Comparação de dois métodos para produção de carvão ativado a partir do pendão de sisal.

Abstract

On the assumption that each year increase the studies related to the fate of residues that are discarded because they have not, we seek this job perform two basic treatments in sisal tassel to produce coals enabled: the first, called "A", was produced from the carbonization of tassel sisal and then activated with NaOH, and the second type, produced from the carbonization of biomass pre-treated with NaOH as activating agent. Was used in treatments separately, a 22 factorial planning with three repetitions at center point, totaling seven experiments for each type of treatment. The produced adsorbents have been characterized as: water content, ash content, point of zero charge, mesoporosidade, percentage of methylene blue removed, microporosity, acidic and basic groups of Boehm and income. Biomass presented 9.84 1.17% ± extractives 25.82 ± 0.19 total% insoluble lignin, 64.20 ± 1.48% to holocelulose, 53.25% cellulose, 9.94 4.06 ± ± 0.04% water content and 1.4 ± 0.02% ash content. Being these characteristics of a good raw material for activated carbon production. The determination of the temperature range and time of operation was carried out by means of thermogravimetric analysis. It was possible to verify that materials presented results according to literature for coals enabled, i.e. low humid (1.79 to 6.92%), high adsorption of methylene blue (99.03 the 99.94%), presence of phenolic groups and absence of carboxylic groups and lactônicos, positively charged surface and satisfactory income (3.23 to 23.22%). It was verified that the coals enabled "B" presented best features of adsorbents when purchased the coals enabled "A". Among the kinetic models tested was the Pseudo-second order that best fit to the experimental data. The activation energy of the adsorption process was calculated and presented values of 106.20 kJ/mol for the activated charcoal 3A and 231.51 kJ/mol for the activated charcoal 2B, that presented a maximum adsorption 117.000, indicating a physical type interaction between methylene blue and molecules active sites of activated charcoal.