Corrosion Inhibition Potential of Ascorbic acid on Carbon Steel in Acid Media

Abstract

Abstract : Ascorbic acid (AA), or vitamin C, is a water-soluble vitamin essential in the human beings, a scavenger of free radicals in biological systems, an antioxidant and a cofactor of several enzymes. It is well known for its ability to increase high-density lipoprotein production, to lower blood sugar and to reduce the risk for cardiovascular diseases. Corrosion control of metals is of technical, environmental, economical, and aesthetical importance. The inhibitive action of Ascorbic acid on the corrosion behavior of carbon steel (CS) in 1M HCl was studied using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and effect of temperature. The results obtained revealed that AA was a good inhibitor in 1M HCl and the inhibition efficiency increased with increasing inhibitor’s concentration. The adsorption of AA was found to obey Langmuir adsorption isotherm, The corresponding activations prametres in the absence and presence of inhibitor were determined and discussed. The inhibition efficiency was closely related to orbital energies (EHOMO and ELUMO). The correlation between quantum parameters and experimental inhibition efficiency has been validated. Keywords: Carbon steel, Polarization curves, Ascorbic acid, Free Energy, Corrosion inhibition,