Green nano multicationic ionic liquid based surfactants for enhanced oil recovery: A comparative study on design and applications

This contribution explores utilizing the novel nanostructure multicationic surface active ionic liquids (MSAILs) as alternatives to conventional surfactants in enhanced oil recovery (EOR). A new MSAIL consisting of three benzimidazole rings and four carbon alkyl chains attached by triazine spacer, namely [(C4benzim)3TA][Cl3], was economically synthesized with a two steps method. Characterization was performed via FT-IR, NMR, XRD, TGA, DTG, SEM, and DLS analysis. The effects of the product on interfacial tension (IFT), micellization, emulsification, and wettability alteration of the crude oil-water system were experimented. The IFT decreased up to 85.9% at critical micelle concentration (CMC) of 8 x 10-3 mol ˑdm- 3. Rising temperature, from 298.2 to 323.2 K, significatly improves the capability of the product in IFT reduction up to 34.9%. Stable emulsion formation of crude oil-aqueous solutions reached to 84.2 and 80.6%after one day and one week, respectively. Furthermore, surface wettability was transferred from oil-wet to water-wet. Compared to other three structurally homologous imidazolium and benzimidazolium MSAILs, the greater effect of [(C4benzim)3TA][Cl3] was revealed at lower concentrations that was attributed to the strong hydrophobic aromatic rings in the structure. The Frumkin adsorption isotherm exactly reproduced the IFT data, and accordingly, the adsorption and thermodynamic parameters were determined.