Sun Wenbin, Xia Longbo, Luo Ping, Zou Dong
School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, China.
State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, China.
Membranes (Basel). 2024 Nov 15;14(11):241. doi: 10.3390/membranes14110241.
Polyvinylidene fluoride (PVDF) membranes are extensively utilized in membrane distillation (MD) for water treatment. However, traditional methods easily form asymmetrical membranes with dense skin layers that are detrimental to membrane flux. Herein, an eco-friendly PVDF membrane was fabricated by utilizing a delayed phase separation process without using any pore-forming agents. In addition, methyl-5-(dimethylamino)-2-methyl-5-oxopentanoate (PolarClean) was used as a green solvent without posing risks to humans and the environment. It was demonstrated that the PVDF concentration is crucial in influencing the microstructures and performance of the resulting membranes. As the PVDF concentration increased, the morphology changed significantly, resulting in a reduction of pore size. When feeding the device with NaCl solution at a concentration of 35 g/L, the MD water vapor flux reached 18.49 kg·m·h, while maintaining a salt rejection of over 99.97% during the continuous operation for 24 h. This work presented a method for producing green PVDF membranes via delayed phase inversion with satisfactory water vapor flux and salt rejection, highlighting their prospect for effective applications in MD for water treatment.
聚偏氟乙烯（PVDF）膜被广泛应用于膜蒸馏（MD）水处理过程中。然而，传统方法容易形成具有致密皮层的不对称膜，这对膜通量不利。在此，通过采用延迟相分离工艺制备了一种环保型PVDF膜，且未使用任何致孔剂。此外，5-（二甲基氨基）-2-甲基-5-氧代戊酸甲酯（PolarClean）被用作绿色溶剂，对人类和环境均无危害。结果表明，PVDF浓度对所得膜的微观结构和性能起着关键作用。随着PVDF浓度的增加，膜的形态发生显著变化，导致孔径减小。当向装置中进料浓度为35 g/L的NaCl溶液时，MD水蒸气通量达到18.49 kg·m⁻²·h⁻¹，并且在连续运行24 h期间盐截留率保持在99.97%以上。这项工作提出了一种通过延迟相转化制备绿色PVDF膜的方法，该膜具有令人满意的水蒸气通量和盐截留率，突出了其在MD水处理中有效应用的前景。
