An experimental and theoretical investigation of adsorption characteristics of a Schiff base compound as corrosion inhibitor at mild steel/hydrochloric acid interface

Abstract

This study investigates the effect of a Schiff base namely 2-[2-(2-(3-phenylallylidene)hydrazine carbonothioyl)hydrazinecarbonyl]benzoic acid (SB), on corrosion inhibition of mild steel in 1 M HCl. Electrochemical impedance measurement, potentiodynamic polarization and weight loss methods were applied to study adsorption of SB at metal/solution interface. Results revealed that SB is an excellent inhibitor for mild steel corrosion in 1 M HCl; showing a maximum efficiency 99.5% at concentration of 1.36 9 10 -6 M. Fourier transform infrared spectroscopy (FTIR) observations of the mild steel surface confirmed the formation of protective film on the metal surface by studied compound. Polarization studies showed that SB is a mixed-type inhibitor. Adsorption process obeyed Langmuir's model with a standard free energy of adsorption (DG°a ds ) of -46.7 kJ mol -1 . Energy gaps for interactions between mild steel surface and inhibitor were found to be close to each other showing that SB possess capacity to behave as both electron donor and acceptor.

Acenaphtho[1,2-b]quinoxaline and acenaphtho[1,2-b]pyrazine as corrosion inhibitors for mild steel in acid medium

“…The capacitance, C dl values were lower due to a decrease in the local dielectric constant and/or an increase in the thickness of the electrical double layer, suggesting that the inhibitor molecules acted by adsorption at the metal/solution interface. The R t value increases while C dl decreases with increasing inhibitor concentration indicates considerable surface coverage by the inhibitor and strong bonding to the surface [52]. In the absence and presence of inhibitors, the phase shift values remain more or less identical, indicating that a chargetransfer process controls the dissolution mechanism of …”

Effect of cysteine on the electrochemical behavior of Cu10Ni alloy in sulfide polluted environments: Experimental and theoretical aspects

“…Moreover, the values of these slopes are nearly identical suggesting that cys blocks some electrode surface area without participating in the mechanism of metal dissolution [41]. The addition of only 80 ppm cys decreases the corrosion rate from 112.9 to 18.36 mm year À1 (Table 1), which is accompanied with a significant increase in the inhibition efficiency up to 83.8%.…”

Corrosion Inhibition of Triazinedithoil for Aluminum Alloy in Hydrochloric Acid Solution

“…With the prolonging of immersion time, the inhibition efficiency decreased slightly, which was due to that the protective inhibitor molecules were incomplete and disorder to induce local corrosion. According to Ahamad et al [16], the decrease of ηw (%) with immersion time is due to increased desorption and decreased adsorption.…”