Advanced evaluation of novel quinoline derivatives for corrosion inhibition of mild steel in acidic environments: A comprehensive electrochemical, computational, and surface study

Corrosion poses a significant threat to the integrity and longevity of iron and its alloys, which are crucial materials for modern industry and infrastructure. This study investigates the effectiveness of two recently synthesized inhibitors based on quinoline structures: MPQ (2-methyl-5-(propoxymethyl) quinolin-8-ol) and AAQ ((((2-aminoethyl)amino)methyl)-2-methylquinolin-8-ol) in protecting steel against environmental degradation, particularly in acidic and chloride-rich conditions such as hydrochloric acid. The inhibitors exhibited significant corrosion inhibition efficiencies of 92.37 % for MPQ and 84.13 % for AAQ, as demonstrated through electrochemical analysis. Surface characterization techniques, including SEM-EDX(Scanning Electron Microscopy with Energy Dispersive X-ray analysis), AFM (Atomic Force Microscopy), and contact angle measurements, revealed the formation of a protective barrier film that reduces the corrosion rate. Additionally, theoretical calculations using the Gaussian package provided insights into the adsorption behaviors and protective mechanisms of the inhibitors on mild steel surfaces. The findings contribute to the ongoing search for viable corrosion inhibitors, offering prospects for application in industries and critical infrastructures to enhance corrosion protection and durability.