Otimização da degradação da tetraciclina utilizando a fotocatálise heterogênea com ZnO como catalisador

Detalhes bibliográficos
Ano de defesa: 2013
Autor(a) principal: Davis, Rafael lattes
Orientador(a): Módenes, Aparecido Nivaldo lattes
Banca de defesa: Martin, Clayton Antunes lattes, Borba, Carlos Eduardo lattes, Manenti, Diego Ricieri lattes
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Estadual do Oeste do Paraná
Toledo
Programa de Pós-Graduação: Programa de Mestrado em Engenharia Química
Departamento: Centro de Engenharias e Ciências Exatas
País: BR
Palavras-chave em Português:
ZnO
Palavras-chave em Inglês:
Área do conhecimento CNPq:
Link de acesso: http://tede.unioeste.br:8080/tede/handle/tede/1845
Resumo: The aim of this work was to determine the optimal conditions for the degradation of the TC, using the heterogeneous phtocatalysis with ZnO catalyst. Preliminary experiments were conducted to evaluate to efficiency of heterogeneous photocatalysis in the degradation of TC. The degradation was carried out using standard solutions of TC 30 mg L 1. The photocatalytic experiments by using a set of high-pressure mercury lamps as artificial UV irradiation source were performed in laboratory scale. As reactor operational parameters to be optimized by a 33 full factorial experimental design: hydrogen peroxide and zinc oxide as well as the initial solution pH were chosen as variables, keeping constant a reaction time of 60 min. The concentration of TC was determined by UV-Vis spectrophotometry and HPLC. Mineralization and toxicity of the treated solution by photocatalytic process were evaluated based on the total organic carbon (TOC) and antibacterial activity. Second-degree models for the degradation of TC were proposed to model the photocatalytic experiments to obtain optimum values of the reactor operating parameters. Second-degree models were also validated by ANOVA. Predicted yields showed good validation with experimental yields. The hydrogen peroxide did not influence significantly the range studied by factorial experimental design. Was necessary to perform photocatalytic experiments at lower concentrations for hydrogen peroxide. The values of the optimized reactor operational parameters were 6, 2 g L-1 and 175 mg L-1 for initial pH, oxide zinc and hydrogen peroxide concentrations, respectively, for photocatalyses heterogeneous process. Based on this optimized experimental conditions, almost 100% of TC degraded. The TOC and antibacterial activity were determined of treated solutions in optimal conditions. Only 46% of the TOC was mineralized, the remainder as intermediate molecules not presented antibacterial activity, not providing risk to the environment.