Remoção de HPA em água produzida utilizando sistema microemulsionado

Abstract

Produced water is the largest volume of disposal fluids generated during the production and processing of petroleum and natural gas and its composition can contain several toxic compounds, among them are the polycyclic aromatic hydrocarbons (PAH), whose presence causes harmful effects to the environment. This paper discusses a study on the removal of 15 PAH in produced water using a microemulsion system. For this, it was developed a pseudo-ternary phase diagram consisting of produced water enriched with PAH, as the aqueous phase (AP), n-hexane as oily phase (OP) and n-butanol and CTAB as cosurfactant (C) and surfactant (T), respectively, to a right C/T = 4. From the diagram's construction was chosen a spot with a high percentage of AP to test the treatment in the region of interest, Winsor II (WII). This spot (90% AP, 5%C/T and 5% OP) was evaluated in two ways: using a precursor of microemulsion formation only with the AP and the active matter and microemulsion formed at that point, by adding the OP. The qualitative assessment, carried out by means of fluorescence spectroscopy, showed that there was water treatment for both methods, however, the quantitative assessment, carried out by means of high performance liquid chromatography with fluorescence detector (HPLC-FLD), showed that extraction using microemulsion was more efficient. With that, it was performed an simplex centroid experimental planning for the study of the influence of the phases and, thus, it was possible to identify the best point of extraction. The samples were analyzed by HPLC-FLD and its results showed that each PAH presented a different response surface, but all of them showed a maximum extraction at the point with microemulsion composition of 90% AP, 5% C/T and 5% OP. This result shows that this technique is promising for the treatment of produced water in removing HPA, constituting an alternative to the treatment of this reject.