PVDF超滤膜制备及在MBR处理洗涤废水中的应用

Preparation of PVDF Ultrafiltration Membrane and Its Application in MBR Treatment of Washing Wastewater

为验证实验室自制的聚偏氟乙烯(PVDF)超滤膜在实际洗涤废水中的处理效果,通过非溶剂致相分离(NIPS)制备了具有孔径小、孔径分布窄、亲水性好的PVDF超滤膜,将膜片组装成膜组件,作为膜生物反应器(MBR)的一部分,进行洗涤废水的中试试验。在抽吸泵开8 min停2 min、风机连续曝气、曝气体积流量为8.6 m^(3)/min、污泥浓度(MLSS)为8~10 g/L、运行通量恒定为20 L/(m^(2)·h)、水力停留时间为24 h的条件下,系统连续运行1 a,考察污泥浓度对跨膜压差(TMP)的影响,以及膜对化学需氧量(COD)、烷基苯磺酸钠(LAS)等污染物的去除效果。结果表明,在上述条件下,PVDF超滤膜适宜的污泥浓度为8~10 g/L,出水水质中COD浓度小于45 mg/L,LAS浓度小于3 mg/L,浊度小于1 NTU。其中COD去除率达到90%以上。膜经化学试剂清洗后,TMP恢复率达85%以上。

In order to verify the treatment effect of laboratory-made polyvinyldene fluoride(PVDF)membrane in actual washing wastewater,a PVDF ultrafiltration membrane with small pore diameter,narrow pore diameter distribution and good hydrophilicity was prepared through non-solvent phase separation(NIPS),and the membrane was assembled into membrane components and as part of membrane bioreactor(MBR)process was washing wastewater.Open the suction pump for 8 min and stop for 2 min,fan continuous aeration,aeration volume flow is 8.6 m^(3)/min,sludge concentration(MLSS)was 8-10 g/L,operation flux constanted 20 L/(m^(2)·h),the system operated continuously for 1 year to investigate the effect of sludge concentration on transmembrane pressure difference(TMP)and the removal effect of membrane on chemical oxygen demand(COD),sodium alkyl benzene sulfonate(LAS)and other indicators.The results show that under the above conditions,the suitable sludge concentration of PVDF ultrafiltration membrane is 8-10 g/L,COD concentration in effluent quality is less than 45 mg/L,LAS concentration less than 3 mg/L,and turbidity less than 1 NTU.Among them,COD is removed by more than 90%.After washing the membranes with chemical reagents,the TMP recovery rate reaches more than 85%.