DETERMINATION OF CHARACTERIZATION CURVATURE OF EMILIA SONCHIFOLIA (NATURAL SURFACTANTS)

Surfactant flooding is a chemical enhanced oil recovery (cEOR) technique in which anionic, cationic, non-ionic, or amphoteric surfactants are injected into reservoirs to mobilize additional hydrocarbons. However, the use of synthetic surfactants often presents economic and environmental concerns. To address these challenges, researchers have recently proposed the application of natural surfactants as environmentally friendly alternatives for EOR processes. In this study, the Cryoscopic method was employed to determine the molecular weight of the natural surfactant. The results showed that the molecular weight of Emilia sonchifolia extract (128.2 g/mol) is lower than that of the reference surfactant. Furthermore, the conductivity method was applied to evaluate the critical micelle concentration (CMC) of surfactant solutions prepared at concentrations of 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, and 9000 ppm of Emilia sonchifolia extract in distilled water. Experimental findings revealed an optimum CMC value of 0.6%. Beyond this concentration, the surface tension remained relatively stable, with only minor changes in slope. Additionally, a phase behavior test was conducted to determine the optimum salinity of the mixture compared with the reference surfactant, sodium dodecyl sulfate (SDS). The characteristic curvature of SDS was found to be –0.92 (Antonio, 2015), while the test surfactant (Emilia sonchifolia) exhibited a curvature of +2.783, indicating hydrophobic behavior. Based on these findings, Emilia sonchifolia demonstrates strong potential as a natural surfactant candidate for chemical enhanced oil recovery, with the ability to effectively reduce interfacial tension between crude oil and connate water in mature oilfields.