Inedible Avocado Extract: An Efficient Inhibitor of Carbon Steel Corrosion in Hydrochloric Acid

The corrosion inhibition of inedible avocado extract (IAE) on the corrosion of carbon steel in molar hydrochloric acid has been evaluated using weight loss method, potentiodynamic polarization measurements and electrochemical impedance spectroscopy. Experimental results obtained revealed that the inhibition efficiency have increased when the concentration of the IAE have increased but decreased with the increase in temperature. Potentiodynamic polarization measurements clearly reveal that the investigated inhibitor is a cathodic inhibitor. The effect of temperature on the corrosion behavior of carbon steel in 1 M HCl without and with addition of 2.00 g.l−1 of IAE was studied in the temperature range from 298 to 328 K. Electrochemical impedance data show that the addition of the IAE in the corrosive solution decreases the double layer capacitance and simultaneously increases the charge transfer resistance of the corrosion process, facilitating the formation of an adsorbed layer over the carbon steel surface. The IAE inhibitor adsorbed physically on the carbon steel surface follows the Langmuir adsorption isotherm. The parameters of activation energy was evaluated and discussed.