Sorption and desorption of lithium ions from activated carbons

The influence of surface functional groups on activated carbons on the adsorption and desorption of lithium ions, present in trace amounts in aqueous solution, has been studied in the absence and presence of an applied electric field. Application of an electric current during the experiments dramatically increased the sorption of the ions. Moreover, lithium could be released into the solution by reversing the current, showing the reversibility of this process. In its absence, a significant enhancement in the lithium sorption uptake was found when phosphoric acid, trapped in the carbon pores was eliminated. To understand the differences induced by the chemical and electrochemical treatments of the materials, pore volumes and surface acidity were characterized. Copyright (C) 1996 Elsevier Science Ltd