Desalination Performance of Modified Multiwall Carbon Nanotubes

Abstract

Modified multiwall carbon nanotubes (MWCNTs) were used as the electrodes of flow–through capacitor for the desalination, which were cost–cutting, energy–saving, and enviromnent–friendly and could be expected to be an altemative technology for reverse osmosis membrane for sea water desalination. Investigated by transmission electron microscope (TEM) and nitrogen adsorption/desorption for modified MWCNTs, it was confirmed that after modification treatment by immersion in diluted HNO₃ solution with ultrasonic and then milling by ball at a high velocity, the metal catalyst particles at the tip of MWCNTs disappeared, the MWCNT length became short, the cap at the tip of nanotube was opened, the internal surface area could be effectively used, leading to the increase of the specific surface area and pore volume, and thus MWCNTs modified by that method had the best desalination performance. This modification technique is simple and the efficiency is high.