Carbon nanotube filters

The fabrication of freestanding monolithic uniform macroscopic hollow cylinders having radially aligned carbon nanotube walls is discussed. The cylindrical membranes are used as filters in the elimination of multiple components of heavy hydrocarbons from petroleum and in the filtration of bacterial contaminants such as Escherichia coli or the poliovirus from water. The microfilters can be cleaned for repeated filtration using ultrasonication and autoclaving. Some specific properties such as thermal and mechanical stability along with cost-effective fabrication of nanotube-membrane allow them to competete strongly with ceramics and polymer based separation membranes.