Interaction of electrolyzed nanomaterials with sandstone and carbonate rock: Experimental study and DLVO theory approach

Abstract

The utilization of nanoparticles (NPs) in various applications, such as water pollution treatment, CO2 geological storage enhancement, and enhanced oil recovery, holds great promise. However, the instability of NPs in fluidic environments severely limits their potential applications. Moreover, NPs tend to adsorb onto the surfaces of sandstones and carbonate rocks in high-saline environments, leading to formation damage. To enable large-scale implementation of NPs, comprehensive research is crucial to understand their stable behavior in harsh saline environments. This study focuses on investigating the interaction of electrolyzed synthesized nanomaterials, specifically titanium dioxide (TiO2), manganese oxide (Mn2O3), and graphene oxide (GO), with the surfaces of carbonate rock and sandstone. To characterize the nanomaterials, various techniques were employed, including Fourier transform-infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), Brunauer−Emmett−Teller (BET), x-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). TiO2, Mn2O3, and GO were synthesized using sol-gel, co-precipitation, and modified Hummer's methods, respectively. The stability of nanofluids was assessed through zeta potential and particle size measurements. The results revealed that the inner-sphere complexes formed by Ca2+ on GO NPs were more effective in neutralizing negative surface charges compared to Mg2+, resulting in a shift of the zeta potential towards lower absolute values. CaCl2 and MgCl2 were found to reverse the charges of Mn2O3 and TiO2 NPs (towards positive values), thus enhancing their stability at higher salt content. SEM images and ultraviolet–visible (UV–vis) spectroscopy measurements demonstrated that Mn2O3 and GO NPs were more prone to adsorption on rock surfaces when Ca2+ and Mg2+ ions were present in the nanofluids, respectively. To assess the interaction energies between NPs and surfaces and investigate the reversibility of NP adsorption, Derjaguin-Landau-Verwey-Overbeek (DLVO) analysis was conducted. The outcomes of this analysis were found to be consistent with the data obtained through SEM and UV–vis spectroscopy.