Experimental and theoretical studies of the inhibition performance of two furan derivatives on mild steel corrosion in acidic medium

Abstract

Inhibition performance of 2‐furanmethanethiol (FMT) and 2‐furonitrile (FN) against mild steel corrosion in 1 M hydrochloric acid was investigated using weight loss, adsorption isotherms, and electrochemical impedance spectroscopy (EIS). The surface morphology was studied by field emission scanning electron microscope (FESEM) and X‐ray photoelectron spectroscopy (XPS). Quantum chemical calculations were carried out to establish the active sites on the inhibitors. The results show that both inhibitors inhibit mild steel corrosion, and their inhibition efficiencies (IE) increase with increasing inhibitor concentration. FMT shows higher inhibiting effect with IE of 94.54% at 0.005 M. The adsorption of the inhibitors onto mild steel surface obeys Langmuir isotherm. FESEM analysis confirms the adsorption of both inhibitors on the surface. XPS analysis proves the adsorption of FMT onto the surface. The active sites on FMT and FN molecules were effectively established using density functional theory (DFT) based on natural atomic charge, Fukui indices, HOMO and LUMO frontier molecular orbitals. The experimental and quantum results prove the inhibition performances of both inhibitors. FMT performs as an efficient inhibitor with a significant and higher IE compared to FN.

Chitosan as a green inhibitor for mild steel corrosion: Thermodynamic and electrochemical evaluations

“…In order to broaden our knowledge of the chitosan/mild steel interactions and to determine the mechanisms by which chitosan inhibited the corrosion of mild steel, the results from the weight loss experiments were analyzed by Langmuir adsorption isotherm with the following equation [28] :…”

“…(7), the Gibbs free energy of adsorption ΔG°a ds À Á which gives a clear indication of the adsorption process was calculated to be −31.4 KJ mol −1 . [28] ΔG°a ds ¼ À RTlnðk ads  C solvent Þ ð 7Þ…”

A novel viewpoint of an imidazole derivative ionic liquid as an additive for cobalt and nickel electrodeposition

“…In general, values of DG a as great as À20 kJ mol À1 are compatible with physical adsorption via electrostatic interaction between the charged molecules and charged metal, whereas values that are more negative than À40 kJ mol À1 are consistent with chemical adsorption via the sharing or transfer of electrons from inhibitor molecules to the metal surface to form a coordination bond. 58 The calculated DG a values of Im-IL in the presence Co 2+ and Ni 2+ are equal to À23.4 and À33.1 kJ mol À1 , respectively, which fall between these two values for physical and chemical adsorption. This result indicates that the adsorption of Im-IL onto the copper substrate surface during the Co and Ni electrodeposition process involves both chemical and physical adsorption (a mixed type) mechanisms.…”

“…From S5a, † for the Co deposit, the plots show one depressed capacitive loop, which is oen attributed to frequency dispersion resulting from inhomogeneity or surface roughness. 58,73 The Im-IL signicantly affects the high-and lowfrequency loop. The diameters of the capacitive loops of Co and Ni in the presence of the Im-IL additive are greater than those for the Im-IL-free baths.…”

“…This result occurs due to formation of a protective layer on the metal deposit surfaces, which happens without changing the corrosion behavior of the surface. 58,74 In the case of the Co deposit, the corrosion behavior does not change due to the presence of the additive in the bath, S5a. † Diffusion behavior is clearly observed on the Ni lm in the presence Im-IL.…”