Banca de DEFESA: ELANO COSTA SILVA
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.STUDENT : ELANO COSTA SILVA
DATE: 23/01/2025
TIME: 14:00
LOCAL: Google meet
TITLE:
KEY WORDS:
Lignin. Adsorption. Produced water. Dye. Corn cob.
PAGES: 92
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Tecnologia Química
SPECIALTY: Tratamentos e Aproveitamento de Rejeitos
SUMMARY:
Population growth and increased consumption have intensified industrial production. This growth has led to more pollutants, which, when improperly disposed of, impact human health and ecosystems. Examples of significant environmental issues include the produced water from oil extraction, which is rich in salts, heavy metals, and organic compounds, and effluents from the textile industry contaminated with chemical dyes. To address these issues, recent research highlights lignin as a promising adsorbent material due to its abundance in nature and its chemical properties, such as high binding capacity with contaminants. Brazil, a major producer of corn, generates significant volumes of corncobs, which contain about 15% lignin, emphasizing their potential for such applications. The objective of this study is to investigate the use of modified lignin extracted from corncobs as an adsorbent material for pollutants in contaminated effluents. An alkaline pretreatment was applied to the corncob biomass to extract lignin. The extracted lignin was modified with reagents such as choline chloride and hydrogen peroxide to enhance its ability to interact with contaminants. Characterization techniques (Zeta potential, TG, FTIR, and SEM) were performed to understand the physical, chemical, structural, and functional properties of the adsorbent materials. Using UV-Vis spectroscopy, bench tests were conducted to evaluate the material’s efficiency as an adsorbent in pollutant removal, considering parameters such as the initial pollutant concentration and contact time. The study of oil removal kinetics through adsorption was conducted using lignin and sodium alginate spheres. The lignin spheres demonstrated superior performance compared to pure alginate spheres. The ELMC sphere achieved the best result, reaching 90% TOG removal, followed by ELOX, with 88.23% removal. The pseudo-first-order model provided the best fit to the experimental data. The maximum adsorption capacities were 172.7 mg/g for ELMC and ELOX, 161.18 mg/g for ELNM, and 84.43 mg/g for EALG (note: the acronyms refer to different types of modified lignin, detailed in the methodology). For Congo red dye, the adsorption kinetics best fit the pseudo-second-order model. The PSO model demonstrated high accuracy in R² values and effectively predicted the qe value. For LNM, the qe values were 35.54, 66.58, and 155.24 mg/g for concentrations of 50, 100, and 250 mg/L, respectively; for LMC, the values were 33.89, 65.95, and 165.79 mg/g. The Langmuir and Freundlich isotherm models showed less accurate fits, with R² values deviating from the ideal. Therefore, the adsorption study using modified lignin extracted from corncobs demonstrated an efficient and sustainable alternative for wastewater treatment, outperforming conventional materials such as activated carbon. This material meets environmental requirements by removing contaminants from produced water during oil extraction as well as Congo red dye, commonly found in textile industry effluents. The modified lignin exhibited high adsorption capacity, highlighting its potential as a promising solution to mitigate environmental impacts.
COMMITTEE MEMBERS:
Presidente - 1753094 - ALCIDES DE OLIVEIRA WANDERLEY NETO
Interno - 3304882 - CARLOS EDUARDO DE ARAÚJO PADILHA
Interno - ***.674.113-** - DENNYS CORREIA DA SILVA - UFRN
Externo ao Programa - 1198847 - JOSE LUIS CARDOZO FONSECA - UFRNExterno à Instituição - HARVEY ALEXANDER VILLA VÉLEZ - UFMA