Modificação de Saccharum ssp. hybrids com íons férricos e óxido de nióbio para processos de degradação e adsorção de corantes reativos.

Abstract

This thesis is about the use of an agro-industrial residue to be applied in water treatment, Brazil is one of the main responsible for the generation of agro-industrial products, having this sector one of the main segments of its economy. Sugarcane bagasse is one of the most produced residues in the country, reaching 83% of the

world’s production of this raw material, which makes it a great generator of this agro- industrial residue. In the period 2021/2020, Brazil contributed to the production of 169

million tons. As this biomass has already shown efficiency in relation to its in nature adsorption potential, physically or chemically activated, it can also be applied to other methods of removing water contaminants such as advanced oxidative processes (AOP). In this work, sugarcane bagasse was modified in two ways: Fe(III) and Nb2O5 ions, and the materials were applied in a photo-Fenton process, heterogeneous photocatalysis, and adsorption to remove reactive black dye 5 (RB5). The modified materials were characterized by X-ray Diffraction (XRD) analysis, vibrational absorption spectroscopy in the infrared region with Fourier transform (FTIR), energy dispersive X-ray spectroscopy (EDS) coupled with scanning electron microscopy ( SEM-FEG), Zeta potential (ζ), Surface area analysis (BET) and Diffuse reflectance spectroscopy (DRS). The characterizations made it possible to observe that the metals were immobilized on the surface of the sugarcane bagasse; and played a fundamental role in the efficiency of the processes when compared to fresh sugarcane bagasse. In addition, the effect of reusing materials up to four times was evaluated. The best results were obtained for the material with a 12h immersion in the Fe(III) ion solution for the photo-Fenton process, which expressed a decrease of approximately 100% of the band responsible for the chromophore group (598nm) and the characteristic band of the aromatic group. (310nm) showed a reduction of approximately 90%, after 60 min, in the spectra. On the other hand, the best yield for the heterogeneous photocatalysis process using Nb2O5 was the material without alkaline treatment and presence of H2O2, which showed a decrease of almost 65% in the chromophore group and approximately 40% in the aromatic group, while for the adsorption it expressed removal always below 50% removal of the chromophore group and practically no change in the aromatic group. The results showed that sugarcane bagasse with immobilized metals can be applied both bioadsorbent material as a support for photocatalytic processes in effluent treatment.