N-Methyl-2-(1-(5-methylthiophen-2-yl)ethylidene) hydrazinecarbothioamide as Corrosion Inhibitor for Mild Steel in HCl Solution: Weight Loss and DFT Investigations

Abstract

For This study investigated the corrosion inhibition performance of N-methyl-2-(1-(5-methylthiophen-2yl)ethylidene)hydrazinecarbothioamide (MTET) on mild steel in hydrochloric acid (HCl) solution using weight loss and density functional theory (DFT) methods. The effects of temperature were also studied at the range of 303 to 333 K. The corrosion inhibition efficiency of MTET increased with increasing concentration and exposure time, while it decreased with increasing temperature. At the highest concentration of 0.0005 M, the inhibition efficiency reached 95.5% after 5 hours of immersion time. The Langmuir adsorption isotherm was found to describe the adsorption behavior of MTET on the mild steel surface, and the free energy value indicated that the inhibition process was both chemical and physical in nature. DFT calculations showed that the adsorption of MTET on the mild steel surface involved the formation of chemical bonds between the nitrogen and sulfur atoms of MTET and the iron atoms of mild steel. Overall, the results suggest that MTET is an effective inhibitor for mild steel corrosion in HCl solution, and the DFT calculations provide valuable insights into the underlying mechanisms of the inhibition process.