UtilizaÃÃo da serragem de Eucalyptus sp. na preparaÃÃo de carvÃes ativados / Utilization of sawdust of Eucalyptus sp. for activated carbons preparation

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The aim of this study was to use the eucalyptus sawdust, waste timber industry, in the preparation of activated carbons (AC) and test them as adsorbents of organic compounds and metal ions. Initially, the Eucalyptus sp sawdust was characterized by chemical analysis like cellulose, lignin, hemicelluloses, ash and extractives content as well as some instrumental analysis like elementary analysis (CHNS-O), thermogravimetric analysis (TGA) infrared spectroscopy (FTIR) and scanning eletronic microscopy (SEM). The activated carbons were prepared by physical activation with carbon dioxide (AC_CO2) and by chemical activation with potassium carbonate (AC_K2CO3). The materials were characterized by CHNS-O, TGA, FTIR, XRD, adsorption/desorption for calculate the BET surface area and SEM. The resulting activated carbons were also tested for their ability of adsorption of contaminants in water and methylene blue (MB), phenol and Cr+6. During the carbonization of AC_CO2, the effluent from the pyrolysis of sawdust (bio-oil) was collected and characterized by gas chromatography-mass spectrometry (GC-MS) and FTIR. After pyrolysis and activation of charcoal, the analysis of CHNS-O showed an increase in carbon content and decrease in levels of oxygen and hydrogen. In the analysis of TGA, we observed higher thermal stability of activated carbons in relation to the sawdust. The FTIR analysis confirmed the carbonization of the materials. The X-ray diffraction showed typical amorphous materials. The ACs produced in this work are predominantly microporosus and AC_K2CO3 showed higher surface area than AC_CO2. The micrographs obtained showed that the activated carbons had higher pore volume than the sawdust. The AC_K2CO3 was more effective in adsorption of phenol and MB compared to AC_CO2. The adsorption of Cr+6 was not effective for any of the activated carbons produced. The analysis of bio-oil by FTIR shows the presence of a range oxygenated compounds, confirmed by analysis of GC-MS.

ASSUNTO(S)

contaminantes actived carbon adsorÃÃo carvÃo ativado tecnologia e utilizacao de produtos florestais residues resÃduo adsorption contaminants

ACESSO AO ARTIGO

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