Macrocyclic pore-apertured carbon nanotube apparatus
A macrocyclic pore-apertured carbon nanotube apparatus is disclosed. The carbon nanotube apparatus can be used to filter or exclude ions, solutes in solution, as well as particles suspended in a colloidal mixture. The nanotube apparatus includes a carbon nanotube having a carboxylated portion at least one pore entrance and at least one molecular aperture adapted to be bonded to the carboxylated portion of the carbon nanotube. The molecular aperture is further adapted to prevent dissolved ions in a solution from entering the pore entrance. Methods for preparing and using the apparatus are also disclosed. The apparatus can also be incorporated into to filtration media for conducting reverse osmosis filtration.
1. A nanotube composition with at least one pore aperture adapted for filtering a solute in a solution, the nanotube composition comprising:
a single-walled carbon nanotube having a pore entrance at an end of the carbon nanotube and a carboxyl group on the pore entrance; and
a macrocyclic molecule bonded to the carboxyl group on the carbon nanotube, the macrocyclic molecule forming a ring having an inner van der Waals diameter of between 0.4 nm and 1.1 nm which forms a molecular aperture that is an aperture for the pore entrance, the macrocyclic molecule being arranged and configured to prevent ions from traversing the pore entrance, and the molecular aperture being sized and configured to allow passage of water molecules therethrough.
2. The nanotube composition of claim 1 , wherein the carbon nanotube is selected from the group consisting of chiral, armchair, and zigzag nanotubes.
3. The nanotube composition of claim 1 , wherein the carbon nanotube has an outer van der Waals diameter from 1.0 nm to 1.7 nm.
4. The nanotube composition of claim 1 wherein the carbon nanotube has a length between 200 nm and 1000 nm
5. The nanotube composition of claim 1 , wherein the macrocyclic molecule is a hydrocarbon-based ring.
6. The nanotube composition of claim 1 , wherein the macrocyclic molecule is selected from the group consisting of polyazacycloalkanes, polyoxacycloalkanes, polythiacycloalkanes, and combinations thereof.
7. The nanotube composition of claim 1 , wherein the macrocyclic molecule includes benzene rings.
8. The nanotube composition of claim 1 , wherein the macrocyclic molecule does not include benzene rings.
9. The nanotube composition of claim 1 , wherein the molecular aperture forms an inner diameter of the macrocyclic molecule ranging between 0.3 nm and 0.6 nm.
10. The nanotube composition of claim 1 , wherein the aperture is structured and arranged to exclude the following ions: Na + , K + , Ca + , Mg + , Cl − , SO 4 2− .