Due to the inadequate disposal of materials containing potentially toxic elements, the concern with the preservation of the environment has increased. Biosolvent materials have been used as an alternative material to treat waste. The objective of this paper was to test the efficiency of banana peel (musa paradisiaca) for the adsorption of Fe ions present in spent motor oils. The banana peels were dried, crushed and sieved (16 mesh). The oil used was collected from the disposal tanks in gas stations in the city of Uberaba, Minas Gerais State, Brazil. The analyses were carried out in batch mode, under agitation, to guarantee contact between the adsorbent and the oil. After contact, oil and adsorbent were separated by centrifugation or by vacuum filtered. The process of liquid-solid separation by centrifugation influenced the results due to the action of the centripetal force causing the separation of the ions by drag but resulted in a removal efficiency of 33.43 to 94.53% of Fe iron removal from the oil, depending on the treatment time. Using vacuum filtration, the process had an efficiency of 38.58%.
I. INTRODUCTIONAccording to the annual report by the National Association of the Automachine Vehicles Manufacturers (Associação Nacional dos Fabricantes de Veículos Automotores -ANFAVEA), 91 million vehicles were produced worldwide in 2019 (ANFAVEA, 2020) and it is estimated that there are 1.4 billion vehicles in use. Lubricating oil is an essential for the operation of these motor vehicles, as it plays a role in reducing friction, heat transfer and corrosion resistance and approximately 40 million tonnes of lubricating oil are required annually to service the world fleet (Lam et al., 2016). Lubricating oils are complex and contain various additives, such as antioxidants, defoamers, anti-wear, thickeners, corrosion protection, detergents, dispersants, pour point depressants and extreme pressure additives (Yash et al., 2015).According to the Brazilian technical standard, NBR 10.004 (ABNT, 2004b), lubricating oil is classified after use as a dangerous waste, due to its characteristics of flammability, corrosivity and reactivity. After use, lubricating oils contain degraded additives and undesired substances that can cause adverse effects that also justify the classification as dangerous waste (Lam et al., 2016).It is a fact that a large part of these lubricants in the post-use phase are discarded and cause pollution of the environment, contaminating soils and groundwater reaching food, harming public health. In Ordinance No. 685, of August 27, 1998, ANVISA establishes maximum levels of contaminants (mycotoxins, inorganic