Ethanolic extract of Ruta chalepensis as an eco-friendly inhibitor of acid corrosion of steel.

Ruta chalepensis extract (Ruta) was tested as a corrosion inhibitor for steel in 1 M HCl. Weight loss measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) were used. The inhibiting action increases with increasing concentration of the tested inhibitor. Efficiency is highest, 87 %, for 3.5 g/L Ruta extract. It acts on the cathodic domain without modifying the reduction mechanism. We note good agreement between gravimetric and electrochemical methods (potentiodynamic polarisation and EIS). Polarization measurements also show that Ruta extract is a good mixed inhibitor. The effect of temperature on the corrosion behaviour of steel in 1 M HCl was also studied in the temperature range 298-338 K. Thermodynamic data for activation were determined. Ruta extract is adsorbed on the steel surface in accordance with a Temkin adsorption model. [ABSTRACT FROM AUTHOR]