Electrospun nanofiber membrane for membrane adsorption, membrane contactor and fouling mitigation in ultrafiltration

纳米尺度的材料可以通过合理的设计展现出新颖的、显著的改进 物理和化学性质。聚合物纳米纤维作为一类重要的纳米材料，在过去的十年中受到越来越多的关注。 特别地，电纺生物膜（ENM）已经被证明可应用于用于水处理的各种膜工艺，例如MF、UF、NF、MD、FO、PRO、膜吸收和实验室规模的膜空气汽提。拟议项目旨在进一步扩大ENM作为水和气体处理过滤膜的适用范围。 目前，ENM水处理即将实现商业化。有些公司的目标是将生物膜用于水处理（例如，Xanofi，2010年在美国NC成立）。该项目将通过展示ENMs的各种新应用，为ENMs的未来商业化做出贡献。 因此，本研究的目标是： 第一章 制备并测试了掺杂金属氧化物纳米粒子的电纺复合膜（以下简称MMENMs）对水中砷的吸附性能 （二） 制备和测试用于从CO2/N2气体混合物中捕获CO2的膜接触器（MC）中的ENM 第三章 制造平行排列的ENM，用于超滤应用中的污垢减轻和洗涤增强 在过去的几十年里，天然水中的砷污染已经引起了重大的环境和公众健康问题，因为它的高毒性，在人体内积累和致癌性。近年来，亲和膜的发展为低压脱砷提供了一种有效的方法。鉴于非常高的孔隙率和互连性，当ENM用于MA时，预期其通量高得多。 膜接触器（MC）是气体和液体在多孔膜的相对侧上流动的过程;气体组分通过膜孔从气相扩散到液相，其中气体被液体中的吸收剂吸收。其应用之一是从天然气和烟道气中去除CO2。膜接触器可以提供比常规分离柱高4至30倍的每单位体积的接触面积。由于其高孔隙率和疏水性，ENM是用于MC的膜的优良候选者。 最近在开发金属氧化物掺入的聚合物膜期间进行了观察;即聚合物结节平行排列，并且通过原子力显微镜（AFM）在膜表面观察到非常清晰的图案。 还发现，当进料流垂直于图案线定向时，膜污染可以显著减少，而当进料流平行于图案线定向时，膜洗涤是有效的。ENM中纳米纤维的平行排列将在膜表面提供完美的图案，从而增强上述效果。

Nano-scale materials can be rationally designed to exhibit novel and significantly improved physical and chemical properties. Polymer nanofibers, an important class of nano-materials, have attracted increasing attention during the past decade. In particular, electro-spun nanofiber membranes (ENMs) have already been proven to be applicable in a variety of membrane processes for water treatment, such as MF, UF, NF, MD, FO, PRO, membrane absorption and membrane air stripping in the laboratory scale. The proposed project aims to widen the scope of the applicability of ENMs as filtration membrane for water and gas treatment even further. Water treatment by ENMs is now on the verge of commercialization. There are companies who are aiming at the commercialization of nanofiber membranes for water treatment (e.g. Xanofi, founded in 2010 in NC, USA). The proposed project will contribute to the future commercialization of ENMs by demonstrating a variety of novel applications of ENMs. Thus, the objectives of this research are: 1) To fabricate and test the metal oxide nanoparticles incorporated electro-spun nanofiber membranes (ENMs) (hereafter called Mixed Matrix ENMs (MMENMs)) for the removal of arsenics from water by membrane adsorption (MA) 2) To fabricate and test ENMs in membrane contactor (MC) application for capturing CO2 from CO2/N2 gas mixtures 3) To fabricate ENMs aligned parallel for fouling mitigation and washing enhancement in ultrafiltration applications In the last few decades, arsenic contamination in natural water has raised significant environmental and public health concerns because of its high toxicity, accumulation in human body and carcinogenicity. Recently, the development of affinity membrane provided an effective method for arsenic removal under low pressure. In view of very high porosity and interconnectivity, a much higher flux is expected by ENMs when they are used in MA. Membrane contactor (MC) is a process in which gas and liquid flow on the opposite sides of a porous membrane; a gaseous component diffuses through the membrane pore from the gas to liquid phase where the gas is absorbed by the absorbent in the liquid. One of its applications is CO2 removal from natural and flue gas. Membrane contactor can provide contact area per unit volume 4 to 30 times higher than the conventional separation columns. ENM is an excellent candidate for membranes for MC for its high porosity and hydrophobicity. An observation was made recently during the development of metal oxide incorporated polymeric membranes; i.e. polymer nodules were aligned parallel, and very clear patterns were observed by the Atomic Force Microscopy (AFM) at the membrane surface. It was also found that the membrane fouling could be reduced substantially when the feed flow was oriented perpendicular to the patterned lines, while membrane washing was effective when the feed flow was oriented parallel to the patterned lines. Parallel alignment of nanofibers in ENM will provide a perfect pattern at the membrane surface and thus enhance the above effects.