Effect of Ajowan seeds as safe inhibitor on the corrosion of steel in 2.0 M sulfuric acid

Abstract

Corrosion inhibition of steel in sulphuric acid by aqueous extract of Ajowan (carom) seeds has been studied using chemical (HE and ML) and electrochemical (EIS and PDP) measurements at 30°C. The results indicated that Ajowan extract inhibit the corrosion process in 2.0M H2SO4 and the inhibition efficiency increase as concentration increased. Impedance studies showed that the charge transfer controls the dissolution mechanism of steel across the phase boundary in the absence and the presence of the inhibitor and potentiodyanaic polarization results indicate that Ajowan seeds act as mixed type inhibitor. The inhibition efficiency obtained from various employed methods is approximately in good agreement. Adsorption process of Ajowan molecules on steel surface is spontaneous and it obeys the Friuendlish adsorption isotherm. © 2010 University of Manchester and the authors.