Experimental Study and Modeling of the Corrosion Inhibition of Mild Steel in 1M Hcl with Novel Friendly Butanolic Extract of Ephedra Major

A novel Butanolic extract of Ephedra major (denoted EBEM) was investigated as corrosion inhibitor for mild steel in 1 M hydrochloric acid solution. The investigation was carried out using weight loss, electrochemical impedance spectroscopy (EIS), Tafel polarization measurements, Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) methods. The effect of temperature on the corrosion behavior of steel in HCl with the addition of the inhibitor was investigated in the temperature range 20-60 degrees C. The inhibition efficiency was observed to increase with increasing concentration of the extract EBEM and deceased with increasing the temperature. Tafel curves have revealed that the EBEM possesses the indices of a mixed inhibitor. The adsorption of the inhibitor on the steel surface, follow Langmuir isotherm and its mode was found to be physical adsorption. Thermodynamic parameter (Delta G degrees(ads)) and activation parameters (E-a, Delta H-a and Delta S-a) were calculated to investigate the mechanism of inhibition. Obtained data were analyzed by suggesting two mathematical models based on linear and quadratic regressions, which takes into account the effect of concentration and temperature upon the inhibition efficiency. Experimental data were in good agreement with those predicted by both models.