Performance evaluation of poly (methacrylic acid) as corrosion inhibitor in the presence of iodide ions for mild steel in H₂SO₄solution

AbstractThe inhibition performance of poly (methacrylic acid) (PMAA) and the effect of addition of iodide ions on the inhibition efficiency for mild steel corrosion in 0.5 M H2SO4 solution were investigated in the temperature range of 303–333 K using electrochemical, weight loss, scanning electron microscopy (SEM), and water contact angles measurements. The results show that PMAA is a moderate inhibitor for mild steel in 0.5 M H2SO4 solution. Addition of small amount of KI to PMAA significantly upgraded the inhibition efficiency up to 96.7%. The adsorption properties of PMAA and PMAA + KI are estimated by considering thermodynamic and kinetic parameters. The results reveal that PMAA alone was physically adsorbed onto the mild steel surface, while comprehensive adsorption mode characterized the adsorption of PMAA + KI. Adsorption of PMAA and PMAA + KI followed Temkin adsorption isotherm. The SEM and water contact angle images confirmed the enhanced PMAA film formation on mild steel surface by iodide ions.Keywords: mild steelcorrosion inhibitionpoly (methacrylic acid)iodide ionssynergism AcknowledgmentsThe support by TWAS, the Academy of Sciences for the Developing World, under the TWAS Grants for Research Units in Developing Countries Program (10-107RG/CHE/AF/AC-G) is gratefully acknowledged. Centre of Research Excellence in Corrosion, Research Institute, and King Fahd University of Petroleum and Minerals (KFUPM) is also gratefully acknowledged for providing some of the facilities for the research.Additional informationFundingThis work was supported by TWAS, the Academy of Sciences for the Developing World, under the TWAS Grants for Research Units in Developing Countries Program [10-107RG/CHE/AF/AC-G].