Synthesis and Corrosion Inhibition Studies of (E)-3-(2-(4‑chloro-2-nitrophenyl)diazenyl)-1-nitrosonaphthalen-2-ol on Mild Steel dissolution in 0.5 M HCl Solution- Experimental, DFT and Monte Carlo Simulations

Abstract

Corrosion process and means of eradicating it continue to gain attention amongst researchers. The use of organic corrosion inhibitors became popular owing to their macroscopic physico-chemical properties. In this study, (E)-3-(2-(4‑chloro-2-nitrophenyl)diazenyl)-1-nitrosonaphthalen-2-ol (CNN) was synthesized and characterized via FTIR, UV–Vis and NMR (1H and 13C) spectroscopy. Its corrosion inhibition efficiency measurements against mild steel corrosion were carried out in acidic condition by gravimetric and electrochemical methods. Quantum mechanical calculations and Monte Carlo (MC) simulation were used to corroborate experimental findings. Kinetic, adsorption and thermodynamics studies revealed CNN as having promising inhibitory action against 0.5 M HCl solution used especially at high dosage. The adsorption mechanism of CNN was found to be complex adsorption mechanism via the most fitted isotherm, Langmuir isotherm. The Tafel plot showed that CNN is a mixed-type inhibitor. Both weight loss measurements and electrochemical studies confirmed that the inhibition efficiency increased with increased concentration of CNN. The SEM/EDS results revealed that the mild steel was protected by the inhibitors. Theoretical results obtained are well in agreement with the experimental results. The MC simulation showed spontaneous adsorption of CNN on Fe(110) surface in hydrochloric acid medium.