TRATAMENTO DO EFLUENTE DE BIODIESEL APLICANDO A TÉCNICA DE ELETROFLOCULAÇÃO COM ELETRODOS DE ALUMÍNIO, ZINCO E AÇO CARBONO

Abstract

In order to meet the quality standards required by the ANP, biodiesel needs to be purified after its production, this generates a high volume of effluent. In the effluent, free fatty acids, alcohol, catalysts and an unreacted oily part are present, so it can not be discarded without first undergoing treatment, in the present work the electroflocculation technique was used to treat the biodiesel effluent, applying a potential between metallic electrodes to flocculate the organic matter, through the stabilization of the ionic charges. The objective of this work was to evaluate the application of the electroflocculation technique for the treatment of biodiesel washing effluent using aluminum, carbon steel and zinc electrodes. Electroflocculation assays were performed at various voltages and times to determine the best condition in which the technique occurred. The effluent was analyzed before and after the electroflocculation by pH, turbidity, BOD, COD and TOG. The electrodes were analyzed before and after the electroflocculation by mass loss tests, MEV and EDS. Using an aluminum electrode in the anode of the cell and iron at the cathode, 99% removal of oils and grease from the effluent was obtained, the pH assumes a value of 7 and the turbidity reduces 90% if it falls within the norms of the resolutions. Although DQO and DBO do not reduce as significantly, electroflocculation is very efficient in the removal of oils and greases. The tests of mass loss, MEV, EDS and surface mapping indicate the dissolution of the aluminum, since after electrocoleculation the aluminum has on its surface corrosion products.