GO/TiO2纳米复合材料改性PVDF膜的制备及其抗污性能

Preparation and antifouling properties of GO/TiO2 nanocomposite modified PVDF film

摘要:

为改善聚偏氟乙烯(PVDF)膜的抗污性能,以GO/TiO₂纳米复合材料为添加剂,通过非溶剂诱导沉淀相分离法制备GO/TiO₂/PVDF复合超滤膜。采用FTIR、SEM和静态接触角分析仪对PVDF膜的结构和形貌进行表征,采用超滤法评价PVDF膜的水通量和抗污染性能。结果表明:当GO/TiO₂纳米复合材料的添加量为0.05wt.%时,GO/TiO₂/PVDF复合超滤膜表现出最佳的亲水性和抗污性能,膜的静态接触角比纯PVDF膜下降8.2o,孔隙率增加13.5%,GO/TiO₂纳米复合材料在PVDF膜中分布较均匀。在0.08MPa的过滤压力下,GO/TiO₂添加量为0.05wt.%时,GO/TiO₂/PVDF膜的纯水通量高达282.44 L/m₂^.h,对腐殖酸(HA)溶液的过滤通量为131.96 L/m₂^.h,水力清洗后的纯水通量为194.98 L/m₂^.h,分别为纯PVDF膜的2.1倍、1.5倍和1.8倍。此外,与纯PVDF膜比较,0.05wt.%GO/TiO₂/PVDF膜对HA的截留率增加8.6%,膜通量恢复率提高24.3%,总污染率下降39.2%,可逆污染率下降18.3%,不可逆污染率下降46.8%。因此,GO/TiO₂纳米复合材料显著提高了PVDF膜抗污性能,是一种有效的添加剂。

Abstract:

In order to improve the antifouling performance of polyvinylidene fluoride (PVDF) membrane, GO/TiO₂/PVDF composite ultrafiltration membrane was prepared by non solvent induced precipitation phase separation method with GO/TiO₂ nanocomposites as additives. The structure and morphology of PVDF membrane were characterized by FTIR, SEM and static contact angle analyzer. The water flux and anti pollution performance of PVDF membrane were evaluated by ultrafiltration method. The results show that when the addition amount of GO/TiO₂ nanocomposites is 0.05wt.%, compared with bare PVDF membrane, GO/TiO₂/PVDF composite ultrafiltration membrane showed the best hydrophilicity and antifouling performance. The static contact angle of the membrane decreased by 8.2 o, and the porosity increased by 13.5%. GO/TiO₂ nanocomposites were evenly distributed in PVDF membrane. Under the filtration pressure of 0.08MPa, when the addition of GO/TiO₂ is 0.05wt.%, the pure water flux of GO/TiO₂/PVDF membrane is as high as 282.44 L/m₂^.h, the filtration flux of humic acid (HA) solution is 131.96 L/m₂^.h, and the pure water flux after hydraulic cleaning is 194.98 L/m₂^.h, which is 2.1 times, 1.5 times and 1.8 times that of bare PVDF membrane respectively. In addition, compared with pure PVDF membrane, the interception rate of HA by 0.05 wt.% GO/TiO₂/PVDF membrane increased by 8.6%, the membrane flux recovery rate increased by 24.3%, the total pollution rate decreased by 39.2%, the reversible pollution rate decreased by 18.3%, and the irreversible pollution rate decreased by 46.8%. Therefore, GO/TiO₂ nanocomposites significantly improve the antifouling performance of PVDF films and are an effective additive.