Surface Corrosion Inhibition of Mild Steel in an Acidic Environment by an Anthelmintic Drug: Experimental, RSM, DFT and MD Simulation Studies

Abstract

Gravimetric, electrochemical, surface investigation, RSM and theoretical computational studies, using DFT and MD, were employed to investigate Ecorr inhibition of MS surfaces in 0.5 M H2SO4, by a worm expelling drug (Wormin® MBZ). The results from computational and RSM optimization and experimental methodologies were all in good accord. After 24 h, IE(%) of 1.5 g/L MBZ on MS corrosion, calculated from WL data, was 96.610%. Maximum IE(%) of 1.0 g MBZ was 96.903% (303 K) and 99.998% (333 K). PDP confirmed MBZ mixed nature of adsorption. The impact of the inhibitor C and IT of MS on IE(%) of MBZ was revealed by statistical evaluation and optimization, using Design Expert software package (Stat-Ease). The optimized IE(%) of 96.6103% was obtained with the inhibitor C of 1.061 g/L, at MS 48.58 h IT. On the MS surface, MBZ behaved according to Langmuir’s adsorption isotherm. MD showed that MBZ had an Einteraction of -536.33 and -694.53 kcal/mol, at 303 and 333 K, respectively. Negative Einteraction forecasts confirmed MBZ-MS surface interaction capability, which reinforced the experimental investigations IE(%) findings