Carbon nanotube membrane for water desalination

This is a review of carbon nanotube membranes with an emphasis on their water desalination applications. Particular attention is given to carbon nanotube preparation, types and properties. The concept of desalination in the context of carbon nanotubes is discussed. The different processes for the manufacture of carbon nanotube membranes are electric arc discharge, laser ablation and Chemical Vapour Deposition (CVD). Out of these, the CVD method is widely used because of its certain characteristics. Different types of carbon nanotubes, such as aligned carbon nanotubes, Multiwalled Carbon Nanotube (MWNT)/active carbon combination electrodes, MWNT/polysulfone (PS) blend membranes, carbonised hot-pressed carbon nanotube electrodes, aligned carbon nanotubes, alumina-supported carbon nanotubes and ceria nanoparticles-supported carbon nanotubes, are discussed with their application and performance. While the research in this area is in its infancy, it is growing at a considerable pace. The challenges to this technology are the reduction in capital cost, understanding of the exact mechanism for water transport, and scale-up. This technology has a potential to replace state-of-the-art desalination technology based on polymeric membranes or thermal desalination.