Experimental and theoretical (DFT & MC) studies for the adsorption of the synthesized Gemini cationic surfactant based on hydrazide moiety as X-65 steel acid corrosion inhibitor

We synthesized new cationic Gemini surfactant (GI-surfactant) namely; N,N '-((ethane-1,2-diylbis(oxy))bis(2oxoethane-2,1-diyl))bis(N,N-dimethyl-4-((E)-(2-((E)-octadec-9-enoyl)hydrazineylidene)methyl)benzenaminium) dichloride and elucidated its chemical structure using different spectroscopic techniques. Polarization curves suggest that the inhibitor being studied is acting as a mixed-type. The higher concentration, the higher inhibition efficiency reaching 94% at 1 x 10(-4)M but it decreases to 64% with raising the temperature to 65 degrees C. Enrichment of GI-surfactant with the centers of high electron density increases the charge transfer resistance (R-ct) of X-65 steel and drops the corrosion rate. Adsorption phenomena was the reason for the inhibition action of the under studied GI-surfactant and followed Freundlich isotherm model. Adsorption affinity of GI-surfactant over X-65 steel was verified via Monte Carlo (MC) simulation and surface morphology study. X-ray diffraction (XRD) analysis indicates the reduction in metal oxides formation after GI-surfactant addition. This supports the inhibitory effect of the tested GI-surfactant.