Banca de DEFESA: LILLYANE RAISSA BARBOSA DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LILLYANE RAISSA BARBOSA DA SILVA
DATE: 31/01/2023
TIME: 14:00
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:

DEVELOPMENT OF SUSTAINABLE NANOCATALYSTS BASED ON SILVER NANOPARTICLES FOR ORGANIC CHEMISTRY

KEY WORDS:

Silver nanoparticles; Nanocatalysis; Chemical Reduction; 4-Nitrophenol; Pollutants.

PAGES: 93
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

Materials have been developed and used with specific characteristics that meet the needs of a modern and complex society. Among the types of materials, we have nanomaterials that are within the advanced materials. Among these materials, a group that stands out for its wide range of applications is metallic nanoparticles, such as silver nanoparticles (AgNPs). AgNPs have excellent characteristics, which are responsible for optical, electronic, and antibacterial properties. AgNPs are also efficient nanocatalysts, showing efficiency in several reactions, such as the catalytic reduction of organic pollutants. Thus, this work had as its main objective the synthesis of metallic nanocatalysts based on silver nanoparticles in water, and to evaluate their catalytic activity in the degradation of 4-nitrophenol (4-NF). The AgNPs were prepared in spherical format, through the chemical reduction method using sodium borohydride. As stabilizers, we used polymers: poly 4-styrene sulfonate, polyvinyl alcohol, sodium polyphosphate, and sodium alginate; and minor ligands: ascorbic acid, succinic anhydride, glycine, tyrosine, and sodium citrate. AgNPs were characterized by UV-Vis spectroscopy, dynamic light scattering, Zeta potential, and ICP-OES. The obtained results indicate the formation of silver nanoparticles with spherical morphology, colloidal stability, and good size distribution. The catalytic reduction of 4-NF to 4-aminophenol in the presence of silver nanocatalysts was studied by UV-Vis spectroscopy, in the presence of sodium borohydride. The catalytic studies were performed using different volumes of AgNPs (0.5, 0.25, and 0.1 µL), and the analysis was performed at 0, 5, 15, and 30 min. Complete degradation of 4-NF was observed in less than 30 minutes with all catalysts, and this catalytic efficiency is dependent on the amount of AgNP used. Thus, the AgNPs studied here have the potential to be used as nanocatalysts in the degradation of organic pollutants.

COMMITTEE MEMBERS:
Presidente - 2330165 - MARIA GORETI CARVALHO PEREIRA
Interno - 1167723 - ARMANDO JUAN NAVARRO VAZQUEZ
Externa ao Programa - 1995320 - LAIS ARAUJO SOUZA - UFPE