Banca de DEFESA: THAMIRIS FERREIRA DE SOUZA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE: THAMIRIS FERREIRA DE SOUZA
DATA: 19/11/2025
HORA: 13:30
LOCAL: Anfiteatro do DQI
TÍTULO:

SUSTAINABLE VALORIZATION OF SUGARCANE BAGASSE INTO BIOCHAR-METAL OXIDES AND LIGNIN FOR HERBICIDE REMOVAL

PALAVRAS-CHAVES:

agro-industrial residues; biochar; pesticides; adsorption; biomaterials.

PÁGINAS: 349
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
RESUMO:

The generation of agro-industrial residues and water contamination by pesticides represent environmental challenges that demand sustainable and innovative strategies. In this context, sugarcane bagasse was explored through two approaches: (i) pyrolysis for the production of biochar-metal oxide composites based on Mn and Fe, and (ii) fractionation using deep eutectic solvents (DES) to obtain lignin fractions, both aimed at developing new adsorbents. The materials produced were characterized by different techniques and evaluated for the removal of
synthetic herbicides from aqueous media, including 2,4-dichlorophenoxyacetic acid (2,4-D), 4-chlorophenoxyacetic acid (4-CPA), and Picloram. Mn-based biochar-oxide composites were obtained from bagasse modified with MnCl2 and KMnO4 via immersion, followed by pyrolysis at 400 °C, evaluating the effect of different Mn precursors on composite formation and their role in 2,4-D adsorption. Fe-based biochar-oxide composites, using FeCl3 as the metallic precursor and obtained at different pyrolysis temperatures (400 and 600 °C), were employed in the removal of 2,4-D and 4-CPA, assessing the role of the adsorbate molecular structure on removal performance. Bimetallic Fe/Mn composites were prepared via pre-pyrolytic modification by immersion and coprecipitation and applied in the removal of 2,4-D and Picloram. The lignin-rich fractions obtained from the optimized fractionation of sugarcane bagasse were tested for their potential in 2,4-D removal. Experimental assays evaluated the effects of pH, ionic strength, adsorption kinetics, and isotherms, as well as the reuse potential. Theoretical studies based on Density Functional Theory (DFT) supported the understanding of interaction mechanisms between herbicides and monometallic composites. For bimetallic materials, leaching tests assessed metal behavior and distribution under adsorption conditions. Adsorption mechanisms were elucidated by X-ray photoelectron spectroscopy (XPS), while seed phytotoxicity tests evaluated the environmental safety of the materials. The results demonstrated that the modulation of the physicochemical properties of the composites determines herbicide removal efficiency, stability, and environmental safety, with the type of metallic precursor, modification route, and pyrolysis temperature being key variables. Additionally, the lignin fractions obtained showed potential for 2,4-D removal. The composite production and lignin utilization strategies highlighted innovative and sustainable solutions for herbicide remediation, promoting residue reuse, water resource protection, and terrestrial life preservation.

MEMBROS DA BANCA:
Interno - FABIANO MAGALHAES (Suplente)
Presidente - GUILHERME MAX DIAS FERREIRA (Membro)
Externo à Instituição - RENATA PEREIRA LOPES MOREIRA - UFV (Suplente)
Externo ao Programa - RAPHAEL LONGUINHOS MONTEIRO LOBATO - DFI/ICN (Membro)
Externo à Instituição - MARIA DO CARMO HESPANHOL - UFV (Membro)
Interno - LUCIANA DE MATOS ALVES PINTO (Membro)
Externo ao Programa - GUSTAVO HENRIQUE DENZIN TONOLI - DCF/ESAL (Membro)