Anti-Corrosion potential of the Ortho and Para-Substituted Schiff Bases of 2- Methoxybenzaldehyde on Fe (110) surface in acid medium: Synthesis, DFT and Molecular Dynamics Studies

Abstract

Corrosion inhibition potential of two synthesised Schiff base ligands; (E)-2-((2-methoxybenzylidene)amino)phenol L1 and (E)-2-((4-methoxybenzylidene)amino)phenol L2 were carried out by Density Functional Theory (DFT) and Molecular dynamics (MD) methods and theoretically explain the inhibitors’ intrinsic properties and adsorption mechanism in the corrosion study. The adsorption mechanism of inhibitor on the surface of the Fe metal occurred via chemisorption inferred from the Gibbs free energy (ΔGads). Scanning electron microscopy (SEM) showed a mild degradation on the surface of the mild steel immersed in the L1, and L2 inhibited acid solution, which could be because of surface coverage. DFT calculations revealed that the hybrid B3LYP functional performed better than M06-2X meta-functional in determining the energies of the synthesized Schiff bases for corrosion inhibition giving lower ΔE values 3.86 eV and 3.81 eV for L1 and L2. The MD simulation revealed that the orientation of inhibitors on the surface of the metal resulted in the coordination bond formation and that the interaction energy of L2 was -746.84 kJ/mol compared to -743.74 kJ/mol of L1. The DFT and MD results were in agreement.

Experimental and computational studies of the corrosion inhibitive effects of Zingiber officinale rhizomes on mild steel corrosion in acidic solutions

“…The impedance results were fitted into an equivalent circuit model R s (Q dl R ct ) to get the impedance data presented in Table 2 and Q dl is the double layer capacitance. This equivalent circuit has been previously used to model impedance result [38][39] for mild steel corrosion in acidic media. The solution resistance in the equivalent circuit was shorted by a constant phase element (CPE) which was subsequently connected parallel to the charge transfer resistance (R ct ).…”