Banca de DEFESA: RAIANA WILSA LINHARES OLIVEIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : RAIANA WILSA LINHARES OLIVEIRA
DATE: 23/02/2024
TIME: 14:00
LOCAL: Sala de seminários
TITLE:

Catalytic reduction of nitroaromatics over biomass-derived magnetic catalysts prepared by the combustion method

KEY WORDS:

Magnetic catalysts; cocoa biomass; combustion method; reduction of nitroaromatics

PAGES: 100
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Inorgânica
SPECIALTY: Físico Química Inorgânica
SUMMARY:

The class of nitroaromatics are among the most frequently detected pollutants in water bodies and effluents, as they provide raw materials for various industrial and agricultural sectors. They are highly toxic, even in low concentrations and have high stability, which ends up hindering biological degradation processes.The main route to attenuating the concentration of these species is catalytic reduction assisted by sodium borohydride with the formation of functionalized amines that serve as raw material for products such as paracetamol, one of the most used drugs worldwide. Associated with this problem, Brazil discards around 7 to 10 tons of cocoa shells annually. Biomasses like this are often associated with application as biosorbents and as catalytic supports in the degradation of species such as nitroaromatics, since they have matrices rich in cellulose, hemicellulose and lignin. The class of magnetic catalysts has an advantage over the others, as they are easily separated from a system only with the help of an external magnetic field. The preference for using iron oxides in the magnetization stage of the biocomposite takes into account their biodegradability, low toxicity and high magnetic potential. An alternative synthesis method that has shown promise is the combustion method, as it is carried out in a single step, is low-cost, self-sustainable, and generates products with interesting characteristics. The catalysts obtained without fuel in the synthesis process obtained better conversion results for 2,4,6-trinitrophenol (2,4,6-TNP) and 3-nitrophenol (3-NP), with values above 90%,while those obtained under stoichiometric conditions obtained better results for the reduction of 4-nitrophenol (4-NP), with values in the same dimension.The reaction rate constants were obtained from the slope values of the pseudo-first order kinetic curves, with values reaching the order of 10^-2 s^-1. It was observed that the catalytic activity of the composites is more prominent in reducing 3-NP and 4-NP than when compared to 2,4,6-TNP, which can be easily explained by the chemical structure of the compound.The catalysts underwent recyclability tests, maintaining conversion values after 5 cycles.

COMMITTEE MEMBERS:
Presidente - 2356272 - ARTUR JOSE SANTOS MASCARENHAS
Interna - 1299469 - LUCIANA ALMEIDA DA SILVA
Externo ao Programa - 1104702 - MAURICIO BRANDAO DOS SANTOS - UFBAExterno à Instituição - RODRIGO DE PAULA - UFRB
Externa à Instituição - TEREZA SIMONNE MASCARENHAS SANTOS - UEFS