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SOLID-STATE 1H NMR STUDY OF ADSORPTION ON ACTIVATED CARBONThierry R. Lopes*, Ewerton B. Junior, Gustavo R. Gonalves, Miguel A. Schettino Jr., Francisco G. Emmerich, Jair C. C. Freitas.Laboratrio de Materiais Carbonosos e Cermicos, Depto Fsica /Universidade Federal do Esprito Santo

Porous carbon materials are used in many fields and applications due to its excellent adsorption properties of liquids and gases. These materials can be obtained in different ways using an organic precursor. The solid state 1H nuclear magnetic resonance (NMR) spectroscopy is a useful technique for studying the properties of molecules adsorbed in the pores of the material, because the spectral characteristics (such as chemical shift and line width) are generally different for free and adsorbed molecules [1,2]. Sample preparation consisted of impregnation of H3PO4 with endocarp of babassu coconut and then were heat-treated under N2 flow at temperatures of 400, 500, 600 and 700 C, obtaining a specific surface area of 1765, 1173, 1494 and 1749 m / g, respectively. The 1H NMR experiments were performed on a Varian/Agilent VNMR 400 MHz spectrometer. All measurements were conducted at room temperature with magic angle spinning (MAS) at a frequency of 14 kHz. There are two major peaks which have a variable displacement according to the activation temperature of each sample. The peaks with a larger line width are associated with the nuclei H groups attached to the aromatic carbons [3], while the other is attributed to the water adsorbed in the carbon pores. It is also possible to observe proton signal related to phosphorus. The reduction of observed chemical shift with increasing activation temperature is assigned to the chemical shielding. Referncias:1. Harris R. K.; Thompson T. V.; Forshaw P.; Foley N.; Thomas K. M.; Norman P. R.; Pottage C. Carbon. 1996, 34, 1275-1279.2. Forse A. C.; Griffin J. M.; Presser V.; Gogotsi Y. e Grey C. P. J. Phys. Chem. 2014, 14, 7508-7514.3. Jger A.; Schaumann G. E.; Bertmer M. Org. Geochem. 2011, 42, 917-925.CNPq; CAPES; FAPES; LMC/UFES; NCQP/UFES