Synthesis and Evaluation of Interfacial Properties and Carbon Capture Capacities of the Imidazolium-Based Ionic Liquid Surfactant.

Ionic liquid as a chemical flooding agent has broad application prospect in enhancing oil recovery. In this study, a bifunctional imidazolium-based ionic liquid surfactant was synthesized, and its surface-active, emulsification capacity, and CO2 capture performance were investigated. The results show that the synthesized ionic liquid surfactant combines the characteristics of reducing interfacial tension, emulsification, and CO2 capture. The IFT values for [C12mim][Br], [C14mim][Br], and [C16mim][Br] could decrease from 32.74 mN/m to 3.17, 0.54, and 0.051 mN/m, respectively, with increasing concentration. In addition, the emulsification index values are 0.597 for [C16mim][Br], 0.48 for [C14mim][Br], and 0.259 for [C12mim][Br]. The surface-active and emulsification capacity of ionic liquid surfactants improved with the increase in alkyl chain length. Furthermore, the absorption capacities reach 0.48 mol CO2 per mol of ionic liquid surfactant at 0.1 MPa and 25 °C. This work provides theoretical support for further CCUS-EOR research and the application of ionic liquid surfactants.