Exploring the potential of a new 1,2,4-triazole derivative for corrosion protection of carbon steel in HCl: A computational and experimental evaluation

Abstract

Carbon steel is a commonly used alloy in petroleum refining equipment. Nonetheless, its weak corrosion resistance is a perpetual problem for these industries. In the present study, we manifest the usefulness of a novel 1,2,4-triazole derivative, namely 5-hexylsulfanyl-1,2,4-triazole (HST) in inhibiting the carbon steel (CS) corrosion in 1.0 M HCl using mass loss measurements, electrochemical, scanning electron microscopy coupled with X-ray detection (SEM-EDX), X-Ray diffraction (XRD) and computational techniques. We deduced from the gravimetric study that the optimal concentration of HST is 10−3 M. Its inhibition efficiency can reach 97 % based on electrochemical data. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) results suggest an increased impedance in the presence of HST and mixed nature of inhibitor action, respectively. The compound HST mitigates corrosion at the temperature range of 298 K–338 K, with an inhibition efficiency of 89 % at 338 K. Free Gibbs energy obtained from the Langmuir isotherm model suggests that the inhibitor molecules hinder the acid attack mainly by chemisorption. A computational study based on Density Functional Theory (DFT) and Molecular Dynamics (MD) simulations was performed in an attempt to identify the factors most associated with anti-corrosive properties of the tested compound.