Influence of the use of surfactants in the treatment of produced water by ceramic membranes

Abstract Surfactant-enhanced oil recovery is a method used to augment residual oil extraction from reservoirsHowever, this kind of procedure can produce stable emulsions of water/oil and oil/water, making the conventional treatment of the produced water more difficult. This study evaluates the performance of ultrafiltration process using ceramic membranes for produced water treatment containing the cationic surfactant Dodecyltrimethylammonium bromide (DTAB). To better understand the process, the effect of DTAB and sodium chloride (NaCl) on interfacial properties of oil/water and oil/water/membrane, such as surface tension, membrane wetting, zeta potential and adhesion map were investigated. It was observed that the surfactant facilitates the oil phase adhesion to the membrane surface, causing a permeate flux reduction. On the other hand, the presence of NaCl in the oily emulsion containing DTAB lead to a permeate flux increase, which indicated that ionic strength modifies the interaction between the oil phase and the membrane surface. Considering the high salinity of the produced water, it is possible to imply that the presence of surfactant can contribute to treatment by ultrafiltration process. Independent of surfactant presence in produced water, the oil and grease (COG) content in the permeate stream was consistently lower than 5 mg/L.