title: Corrosion inhibition and adsorption behavior of methionine on mild steel in sulfuric acid and synergistic effect of iodide ion.
abstract: The corrosion inhibition of mild steel in sulfuric acid by methionine (MTI) was investigated using electrochemical techniques. The effect of KI additives on corrosion inhibition efficiency was also studied. The results reveal that MTI inhibited the corrosion reaction by adsorption onto the metal/solution interface. Inhibition efficiency increased with MTI concentration and synergistically increased in the presence of KI, with an optimum [KI]/[MTI] ratio of 5/5, due to stabilization of adsorbed MTI cations as revealed by AFM surface morphological images. Potentiodynamic polarization data suggest that the compound functioned via a mixed-inhibition mechanism. This observation was further corroborated by the fit of the experimental adsorption data to the Temkin and Langmuir isotherms. The inhibition mechanism has been discussed vis-à-vis the presence of both nitrogen and sulfur atoms in the MTI molecule.
authors.affiliation: State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China. oguziemeka@yahoo.com
authors.forename: E E
authors.initials: EE
authors.lastname: Oguzie
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: F H
authors.initials: FH
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D003343:Corrosion; D008715:Methionine / Q000494:pharmacology*; D018625:Microscopy, Atomic Force; D011193:Potassium Iodide / Q000737:chemistry*; D013232:Steel / Q000737:chemistry*; D013464:Sulfuric Acids / Q000737:chemistry*
chemical_list: D013464:Sulfuric Acids; D013232:Steel; D011193:Potassium Iodide; D008715:Methionine; C033158:sulfuric acid