Electro-flocculation associated with the extract of Moringa oleifera Lam as natural coagulant for the removal of reactive blue 5G dye

Abstract

Although an important significant sector in world economy, the textile industry is known for its large volumes of wastewater generated in production processes. In the search for cleaner technologies, the application of electrochemical processes, such as electro-flocculation, or natural coagulants, such as Moringa oleifera Lam extract, have become recurrent in literature. Since the required operating conditions for alternative technologies are such that they hamper effective application, current paper presents results obtained with the use of a hybrid system of treatment which combines electro-flocculation and the aqueous extract of Moringa oleifera lam to evaluate the removal of reactive blue 5G dye from aqueous solutions. Milder conditions of electric current intensity (0.10 - 1.50 A) and natural coagulant concentration (250-2000 mg L^-1) were tested. Through a Central Composite Rotatable Design, it was possible to obtain a quadratic model which subsidized the optimization of operating conditions. Applying an electric current of 0.97 A to sacrificial electrodes of iron and a concentration of 2000 mg L^-1 for the extract of Moringa oleifera Lam, an average 86.79% color removal was obtained, considered a satisfactory rate.