FUNCTIONALIZATION OF ACTIVATED CARBON BRIQUETTES Luiz C. M. Costa 1 , Karim Sapag 2 , Mariana Garcia 1 , Maria Helena Araujo 1 , Rochel Montero Lago 1 , Fabiana Sardella 3 , Hugo Silva 3 , Cristina Deiana 3 * 1 Departamento de Quimica – ICEx – UFMG – Belo Horizonte – Brasil – 31270-901 2 Lab. Ciencias Sup. Medios Porosos – Dep. Fisica - UNSL – San Luis – Argentina 3 Inst.Eng.Quimica – Fac. Engenharia - UNSJ – San Juan - Argentina Corresponding author e-mail address:cdeiana@unsj.ar Introduction The surface chemistry of activated carbons has been extensively studied due to its importance for many applications [1]. Carbon functionalization with oxygen, nitrogen and sulfur groups has been widely investigated [2, 3]. Surface oxygen containing groups such as carboxylic, phenolic, lactone, ether, pyrone, chromene, are by far the most important being responsible for several properties of carbons such as hydrophilicity, acidic, redox and catalytic. In this work, it was studied the functionalization of briquettes by two simple reactions, i.e. the oxidation with HNO 3 and the sulfonation with H 2 SO 4 /SO 3 . Functionalized activated carbon briquettes may present several technological applications, for example in the adsorption of especial molecules or metallic ions. Hereon it is investigated whether these classical reagents HNO 3 and H 2 SO 4 /SO 3 are capable of functionalizing the carbon located in the most internal part of the briquettes. Experimental The briquettes (1 g, 10 mm diameter x 13 mm length) have been prepared from chars obtained from two different precursors, eucalyptus and poplar trees, using concentrate grape must as binder (binder:char ratio of 1:4) in a mold held in a hydraulic press at 1400 kg cm -2 . The briquettes were thermally treated at 15 K/min up to 1153 K under N 2 flow, and activated with steam (1.7 g H2O g carbon -1 h -1 ) for 105 min in a stainless steel reactor. Detailed characterization of these briquettes have been published elsewhere [4]. The oxidation with concentrated HNO 3 was carried out under reflux for 15 and 60 min. After reaction the carbons were extensively washed with water until the pH rinsing water was neutral. The sulfonation reaction used fuming sulfuric acid for 1 h at 298 and 353 K. The obtained materials were dried in oven at 333 K for 24 h. The number of acid sites was determined by acid-base titration according to the literature [5]. The obtained briquettes were separated using a blade into three layers: outer, middle and inner layer, all with same weight. The obtained materials were analyzed by TG (Metler, 10 K/min, N 2 ), BET (Quantachrome Autosorb 1, 77K, N 2 ), IR (Perkin Elmer).