Study of the efficiency of the algae Prasiola crispa extract as a corrosion Inhibitor in HCl 1 mol L^-1

The algae Prasiola crispa extract was investigated as a possible corrosion eco-inhibitor for carbon steel in HCl 1 mol L^-1 medium. The techniques used for the evaluation were the gravimetric tests, electrochemical polarization and electrochemical impedance spectrometry. The analysis showed that the extract has a great corrosion efficiency, reaching 95.9 % efficiency in the concentration of 0.800 g L^-1. The mechanism of inhibition is based on the adsorption of molecules on the steel surface generating a protective barrier. The study of the adsorption isotherms showed that the Langmuir model is the most appropriate and that the adsorption process is spontaneous presenting a ΔG_ads of -27.9 kJ mol^-1 which constitutes an intermediate behavior between a physical and chemical adsorption. (author)