Banca de DEFESA: RODRIGO SANTOS GONZAGA MENEZES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : RODRIGO SANTOS GONZAGA MENEZES
DATE: 05/04/2024
TIME: 14:00
LOCAL: Sala de Seminários do Instituto de Química
TITLE:

Capture of VOCs on activated carbons prepared from the aquatic plant Eichhornia Crassipes: A thermogravimetric study

KEY WORDS:

VOC capture; Activated carbons; Eichhornia Crassipes; Thermogravimetry

PAGES: 90
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Inorgânica
SPECIALTY: Físico Química Inorgânica
SUMMARY:

The high dispersion of volatile organic compounds in the environment raises the need to develop methods to capture these vapors, as they are chemical species with the potential to cause damage to human health and environmental problems, and several essential human activities emit these compounds daily. Adsorption is a technique that deserves to be highlighted in the application for capturing these vapors, as it is a simple procedure, generally does not use expensive materials and, depending on the adsorbent-adsorbate interaction, it is a reversible process that allows the reuse of adsorbents and even a utilization of captured compounds. Activated carbon is an easy material to produce, it has a large surface area making it efficient in adsorption processes. In this work, activated carbons were produced under different pyrolysis and activation conditions, and were subsequently evaluated for the capture of different volatile organic compounds, among which the most adsorbed compound was dichloromethane (301 mg/g). For the evaluation of the adsorptive properties of activated carbons, Thermogravimetry was an excellent ally due to the ease of using the technique for this purpose and acquiring the results, compared to other techniques available in the literature. In the production of activated carbons, biomass derived from an aquatic plant called Eichornnia Crassipes, popularly known as baronesa, was used. This plant was chosen because it has a high reproduction rate and where its proliferation occurs it causes ecological and financial problems, which leads to its mechanical removal and disposal without any destination. Initially, biomass characterizations were carried out to obtain the moisture content, fixed carbon, ash, macrocomponents and quantification of inorganics. At this stage, modern procedures using Thermogravimetry were also applied for comparative purposes with techniques that are commonly used in the literature. Initial characterizations of the biomass showed fixed carbon contents in a range of 28 – 31%, which is one of the most relevant parameters for the production of activated carbon. After the production of coals, it was verified that the surface area of B.E.T. of coals varied in a range from 333 to 950 m2 /g and micropore area between 421 and 1200 m2 /g. With activated carbon with the largest surface area, the adsorption capabilities of volatile organic compound vapors were evaluated, using thermogravimetry, as well as the thermodynamic and kinetic properties of the adsorption processes. A decrease in adsorption capacity was observed with increasing temperature, characteristic of a physisorption process. The adsorption curves were correlated with pseudo-first-order, pseudo-second-order adsorption mathematical models and the Avrami model. These correlations showed higher coefficients with the pseudo-first order model (r2 = 0.9562 – 0.9915), which also indicate that physical adsorption is the dominant process, but the significant values of the correlations with the Avrami model ( r2 = 0.9899 – 0.9955) indicate a contribution from chemical adsorption between the vapors of the studied compounds and the activated carbon.

COMMITTEE MEMBERS:
Presidente - 2362069 - RAILDO ALVES FIUZA JUNIOR
Interna - 1299469 - LUCIANA ALMEIDA DA SILVA
Interno - 2356272 - ARTUR JOSE SANTOS MASCARENHAS
Externo à Instituição - RODRIGO DE PAULA - UFRB
Externa à Instituição - TEREZA SIMONNE MASCARENHAS SANTOS - UEFS