Isoxazole-based corrosion inhibitor for mild steel in acidic medium: adsorption, electrochemical, and computational studies

A novel heterocyclic isoxazole compound was assessed as an efficient corrosion inhibitor for mild steel in 1 M HCl. The corrosion inhibition performance was systematically evaluated using gravimetric and electrochemical impedance spectroscopy techniques. Thermodynamic parameters were computed and discussed in this investigation. Computational methods, including density functional theory (DFT) calculations and molecular dynamic simulations (MD), were conducted to provide valuable insights into the electronic properties and adsorption mechanism. Besides, molecular docking simulations (MDOC) were performed to study the bending affinity toward Acidithiobacillus ferrooxidans and Thiobacillus ferrooxidans bacteria, both of which play a role in microbiologically influenced corrosion. As a result, at an optimal concentration of 5 × 10− 4 (M) and 303 K, the corrosion inhibition performance for the gravimetric test achieved over 90%. Electrochemical impedance spectroscopy indicated a significant enhancement in charge transfer resistance (Rct) and a notable decrease in double-layer capacitance (Cdl) when the inhibitor was introduced at various concentrations. The adsorption behavior was well described by the Langmuir isotherm model. Both DFT calculations and MD simulations exhibited a strong anticorrosion performance, and (MDOC) simulations revealed a strong tendency of the isoxazole compound to mitigate Acidithiobacillus ferrooxidans and Thiobacillus ferrooxidans bacteria.