Alkaline ethanolamine as dual-functional agent: Effective CO2 capture agent and corrosion inhibitor for structural applications

• CO 2 is no more detrimental to steel rebar corrosion in presence of alkanolamines. • MAE reduce atmospheric CO 2 and enhance corrosion resistance. • Alkanolamine usage is a free energy technique towards zero carbon emissions. • MAE is an excellent CO 2 absorbent for civil infrastructure. • MAE is an excellent corrosion inhibitor for steel rebar in concrete application. Continuous CO 2 emissions from automobiles and industrial sources pose significant environmental challenges. Concrete absorbs CO 2 from the atmosphere which accelerates corrosion of rebar. The objective of this study is to propose a revolutionary technique to use 2-(methylamino)ethanol (MAE) and N-Methyldiethanolamine (MDEA) as dual-functional agents for CO 2 absorption and corrosion inhibition. This study investigates the effect of MAE and MDEA on the carbonation of a simulated concrete pore solution (saturated Ca(OH) 2 solution containing NaCl) and simultaneously analyses the changes in microstructure, composition, and electrochemical properties of the steel exposed. Results showed that the presence of 5–10 mass% of MAE and MDEA in solution effectively absorbs CO 2 , stabilizing pH between 8 and 9. XRF analysis showed that adsorbed Ca on steel was decreased from 30 mass% to 1 mass% due to the presence of 0.1 mol/dm −3 (−|-) NaCl in a saturated Ca(OH) 2 (S1C) solution. Electrochemical test results showed that 10 mass % of MAE and MDEA addition in S1C exhibited an outstanding inhibition performance with 99.5 % inhibition efficiency. The excellent polarization resistance of steel with a low i corr value of 70nA cm −2 was observed in a carbonated SIC solution containing 10 mass % of MAE. Furthermore, local electrochemical measurements using a newly designed flow-type droplet cell showed that 10 mass% MAE is an effective inhibitor at welded zones. These findings highlight MAE as a promising candidate for corrosion inhibition of rebar in carbonated Ca(OH) 2 solution, suggesting valuable applications in enhancing the safety of critical infrastructures.