Abstract:

A polyethersulfone (PES) ultrafiltration membrane modified with polydopamine (PDA) was deposited by different amounts of titanium dioxide (TiO₂) nanoparticles to fabricate support membranes with different morphology for graphene oxide (GO) composite membranes. The prepared GO membranes with and without TiO₂ were characterized by SEM, water contact angle analyses, Zeta potential and XRD. The results indicated that the TiO₂ clusters distributed on the surface of the PES membrane uniformly and showed an increased density with the increase of the deposited TiO₂ amount. The peak and valley structures on the surface of membranes could be seen even after GO deposition. The interlayer spacing of GO did not change obviously with the deposition of TiO₂ layer. The TiO₂/GO membranes showed enhanced water flux with the amount of deposited TiO₂. This increase in flux is more obvious when the GO deposition is low. When the amount of GO deposition was 4.11 μg/cm² and TiO₂ was 20.55 μg/cm², the water flux of the composite membrane was 108.38% higher than that without TiO₂. The rejection performance of the composite membrane for inorganic salt solutions is mainly based on the negatively charged Donan repulsion effect on the membrane surface. The rejection of Congo red of the prepared TiO₂/GO membranes was higher than 99%. The rejection of methyl orange was up to 82%. The addition of the TiO₂ intermediate layer did not reduce the rejection effect of the composite membrane.

Key words: titanium dioxide, graphene oxide, membrane, preparation, nanoparticles

摘要：

以聚醚砜(PES)超滤膜为基膜，通过聚多巴胺(PDA)表面改性后压力沉积不同量的二氧化钛(TiO₂)纳米粒子作为基底，再沉积氧化石墨烯(GO)片层制得TiO₂/GO复合分离膜，重点考察基膜表面形貌对GO膜分离性能的影响。通过扫描电子显微镜、接触角测试仪、固体表面Zeta电位分析仪、X射线衍射分析仪等对有无TiO₂沉积层的GO复合膜进行表征，并考察TiO₂沉积量对GO复合膜分离性能的影响。结果表明，TiO₂纳米粒子以团簇状态均匀分布在改性的超滤膜表面，随TiO₂沉积量的增加，团簇密度增大，GO沉积后表层的峰谷结构更为明显，但表层的层间距并无明显改变。TiO₂/GO复合膜的水通量随TiO₂沉积量的增加而明显增大，TiO₂的沉积对GO沉积量低的复合膜通量的影响更明显，当 GO沉积量为4.11 μg/cm²，TiO₂沉积量为20.55 μg/cm²时，复合膜的水通量较无TiO₂的复合膜提高了108.38%。复合膜对无机盐溶液的截留性能主要基于膜表面所带负电的道南排斥作用，TiO₂/GO复合膜对刚果红的截留率在99%以上，对甲基橙的截留率可达82%，TiO₂层的加入并未降低复合膜的截留效果。

关键词: 二氧化钛, 氧化石墨烯, 膜, 制备, 纳米粒子