Electrochemical Assessment of Rhus typhina L. Leaf Extract as a Novel Green Corrosion Inhibitor for OL37 in 1 M HCl Medium.

This study evaluates the corrosion-inhibiting effects of the methanolic (P1) and the hydroalcoholic (P2) extracts of the Rhus typhina L. leaves on carbon steel (OL37) in 1 M HCl. Extracts were prepared with microwave-assisted extraction and characterized using HPLC and LC-MS. Electrochemical methods (OCP, EIS, PDP) and surface analyses (SEM, EDX) assessed the performance of both extracts. The results showed that the P1 and P2 extracts significantly reduced corrosion rates by forming protective layers on the metal surface, with inhibition efficiencies exceeding 90%, at 1000 ppm concentration, for P1 (93%), for P2 at 800 ppm (91%) and 1000 ppm (94%). The P2 extract demonstrated superior long-term performance, maintaining protection after 96 h of immersion. The extracts function as mixed-type inhibitors, affecting both anodic and cathodic reactions, with physicochemical adsorption demonstrated by the Langmuir isotherm. Overall, the Rhus typhina leaf extracts, particularly the P2 extract, offer a promising, eco-friendly approach to corrosion prevention in acidic environments.