Titanium dioxide (TiO2) nanoparticles exhibit many merits,like hydrophilic,non-toxic,photocatalytic active,cost effective,etc,so they are widely used in polyvinylidene fluoride (PVDF) membrane modification.Actually,a large proportion of TiO2 nanopartices were imbedded in the macroporous support layer of the PVDF-TiO2 membrane and they cannot fully played their role on enhancing the hydrophilcity and anti-pollution performance of the PVDF-TiO2 membrane.In this paper,PVDF -TiO2 with different TiO2 modified layer thichkness have been prepared through stepwise knifing.Experiments have revealed that the TiO2 dosage of the M50 membrane only accounts for 20％ of the regular PVDF-TiO2 modified membrane M250 while its pure water flux achieved 90％ of the regular PVDF-TiO2 modified membrane.The flux recovery rate (FRR) of the M50 after filtering BSA solution and mimetic sewage reached at 99％ and 100％ of the M250 respectively.A novel strategy to further decrease the cost of PVDF modified membranes is provided.%TiO2纳米颗粒具有亲水、无毒、光催化活性和廉价易得等优点,在PVDF改性膜制备方面应用广泛.通过常规共混法制备的PVDF-TiO2改性膜,大部分TiO2颗粒被掺杂于较厚的大孔支撑层中,未充分发挥作用.通过分层刮膜的方式,控制含有TiO2纳米颗粒的铸膜液的刮制厚度,制备了TiO2改性层厚度不同的PVDF-TiO2改性膜.实验发现,采用分层刮膜方式制备的M50改性膜中TiO2添加量仅为常规PVDF-TiO2改性膜(M250)的20％,但其纯水通量可以达到M250膜的90％.过滤BSA溶液和模拟生活污水并经过用纯水简单清洗后,M50膜通量恢复率(FRR)分别达到M250膜的99％和100％.提供了一种进一步提高PVDF改性膜经济性的新思路.
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