A new method for the regeneration of activated carbon

Abstract

[EN]Activated carbon is mainly used for the removal of gaseous contaminants, the treatment of waste water and the purification of drinking water. One of the advantages of the use of activated carbon is that it is able to eliminate highly toxic substances found at very low concentrations. The regeneration of activated carbon is essential for the economy of the whole process of contaminant retention. Current methods of regeneration can be classified under three headings: thermal, chemical and biological methods. The thermal method is the most used. Its disadvantages are the high temperatures required (800-1000{degrees}C) and the loss of carbon by oxidation (5-10%). This method has been used for the regeneration of activated carbon exhausted with phenolic compounds and trichloroethane. In the case of phenols, the adsorption capacity decreases rapidly with the number of regenerations. By contrast, in the study of trichloroethane a 10% decrease occurs in the adsorption capacity during the first regeneration but this is maintained during successive regenerations. In chemical regeneration, the porosity of the carbon and the solvent used are important factors. In general, the results obtained are worse than those achieved with thermal regeneration. Recently, extraction with supercritical fluids has been used. In the present work we propose a new method based on the use of water at high temperatures for the regeneration of activated carbon.