Patent ID: 7625426

Claim:
A method for making a nano-scale filter, comprising: providing a plurality of carbon nanotubes, said carbon nanotubes comprising a plurality of multi-junction carbon nanotubes, said multi-junction carbon nanotubes being selected from the group consisting of two-dimensional junction carbon nanotubes, three-dimensional junction carbon nanotubes and an admixture thereof, a diameter of each of said carbon nanotubes being in the range of about 15˜100 nanometers; oxidizing said carbon nanotubes; dispersing said carbon nanotubes into a liquid medium to form a suspension; filtering said suspension by a filtration film; firing said filtration film with said carbon nanotubes thereon at a temperature of about 20° C.˜100° C. in a vacuum for about 1˜3 hours, whereby some or all of said carbon nanotubes form bands with at least one corresponding adjacent carbon nanotube thereby forming a carbon nanotube filtration membrane with a plurality of nano-scale pores therebetween; and removing said carbon nanotube filtration membrane from said filtration film, and attaching said carbon nanotube filtration membrane onto a porous supporting component to provide said nano-scale filter.