Experimental investigation of the adsorption process of the surfactant-nanoparticle combination onto the carbonate reservoir rock surface in the enhanced oil recovery (EOR) process

Nowadays, the application of materials, such as surfactants and nanoparticles in enhanced oil recovery (EOR) projects has been widely studied. So, the adsorption process of these substances is one of the important methods to increase the oil recovery factor from carbonate oil reservoirs. However, understanding how the surfactant-nanoparticle combination interacts through the adsorption process onto the carbonate reservoir rocks surface is not well discussed. In this paper, the adsorption process of saponin extracted from the Glycyrrhiza glabra plant as a natural non-ionic surfactant (GG surfactant) with the presence of hydrophilic titanium dioxide nanoparticles (HITNPs) onto the carbonate reservoir rock (adsorbent) surface has been investigated for mobilizing the crude oil remaining to increase the oil recovery factor. Hence, this study highlights the equilibrium adsorption rate and the adsorption kinetics of these materials in aqueous solutions for chemical EOR schemes. Also, analyses of X-ray diffraction (XRD) spectrometry, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy have been applied to confirm and determine the physicochemical changes and properties of materials. To evaluate the adsorption rate and the relationship between surfactant concentration with the presence of nanoparticles and adsorption density on the adsorbent surface in the aqueous phase, batch adsorption tests under atmospheric conditions at different concentrations and times have been used to comprehend the impact of adsorbate dose on the sorption efficiency. Therefore, the electrical conductivity (EC) technique was used for measuring the adsorption rate of surfactant with the presence of HITNPs in the aqueous phase on the adsorbent surface. The adsorption kinetics process was experimentally investigated at laboratory temperature (25 °C) by monitoring the uptake of solutions on the adsorbent surface as a function of time. The experimental adsorption data were also examined by different equilibrium and kinetic models of adsorption. Hence, the adsorption parameters were determined for each model. Langmuir isotherm was the best model according to the higher values of the correlation coefficient (R2) for GG surfactant and surfactant nanofluid solutions on the adsorbent surface. Furthermore, the pseudo-second-order kinetic model could satisfactorily estimate the adsorption kinetics of GG surfactant and surfactant nanofluid solutions on the adsorbent surface. Results indicated that the adsorption process of GG surfactant and surfactant nanofluid solutions on the adsorbent surface is characterized by a short period of rapid adsorption, followed by a long period of slower adsorption. Moreover, the results of the IFT experiment of these materials showed that GG surfactant and surfactant nanofluid solutions could significantly reduce the IFT value between oil and water system. Finally, the results obtained from this study can help in selecting appropriate surfactants and metal oxide nanoparticles for the design of EOR projects, especially reservoir simulation schemes and chemical flooding processes for carbonate oil reservoirs.