Three imidazole ionic liquids as green and eco-friendly corrosion inhibitors for mild steel in sulfuric acid medium

• Published in: Journal of molecular liquids Vol. 324; p. 115063
• Main Authors: Zeng, Xianguang, Zheng, Xingwen, Guo, Lei, Xu, Qian, Huang, Hui, Tan, Bochuan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.02.2021
• Subjects: Adsorption; H2SO4; Ionic liquids; Mild steel; SEM; H2SO4; Ionic liquids; SEM; Mild steel; Adsorption
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2020.115063

In this paper, the corrosion inhibition performance of eco-friendly corrosion inhibitors 1-propyl-3-methylimidazolium bromide ([PrMIm]Br), 1-aminopropyl-3-methylimidazolium bromide ([APMIm]Br) and 1,4-bis(3-methylimidazolium-1-yl)butane dibromide ([BMImB]Br2) was investigated for mild steel (MS) in H2SO4 medium via experimental and theoretical methods. The results of electrochemical experiments show that the order of their corrosion inhibition is [BMImB]Br2 > [APMIm]Br > [PrMIm]Br. The corrosion inhibition efficiency of [BMImB]Br2, [APMIm]Br and [PrMIm]Br are 92.9%, 88.0%, and 69.6% at the 303 K, respectively. The scanning electron microscope (SEM) morphology test results vividly prove that [BMImB]Br2 has higher corrosion inhibition performance for [APMIm]Br and [PrMIm]Br. Weight loss experiments show that [BMImB]Br2 and [APMIm]Br can still exhibit good corrosion inhibition nature with increasing temperature. Besides, the adsorption of three imidazole ionic liquids on the MS/solution interface is conform to Langmuir single-layer model, and they belong to the physical and chemical adsorption on the MS surface. Theoretical calculations explain their corrosion inhibition mechanism from an atomic or molecule perspective. •Electrochemical test data indicate [BMImB]Br2, [APMIm]Br and [PrMIm]Br belong to mixed-type corrosion inhibitor.•The corrosion inhibition performance is [BMImB]Br2 > [APMIm]Br > [PrMIm]Br.•The corrosion inhibition mechanism was revealed by thermodynamic and kinetic analysis and theoretical calculation.