Investigating the Corrosion Inhibition Performance of Methyl 3H-2,3,5-triazole-1-formate for Mild Steel in Hydrochloric Acid Solution: Experimental and Theoretical Insights

Corrosion presents a formidable challenge to the durability of metallic materials, especially in aggressive environments. This study delves into the corrosion inhibition capabilities of Methyl 3H-2,3,5-triazole-1-formate when applied to mild steel immersed in a 1 M HCl solution. Weight loss techniques meticulously scrutinize the inhibitor's efficacy across concentrations (0.1, 0.2, 0.3, 0.4, 0.5, and 1 mM). Immersion durations (1, 5, 10, 24, and 48 hours), all conducted at a constant temperature of 303 K. Furthermore, we explore the influence of temperature fluctuations (ranging from 303 to 333 K) on varying inhibitor concentrations (0.1-1 mM) through a 5-hour immersion period. To delve deeper into the molecular interactions underpinning the inhibitor's effects, we employ Density Functional Theory (DFT) calculations, harnessing the Gaussian 09 software package. Leveraging the B3LYP method, which fuses exchange and correlation functionals alongside a 6-31G++(d,p) basis set, our investigation yields critical insights. Complementary to this analysis, we determine pivotal molecular descriptors, encompassing electronegativity (χ), hardness (η), softness (σ), and transferred electrons fractional number (ΔN). Our experimental findings underscore the inhibitor's prowess, showcasing an impressive inhibition efficiency of 93.8 % at the optimized concentration of 5 mM and an immersion duration of 5 hours at 303 K. Also, we discern that the adsorption behavior of the inhibitor on the mild steel surface aligns with the Langmuir adsorption isotherm, shedding light on its interaction mechanisms. These comprehensive findings hold profound implications for advancing corrosion protection strategies and optimizing inhibitor applications across diverse industrial settings.