In this work the surface of activated carbon was chemically modified in order to introduce O, S and N containing groups. The activated carbon surface was selectively oxidized with concentrated HNO 3 under controlled conditions. Characterization by thermogravimetric analyses, infrared spectroscopy and NaOH titration suggested the formation of mainly -COOH and small amounts of -OH groups, with concentration of approximately 4.10 21 groups/g of carbon. These -COOH functionalized carbons showed high adsorption capacity for metal cations in aqueous solution in the following order: Pb ]. These -COOH surf groups can be reacted with SOCl 2 to produce a surface acylchloride group, -COCl. This surface -COCl group proved to be a very reactive and versatile intermediate for the grafting of different S and N containing molecules onto the carbon surface, such as 1,2-ethaneditiol (EDT-, HSCH 2 CH 2 SH) 1,7-dimercapto-4-thioheptane (DMTH-HSCH 2 CH 2 CH 2 SCH 2 CH 2 CH 2 SH) or 1,2-ethylenediamine (EDA-NH 2 CH 2 CH 2 NH 2 ) and triethyltetraamine, TEA (H 2 NCH 2 CH 2 NHCH 2 CH 2 NHCH 2 CH 2 NH 2 ). The characterization of these materials was carried out by TG, IR and TPDMS (Temperature Programmed Decomposition Mass Spectrometry) experiments suggesting the formation of thioesther and amide surface groups, i.e. -COSR and -CONHR, with yields of approximately 50 and 75% for the reaction with DME and EDA, respectively. Preliminary adsorption experiments showed that these materials can efficiently remove metals such as Pb +2 , Cu +2 and Ni +2 from aqueous medium.

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