Estudo do potencial de biossorção do corante Rodamina B por células inativas de Aspergillus oryzae

Abstract

The application of new materials biosorbents is consolidating itself as an attractive alternative to complement or even replace traditional treatments used for textile effluents. With the goal of proposing an efficient and low cost treatment, this work studied the biosorption potential of the dye Rhodamine B through the use of inactive fungal biomass of Aspergillus oryzae. From the factorial design 2³, different compositions of culture media were analyzed and the variables that produced the biosorbent with the most satisfactory characteristics for the dye biosorption were defined, being this okara and dextrose without the presence of salts. It was verified through a study of the effect of the granulometry that the milled biomass with average Sauter diameter of 0.90mm presented better results than the biomass chopped with particles of average diameter of 3.75mm. The milled biomass showed higher biosorption rates and greater process control, resulting in an uniform biosorbent. SEM analysis showed the influence of the culture medium on the surface of the biosorbent and the FTIR analysis showed that the structural changes directly affect the biosorption process. The kinetic model of pseudo-second order was the best fit to the experimental data showing the linear correlation coefficient (R ²) greater than 0.99 for all experiments. The equilibrium of the biosorption process is described by the Freundlich adsorption isotherm model (R² > 0.97). By analyzing the coefficients of this model it can be stated that the biosorption process is favorable since n has values higher than 1.0. The thermodynamic study indicated that the biosorption process is spontaneous , endothermic and that randomness at the biosorbent interface / solution increases during the biosorption process . During the desorption test it was found that the most effective desorbent for regeneration of the inactive cells was , which had removal efficiency greater than 80%.