Abstract:

FO membranes were constructed by interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC) directly in the porous spaces of polyester non-woven (NV) fabrics. The multi-layer three-dimensional (3-D) polyamide structure formed by the NVC-FO membrane inside the non-woven fabric was distributed inside the PET support material with a depth of 30~50μm. This relatively loose 3-D polyamide network not only had a large water-permeable surface area, but also avoided high salt leakage caused by thin-layer polyamide defects with a low reverse salt flux. Further research found that reducing the monomer concentration (1%~0.01% MPD, 0.5%~0.005% TMC) within a certain range can form a wider 3-D polyamide network structure, while maintaining a low reverse salt flux and a higher water flux. The optimized NVC-FO membrane water flux can reach a maximum of 193.54L/(m²·h), and the reverse salt flux was 0.047mol/(m²·h) by using 1mol/L NaCl as the draw solution. It was found from the pressured forward osmosis experiments that the salt penetrating rupture pressure of these high-throughput NVC-FO membranes was between 200~1400Pa, confirming that reducing the monomer concentration would cause a significant decrease in the pressure resistance performance of the membranes. Although the pressure resistance of NVC-FO membrane needed to be improved, this research may provide a new idea for the construction of FO membrane with high desalination performance.

Key words: forward osmosis, membrane, polyamide, none-woven, three-dimensional (3-D), desalination, permeation

摘要：

利用间苯二胺（MPD）和均苯三甲酰氯（TMC），直接在聚酯无纺布（NV）织物的多孔空间中进行界面聚合，形成大通量无纺布复合正渗透（NVC-FO）膜。NVC-FO膜在无纺布内部形成的多层次三维（3-D）聚酰胺结构，分布在30~50μm深的聚对苯二甲酸乙二醇酯支撑材料的内部。这种相对松散的有深度的3-D聚酰胺网络，不仅透水表面积大，而且可以避免薄层聚酰胺缺陷导致的高漏盐性，有较低的反向盐通量。进一步研究发现，在一定范围内降低单体质量分数（MPD 1%~0.01%，TMC 0.5%~0.005%），可以形成更宽广的3-D聚酰胺网络结构，在保持较低的反向盐通量的同时得到更高的水通量。使用1mol/L NaCl作为汲取溶液，优化的NVC-FO膜水通量最高可以达到193.54L/(m²·h)，反向盐通量为0.047mol/(m²·h)。采用加压正渗透实验，发现这些高通量NVC-FO膜的盐穿透破裂压力在200~1400Pa之间，而且证实了降低单体质量分数会导致膜的耐压性能显著降低。尽管NVC-FO膜的耐压性能有待提高，但是该研究有可能为构建高脱盐性能的FO膜提供一条新的思路。

关键词: 正渗透, 膜, 聚酰胺, 无纺布, 三维（3-D）, 脱盐, 渗透