Electrochemical and Quantum Chemical Studies of Adsorption and Corrosion Inhibition of Two New Schiff Bases on Carbon Steel in Hydrochloric Acid Media

Abstract

The inhibiting effect of two newly synthesized Schiff bases was investigated on the corrosion of carbon steel in 1M hydrochloric acid solution under various conditions by weight loss, impedance, and potentiodynamic polarization measurements. The Schiff bases used were 4,4'-bis (2-hydroxy-1-naphthaldehyde imine) diphenylether (L1) and 4,4'-bis(2-Hydroxy-1-naphthaldéhyde imine) diphenylmethane (L2). The inhibition efficiency of these compounds varied with concentration and immersion time. Potentiodynamic polarization study indicated that the tested compounds are mixed type (cathodic/anodic) inhibitors. Electrochemical impedance spectroscopy was also used to investigate the mechanism of corrosion inhibition, it showed that the charge transfer resistance (R ct ) increased and double layer capacitance (C dl ) decreased with an increase in the inhibitor concentration. The inhibition efficiency was found to increase with increasing inhibitor concentration. The adsorption of the inhibitor on the metal surface obeys Langmuir isotherm.

Experimental and In-Silico Computational Modeling of Cerium Oxide Nanoparticles Functionalized by Gelatin as an Eco-Friendly Anti-Corrosion Barrier on X60 Steel Alloys in Acidic Environments

“…In addition, the fraction of electron transfer and ∆E back-donation are pivotal directories to clarify the electron-donating or accepting ability of inhibitor molecules. Hence, if the ∆N values are >0, the electron transfer is feasible from inhibitor to steel interface atoms, whilst if the ∆N values are <0 zero, the electron transfer is possible from metal atoms to inhibitor molecules (i.e., back-donation) [51]. According to the ∆N value recorded in Table 3, the ∆N value for examined molecules is greater than zero (1.85) and higher than the CeO 2 and gelatin molecules, demonstrating that the CeO 2 @gelatin molecule is able to contribute electrons to the steel surface.…”

PHENOLICS COMPOSITION, ANTIOXIDANT AND CORROSION INHIBITION EFFICIENCY, CAPACITY OF F raxinus Excelsior EXTRACTS

“…The impedance spectra showed the single semicircle and the diameter of semicircle increases with increasing concentration of the inhibitor [50]. The semicircles show slight irregularity which may be attributed to the roughness, impurities, dislocations, or non-homogeneous nature of the metal surface [51][52][53][54][55][56]. The capacitance loop intersects the real axis at higher and lower frequencies.…”

Reaction Products of Crude Palm Oil-based Fatty Acids and Monoethanolamine as Corrosion Inhibitors of Carbon Steel

“…This result that more energy was required for the corrosion reaction to proceed with the inhibitor on the carbon steel metal surface. Δܵ* was higher for the sample compared to the blank, indicating an increase in Δܵ* when the reactant changed into activated complex, making the inhibitor easier to attach to the metal surface [19-The kinetic parameter was determined by reviewing the Ea calculated from the relationship between ln Cr and 1/T based on the following Arrhenius equation [20]:…”

“…The kinetic parameter was determined by reviewing the calculated from the relationship between ln Cr and 1/T based on the following Arrhenius equation [20]: 4is activation energy of the corrosion process ), R is the ideal gas constant (8.314 J mol −1 ), and A is the Arrhenius constancy determined empirically from the relationship of slope between ln Cr vs (1/T) as shown in Figure 5b. Positive value of the Ea sample was higher than the blank from 0.01 to +12.69…”