Banca de QUALIFICAÇÃO: Natália Cristina Fernandes Machado
Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.DISCENTE : Natália Cristina Fernandes Machado
DATA : 27/03/2020
HORA: 14:00
LOCAL: CEFET-MG - Campus 6
TÍTULO:
Synthesis and characterization of the Fe/activated carbon composite from polystyrene foams: a new magnetic adsorbent for the removal of organic contaminants
PALAVRAS-CHAVES:
activated carbons, magnetism, composites, iron, adsorption
PÁGINAS: 89
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Físico-Química
ESPECIALIDADE: Química de Interfaces
RESUMO:
Recently, activated carbons (CAs) derivated from plastic waste have been highlighted in the removal of contaminants due to their excellent textural properties and high adsorption capacity of organic contaminants. Obtaining CAs with magnetic properties makes them even more attractive, due to the technical easiness of its removing from the bulk of aqueous solutions. In this sense, two CAs, one being magnetic (CAM) and another non-magnetic (CA), are synthesized from expanded polystyrene (PEE) residues. Both were prepared through of carbonization of PEE dissolved in ethyl acetate (containing iron (III) tris(acetylacetonate) for magnetic), with chemical activation by KOH at 800 ºC. This work reports for the first time the direct synthesis of a magnetic activated carbon composite derivated from PE.
The materials are characterized by N2 adsorption/desorption, X-ray diffraction, thermogravimetry, scanning electron microscopy (SEM), Mössbauer spectroscopy and zeta potential. The iron phases present in the CAM are: Fe0, Fe3C and Fe3O4; being the last one responsible for the material's magnetism. The high specific surface areas and the total volume of CAM pores are highlighted and are equal to 672.41 m2/g and 0.345 cm3/g, respectively. Despite of the lower values of these textural properties in relation to CA, these are still situated among the highest valeus found in the literature of magnetic composites.
Considering the application of CAs, the materials are evaluated in the removal of the following contaminants: methylene blue (AM), indigo carmine (IC) and phenol (FE). For CAM, the maximum adsorbed amounts of AM, IC and FE correspond to 275, 536 and 116 mg/g in the optimal pH. In the optimal pH and at 25 ° C, the kinetics and adsorption isotherms are studied and the thermodynamic properties are calculated by a basic model of mechanical statistics. Finally, the regeneration capacity of CAs as adsorbents is available in 5 cycles of adsorption, with emphasis on CAM that removes 60% of its removal capacity by the end of the fifth cycle, while CA is able to retain only 20%.
MEMBROS DA BANCA:
Presidente - PRISCILA PEREIRA SILVA CALDEIRA
Externo à Instituição - JOÃO PAULO CAMPOS TRIGUEIRO - IFMG