高性能MWCNTs-OH修饰聚偏氟乙烯中空纤维超滤膜的制备

The Fabrication of High Performance PVDF Hollow Fiber Ultrafiltration Membranes Modified by MWCNTs-OH

以羟基多壁碳纳米管(MWCNTs-OH)作为添加剂,采用非溶剂致相转化法制备MWCNTs-OH修饰聚偏氟乙烯中空纤维超滤膜.先将MWCNTs-OH加入溶剂N,N-二甲基乙酰胺(DMAC)中超声处理以加强其分散性,力求制得均一铸膜液.通过水通量、截留率、红外光谱,XRD及力学性能测试表征膜性能,并用SEM观察其形貌.重点考察MWCNTs-OH对中空纤维膜通量、截留和力学性能的影响.结果表明,当MWCNTs-OH质量分数从0增加到0.09 wt%时,修饰膜的水通量由376.40 L/m2h增加到510.90 L/m2h,而对BSA截留率保持稳定(95%以上);膜的拉伸强度由1.68 MPa提高到2.42 MPa,断裂伸长率由44.18%提高到76.93%.SEM和TEM研究表明,MWCNTs-OH添加量较少时,在膜中可均匀分散,添加量大时则容易团聚.XRD和IR图谱分析表明MWCNTs-OH参与聚合物结晶过程而未改变聚合物晶型.

With hydroxyl multi-walled carbon nanotubes（ MWCNTs-OH） as carbonous fillers the high performance PVDF hollow fiber ultrafiltration membranes modified by MWCNTs-OH were prepared by the nonsolvent induced phase inversion process. Adding MWCNTs-OH into N,N-dimethyl acetamide（ DMAC）solvent with ultrasonic treatment could strengthen their dispersion,and produce uniform casting membrane solution. The morphology and performances of modified membranes were characterized by scanning electron microscopy（ SEM）,Fourier transform infrared spectroscopy（ FTIR）,X-ray diffraction（ XRD）,dynamic contact angle（ DCA） and mechanical properties tests. The effects of MWCNTs-OH on the water flux and rejection as well as mechanical properties of the resulted hollow fiber membranes were investigated. The results showed that the water flux increased from 376. 4 L / m2 h to 510. 9 L / m2 h,while the rejection stabilized around95. 0% as the MWCNTs-OH loading increased from 0 to 0. 09 wt%. The tensile strength and elongation at break increased from 1. 68 to 2. 42 MPa and 44. 18% to 79. 18%,respectively. The SEM and TEM images indicated that MWCNTs-OH were easy to reunite in the matrix along with the increase of contents of MWCNTs over 0. 09 wt%,resulting in the decrease of the membrane tensile strength and water flux. The crystal form of the hollow fiber membranes changed little with the addition of MWCNTs-OH which was evidenced by the analysis of Fourier transform infrared（ FTIR） spectroscopy and X-ray diffraction.