Anticorrosion properties of ionic liquid functionalized graphene oxide epoxy composite coating on the carbon steel...

The adoption of carbon capture, utilization, and storage (CCUS) technology is increasingly prevalent, driven by the global initiative to conserve energy and reduce emissions. Nevertheless, CCUS has the potential to induce corrosion in equipment, particularly in high-pressure environments containing carbon dioxide (CO₂). Therefore, anti-corrosion protection is necessary for the metal utilized for CO₂ production and storage equipment. Herein, an ionic liquid (triethylsulfonium bis-trifluoromethylsulfonyl-imide) was used to functionalize graphene oxide (prepared via the improved Hummers method). Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) confirmed ionic liquids (IL) were successfully attached to the graphene oxide (GO) lattice. Afterwards, 0.5 wt% and 1 wt% IL-GO composites were separately incorporated into the epoxy and coated on the carbon steel substrate with a thickness of 50 ± 2 µm. The surface examinations demonstrated a consistent distribution of the ILGO composite in the epoxy matrix and achieved a uniform surface. The anti-corrosive properties of 0.5 wt% and 1 wt% IL-GO/epoxy coatings were evaluated using electrochemical tests such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) after immersion in the CO₂ (1.5 MPa) and 3.5 wt% sodium chloride (NaCl) systems. After 48 h of immersion in a corrosion environment (CO₂-NaCl), the protection efficiency of 0.5 wt% and 1 wt% IL-GO/epoxy coatings is 86.41 ± 0.55 and 92.59 ± 0.83 (%), respectively. The findings of this study demonstrated that the ILGO composite-reinforced epoxy coating exhibited exceptional corrosion resistance when exposed to CO₂.