Enhanced water flux in vertically aligned carbon nanotube arrays and polyethersulfone composite membranes

We describe a novel preparation concept for a unique class of high-flux ultra-filtration membrane comprising a pre-aligned multi-walled carbon nanotube (MWCNT) array and polyethersulfone (PES). This membrane contains vertically aligned CNTs uniformly distributed inside a PES matrix. The vertically oriented water transportation pathway along the CNTs is verified to facilitate a dramatic enhancement in the water flux through the membrane. The water transportation speed increases about 3 times over the simply mixed CNT/PES membrane with random orientation and more than 10 times over the pure PES membrane under the same pressure load. Low working pressures as well as good retention properties enable this new composite membrane to be an ideal candidate for the future design of a highly efficient filtration membrane. This facile technique can potentially be applied to other filtration membrane systems to improve the separation efficiency.