Enhanced Water Flux In The Vertically Aligned Carbon Nanotube Array/Polymer Composite Membrane

Being the most commonly used membrane materials, polymers have many advantages,such as flexible, simple preparation, economical and easy processing. However, it is veryhard to achieve high separation efficiency and permeability at the same time. Pre-modifiedor unmodified carbon nanotubes were added into a polymer film as effective fillers toincrease the mechanical strength and increase water flux of the membrane. Theoreticalsimulation speculated the key to get the highest transfer rate when all the carbon nanotubeswere perpendicular to the membrane plane. Therefore, controlling the orientation of thecarbon nanotubes in the membrane was crucial to improve the flux and separationefficiency. However, the traditional method to prepare a mixture of carbonnanotube/polymer composite film was difficult to control the distribution and orientation ofcarbon tubes. It thus can not achieve an optimized filtration membrane structure.In this study we describe a novel preparation concept for a unique class of high-fluxultra-filtration membrane comprising a pre-aligned multi-walled carbon nanotube(MWCNT) array and a polymer（polyether sulfone or cellulose acetate）. This kind ofmembrane contains vertically aligned CNTs uniformly distributed inside a polymer matrix.The vertically oriented water transportation pathway along the CNTs is verified to facilitatea dramatic enhancement in the water flux through the membrane. Low working pressuresas well as good retention properties enable this new kind of composite membrane to be anideal candidate for the future design of high-efficient filtration membrane.