采取超滤膜对乳清进行预处理，研究了不同操作条件下NF270纳滤膜的通量衰减规律以及对乳清中盐和乳糖的分离效果， 结果表明：压力由0.4 MPa增加到0.6 MPa时，纳滤膜稳定通量增大，膜通量衰减加重。纳滤膜的盐截留率先下降后上升，乳糖透过率略有增加，增加压力有利于的乳糖和盐之间的分离；当压力为0.6MPa，转速为418.6 rpm，在蛋白质的等电点pH值为4.8时，纳滤膜通量小且膜污染最为严重，此时盐截留率最低；pH值为3时所对应的膜通量与料液呈中性时相比，乳清通量增加，且通量衰减幅度小，此时盐截留率为30%，乳糖透过率达80%，因此酸性条件有利于提高通量及乳糖和盐之间的分离效果；提高膜表面的湍动程度时，膜通量增加且膜污染减弱，相应的纳滤膜的盐截留率较小，而对乳糖的透过率影响不明显。

In this study, ultrafiltration membrane was used to pretreat with whey, then NF270 nanofiltration membrane was adopted to treat with whey and the flux attenuation, desalination and lactose separation performance influenced by operating conditions was investigated. The results showed that improving pressure from 0.4 MPa to 0.6MPa, the steady flux of nanofiltration membrane increased and the corresponding flux attenuation was strengthened, the corresponding salt rejection rate improved with the pressure then decreased and lactose penetrate rate slightly increase with operating pressure which indicated that increasing pressure is conducive to separation salt and lactose. When the operating pressure was 0.6MPa, rotate speed is 418.6 rpm and pH is the protein isoelectric pH value 4.8, the nanofiltration membrane flux is minimum and membrane pollution is the most serious, the salt rejection rate decline.When PH value is 3, compared with neutral solution, the membrane flux increase and the flux decline range is small. At the same time, the salt rejection rate reached to 30%, lactose permeate rate is about 80%. So, the appropriate operating conditions should be under acid condition to improve separation effects. Increase the rotating rate on the surface of the membrane, flux increase and membrane fouling is weaken, the salt rejection rate of nanofiltration membrane drop and no obvious effect on the transmittance of lactose.
 

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