Plant derived corrosion inhibitor for copper: Integrated electrochemical and molecular insights into Ailanthus altissima seed extract performance in saline media

The search for environmentally friendly corrosion inhibitors has intensified as a sustainable alternative to toxic synthetic chemicals. This study reports, for the first time, the use of Ailanthus altissima seed extract (AASE) as a green inhibitor for copper corrosion in 3.5 wt% NaCl solution. What makes this research unique is that the seeds of this deciduous tree are naturally abundant, cost-effective, and environmentally friendly, making them an attractive, sustainable source of inhibition agents. Gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared (FT-IR) spectroscopy analysis confirmed the presence of heteroatom-containing phytochemicals (N, P, O, F) in AASE, suggesting its strong inhibitory potential. Electrochemical measurements, including potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), demonstrated that AASE acts as a mixed-type inhibitor, reducing corrosion by forming a protective film, with inhibition efficiency ( IE% ) reaching up to 94 % as further confirmed by weight loss tests. However, IE% decreased with rising temperature, indicating a temperature-dependent adsorption mechanism. Surface characterization via atomic force microscopy (AFM), scanning electron microscopy (SEM), and contact angle analysis confirmed inhibitor adsorption and surface modification. Adsorption studies revealed that AASE obeys the Langmuir isotherm at 298–338 K. Molecular dynamics (MD) simulations identified 3-benzyloxy-2-fluoro-4-methoxy (BABFM) as the most active constituent responsible for strong surface passivation. Overall, these findings establish AASE as a promising, sustainable, and eco-friendly corrosion inhibitor for copper in chloride-rich environments, offering a viable alternative to conventional synthetic inhibitors.