Carbon steel is widely used in various fields such as the field of agri-food their use in tins and materials used in the food producing seen this material and susceptible to corrosion phenomena are in their environmental which produces toxic compounds in the environmental medium of this material. To this end we investigated in this direction by study of the inhibition of the phenomenon of corrosion of this material. Grapefruit oil extract (GO) was tested as corrosion inhibitor for mild steel in 1M HCl. Electrochemical impedance spectroscopy (EIS) method are used. The inhibiting action increases with the concentration of the tested inhibitor. The highest efficiency 86.15% is obtained at 1g/L of GO. Effect of temperature is also studied between 298 K and 328 K; GO presents best inhibition efficiency even at elevated temperature, GO is adsorbed on the steel surface according to a Langmuir isotherm adsorption model. The thermodynamic data of activation are determined. In this study fatty acid composition contents of Grapefruit were determined. The used methods indicate that the Grapefruit oil extract is a good inhibitor in 1.0 M HCl. Some thermodynamic functions of the carbon steel dissolution process in acid medium were also determined and discussed
