Emprego de auxiliar natural de floculação para remoção de cor pelo processo de coagulação/floculação

Abstract

The textile processing is large amount of highly polluting dumps generator that are toxic to humans and the environment. A key feature of effluents from textile industry is the presence of color. In this work, we evaluated the use of natural polymer Abelmoschus eschulentus (L.) Moench (okra) as an auxiliary flocculation for color removal of aqueous solution prepared with red textile dye by coagulation / flocculation process. By sweeping method were determined wavelength (274nm) calibration curve for this dye. With the help of a factorial design 2³, it was possible eight trials varying the chemical coagulant concentrations, dye and flocculation aid. The best color removal and sludge volume results in these tests were found when the coagulant concentration was in the lower level. For a more detailed these results, it developed a mathematical model using the method of least squares. This method normalized probability distribution curves were constructed for the purpose and also standardized response surfaces, which allowed confirm that the best results are lower than the values of chemical coagulant and dye, the concentration of flocculation aid does not interfere and so the end result from the mathematical model and the response surfaces, concentrations that would promote the greater color removal and greater sludge generation were chosen. The concentrations were: 0.75 g / L of chemical coagulant, 0.075 g / L and dye 0.1 and 0.2 ml of flocculating aid. Accordingly, there was approximately 97% color removal. For the evaluation of the generated sludge, the volume generated was analyzed using Imhoff cones, density, moisture, organic matter and aluminum. Thus, it was concluded that the best results were achieved with coagulant concentrations and dye on the lower level and flocculation aid concentration did not affect the result, which does not mean that their presence is not important. Thus, it is demonstrated that the application of okra solution as flocculating aid is promising to improve the color removal of textile effluents.