CORROSION INHIBITION AND ADSORPTION BEHAVIOR OF MALACHITE GREEN DYE ON ALUMINUM CORROSION

Abstract

Malachite green dye (MG) was studied as a corrosion inhibitor for aluminum in 1.0 mol dm−3 HCl and 0.5 mol dm−3 KOH using the gravimetric technique. The results revealed an inhibiting effect of MG, which was highly restrained in 0.5 M KOH and pronounced in 1.0 M HCl. MG inhibited the corrosion reaction in the acidic medium by adsorption on the metal/solution interface following the Flory-Huggins isotherm. Inhibition efficiency increased with MG concentration and synergistically increased in the presence of iodide ions, but decreased with a rise in temperature. The local reactivity of the MG molecule was analyzed theoretically using the density functional theory to explain the adsorption characteristics, while molecular dynamics simulations were performed to illustrate the adsorption structure of MG at a molecular level. The theoretical predictions showed good agreement with experimental results.