Banca de DEFESA: LARISSA NASCIMENTO LÔBO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LARISSA NASCIMENTO LÔBO
DATE: 21/03/2024
TIME: 14:00
LOCAL: Defesa na forma remota pela plataforma google meet
TITLE:

OBTAINING NANOLIGNIN FROM THE SHELL AND FIBER OF GREEN COCONUT (Cocos sp.)


KEY WORDS:

Green coconut, Lignin, Acetosolv pulping, Ultrasonication


PAGES: 60
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Processos Industriais de Engenharia Química
SPECIALTY: Processos Bioquímicos
SUMMARY:

Lignin, the second most abundant biopolymer in nature, plays vital roles in plants and possesses attractive properties for industrial applications. Various lignin extraction methods are mentioned, with acetosolv pulping being highlighted for its effectiveness and sustainability. This research aimed to obtain nanolignin from lignin derived from green coconut husk and fiber (Cocos nucifera) using the acetosolv method. The research began with the collection of green coconut residues, commercially available near the Federal University of Alagoas, and their preparation to obtain flour. The flour was then characterized for total extractives, ash content, lignin, moisture, holocellulose, alpha-cellulose, and hemicellulose. Acetosolv pulping was carried out in two stages, varying temperature conditions and the presence or absence of extractives. Lignin was obtained through precipitation and subsequently characterized through chemical and morphological analyses. The study comprised five main stages. Analysis of the primary components of coconut husk and fiber showed lignin content of 40%, cellulose content of 15.90%, and hemicellulose content of 15.86%, within ranges found in other studies. Physicochemical characterization of green coconut flour revealed extractives content ranging from 2.6 to 19.26%, moisture from 9.22 to 10.5%, ash from 0.98 to 5.12%, and proteins from 3.56 to 8.27%. These results indicate that green coconut husk and fiber are rich sources of lignin compared to other lignocellulosic biomasses. When comparing the data with previous references, it was found that the results obtained in this dissertation align with trends presented in earlier studies on primary and secondary components of green coconut. Next, nanolignin was produced through ultrasonication. The characteristics of the obtained products were analyzed, considering the influence of temperature and the presence of extractives. Finally, the nanolignin under the best condition was subjected to comprehensive qualitative and quantitative characterization. The results revealed an average yield of 13.86%, with variations related to temperature and biomass type. The purity of lignin was confirmed by moisture content, ash content, and Klason lignin content, indicating consistent values. Thermogravimetric analysis demonstrated the thermal stability of lignin, while FTIR revealed typical lignin characteristics such as ketone groups, aromatic structure, and methylation. Scanning electron microscopy highlighted the formation of clusters and porosities in lignin, suggesting a complex structure. These results contribute to a comprehensive understanding of acetosolv lignin extraction and its structural properties.


COMMITTEE MEMBERS:
Presidente - 1456420 - RENATA MARIA ROSAS GARCIA ALMEIDA
Interno(a) - 3081569 - CARLOS EDUARDO DE FARIAS SILVA
Externo(a) à Instituição - FRANCINE PIMENTEL DE ANDRADE - UFAL
Externo(a) à Instituição - MÁRCIA ANDRÉA GOMES - IFAL
Notícia cadastrada em: 21/03/2024 15:20
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