纳米ZnO改性PVDF超滤膜的性能

 为改善聚偏氟乙烯(PVDF)超滤膜的亲水性,增强其在水处理中的应用能力,采用相转化法制备了纳米ZnO 改性PVDF超滤膜。分析了纳米ZnO 的添加量对膜结构及性能的影响。通过孔隙率测定、接触角测量、扫描电子显微镜、原子力显微镜、材料试验、超滤实验分别对膜的孔隙率、亲水性、微观结构、机械强度、纯水通量、蛋白截留率及水通量恢复率进行表征。结果表明,纳米ZnO 的质量分数为0.2%时,膜的接触角从改性前的76.3°降至63.4°,亲水性得到明显改善;孔隙率由53.4%升至54.1%;拉伸强度由2.09 MPa 升至2.82 MPa;纯水通量、蛋白截留率及水通量恢复率均有一定程度的提高;膜的断面结构规整,指状孔的尺寸较大,膜表面较光滑。

Study on the performance of PVDF ultrafiltration membrane modified by nano-ZnO

Polyvinylidene fluoride (PVDF) ultrafiltration membranes modified by nano-ZnO are prepared by phase inversion method to improve their hydrophilicity and enhance application in water treatment. The effects of nano-ZnO amount on the structure and performances of the membranes are investigated. The porosity, hydrophilicity, microstructure, mechanical strength, pure water flux, protein rejection and flux recovery efficiency are characterized by porosity measurement, contact angle measurement, scanning electron microscopy (SEM), atomic force microscopy (AFM), mechanical property test and ultrafiltration experiments, respectively. The results show the following. When the mass fraction of nano-ZnO is 0.2%, the contact angle of the membrane is decreased from 76.3° to 63.4°, indicating a significant hydrophilic improvement. The porosity increases from 53.4% to 54.1% and the tensile strength increases from 2.09 MPa to 2.82 MPa. Pure water flux, protein rejection and flux recovery efficiency are improved to a certain degree. The cross-section structure of the membrane is regular, the size of finger-like hole is large and the surface of the membrane is smooth.