Study of Malt Bagasse Biomass as Biosorbent for Acetic Acid Removal in Effluents

In the present work, the biomass known as the malt bagasse, a by-product of the brewing industry, was studied as a biosorbent of acetic acid, in order to evaluate its potential use as an ion exchanger in effluent treatment systems. The process is based on the phenomenon of biosorption, an interface phenomenon, which is the natural accumulation of a solute on the surface of a solid. The studied phenomenon is that of acetic acid adsorption in malt bagasse biomass. In the present work, the influence test of the biomass quantity was carried out, and it was verified that 40 g/L is the ideal concentration of malt bagasse in the acetic acid adsorption process. A kinetic study was also carried out, where a contact time of 20 minutes was defined to reach the balance between the solid/liquid phase. In the identification of the pseudo-second order kinetic model, it was the one that best fitted the experimental data, and based on the intra-particle diffusion model, it was found that more than one step comprises the biosorption mechanism, with intra-particle diffusion being limiting step. Based on this information, the chemical equilibrium test of the solid/liquid phase was performed using the mathematical models of Langmuir and Freundlich, thus presenting, for the malt bagasse, a maximum acetic acid adsorption capacity of approximately 30 mg/g. Where experimental data best fit the Langmuir isotherm. The results show a significant potential for the malt bagasse to remove organic acid in effluents.