Introduction of ion-exchange moieties to reticulated vitreous carbon by direct chemical modification

Reticulated vitreous carbon (RVC) disks were successfully modified by covalent attachment of functional groups capable of metal ion exchange. Modification was accomplished through a three-step procedure. Oxidation of the RVC material with a mixture of H2SO4 and HNO3 significantly increased the number of carboxylic acid groups on the surface. These were converted to the acid chloride using oxalyl chloride and the ion-exchange moieties were attached through amide formation. Metal-ion uptake was determined by subjecting the modified electrodes to solutions of four different metal cations. Inductively coupled plasma spectroscopy was employed to determine the metal ion concentration both before and after introduction of the modified RVC material. Uptake ranged from 20% to 99%, depending on the ion-exchange moiety and metal cation. Electrochemical analysis revealed that the modified RVC is no longer suitable for use as an electrode.