力较强,致使运行初期膜通量的大幅度下降,是PVDF膜的优势污染物。但是,针对实际污染物,运行后期,疏水性有机物之间较强的相互作用力使得其取代了亲水性有机物,成为膜的优势污染物。此外,模拟亲疏水性有机物的膜污染变化规律与实际亲疏水性有机物相似,表明使用模拟污染物可一定程度上预测实际废水中相应性能污染物的膜污染行为。

To further determine the fouling behaviour of both hydrophilic and hydrophobic organic matters,fouling experiments were carried out. In these experiments,we tested the polyvinylidene fluoride( PVDF) ultrafiltration membranes and model and actual hydrophilic and hydrophobic organic matters. The interaction forces between PVDF membrane and each type of foulant and between foulant and foulant were investigated. Results showed that the membrane-foulant and foulant-foulant interaction forces played crucial roles in controlling membrane fouling behavior. In the initial filtration stage,the hydrophilic organic matters are the dominant foulants responsible for membrane fouling. This is mainly due to the stronger interaction forces between PVDF membrane and hydrophilic organic matters. This strong interaction caused a higher decrease in the membrane flux. However,for actual foulants,in the later filtration stage,the hydrophobic organic matter became the dominant foulant responsible for membrane fouling. This was mainly attributed to the stronger intra hydrophobic-fraction interaction forces. Moreover,the fouling behaviour of model hydrophilic and hydrophobic organic matters was very similar to that of actual hydrophilic and hydrophobic organic matters. This indicated that the actual organic matters fouling behaviour could be predicted by model foulants.