The role of adsorption of a natural surfactant at oil–water interface in enhanced oil recovery: interfacial rheology, and structural, and emulsifying analyses

Abstract

The enhanced oil recovery (EOR) method is widely used for recovering residual crude oil after implementing conventional oil recovery techniques. Chemical additives, such as surfactants, are considered beneficial for EOR. Their efficacy is assessed based on their ability to reduce interfacial tension, modify wettability, and establish a stable emulsion system. Understanding the mechanism of surfactant adsorption at the oil–water interface is critical for effectively implementing surfactant flooding. In this work, we have studied the adsorption of a natural surfactant synthesized from Eichhornia crassipes at the oil–water interface using numerous interfacial analyses. The results show substantial adsorption at the oil–water interface, indicated by a 27% increase in zeta potential (i.e. −25.2 to −37.2 mV) and ∼27 times increase in film elasticity (i.e. 0.15–4.12 Pa at 0.01 Hz frequency and 0.01% strain). The synthesized natural surfactant demonstrates a noteworthy improvement in the stability of the oil-in-water emulsion and interfacial rheological properties, indicating its potential application in EOR.