Application of Butea monosperma (Palasha) Leaves Extract as Green Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Solution: A Theoretical and Electrochemical Approach

The inhibition effect of Palasha (Butea monosperma) leaves extract on mild steel in 1M HCl was investigated using gravimetric, potentiodynamic polarization and electrochemical impedance spectroscopy. Potentiodynamic polarization results revealed that the studied extract is a mixed-type inhibitor. The inhibition efficiency increased up to 96% at 300 ppm. The R-ct of inhibited system increased and double layer capacitance C-dl decreased with increasing inhibitor concentration. UV-Visible spectroscopic investigation of inhibited system suggested a complexation between the active molecules of extract and the metal surface atoms. Quantum chemical calculations supported the adsorption of inhibitor molecules onto the metal surface.