Singapore-MIT Alliance, National University of Singapore, 10 Kent Ridge Crescent, Singapore.
Environ Sci Technol. 2011 May 1;45(9):4003-9. doi: 10.1021/es200345q. Epub 2011 Apr 1.
This study aims to develop a positively charged nanofiltration (NF) hollow fiber membrane for effective removal of ciprofloxacin from water. A novel NF membrane was fabricated by hyperbranched polyethyleneimine (PEI) induced cross-linking on a polyamide-imide hollow fiber support. The spongy-like, fully porous membrane support provides minimal transport resistance and sufficient mechanical strengths for water permeation under high pressures. It is found that the PEI modification significantly influences NF performance through the mechanisms of size exclusion, charge repulsion, and solute-membrane affinity. Specifically, after PEI induced cross-linking, the membrane pore size is significantly reduced. The membrane surface becomes more hydrophilic and positively charged. As a result of these synergic effects, the rejection of ciprofloxacin is substantially enhanced. Furthermore, experimental results show that the molecular weight of PEI has tremendous effect on NF performance of the as-modified membrane. The NF membrane modified by a high molecular weight PEI_60K exhibits the highest rejection, the lowest fouling tendency, and keeps a constant flux over the whole pH range. This study may have great potential for developing high-performance antifouling NF hollow fiber membranes for various industrial applications.
本研究旨在开发一种带正电荷的纳滤（NF）中空纤维膜，以有效去除水中的环丙沙星。通过在聚酰胺-酰亚胺中空纤维支撑体上用超支化聚乙烯亚胺（PEI）诱导交联，制备了一种新型 NF 膜。海绵状的全多孔膜支撑体在高压下提供最小的传输阻力和足够的水渗透机械强度。研究发现，PEI 改性通过尺寸排除、电荷排斥和溶质-膜亲和力等机制显著影响 NF 性能。具体而言，PEI 诱导交联后，膜孔径明显减小。膜表面变得更加亲水和带正电。由于这些协同效应，环丙沙星的去除率大大提高。此外，实验结果表明，PEI 的分子量对改性膜的 NF 性能有巨大影响。用高分子量 PEI_60K 修饰的 NF 膜表现出最高的截留率、最低的污染倾向，并在整个 pH 范围内保持恒定的通量。这项研究对于开发用于各种工业应用的高性能抗污染 NF 中空纤维膜具有很大的潜力。
