Extraction, Characterization and Anticorrosion Potential of an Essential Oil from Orange Zest as Eco-friendly Inhibitor for Mild Steel in Acidic Solution

Current research efforts now focus on the development of novel, cheaper, nontoxic, highly efficient and eco-friendly corrosion inhibitors as alternatives to different inorganic and organic compounds. In this context, orange zest essential oil (OZEO) was investigated as corrosion inhibitor for mild steel in 1 M HCl medium utilizing different techniques such as gas chromatography–mass spectrometry (GC–MS), mass loss, electrochemical and scanning electron microscope (SEM) associated with energy-dispersive X-ray spectroscopy (EDX). The obtained results indicated that this OZEO acted as an efficient corrosion inhibitor and the inhibition efficiency reached up to 75.64% at 2.5 g L−1 of OZEO. The potentiodynamic curves revealed that OZEO acted as mixed inhibitor with a predominantly anodic action, facilitating the formation of an adsorbed film over the mild steel surface. The adsorption data is fitted to Langmuir, Flory–Huggins, Freundlich, El-Awady, Temkin, Frumkin, Langmuir–Freundlich and Dubinin–Radushkevich isotherms models and involve chemisorption mechanism. SEM examination and EDX analysis of the mild steel surface confirmed the existence of a protective adsorbed film.