Aplicação de organoargilas e aluminosilicatos para tratamento de misturas óleo/água

Abstract

The scarcity of water and clean energy presents itself as one of the biggest challenges for modern societies. Oil contamination becomes a major environmental concern, as residues of these materials are generated, for example, by the leather, textile, food, steel, petrochemical, mining and metallurgy industries; in addition to pollution caused by edible oils. The oil industry, in addition to its importance in the global economy, is associated with two fundamental problems: the generation of produced water – its effluent generated in greater quantity – and environmental accidents with oil spills. Among the conventional strategies of treatment and remediation of effluents and environmental impacts involved in these problems are traditional techniques such as flotation, hydrocyloning, use of barriers and skimmers. Nowadays, however, bioinspired strategies and the use of natural materials for oil and water separation are increasingly growing. In this context, this work investigates the application of composite materials produced by modifying natural vermiculite from the state of Paraíba, functionalized with cetyltrimethylammonium bromide and niobic acid, beyond the effect of alkaline treatment with NaOH, analyzing its application in adsorptive and separation strategies, to treat mixtures of water and oil, emulsified or not. The developed materials were characterized by XRD, TGA, infrared spectroscopy, SEM and EDS. These results showed that the organophilization of the vermiculite matrix occurs with adhesion of the surfactant in the interlamellar region of the clay mineral. This process introduces a partial positive charge on the surface of the material, allowing the deposition of niobic acid and the formation of a micro/nanostructured hierarchical roughness. Adsorption tests, carried out with mixtures of water and kerosene, showed that the solids developed adsorb oil, with efficiencies above 75%. The kinetic adsorption models showed adequate fit to the pseudo second order model, with percentage errors below 4%. In the separation strategies using skimmers, the organophilic sample with niobic acid incorporation showed much higher efficiency than the others, capturing an oil mass almost 30 times greater than the solid mass used. In the filtration strategies, the materials modified with niobic acid and submitted to alkaline treatment, when previously hydrated, showed the ability to separate biphasic mixtures of kerosene and water, with oil retention. These filters have demonstrated repeatability of use with recovery efficiencies of the used oil mass above 94%.