Electrochemical study of corrosion inhibition and adsorption behaviour for pure iron by polyacrylamide in H 2SO 4: Synergistic effect of iodide ions

Abstract

Corrosion inhibition and adsorption behaviour for pure iron in 0.5 M H 2SO 4 by polyacrylamide (PA) were investigated using electrochemical techniques. The effect of iodide ion additives was also studied. It was found that inhibition efficiency increased with PA concentration. Corrosion inhibition was afforded by adsorption of PA onto the metal following El-Awady kinetic–thermodynamic adsorption isotherm model via chemisorption mechanism. A mixed inhibition mechanism is proposed for the inhibitive effects of PA as revealed by potentiodynamic polarization technique. A synergistic effect was observed between PA and KI as evident from the values of synergism parameter found to be greater than unity.