The adsorption characteristics of coal fly ash have been enhanced by mechano-chemical activation with a high energy mono-planetary ball mill. The best performing sample for the adsorption of phenol from aqueous solution (i.e., fly ash with the higher carbon content and mechano-chemically activated for 4 h in N-2 atmosphere) was compared with powdered activated carbon, yielding quite encouraging results such as favorable adsorption isotherms, improved specific adsorption capacity and very fast adsorption rate. This provides new opportunities for utilizing fly ash in environmental protection applications like the stabilization/solidification treatment of hazardous waste and contaminated soil. (C) 2009 Published by Elsevier B.V.