Summary: LETTERS
610 nature materials | VOL 3 | SEPTEMBER 2004 | www.nature.com/naturematerials
O
ver the past decade of nanotube research1
,a variety of organized
nanotube architectures have been fabricated using chemical
vapour deposition2­5
. The idea of using nanotube structures in
separation technology has been proposed6­8
,but building macroscopic
structures that have controlled geometric shapes, density and
dimensions for specific applications still remains a challenge. Here we
reportthefabricationof freestandingmonolithicuniformmacroscopic
hollow cylinders having radially aligned carbon nanotube walls, with
diameters and lengths up to several centimetres. These cylindrical
membranes are used as filters to demonstrate their utility in two
important settings: the elimination of multiple components of heavy
hydrocarbons from petroleum--a crucial step in post-distillation of
crude oil--with a single-step filtering process, and the filtration
of bacterial contaminants such as Escherichia coli or the nanometre-

Source: Ajayan, Pulickel M. - Department of Mechanical Engineering and Materials Science, Rice University

Collections: Materials Science