Avaliação e Caracterização dos adsorventes carvão ativado e argila bentonita na remoção do inibidor fermentativo furfural

Abstract

With the incessant search for clean energy sources to reduce environmental impacts, the adoption of new technologies is gaining ground with the use of sustainable raw materials. The present work had the objective of evaluating the adsorption capacity of furfural, an inhibitor present in the prehydrolysed liquor of the cashew fruit bagasse, by the adsorbents activated carbon and bentonite clay, for the viability of the fermentation process of the liquor in the production of bioethanol. The adsorption studies were conducted in a batch system, synthetic solution with 0.1% furfural and pH = 4. The effect of adsorbent mass by volume of adsorbate ratio and contact time were evaluated. The kinetic data were adjusted to the pseudofirst order, pseudosecond order and intraparticle diffusion models. The physical properties of the adsorbents were determined by adsorption-desorption isotherms of N2. According to the results of the characterization of adsorbents in ASAP 2020 microporosimeter, it can be verified that among the adsorbents in the study, the activated carbon had more active sites for the adsorption. Through adsorption/desorption isotherms and physical characterizatio of activated carbon, the results showed that it is a predominantly mesoporous solid. The same characterization for the clay showed that it is a macroporous solid and that, according to its isotherm, it can be said that the clay has low interaction with the molecules of the adsorvate. The results indicated that among the studied adsorbents, the activated carbon was the most viable in the adsorption of furfural, since, with a mass of 5.0 g, it adsorbed about 88,51,9% of the furfural present in a synthetic solution; it was found that 15 minutes was sufficient time for the reaction to enter kinetic equilibrium; the adsorption kinetics data better fit the pseudo-second order model, which indicates that the mechanism controlling the reaction is the chemisorption. In the experiment carried out with the pre-hydrolyzed liquor, it was verified that 94.2% of the furfural present in the sample was adsorbed. For the clay, 254,9% furfural removal in synthetic solution and 48.6% in the pre-hydrolyzed liquor were observed, with an adsorbent mass of 4.0 g and an equilibrium reach time of more than 5 hours