Comprehensive evaluation of lignin extracted from Reseda luteola L. waste: corrosion inhibition performance for XC48 carbon steel and ecotoxicological effect.

Corrosion poses significant challenges, leading to economic losses and safety hazards. Conventional inhibitors, often containing harmful substances, raise environmental concerns. This study explores the corrosion inhibition properties of lignin extracted from Reseda luteola L. waste for XC48 carbon steel in 1 M HCl. Electrochemical impedance spectroscopy, potentiodynamic polarization, and weight loss measurements reveal that lignin acts as an effective mixed-type inhibitor, achieving 93.03% inhibition efficiency at 500 ppm. Adsorption follows the Langmuir isotherm model, indicating monolayer coverage, and thermodynamic data suggest a combination of physical and chemical adsorption mechanisms. The inhibitor forms a protective layer on the steel surface, inhibiting both anodic and cathodic reactions. Scanning electron microscopy and spectroscopic analysis confirm this mechanism. Furthermore, acute toxicity tests with Artemia salina validate lignin's eco-friendly nature, positioning it as a sustainable corrosion inhibitor for carbon steel in acidic media.