Purificação de efluentes contaminados com hidrocarbonetos por adsorção em leito fixo de biomassa.

Abstract

In this work the biomasses, cane pulp and coconut mesocarp were used as hexane, heptane and isooctane adsorbents, polluting hydrocarbons, presents in several effluents. Initially it was made the characterization of the biomasses and soon after, kinetic evaluations were accomplished and of balance for the hydrocarbons front to the specified biomasses, which were shown efficient in the retention of the same ones. For the kinetic curves, experiments were accomplished with reason volume of hydrocarbon per gram of biomass equal to 10, with initial concentration equal to 23,1% maintained under constant agitation for a previous time that varied from 5 to 60 minutes. The kinetic curves showed a fast kinetics, in which the influence of the adsorption of the water was observed contained in the dispersion by the biomasses. The kinetic curves were adjusted by a model diffusional presenting a good adjustment. The isotherms of adsorption were obtained to 25 0C, using several combinations of concentrations of the hydrocarbons and being varied the global initial concentration from 5 to 50%. All the curves showed a behavior of avorable Langmuir isotherms, being adjusted for the model of Langmuir Isotherm. For the experiments in fixed bed, it was made an experimental planning 23 with two experiments in the central point. Through the experimental planning it can be observed that the concentrations of the hydrocarbons exercise influence in the time of operation of the bed capable to retain 100% (curves of rupture), 80% and 70% of the hydrocarbons. Besides the individual effect, there are the effects also caused by the interactions among the hydrocarbons, the ones which are also significant, according to the statistical model. They were obtained rupture curves, through the ones which, for gaseous chromatography, it was possible to calculate the amount adsorbed of each one of the hydrocarbons along the time of operation of the bed. All the analyses confirmed the indication of the biomasses, cane pulp and coconut mesocarp as adsorbents for hydrocarbons removal.