Corrosion Inhibition of S275 Carbon Steel in CO ₂ Capture Systems Using Monoethanolamine (MEA) Solvent

ABSTRACT Corrosion in CO 2 capture units significantly impacts safety and costs. This study evaluates S275 carbon steel in CO 2 ‐loaded monoethanolamine (MEA) as a cost‐effective alternative to 316 L stainless steel, testing various inhibitors: methionine, imidazole, sodium sulfite, sodium metavanadate (NaVO 3 ), and copper(II) sulfate (CuSO 4 ). Corrosion performance is assessed using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), while SEM and confocal microscopy analyze surface mechanisms. Results show that NaVO 3 and CuSO 4 provide the highest protection, reaching inhibition efficiencies of 94% (750 ppm) and 98% (1000 ppm), respectively. Polarization curves indicate that both inhibitors act as anodic inhibitors by forming protective layers. SEM confirm iron‐based oxides in NaVO 3 ‐treated samples and mixed copper–iron oxides in CuSO 4 ‐treated ones. Overall, S275 steel shows high potential for CO 2 capture systems when paired with effective inhibitors.