Corrosion Inhibition of Methionine as a Green Corrosion Inhibitor for Carbon Steel in the Presence of Methanol and Monoethanolamine
Abstract - The study of carbon steel corrosion is paramount in many industries as corrosion of metal surfaces incurs massive losses to the industries. Numerous authors worked on corrosion inhibitors but the results shown by the amino acids are promising. Due to this fact, the corrosion rate of aqueous methionine solvents against carbon steel with the weight-loss method was studied in this work. In this weight-loss method, the metal specimens were dipped in aqueous methionine solvents for a specified time. After the exposure, values were put into the formula for calculating results. The results showed that without using the aqueous methionine solution, the corrosion of carbon steel was 2.41 mm/year. For a lower methionine concentration solution (2% MTH, 8% Methanol, and 20% MEA), the corrosion against carbon steel dropped to 0.85 mm/year with a protection efficiency of 62.40%. For a medium concentration solution (5% MTH, 5% Methanol, and 20% MEA), the corrosion reached 0.82 mm/year with a protection efficiency of 63.77%. But as the concentration of methionine was increased, it was found that the corrosion also increased greatly, because, at a higher concentration of methionine (8% MTH, 2% Methanol, and 20% MEA), corrosion became 0.76 mm/year with a protection efficiency of about 66.81%. The presence of methionine lowers the corrosion rate even much better than other amino acids. The inhibition efficiencies of methionine are augmented with improved methionine concentration. The new solvent mix can be employed as an efficient corrosion inhibitor.
Keywords - Corrosion, Carbon Steel, MTH (Methionine), Amino Acids, Methanol, MEA (Monoethanolamine), Weight Loss Method.