Carvão ativado da casca da castanha-do-brasil (Bertholletia excelsa) : produção, caracterização e adsorção de 2,4 - diclorofenóxiacético

Abstract

The activated carbon is an adsorbent characteristics material because of its large surface area and high porosity. Its production is performed from carbonaceous materials with high lignin and celulose content. The Brazil-nut shell is a material that can advantage the production of a quality activated carbon with low-cost. In addition, the processing of the nut generates a large quantity of this residue, necessitating an adequate final destination. The aim was to produce and activate the charcoal of Brazil-nut shell at the temperatures of 600, 700 and 800 °C by the physical method using water vapor or CO2. Tests of water content, volatile materials, ashes, density and pH, besides the calculation of yield and fixed carbon were realized. The identification of possible functional groups present on the surface of the activated carbon through infrared spectroscopy and the adsorption isotherms of BET were obtained from the coals produced at 600, 700 and 800 ° C. The yield of the activated carbon was similar, regardless of the activation method. The fixed carbon contents remained between 79 and 84% for the samples produced at the three temperatures and with both atmosphere, steam and CO2, respectively. The pH was higher than 7, the activated carbons classified as basic and with density 0.25 ± 0.03 g/cm3 . The largest surface areas were observed in the activated carbons obtained at 800 ° C of each activation. 19 These results indicate that the activated carbon produced at 800 °C and activatd with water vapor for the purpose of adsorbing acidic substances may be the most advantageous for the industry.