Superior Performance and Adsorption Mechanism of Corydalis govaniana Root Extract as a Novel Green Inhibitor for Mild Steel Corrosion in One Molar Sulfuric Acid

Green corrosion inhibitors are widely recognized for their eco‐friendly and sustainable applications in protecting metallic substrates during acid cleaning processes. In this study, the methanol extract of Corydalis govaniana root was investigated as a potential green inhibitor for mild steel in 1 M H 2 SO 4 . The extract was successfully prepared and characterized using Fourier transform infrared (FTIR) spectroscopy, confirming the presence of organic functional groups responsible for corrosion inhibition. The inhibitory performance was evaluated using weight loss measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) methods, yielding inhibition efficiencies of 94.59%, 92.85%, and 80.23%, respectively. Surface morphological analysis via scanning electron microscopy (SEM) further validated the effectiveness of the inhibitor in protecting the mild steel surface. At the same time, thermodynamic studies revealed a strong adsorption behavior, as indicated by the Langmuir isotherm model. These findings collectively demonstrate that the methanol extract of Corydalis govaniana root exhibits excellent corrosion inhibition properties, positioning it as a viable, environmentally benign alternative to conventional inhibitors for industrial applications in acidic environments.