Removal of hexavalent chromium and metal cations by a selective and novel carbon adsorbent Original Research Article

Carbon produced by the contact arc method (whereby graphite electrodes are arced in an inert atmosphere) was employed for the removal of hexavalent and trivalent chromium ions as well as other metal cations from aqueous solutions. It is known that hexavalent chromium is present as an anionic species in the solution. The carbon adsorbent used in this study selectively removed the anions of hexavalent chromium from the solution, whereas, depending upon the solution pH, no or very small uptake of metal cations was observed. On the other hand, commercial activated carbon showed great affinity for cations of lead, zinc, and trivalent chromium but none for the anion of hexavalent chromium.