Obtenção de Biochar a partir da pirólise catalítica do resíduo lignocelulósico das pontas e palhas da cana-de-açúcar do etanol 2G

Abstract

Ethanol 2G is one of the main technological innovations of the sugar and alcohol sector in the state of Alagoas. Despite the great advantages and benefits, the generation of solid waste, which is applied to burning for electricity generation, still requires greater applicability. The residue, called Lignocellulosic Residue (RLC), is provided with a chemical structure of vast industrial applicability. Due to these characteristics, it was decided to evaluate the possibility of an alternative route for the treatment of effluents. For this, the RLC went through the process of degradation by controlled heating: Pyrolysis. Aiming at higher quantitative yields related to solid phase production (called biochar), the pyrolysis technique was performed with the addition of NaOH, which acts as catalyst. The pyrolytic process studies were modeled using a 3k Planning, using Temperature, NaOH Quantity and Biomass Particle Diameter as independent variables, and product yield as response variable for optimization of the biochar degradation process. A thermogravimetric analysis (TGA) was performed to determine the temperature values to be put in the planning and evaluation of mass loss as a function of heating. The biochar that showed the best yield in the pyrolysis process, as well as the RLC, were designated for analysis of Fourier Transform Infrared Spectroscopy (FTIR). In addition to the aforementioned analyses, the biochar produced went through the analysis of Scanning Electron Microscopy (SEM) and the adsorptive studies of Kinetics, Isotherm and Adsorption Thermodynamics. Seeking to evaluate the adsorptive efficiency of biochar for effluent treatment, it was decided to study the adsorption of biochar in the removal of dyes, using Methylene Blue as a reference pollutant. The results showed that the addition of NaOH reduced the mass loss during heating, but maintained the highest degradation temperature of 350°C. Due to the results obtained, it was defined that catalytic pyrolysis increased biochar production when compared to the standard process. Among the biochars produced by Pyrolysis Catalytic, the solid generated from a biomass heated to 500°C, with the addition of NaOH equivalent to 100.0% Of RLC, with a diameter of 300μm plus appropriate in quantitative terms. From the response surface generated by the results, it was possible to define that the variables used in the study have a quadratic effect in relation to the yield of biochar production. Spectroscopic analyses proved the degradation efficiency as well as the determination of the biochar activator profile due to the amount of existing pores. In the adsorptive study, the biochar showed a greater tendency to the sips mathematical model, showing significant heterogeneity between adsorbent and adsorvato, defining a chemical interaction between them. The mass transfer rate in the process presented a second order, proving the interaction between the chemical characteristic components. Therefore, based on the conclusions postulated according to the results obtained, the RLC is attributed to the applicability directed to the treatment of effluents, being possible, with the biochar generated to attribute other applicability beyond its burning.