Understanding the corrosion inhibition of mild steel by selected green compounds using chemical quantum based assessments and molecular dynamics simulations

Both quantum chemical calculations and molecular dynamics simulations enabled better understanding of mild steel corrosion inhibitions by citrulline (CE), quercetin (QN), and bonducellin (BN) as green compounds, at molecular level. The theoretical study gave insights to the active sites, chemical reactivity and possible interaction mechanism between the inhibitor compounds and mild steel surface. The compounds showed sufficient nucleophilicity in sulfuric acid medium to indicate their low propensity to accept electron from mild steel, to affirm their corrosion inhibition effects. Based on the obtained theoretical parameters, these compounds could be ranked in the order of QN > BN > CE for their degrees of inhibition efficiencies. These compounds bound onto iron surface spontaneously with binding energies of 570.95 kcal/mol, 563.96 kcal/mol, and 539.23 kcal/mol for QN, BN, and CE respectively. (C) 2019 Elsevier B.V. All rights reserved.