整体非对称性PVDF中空纤维膜在真空膜蒸馏中的应用

Application of integrated asymmetric PVDF hollow fiber membrane for vacuum membrane distillation

采用乙醇与次氯酸钠溶液去除商品化聚偏氟乙烯（PVDF）中空纤维膜中的亲水性物质，从而恢复PVDF膜材料本征的疏水性，并将疏水膜应用于真空膜蒸馏（VMD）脱盐试验中。在进料温度为70℃，进料流量为120L／h，真空度为一90kPa的操作条件下考察了次氯酸钠溶液浓度，pH值，温度对PVDF中空纤维膜在真空膜蒸馏海水淡化中的处理效果。结果表明：次氯酸钠浓度为8000mg／L，pH为11，温度为45℃时，处理效果最优，并将最优条件下处理所得中空纤维膜应用在真空膜蒸馏稳定性实验中，在200h的运行过程中，通量稳定在5-6kg／m^2·h，同时脱盐率可稳定在99．9％。

Hydrophilic substances entrapped in the commercially available poly （vinylidene fluoride）（PVDF）hollow fiber membrane was removed by ethanol and sodium hypochlorite,and then the treated hydrophobic membrane was used in vacuum membrane distillation for desalination tests. The effects of sodium hypochlorite solution concentration, pH, temperature on the performances of the vacuum membrane distillation were investigated under the feed temperature 70℃, feed flow rate 120L/h and vacuum -90kPa. The results showed that the optimal sodium hypochlorite treatment was concentration 8000mg/L, pH l l,temperature 45 ℃. The VMD performances of the membrane was treated under the optimal conditions during long-term operation was studied. In the 200h operation process, the water permeating flux fluctuated between 5 and 6kg/m^2. h,and the desalting rate can be stable at 99.9%.