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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

S?ntese e caracteriza??o de catalisadores baseados em vermiculita modificada com ferro: aplica??o em processos do tipo foto-fenton / Synthesis and characterization of catalysts based in vermiculite modified with iron: application in type photo-fenton processes

Oliveira, Jo?o Leonardo Freitas 26 January 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-09T23:10:26Z No. of bitstreams: 1 JoaoLeonardoFreitasOliveira_DISSERT.pdf: 3296758 bytes, checksum: 105b144fc3affbe55e42b5df17981966 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-11T19:57:37Z (GMT) No. of bitstreams: 1 JoaoLeonardoFreitasOliveira_DISSERT.pdf: 3296758 bytes, checksum: 105b144fc3affbe55e42b5df17981966 (MD5) / Made available in DSpace on 2016-03-11T19:57:37Z (GMT). No. of bitstreams: 1 JoaoLeonardoFreitasOliveira_DISSERT.pdf: 3296758 bytes, checksum: 105b144fc3affbe55e42b5df17981966 (MD5) Previous issue date: 2015-01-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / As argilas s?o materiais com propriedades particulares que as tornam promissoras para diversos estudos. Neste trabalho foi utilizada a argila vermiculita como suporte para compostos de ferro, com intuito de obter materiais promissores para aplica??es no processo do tipo foto-Fenton heterog?neo. Ao todo, o estudo contou com seis s?lidos, partindo da vermiculita (V0) obteve-se a vermiculita calcinada (V0-C), o material misto (V0/?-FeOOH) formado por vermiculita mais akaganeita, vermiculita trocada (V0t-C), vermiculita impregnada por via ?mida (V0u-C) e a V0u-CL que representa o s?lido obtido por impregna??o com uma posterior lavagem. Os s?lidos do estudo tiveram suas caracter?sticas f?sico-qu?micas investigadas pelas seguintes t?cnicas de caracteriza??o: Difratometria de Raios-X (DRX), Espectroscopia de Infravermelho (IV), Espectroscopia de Energia Dispersiva (EDS), Fluoresc?ncia de Raios-X (FRX), UV-Vis por Reflect?ncia Difusa (UV-Vis RD), An?lise Termogravim?trica (TGA) e Microscopia Eletr?nica de Varredura (MEV). O material V0 apresentou tr?s fases distintas, sendo estas, a pr?pria vermiculita, hidrobiotita e biotita, as duas ?ltimas fases fazem parte do processo geol?gico de forma??o da vermiculita. Os s?lidos obtidos ap?s as modifica??es apresentaram aumento na quantidade de ferro presente na argila, sendo estas quantidades, importantes para aplica??o em rea??es do tipo foto-Fenton. As micrografias e os dados de EDS, demonstram que ap?s os tratamentos de adi??o do metal, o ferro foi intercalado na estrutura da vermiculita para os s?lidos V0t-C e V0u-C, no entanto, o mesmo n?o ocorreu com material misto. No processo foto-Fenton, observou-se uma remo??o m?xima de 88,8% da colora??o do corante azul de metileno para o catalisador V0/?-FeOOH, enquanto que para os outros s?lidos obteve-se valores entre 76,8 e 62,6%, contra apenas 37,8% de descolora??o sem presen?a de catalisador. Portanto, conclui-se que a argila vermiculita apresenta-se como um bom catalisador e suporte para o ferro, al?m de apresentar um baixo custo devido sua elevada abund?ncia. / Clays are materials with specific properties that make them promising for various studies. In this work we used the vermiculite clay as support for iron compounds, in order to obtain promising materials for application in the heterogeneous type photo-Fenton process. In all, the study included six solid, starting from the vermiculite (V0) was obtained calcined vermiculite (V0-C), the mixed material (V0/?-FeOOH) formed by vermiculite more akaganeite, exchanged vermiculite (v0t-C), vermiculite impregnated Wet (V0u-C) and V0u-CL that is the solid obtained by impregnating with a back washing. The solids of the study had their physical and chemical characteristics investigated by the following characterization techniques: X-Ray Diffraction (XRD), Infrared Spectroscopy (IR), Energy Dispersive Spectroscopy (EDS), X-Ray Fluorescence Spectroscopy (XRF), UV-Vis by Diffuse Reflectance (DR UV-Vis), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). The V0 material showed three distinct phases, which are the very vermiculite, hidrobiotite and biotite, the last two phases are part of the geological of formation process vermiculite. The solids obtained after the modification showed an increase in the amount of iron present in the clay, these being quantities important for application in photocatalysis. The micrographs and EDS data, show that after treatment of addition of the metal , the iron was intercalary in structure of vermiculite for solid V0t-C and V0u-C, however, this did not occur with mixed material. In the photoFenton process, was observed a maximum removal of 88.8% of the dye methylene blue coloring for the catalyst V0/?-FeOOH, while for the other solids was obtained values between 76.8 and 62.6%, compared to 37.8% of discoloration without the presence of catalyst. Therefore, it is concluded that the vermiculite clay presents as a good catalyst and iron support for the, beyond of presenting a low cost because of its high abundance.

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