聚偏氟乙烯中空纤维疏水膜及其初步应用

Polyvinylidene Fluoride Hollow Fiber Hydrophobic Membrane and Its Application

使用聚偏氟乙烯中空纤维疏水膜,比较了三种膜蒸馏过程用于质量分数为3.5%的氯化钠溶液的脱盐效果。实验结果表明:真空膜蒸馏的通量最大,达到21.8 kg/(m^2·h),其次为直接接触式膜蒸馏,气扫式膜蒸馏的通量最小;三种膜蒸馏过程的脱盐率均在99.99%以上;膜蒸馏通量随膜内径增加略有增加,与膜壁厚呈反比。真空膜蒸馏法可用于反渗透浓水的进一步处理,当反渗透浓水浓缩4倍时,原水电导率从5 980 μS/cm 增加到22 800 μS/cm,膜蒸馏产水电导率保持在1.8～1.9 μS/cm 以内,脱盐率大于99.99%。

The three processes of vacuum membrane distillation （VMD）, sweeping gas membrane distillation （SGMD） and direct contact membrane distillation （DCMD） were compared using microporous hydrophobic polyvinylidene fluoride （PVDF） hollow fiber membrane as distillation membrane and NaCl solution with 3.5% of mass concentration as testing solution. The results show that： The flux of VMD process with 21.8 kg/（ m^2·h） is the highest, and that of SGMD is the lowest; The desalting efficiencies of the three processes are all over 99. 99%; The membrane distillation flux increases exiguously with the increasing of the hollow fiber inner diameter, and is inversely proportional to the membrane thickness. VMD process was used to process reverse osmosis （RO） drain, when RO drain is concentrated by 4 times, its conductance increases from 5 980 μS/cm to 22 800 μS/cm, and the conductance of VMD process product is 1.8 - 1.9 μS/cm, the desalting efficiency of VMD is over 99.99%.