Membranes Assembled from Narrow Carbon Nanotubes Block Proton Transport and Can Form Effective Nano-Filtration Devices

The use of carbon nanotubes in various filtration devices is a promising current direction in nano-technology. The direction of progress is, however, far from obvious when it involves devices that can allow water to be transferred while blocking proton transport. This problem is addressed in the present paper by exploiting the perspective that emerge from our recent studies of the mechanism of proton blockage in aquaporins. The paper focuses on a computational study of the free energy barriers for transfer of proton and water molecules through the membrane assembled from the double wall (5;5)@(10;10) armchair carbon nanotubes. It shows that such system can be used as a water nano filter that allows water transfer while blocking protons. Thus such carbon nanotube membrane will work as an artificial analog of aquaporin water channel. The general mechanisms of proton transfer/blockage in biological and artificial nanosystems are also discussed.