Experimental and theoretical studies of five imidazolium-based ionic liquids as corrosion inhibitors for mild steel in H<sub>2</sub>S and HCl solutions
Fusheng Cui, Yuqing Ni, Juncheng Jiang, Lei Ni, Zhirong Wang
Abstract
In this study, the mild steel corrosion inhibition performance and the corresponding mechanisms of five imidazolium-based ionic liquids (ILs) in hydrogen sulfide (H2S) and hydrochloric acid (HCl) solutions were investigated using electrochemical experiments, weight loss measurement, morphology analysis, and quantum chemical calculation. The results revealed that these ILs inhibited the corrosion of mild steel in H2S and HCl solutions and did not change the corresponding mechanism of the corrosion reaction. The corrosion inhibition ability of these ILs decreased when the temperature increased. 1-Allyl-3-methylimidazolium bromide ([Amim]Br) exhibited the strongest mild steel corrosion inhibition capacity in H2S and HCl solutions. The corrosion inhibition capacity of the ILs can be attributed to their adsorption on metal surfaces, which obeys the Langmuir adsorption isotherm. EHOMO exhibited a higher influence than ELUMO on the corrosion inhibition performance of the imidazolium-based ILs.