Membranas de fibra oca de polietersulfona (PES)/argila para tratamento de água - óleo.

Abstract

Hollow fiber membranes were produced from polyethersulfone (PES), with3 and 5% of two types of clays (Brasgel PA - MMT and Cloisite Na - CLNa). The membranes were obtained from the phase inversion method by the cold extrusion technique with the precipitation by immersion. In the preparation of the membranes, the internal liquid was changed and distilled water (non-solvent) and N, N-dimethylformamide(DMF) were used as the solvent in the internal liquid. Initially, flat membranes were produced and characterized by X-ray diffraction and contact angle. Then hollow fiber membranes were characterized by scanning electron microscopy and flow measurements. The water-oil emulsions and the permeated obtained in the flow measurements were characterized by ultraviolet spectrophotometry. By X-ray diffraction it was possible to evaluate that the membranes with the presence of clay formed a structure of nanocomposites in the exfoliated and/or partially exfoliated form. For the membrane with 5% CLNa a shoulder was observed, which can refer to an intercalated structure and/or a formation of a microcomposite. From the contact angle with distilled water it was observed that the presence of clay favored an increase in the hydrophilicity of the membranes. Scanning electron microscopy reveals that the content and type of clay modified the morphology of the membrane, altering the uniformity of the fingers and the macropores. On the other hand, the addition of dimethylformamide in the internal liquid modified even more the morphology, reducing the dense layer at the center of the membrane porous support and also altering the fingers and the macropores. In the flow measurements with distilled water the membranes containing solvent in the internal liquid obtained better flows and for the measurements with the oily emulsion the same behavior was observed, showing that the nature of the fluid did not change in the permeability of the membrane. The oil and grease content (OGC) showed a significant reduction in the concentration of oil in the permeate, and was more pronounced at 5% CLNa at 1.5 bar.