考察了膜孔径、膜孔隙率以及水中溶解性有机物(DOM)相对分子质量分布对二级出水超滤膜过程的影响。结果表明,膜孔孔径对膜污染特性有一定影响,孔径越大,则膜纯水通量越大,单位时间在膜表面和膜孔内形成污染的有机物也越多,膜污染也越严重,导致通量衰减幅度较大;对于膜孔径相近的膜来说,孔隙率大意味着水通量大,过滤过程对膜产生的污染也越严重,其通量衰减也就越快;二级出水中相对分子质量30×103~50×103和50×103~100×103的有机物对膜通量衰减起主导作用;浓差极化阻力所占比例较大,主要由水中相对分子质量〉30×103的有机物产生,滤饼阻力则主要由相对分子质量〉10×103的有机物产生,大分子有机物在膜面形成的污染层对小分子有机物有一定的截留和阻碍作用,使这部分有机物在膜孔内吸附和累积形成堵孔的几率降低,因此膜堵孔阻力所占比例较小。
The paper mainly studied the influence of the membrane pore,membrane porosity and the distribution of DOM relative molecular mass on ultrafiltration process of secondary effluent.The results showed that membrane pore size had certain effect on fouling characteristics,the greater and higher the density membrane pore was,the larger pure water flux of the ultrafiltration membrane was,and in unit time,the more fouling of organic matters on the membrane surface and in membrane pore were,as a result,the more serious ultrafiltration membrane fouling,which may result in flux decline to a larger extent.For the similar membrane pore,the greater porosity of the membrane,the bigger water flux would be.When the fouling of ultrafiltration membrane was more serious,the flux of ultrafiltration membrane would decline more quickly.The macromolecular organic matters in secondary effluent,in the 30×103~50×103 and 50×103~100×103 range,played an important role in flux decline of membrane;the resistance of concentration polarization took a large proportion,mostly generated by relative molecular mass 30×103 of organic matter,the resistance of filter cake was mostly generated by relative molecular mass 10×103 of organic matter.Because the fouling layer formed by macromolecular organic matters in the membrane surface had the interception and inhibition effect on the small molecular organic,this would decrease the chance of forming the membrane pores blockage by the above part of organic through the membrane pore adsorption and accumulation,so the membrane plugging pore resistance accounted for smaller proportion.