Abstract
The present work shows the chitosan composite development using Salicylaldehyde (Sali-Cht). The developed composite was used as P110 steel corrosion inhibitor in 15% HCl under dynamic condition at 1500 rpm using electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM), and potentiodynamic polarization (PDP). The EIS results disclosed that Sali-Cht inhibits corrosion via charge transfer process. The PDP data indicated that Sali-Cht suppresses both the cathodic and anodic corrosion process. The maximum inhibition efficiency of Sali-Cht is 89.23% (400 mg/L). The adsorption of Sali-Cht over the steel surface was confirmed using X-ray photoelectron spectroscopy (XPS). Morphological changes on the steel surface were monitored by scanning electron microscopy (SEM). The thermodynamic parameters such as the adsorption equilibrium constant (Kads) and the free energy of adsorption (ΔGads) were calculated and discussed. Several adsorption isotherms were tested and the experimental data fitted well with the Langmuir adsorption isotherm. Density functional theory (DFT) suggests that protonated forms of Sali-Cht have more adsorption ability than neutral forms. Molecular dynamic simulation (MD) study revealed that protonated form adsorbed flatly over the P110 steel surface, while neutral form adsorbed in a twisted manner.
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•The inhibition efficiency of Sali-Cht is 89.23% (400 mg/L) in 15% HCl at 1500 rpm.•DFT reveals participation of both neutral and protonated form in inhibition process.•MD reveals Sali-Cht configuration is flat and twisted in neutral and protonated forms respectively.•PDP suggests that inhibition action of Sali-Cht is a mixed type.•SEM and XPS studies confirmed Sali-Cht adsorption.