Avaliação do uso de resíduo da indústria siderúrgica na descolorização de efluentes têxteis através de processos oxidativos avançados

• Autor(a) principal: Camila Costa de Amorim
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/BUDB-8APPQN
• topic: isotermas; reactive red 195; resíduo do alto forno; fenton heterogêneo; cinética; processos oxidativos avançados; foto-fenton; Adsorção; fenton homogêneo; Reciclagem Indústria; Meio ambiente; Águas residuais Purificação Oxidação; Indústria têxtil; Engenharia sanitária

The textile industrial wastewaters are characterized by the high organic load, and resistance towards biological treatment. In order to remove organic substances to comply with the environmental legislation it is normally required the implementation of more expensive treatment units, such as flocculation-precipitation, adsorption onto activated carbon,evaporation, chemical oxidation or incineration, either combined or not combined to biological treatment. The advanced oxidative processes (AOP) have been described as a promising option for the removal of persistent pollutants present in wastewaters of high organic load, since conventional treatment do not result in satisfactory efficiencies. This studyaimed at the investigation of the applicability of a siderurgical waste in the Fenton process applied for the treatment of textile industrial wastewater. The waste tested in this research was a fine powder from blast furnace unit, which presented high carbon and iron content. This waste was used as source of iron in the Fenton reaction aiming at the decolorization of the dye Reactive Red 195. The adsorption of the dye onto the waste was first investigated, and the experimental data were analyzed by the Langmuir, Freundlich and Brunauer, Emmett and Teller (BET) adsorption isotherms. The capacity adsorption of the siderur gical waste in the equilibrium followed the BET model of adsorption. The rates of adsorption showed a good correlation with the pseudo-second order kinetics. In this research it was tested the Fenton process with and without ultraviolet radiation, as well as the nature of the Fenton reaction, i.e., homogeneous or heterogeneous. The results of such experiments indicated that the largest degree of decolorization was attained with the homogeneous reaction. Although the heterogeneous reaction resulted in less efficiency, it contributed for the increase in reaction velocities. The applicability of the residue as a catalyst has been proven through the kineticsof decomposition of hydrogen peroxide in the presence of the waste, which followed the EleyRiedeal model. The results showed that the use of the UV light increased the rate of reaction, eventhough for application of the photochemistry economic viability must be analyzed. The Fenton and Photo-Fenton reactions studied followed the pseudo- first order kinetics model. Therefore, the practical use of the siderurgical waste is romising, since it enables an easy solid-liquid separation due to its high density.