Surface modified carbon felts were utilized as an electrode for the removal of inorganic ions
from seawater. The surfaces of the carbon felts were chemically modified by alkaline and
acidic solutions, respectively. The potassium hydroxide (KOH) modified carbon felt exhibited
high Brunauer-Emmett-Teller (BET) surface areas and large pore volume, and oxygencontaining
functional groups were increased during KOH chemical modification. However,
the BET surface area significantly decreased by nitric acid (HNO3) chemical modification
due to severe chemical dissolution of the pore structure. The capability of electrosorption by
an electrical double-layer and the efficiency of capacitive deionization (CDI) thus showed
the greatest enhancement by chemical KOH modification due to the appropriate increase of
carboxyl and hydroxyl functional groups and the enlargement of the specific surface area.