用于高浓度含油污水处理的亲水改性聚偏氟乙烯膜

Hydrophilic Modified Polyvinylidene Fluoride Membrane for High Concentration Oily Wastewater Separation

高浓度含油污水处理困难,而利用亲水性膜有望实现高效处理。利用臭氧活化接枝丙烯酸侧链的PVDF材料通过非溶剂致相转化法制备了亲水性超滤膜,并用于高浓度含油污水处理。结果表明,分离过程分为破乳阶段和筛分阶段。在破乳阶段,孔径无明显影响,亲水性强的膜具有较高的通量和截留率,并在进料侧产生较多的浮油,且进入筛分阶段较早。在筛分阶段,孔径越大的膜通量越高而截留率越低。这种亲水性超滤膜能将初始浓度为108 g/L的含油污水浓缩到390 g/L,截留85%的煤油,平均通量为114.5 L/(m^2·h)。

High concentration oily wastewater is difficult to treat. Hydrophilie membrane can be a hopeful solution for treating high concentration oily wastewater. Acrylic acid was grafted onto polyvinylidene fluoride （PVDF） materials by ozone induced graft polymerization, and hydrophilic ultrafiltration membranes were prepared using hydrophilic modified PVDF materials by non-solvent induced phase separation and used for high concentration oily wastewater separation. The results show that the oil/water separation process is a two-step process, including an initial de-emulsification stage and a later sieving stage. Better hydrophilicity leads to higher retention in the de- emulsification stage and higher flux, but show no apparent effect on retention in the sieving stage. On the other hand, pore size has no apparent effect on retention in the de-emulsification stage. However, in the sieving stage, larger pores lead to lower retention and higher flux. The membrane with the optimized parameters can concentrate the oil/water emulsion from 108 g/L to 390 g/L while keeping 85 % of total kerosene, and the average flux is 114.5 L/（m2.h）.