Estudo da formação de sub-produtos da degradação de clorobenzeno e 1,2-dicloroetano a partir da reação com reagente de Fenton em solução aquosa utilizando diferentes fontes de ferro

• Ano de defesa: 2015
• Autor(a) principal: Fernandes, Diego Luiz de Sousa
• Orientador(a): Silva, Alexsandro Araújo da
• Banca de defesa: Maria, Luiz Cláudio de Santa , Martins, Marco Antonio
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade do Estado do Rio de Janeiro
• Programa de Pós-Graduação: Programa de Pós-Graduação em Química
• Departamento: Centro de Tecnologia e Ciências::Instituto de Química
• País: BR
• Palavras-chave em Português: Reagente de Fenton; compostos organoclorados; oxidação química in situ; óxido de manganês dopado com ferro; latossolo vermelho
• Palavras-chave em Inglês: organochlorine compounds; in situ chemical oxidation; manganese oxide doped with iron; oxisol
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ANALITICA::ANALISE DE TRACOS E QUIMICA AMBIENTAL
• Link de acesso: http://www.bdtd.uerj.br/handle/1/15807

Pollution of water and soil are two of the five basic types of environmental pollution. The other three are from air, noise and light. Pollution occurs when a material and/or chemical is added to the environment affecting it adversely. Once pollution exists, return the affected array into its previously unpolluted state becomes very difficult or even impossible in some cases. The organochlorine compounds (OC) represent an important group of persistent organic pollutants (POPs), because of its toxicity and high persistence in the environment. Different soil remediation techniques and groundwater have been developed with the objective of repairing contaminated areas possible in less time and cost, and thus the in situ chemical oxidation has been an increasingly attractive technique because of its simplicity and low cost. The degradation of two organochlorine compounds via chemical oxidation by Fenton's reagent in aqueous solution is the object of this work. For this, two compounds were selected, one aliphatic and another aromatic. Thus, the conditions of degradation of organic compounds in relation to oxidant concentrations at various reaction times, different sources of catalyst were evaluated and qualitatively, what were the main by-products formed. The oxidation tests were carried out in aqueous solution with a controlled temperature of 25 °C and 3 settings of [Fe2+] and [H2O2]. The extraction of compounds of interest into the organic phase was also studied. Analysis of the extracts showed that ethyl acetate was the best solvent for the extraction. In addition, were evaluated two other sources of Fe(II), 11 manganese oxides doped with iron and the predominant soil type in the country, which is characterized by its high concentration of endogenous iron (Oxisol). The test among the iron sources revealed that both Mn oxide as oxisol produced fewer byproducts in relation to the reaction with iron(II) sulphate solution. However, quantitatively, the reduction in the concentration of chlorobenzene was more effective in reaction with Fe(II) sulphate solution (about 63%). The by-products identification was made from the analysis in chromatograph coupled to the gas mass spectrometry and spectra comparative analysis with the NIST library. The oxidation tests revealed that at low oxidant concentrations there is the possibility of generating more toxic byproducts than the reactants, such as hexachlorocyclohexane and polychlorinated biphenyls in the reactions with 1,2-dichloroethane and chlorobenzene, respectively