不同组分的有机物对膜过滤通量下降的影响

采用DAX-8、XAD-4、IRA-958型树脂将自来水中有机物分离成强疏水性、弱疏水性、极性亲水性、中性亲水性有机物，以聚偏氟乙烯、聚醚砜、醋酸纤维3种材质的膜对各组分水样进行膜过滤试验，研究不同组分的有机物对膜过滤通量的影响.结果表明，过滤原水时，PES膜、PVDF膜和CA膜的通量分别比初始通量下降了67%、 59%和19%，表明疏水性越强的膜，越容易造成污染.就各种组分对通量的影响而言，过滤中性亲水性组分的通量下降为初始通量的41%～75%，而弱疏水性组分为6%～33%，表明中性亲水性组分对膜过滤通量的影响最大.3种膜中，CA膜对中性亲水性组分的截留率最高，达14.69%，但通量下降程度却最小，说明膜通量下降的程度并不与有机物截留总量正相关.对膜污染机制进行探讨后发现，对于截留分子量较大的超滤或微滤膜，相对分子质量>3×10⁴的中性亲水性组分通过堵塞膜孔内部,从而造成严重的膜污染；而对于截留分子量较小的超滤膜，中性亲水性组分由于无法进入膜孔，主要在膜表面形成滤饼层，从而对膜通量的影响较小.

Effect of Different Organic Fraction on Membrane Flux Declines

Organic matter in the tap water was isolated into strongly hydrophobic acids,weakly hydrophobic acids,charged hydrophilic and neutral hydrophilic by DAX-8,XAD-4 and IRA-958 synthetic resins.Filtration tests using polyvinylidene fluoride(PVDF),polyethersulphone(PES)and cellulose acetate(CA)membranes were conducted to investigate the contribution of different organic fractions to membrane fouling.The results show that in filtration of raw water,flux declines with PES,PVDF and CA membrane are 67%,59% and 19% o...