微量1,6-己二胺改性纳米Fe_3O_4对PVDF共混膜性能的影响

Effect of trace 1,6-hexanediamine-modified nano-Fe_3O_4 on physiochemical properties of PVDF composite membrane

以微量的改性纳米四氧化三铁与聚偏氟乙烯(PVDF)共混,制备具有良好亲水性、纯水通量和防污性能的PVDF复合膜。通过溶剂热法合成了经1,6-己二胺改性的纳米四氧化三铁(H-Fe_3O_4),同时比较了未经改性的四氧化三铁(Fe_3O_4)和改性后的四氧化三铁(H-Fe_3O_4)的结构性能差异。通过相转化法制备了H-Fe_3O_4(质量分数小于1.0%)与PVDF的共混复合膜(H-Fe_3O_4@PVDF复合膜)。通过测试膜的晶相组成、表面和断面形貌、静态纯水接触角、平均孔隙率、平均孔径、纯水通量、牛白蛋白截留率以及通量恢复率,研究微量H-Fe_3O_4的投加对复合膜性能的影响。结果表明,经1,6-己二胺调控合成的H-Fe_3O_4,比Fe_3O_4拥有更小的粒径、更好的单分散性以及更多的亲水官能团。向膜中添加0.3%的H-Fe_3O_4,可使复合膜的静态纯水接触角由80.9°降到66.6°,亲水性得到良好的改善。复合膜的平均孔隙率、平均孔径、纯水通量以及通量恢复率随H-Fe_3O_4投加量的增加均明显提高。当H-Fe_3O_4质量分数为0.4%时,复合膜的纯水通量从原膜的10.4 L·(m^2·h)^(-1)增加到了144.0 L·(m^2·h)^(-1),通量恢复率也从原膜的51.4%增加到了87.5%。微量H-Fe_3O_4的添加较好地改善了PVDF膜的性能,具有较好的实用价值。

A composite polyvinylidene fluoride(PVDF) membrane with good hydrophilicity, pure water flux and antifouling property was prepared by blending trace modified nano-Fe3O4(H-Fe3O4) with PVDF. This H-Fe3O4 was synthesized in the presence of 1,6-hexadiamine via solvothermal method. The structure and performance differences between H-Fe3O4 and Fe3O4 were compared. H-Fe3O4@PVDF composite membranes with different amounts of H-Fe3O4(mass fraction less than 1.0%) were prepared by phase inversion process. Meanwhile, the effect of H-Fe3O4 adding amounts on the physiochemical properties of the composite membrane was studied through determining the crystal structure, surface and cross-section morphology, static pure water contact angle,average porosity, mean pore size, pure water flux, bovine albumin rejection rate and flux recovery ratio. The results showed that H-Fe3O4 had smaller particle size, better monodispersity and more hydrophilic functional groups than Fe3O4. In comparison with pure PVDF membrane, this composite membrane modified with 0.3% of H-Fe3O4 reduced its static pure water contact angle from 80.9° to the lowest 66.6°, improving its hydrophilicity accordingly. The average porosity, mean pore size, pure water flux and flux recovery ratio of this composite membrane increased with the increase of H-Fe3O4 adding amounts. When 0.4% of H-Fe3O4 was incorporated, the pure water flux of this composite membrane increased from 10.4 L·(m2·h)-1 of pure PVDF membrane to 144.0 L·(m2·h)-1, and the flux recovery ratio also increased from 51.4% of pure PVDF membrane to 87.5%. The addition of trace H-Fe3O4(mass fraction less than 1.0%) could improve the performance of the composite membrane,which shows a good potential for practical use.