Abstract
One of the main challenges in the surfactant flooding process, used as a chemical based enhanced oil recovery (EOR) method, is the surfactant adsorption phenomenon. This paper highlights the adsorption equilibrium of Morus nigra leaf extract in aqueous solutions as a newly introduced cationic biosurfactant on carbonate minerals. A conductivity technique utilized to assess the adsorption of the surfactant in the aqueous phase. The adsorption data examined using four different equilibrium adsorption isotherm models (Langmuir, Freundlich, Temkin, and linear). The results confirm that the Langmuir isotherm model has the best match to experimental data with a coefficient of determination of 0.9960. Moreover, a comparison between the adsorption density of Morus nigra and Ziziphus Spina Christi (a nonionic biosurfactant) on two similar carbonate samples performed based on their adsorption mechanisms and pH values. The results of this paper can be useful in surfactant selection in EOR processes, especially for chemical flooding schemes.