Aqueous Extract of Ammodaucus leucotrichus L. as an Eco-Friendly Corrosion Inhibitor for Mild Steel Under Acid Pickling Conditions: Electrochemical, SEM/EDS, and DFT Study
Year: 2026
Type: article
Abstract: The aqueous seed extract of Ammodaucus leucotrichus Cosson & Durieu (AL-AE), a Saharan annual herb of the family Apiaceae, was evaluated for the first time as a green corrosion inhibitor for mild steel in 1.0 M hydrochloric acid. GC-MS analysis after acetylation derivatization identified ten constituents representing 99.22% of the total detected area, with 17-pentatriacontene (47.69%), 2,4-di-tert-butylphenol (13.24%), and myo-inositol (8.62%) as the dominant species. Inhibition performance was assessed by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) over 25–100 ppm at 298–328 K. At 100 ppm and 298 K, AL-AE achieved 96.17% by EIS and 97.10% by PDP. Adsorption obeyed the Langmuir model with a standard free energy of adsorption of −38.2 kJ mol−1, consistent with a mixed physisorption–chemisorption mechanism. SEM/EDS confirmed protective film formation, with surface oxygen dropping from 34.9 to 4.1 wt%. Density functional theory (DFT) calculations at the B97-3c/CPCM (water) level in ORCA 6.1 identified 2,4-di-tert-butylphenol as the most reactive constituent, while Fukui index analysis based on Mulliken population analysis located the preferential adsorption sites on each molecule.
Source: Coatings
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,137
OpenAlex ID: W7167635299