Palmitic acid based environmentally benign corrosion inhibiting formulation useful during acid cleansing process in MSF desalination plants

Palmitic acid imidazole (PI) was synthesized in microwave reactor. The obtained product was explored to reveal the mild steel's corrosion inhibiting property in 1 mol L⁻¹ H₂SO₄. It gave maximum inhibition efficiency of 90% at ambient condition. Addition of little amount of KI (6 × 10⁻³ mol L⁻¹) into 1× 10⁻³ mol L⁻¹ of PI further increased its efficiency up to 98%. High corrosion inhibiting property of PI was observed owing to its adsorption on mild steel surface. The synthesized inhibitor molecule adsorbs via physisorption and chemisorption phenomenon; and followed Langmuir adsorption isotherm. Synergistic effect of KI addition with inhibitors was investigated and the obtained synergism parameters revealed a co-operative mechanism. The surface topography analysis and water angle measurements exhibited surface protective and water repelling property of PI. Furthermore, DFT, FIs analysis, MD simulations and RDF analysis were performed for exploring intrinsic molecular property and insightful elucidation of corrosion inhibiting mechanism. It unveiled spontaneous and strong adsorption of both neutral and protonated PI on metals' surfaces in presence of iodide ions. The obtained outcomes suggested that the combination of KI and PI may be the preferable corrosion inhibitor during acid cleansing process in MSF desalination plants.