Enhanced corrosion inhibition effect of polypropylene glycol in the presence of iodide ions at mild steel/sulphuric acid interface

Abstract The corrosion inhibition effect of polypropylene glycol (PPG) without and with addition of iodide ions at mild steel/0.5 M H₂SO₄ solution interface was investigated using chemical, electrochemical, and surface analysis methods at different temperatures. Results obtained showed that PPG inhibited the corrosion of mild steel in the acid environment. Addition of iodide ions to PPG is found to synergistically enhance the corrosion inhibitive ability of PPG with efficiency in the vicinity of 98.4%. Temperature-inhibition efficiency relationship suggest physisorption of PPG onto mild steel surface and chemisorption when PPG was combined with iodide ions. Potentiodynamic polarization results showed that PPG behaved as mixed type inhibitor but under anodic control when combined with iodide ions. The adsorption of PPG and PPG-iodide ions mixtures onto the metal surface followed Temkin adsorption isotherm model.