Decrease Size Increase Size Print PDF

Already a Chemical Engineering gold or platinum member? You must be logged in to view this page. LOGIN Forgot your username/password? Log In Not yet a member? Register for Membership Access Contact Sarah Garwood, Audience Development Director, for site license, single and group subscription questions.

Carbon nanotube membranes are being developed for water desalination and carbon dioxide sequestration by Porifera Inc. (Hayward, Calif.; www.poriferanano.com) under an exclusive license from Lawrence Livermore National Laboratory (LLNL, Livermore, Calif.). Porifera, a new company, expects to commercialize desalination membranes within two years. Laboratory tests indicate that the membranes will have “something like 10 to 100 times the flux of polymeric reverse osmosis (RO) membranes, due to a nanofluidic effect unique to carbon nanotubes,” says Olgica Bakajin, Porifera’s chief technology officer and a former team leader at LLNL. She adds that the membranes will enable an energy reduction of up to 70% in desalination, compared to the use of conventional RO membranes. The nanotubes are produced by chemical vapor deposition from ethylene or other carbon-bearing gases at 800–850°C, under low or atmospheric pressure. The carbon deposits onto multiple iron-based nanoparticle catalysts, forming an integrated miniature forest of nanotubes. The dimensions of the tubes can be precisely controlled, says Bakajin. The diameters can be controlled within a range of 1–10 nm. The height or length of the tubes, which…