Abstract
Prickly pear seed oil extract (PPSO1) was tested as corrosion inhibitor for mild steel in 1M HCl. Weight loss measurements, potentiodynamic polarizations and electrochemical impedance spectroscopy (EIS) methods are used. The inhibiting action increases with the concentration of the tested inhibitor. The highest efficiency 90% is obtained at 5 g/L of PPSO. We note good agreement between gravimetric and electrochemical methods (potentiodynamic polarisation and EIS). Effect of temperature is also studied between 298 K and 328 K; PPSO presents best inhibition efficiency even at elevated temperature. Polarization measurements show also that PPSO1 act as good mixed inhibitor. PPSO1 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 prickly pear seeds were determined. Palmitic acid contents of seed oils ranged between 7.3% (PPSO15) and 12.6% (PPSO3). While oleic acid contents varied between 15.0% (PPSO12) and 20.8% (PPSO5), linoleic acid contents ranged from 61.8% (PPSO16) to 68% (PPSO15).