Nanoarchitecturing of carbon nanospheres onto the surface of activated carbon (AC) gives birth to a new composite carbon material that features a hierarchical structure with macro- and nanometer dimensions of the respective carbon components and exhibits a remarkably enhanced adsorption capability for heavy-metal ions (CrO42- and Fe3+) from aqueous solution as compared 4 to AC. Thus, we first propose that nanoarchitecturing of AC can be utilized not only as a flexible method for the synthesis of novel, hybrid, nanostructured composite carbon materials but also as a new and "green-route" strategy for functionalization of the surface of AC in an effective manner. Hence, there is scope for a possible new concept. in the functionalization of industrial AC for specific applications.