Novel bisbenzoxazole derivative as an effective corrosion inhibitor for C38 steel in hydrochloric acid medium: experimental and theoretical investigations

Abstract

ABSTRACT This study examines the inhibitory capacity of synthesised bis-benzoxazole (BBOSZ) for C38 steel, in hydrochloric acid medium, using electrochemical techniques (EIS and PDP methods), as well as spectroscopic methods. The polarisation results reveal the mixed character of the BBOSZ inhibitor's properties. The obtained efficiency is about 96.89% at 5.10−4 M BBOSZ. The isotherm of adsorption indicates that the inhibitor adsorbs onto the surface via the Langmuir model, with ΔG°adsorption around −41.12 (kJ mol–1), this suggests the inhibitor reduces corrosion via chemical and physical adsorption. Scanning electron microscopy analysis confirms the adsorption mechanism. The interaction between the inhibitor, hydrochloric acid, water, and the iron surface was analysed using theoretical methods such as DFT, MC, and MD simulation. The provided results by theoretical calculations and experimental data proved highly consistent. The data reveals that the adsorption of bis-benzoxazole provides a barrier layer onto the metallic surface, contributing to corrosion prevention.