ESTUDO CINÉTICO DA REAÇÃO DE FENTON COM PÓ DE MINÉRIO NO TRATAMENTO DE ÁGUAS DE LAVAGEM DE BIODIESEL E AVALIAÇÃO DA LIXIVIABILIDADE DO RESÍDUO

In biodiesel production through the transesterification process, there is a high consumption of water in the stage of purification of the product and, therefore, forms of reuse or disposal of this generated effluent must be investigated. However, these alternatives can only be applied after appropriate treatment, following the laws and normative procedures, in order to reduce environmental impacts Thus, in this work, the effluent was treated by the Fenton reaction, which promotes the transformation of organic matter by oxidation, having hydroxyl radicals as the main agents responsible for the process. These radicals are produced by the decomposition of hydrogen peroxide (H2O2) in the presence of iron ion catalysts. The process lead to organic matter removal of 90%, and the collected data was better adjusted to the kinetic model proposed by Chan and Chu (2003), with initial reaction rate of 1/ρ = 3,367 min-1. Regarding the iron leaching to the aqueous medium, the influence of temperature, contact time and H2O2 content in the process were evaluated. In these tests, it was found that the amount of leachate varied with time and temperature, but not in a linear and increasing manner. Concerning the presence of H2O2, it was observed an increasing content of iron (Fe2+) in the solution containing hydrogen peroxide. This behavior was not observed when the tests were carried out in distilled water, at the same temperature and contact time.