Isatin Schiff base is an effective corrosion inhibitor for mild steel in hydrochloric acid solution: gravimetrical, electrochemical, and computational investigation

Abstract

This paper describes the synthesis and characterisation of an isatin Schiff base, namely 2-(2-oxoindolin-3-ylidene) hydrazinecarbothioamide (OHB). The chemical structure of OHB was elucidated through proton-nuclear magnetic resonance (1H-NMR), carbon-nuclear magnetic resonance (13C NMR), and Fourier-transform infrared (FT-IR) spectroscopic techniques. OHB was evaluated for its corrosion inhibition ability on mild steel specimens in 1 M HCl using gravimetrical methods and electrochemical measurements such as electrochemical impedance spectroscopy (EIS) and potentiodynamic techniques complemented with microscopic analysis. The results indicated that OHB is a mixed-type inhibitor and showed good corrosion inhibition, with a maximum corrosion inhibition efficiency of 96.7% at a concentration of 0.5 mM and 303 K. The inhibition performance increased with an increasing OHB concentration and decreased with increasing temperature. The inhibition efficiency was attributed to the formation of a protective film on the surface of the tested mild steel coupon. The electrochemical impedance studies also indicated that the charge transfer resistance increased with an increase in OHB concentration. The morphological analysis confirmed the inhibition performance of OHB and the protective barrier film conformed to Langmuir monolayer adsorption. The experimental and theoretical corrosion kinetics and thermodynamic parameters were in agreement and revealed that an adsorption film of Fe–N coordination bonds formed on the mild steel surface.

WITHDRAWN: N,N′-bis(salicylidene) butylene-1,4-diamine, a synthesized Schiff base, as a mixed-type inhibitor for carbon steel in HCl medium: Experimental and theoretical approaches

“…A class of organic compounds known as Schiff's bases are synthesized by condensation of aliphatic or aromatic amines with aldehyde. Recently, they have been found to be excellent corrosion protectors for CS in several environments, especially sulphuric and hydrochloric acids [7][8][9][10][11][12][13][14][15][16][17][18][19]- [20]. A few scientists attributed the inhibition e cacy to the existence of vacant π* orbitals in Schiff base molecules.…”

“…They claimed that raising the concentration of the synthetic inhibitor improves inhibition effectiveness. 2-(2-oxoindolin-3-ylidene) (OHB), an isatin Schiff base, was synthesized and described by Al-Ameriy and coworker [17]. Using gravimetric techniques and electrochemical tests, they assessed the mild steel specimens' capacity to suppress corrosion in 1 M HCl.…”

Novel high-performance and cost-effective green inhibitor based on fundamental theoretical evaluations combined with electrochemical/surface examinations of Arachis hypogaea shell extract for pipeline steel corrosion in 1 M H2SO4 solution

“…Observation from figure 5 shows that without AHS, severe damage, with pit and cavity, showed on the steel surface. This illustration discloses that the passive films covered the steel surface effectively and blocked the active site [40]. It is obvious from this result that the AHS molecules adsorbed on the steel substrates results to a reduced roughness on the metal surface [41,42].…”

Corrosion Prevention of Copper in 2.0 M Sulfamic Acid Using Novel Plant Extract: Chemical, Electrochemical, and Theoretical Studies

“…The corrosion rate decreases as the inhibitor concentration rises, and the effectiveness of the inhibition also rises . To maximize the effectiveness of inhibition, a protective coating must be formed via adsorption or by covering the electrode surface with inhibitor molecules . This is interpreted as an increase in the efficiency with increasing concentration.…”