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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 de Hidr?xido de ?ndio (III) substitu?do parcialmente por Zn+2 com propriedades fotocatal?ticas e Ag+ com propriedades bactericidas

Tavares, Mara Tatiane de Souza 26 July 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-17T21:26:30Z No. of bitstreams: 1 MaraTatianeDeSouzaTavares_TESE.pdf: 3624533 bytes, checksum: fd1f8f479ff20180ca99cd3c488a4834 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-18T21:34:42Z (GMT) No. of bitstreams: 1 MaraTatianeDeSouzaTavares_TESE.pdf: 3624533 bytes, checksum: fd1f8f479ff20180ca99cd3c488a4834 (MD5) / Made available in DSpace on 2017-04-18T21:34:42Z (GMT). No. of bitstreams: 1 MaraTatianeDeSouzaTavares_TESE.pdf: 3624533 bytes, checksum: fd1f8f479ff20180ca99cd3c488a4834 (MD5) Previous issue date: 2016-07-26 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Atualmente vem sendo investigada uma nova classe de materiais inorg?nicos que surgem como uma op??o promissora com alto desempenho em diferentes aplica??es, tais como fotocatal?ticas e bactericidas. O Hidr?xido de ?ndio (III) ? um semicondutor que apresenta bom desempenho em propriedades ?ticas e t?m gerado intensas investiga??es para compreens?o de novas aplica??es. A dopagem de semicondutores com diferentes elementos ? conhecida por afetar grandemente muitas das suas propriedades b?sicas. Para obter as propriedades desejadas, atualmente muitos pesquisadores estudam s?ntese de semicondutores puros e dopados, em uma grande variedade de materiais. Neste trabalho, estruturas cristalinas de hidr?xido de ?ndio puro e dopado com ?ons de zinco e ?ons de prata foram sintetizadas pelo m?todo hidrot?rmico assistido por micro-ondas (HM) utilizando patamar de tratamento hidrot?rmico de 30 minutos. As amostras foram caracterizadas por difra??o de raios-X (DRX), microscopia eletr?nica de varredura com emiss?o de campo (MEV-FEG), fotoluminesc?ncia (FL) e espectroscopia UV-vis?vel (UV-vis). Para verificar a aplicabilidade foram realizados nas amostras de In1-x(OH)3Znx teste fotocatal?tico e nas amostras de In1-x(OH)3Agx teste bactericida. Os resultados de difra??o de raios-X confirmaram a forma??o da fase c?bica de In(OH)3, mesmo com o teor m?ximo de dopantes (0,04 de Zn+2 e 0,04 de Ag+). Imagens de MEV mostraram que as amostras de In(OH)3 puro exibe morfologia na forma de cubos com diferentes tamanhos de part?culas, j? nas amostras dopadas com ?ons de Zn+2 e Ag+ houve altera??es significativas na morfologia apresentando compostos agregadas com diferentes tamanhos de part?culas. Os espectros de fotoluminesc?ncia apresentaram diminui??o na intensidade com o aumento da concentra??o de ?ons de Zn+2 na matriz hospedeira, j? as amostras dopadas com 0,02 e 0,04 de ?ons de Ag+ apresentam um desvio para o vermelho. Os espectros de reflect?ncia de UV-vis indicaram que a dopagem com ?ons de Zn+2 e Ag+ causaram uma diminui??o na banda de gap com o aumento da dopagem de 0 para 0,04 de Zn+2/Ag+. No teste fotocatal?tico das amostras de In1-x(OH)3Znx (x=0,04) o corante rodamina B (RhB) degradou em apenas 16 minutos sob irradia??o UV. As amostras do In(OH)3 puro degradaram o corante ap?s 30 minutos sob irradia??o UV. Estes resultados indicaram que, mesmo sem qualquer dopagem, a efici?ncia desse semicondutor na fotodegrada??o do rodamina B (RhB) ? alta. A atividade bactericida das amostra de In1-x(OH)3Agx foi avaliada utilizando bact?rias Gram negativa (Escherichia coli) e bact?rias Gram positivas (Staphylococcus aureus). A presen?a de uma zona de inibi??o indica claramente o efeito antibacteriano das amostras dopadas com Ag+ para ambos os tipos de bact?rias (E. coli e S. aureus), enquanto as amostras de In(OH)3 puro n?o apresentam qualquer efeito antibacteriano. / Currently is being investigated a new class of inorganic materials occurring as a promising option with high performance in different applications, such as photocatalytic and bactericidal. The Hydroxide of Indium (III) is a semiconductor that performs well in optical properties and have generated intense research to understand new applications. The doping of semiconductors with different elements is known to greatly affect many of their basic properties. To obtain the desired properties, currently many researchers study synthesis of pure semiconductors and doped, in a the wide variety of materials. In this work, crystal structures of pure indium hydroxide and doped zinc ions and silver ions were synthesized by hydrothermal method assisted by microwave (MAH) using hydrothermal treatment level of 30 minutes. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy, with field emission (SEM-FEG), photoluminescence (PL) and UV-visible (UV-vis). To verify the applicability were conducted on samples In1-x(OH)3Znx photocatalytic test and samples the In1-x(OH)3Agx bactericidal test. The results of X-ray diffraction confirmed the formation of cubic phase of In(OH)3 even with the maximum level of doping (0,04 Zn2+ and 0,04 Ag+). SEM pictures showed that the samples of pure In(OH)3 exhibits morphology in the form of cubes with different sizes of particles, since at the samples doped with Zn2+ and Ag+ ions were no significant changes in morphology compounds having aggregate with different sizes of particles. The photoluminescence spectra show decrease in intensity with increased concentration of Zn2+ ions in the host matrix, since the samples doped with 0,02 and 0,04 Ag+ ions have a redshift. The reflectance spectra of UV-vis indicated that doping with Zn2+ and Ag+ ions caused a decrease in the band gap with increasing doping of 0 to 0,04 Zn2+/Ag+. In the photocatalytic test sample of In1-x(OH)3Znx (x=0,04) the rhodamine dye (RhB) degraded in about 16 minutes under UV irradiation. The samples pure In(OH)3 dye degraded after 30 minutes under UV irradiation. These results indicated that even without doping, the efficiency of this semiconductor in photodegradation of rhodamine B (RhB) is high. The bactericidal activity of the sample In1-x(OH)3Agx was evaluated using Gram negative bacteria (Escherichia coli) and Gram positive (Staphylococcus aureus). The presence of a zone of inhibition clearly shows the antibacterial effect of Ag+ doped samples for both types of bacteria (E. coli and S. aureus), while samples of pure In(OH)3 show no antibacterial effect.

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