Electrochemical and computational investigation of adsorption and corrosion inhibition behaviour of 2-aminobenzohydrazide derivatives at mild steel surface in 15% HCl

The anti-corrosion behaviour of synthesized 1-(2-(5-mercapto-4-phenyl-4H-1,2,4-triazole-3-yl)phenyl)-3-phenylthiourea (MTPT) and 1-phenyl-3-(2-(5-(phenylamino)-1,3,4-thiadiazol-2-yl)phenyl)thiourea (PDPT) were examined by weight loss and electrochemical approaches for the oil well and pipeline steel tube (mild steel) in 15% HCl solution. The output of inhibition efficiencies from weight loss analysis at 303 K temperature and 100 ppm concentration of PDPT and MTPT inhibitor in 15% HCl solution was 97.7 and 94.3%, respectively. The electrochemical studies results well approve the weight loss results. Polarization studies suggested that both inhibitors control the anodic as well as cathodic reactions and act as mixed type inhibitor. The adsorption studies indicate, both inhibitors obey Langmuir adsorption isotherm through mixed adsorption (physisorption as well as chemisorption) process. The formation of organic-inorganic film on the mild steel (MS) surface was investigated by FESEM and AFM studies whereas the composition of the film was investigated by EDX and XPS studies. The theoretical justification of the experimental results was studied through DFT and Monte Carlo simulation (MCS) analysis.