论文部分内容阅读
探讨了3种不同预处理技术对延缓超滤膜污染的作用.试验表明,前臭氧+在线混凝+超滤(工艺1)、前臭氧+超滤(工艺2)、前臭氧+预氯化+超滤(工艺3)3种工艺超滤膜过滤的临界通量分别为86.5,59.8,68.1L·(m2·h)-1.其中工艺1临界通量最大,且其稳定运行的时间最长(约190h),能够在一定程度上控制膜污染,这主要是因为水中的有机污染物质通过“矾花”被吸附到胶体类颗粒物上,通过膜筛分截留,减缓了有机污染物质与膜表面的接触与相互作用.控制、缓解膜污染方面,工艺3效果最好,其原因是在NaClO作用下有机物分子特征改变,一方面降低膜的通量负荷,改变其亲疏水性,另一方面NaClO使得滤饼层的电负性增大,过滤截留物和溶解性有机物较易在水力冲洗中被冲掉,跨膜压差得到很好恢复.通过扫描电镜发现,超滤膜表面附着一层滤饼层,滤饼层较疏松,而膜孔已被污染物堵塞;红外光谱研究发现,超滤膜经过氧化预处理和化学清洗,膜表面的某些基团被氧化,膜表面特性被改变.
The effects of three kinds of pretreatment technologies on delaying the ultrafiltration membrane pollution were discussed.The results showed that the former ozone + on-line coagulation + ultrafiltration (process 1), pre-ozone + ultrafiltration (process 2) + Ultrafiltration (process 3) The critical fluxes of the three kinds of process ultrafiltration membranes were 86.5, 59.8 and 68.1 L · (m2 · h) -1, respectively, of which the critical flux of process 1 was the largest and the stable operation time Long (about 190h) can control membrane fouling to a certain extent. This is mainly because organic pollutants in water are adsorbed to colloidal particles through “alum flower”, and they are trapped by membrane sieving to slow down the organic pollutants And membrane surface contact and interaction.Control and mitigation of membrane pollution, the best effect of the process 3, the reason is that under the action of NaClO molecular characteristics of organic matter changes, on the one hand to reduce the membrane flux load, to change its hydrophilicity and hydrophobicity, the other In the aspect of NaClO, the electronegativity of the filter cake layer is increased, the filter retentate and the dissolved organic matter are easily washed away in the hydraulic washing, and the transmembrane pressure difference is well recovered. The scanning electron microscope shows that the surface of the ultrafiltration membrane adheres Layer filter cake layer, cake layer is more loose, and membrane pores have been blocked by pollutants; Infrared spectroscopy It was found that the ultrafiltration membrane was oxidized pretreatment and chemical cleaning, the membrane surface of some groups are oxidized, the membrane surface properties are changed.