聚合物含量对膜蒸馏用聚偏氟乙烯电纺纳米纤维膜的影响

Effect of Polymer Content on the Properties of PVDF Electro-spinning Nanofiber Membrane for Membrane Distillation

为考察聚合物含量对聚偏氟乙烯(PVDF)静电纺丝纳米纤维膜的结构和性能的影响,在二甲基甲酰胺与丙酮质量比为9:1的条件下,制备了无纺布支撑的PVDF静电纺丝纳米纤维膜,进行了聚合物PVDF含量对纺丝液基本性质与膜的形貌结构及分离性能的影响分析。结果表明,提高纺丝液中PVDF含量,纺丝液的表面张力与电导率降低,纳米纤维间珠粒数量减少,纤维直径增大。直接接触式膜蒸馏脱盐应用实验表明,PVDF的质量分数为12%条件下制备的疏水膜,在盐溶液与冷侧循环水温度分别为80℃与20℃时,其通量可达62.38 kg/(m^2·h),产水电导率为8μS/cm,盐截留率达到99.99%以上。

Polyvinylidene fluoride （PVDF） electro-spinning nanofiber membranes based on the support ofnonwoven fabric were prepared with mass ratio of N,N-dimethyl formamide （DMF） and acetone at 9：1, and the influence of polymer content on the structure and performance of the membranes were investigated. Effects of polymer content on the properties of spinning dope, the morphology and the characteristics of the resultant membranes were investigated in detail. It was found that the surface tension and the conductivity of the dope declined with the increase of PVDF content, the number of beads in the nanofibers reduced and the fiber diameter increased. In the direct contact membrane distillation test, the hydrophobie membrane was prepared under the condition of the mass fraction of PVDF being 12%. And its permeate flux could reach 62.38 kg/（m2·h） with the hot feed temperature and cold distillate temperature at 80 ℃ and 20 ℃, respectively, the permeate conductivity was as low as 8μS/cm, and the membrane salt rejection rate was more than 99.99%.