Understanding interfacial tension and viscoelastic properties of fluid interfaces is critical for enhancing oil-water separation and emulsion stability. This study examines the interfacial and dilatational characteristics of cyclohexane in contact with synthesized produced water (PW), which contains complex chemical constituents such as salts and organics. The impact of adding sodium dodecyl sulfate (SDS) surfactant at varying concentrations (0.001–1 g/L) was investigated using the pendant drop method over oscillatory frequencies ranging from 0.1 to 0.5 Hz. The interfacial tension of cyclohexane and synthetic PW, which comprises a variety of chemicals, was lower than in pure water-cyclohexane systems, with the critical micelle concentration (CMC) at 0.1 g/L, much lower than in pure water systems (1.8 g/L). Peak moduli were observed at an SDS concentration of 0.01 g/L for PW, while with the Di water-cyclohexane system, it was observed at 0.1 g/L. This indicates that the phase angle increased (more quickly than the water-cyclohexane system) and shifted toward viscous-like behavior. These results demonstrate the intricate relationships that exist between SDS molecules and the components of the PW, which have an impact on interfacial dynamics and surfactant adsorption. In order to optimize surfactant utilization in oil-water separation and other industrial processes involving complicated fluid interfaces, this study highlights the crucial role that water chemistry plays in modifying surfactant effectiveness and interfacial features.
