Title:	Obtenção do SrSnO3 e do SrSnO3:N para o tratamento fotocatalítico da água de lavagem do biodiesel
Authors:	Lobo, Tatiane Martins
Orientador(es)::	Weber, Ingrid Távora
Coorientador(es)::	Almeida, Fernanda Vasconcelos de
Assunto::	Fotocatálise Biodiesel Água - tratamento
Issue Date:	18-May-2016
Data de defesa::	8-Dec-2015
Citation:	LOBO, Tatiane Martins. Obtenção do SrSnO3 e do SrSnO3:N para o tratamento fotocatalítico da água de lavagem do biodiesel. 2015. xvi, 153 f., il. Tese (Doutorado em Química)—Universidade de Brasília, Brasília, 2015.
Abstract:	Strontium stannate, SrSnO3, is a ceramic material which presents an orthorhombic structure, compatible with a distorted perovskite. It has been extensively studied due to its potential to several application, including application as a photocatalyst. In this work, SrSnO3 was synthesized by combustion and solid state reaction. Subsequently, the samples were submitted to a thermal treatment under NH3 in order to obtain the oxynitride and then to promote photocatalytic activity in the visible region. Photocatalytic activity of SrSnO3 and SrSnO3:N were evaluated under UV and visible radiation. First of all, oxidation of the dye methylene blue was investigated as a probe reaction and then SrSnO3 and SrSnO3:N were employed to degrade the residual organic matter from the washing process of biodiesel. The synthesis methods showed to not influence in the N content of nitrided samples. Moreover, the results suggest that the incorporation of N occurs preferencially at the surface of the SrSnO3 and that it occurs by two different mechanism of charge compensation. Nevertheless, the SrSnO3nitridation, performed at different conditions, increases the specific surface area, the short-range order and the photocatalytic activity under visible light. For the methylene blue, using UV light, the SrSnO3:N showed a smaller photocatalytic activity if compared to TiO2.. However, using visible light, the oxinitrides presented the better photocatalytic performance (7 times higher than non-nitred samples and 4 times higher than TiO2. For biodiesel wastewater treatment it was observed that wasterwater is a very complex substrate with a very high organic content. Part of this organic content is quite difficult to be oxidized. Either photolysis andphotocatalysis could reduce significantly the TOC content after 4h of UV irradiation, nevertheless a residual part of organic matter (probably oils and grease) remained after both treatment. Using visible radiation, only the SrSnO3:N, obtained through both methods of synthesis, could degrade pollutants present in the wastewater. Moreover, acute ecotoxicity tests indicated that the direct photolysis/UV makes the wastewater even more toxic to the Danio rerio embryos than photocathalysis. Thus, SrSnO3:N/Vis becomes an even more attractive option, reducing up to 57.4% of TOC (although the ecotoxicity test of this treatment could not be performed). In general, it was possible to observe that the nitridation of SrSnO3 increases the absorption of visible light and the SrSnO3:N produced are promising photocatalysts for the photodegradation of organic dye and the wastewater from biodiesel, being used as an active photocatalyst with sun light.
metadata.dc.description.unidade:	Instituto de Química (IQ)
Description:	Tese (doutorado)—Universidade de Brasília, Instituto de Química, Programa de Pós-Graduação em Química, 2015.
metadata.dc.description.ppg:	Programa de Pós-Graduação em Química
Licença::	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
DOI:	http://dx.doi.org/10.26512/2015.12.T.20302
Appears in Collections:	Teses, dissertações e produtos pós-doutorado

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.