Synergistic effect of iodide ion and polyacrylic acid on corrosion inhibition of iron in H₂SO₄ investigated by electrochemical techniques

Corrosion inhibition of iron in H₂SO₄ by polyacrylic acid (PAA) was investigated using electrochemical techniques at 30°C. Results obtained indicate that PAA inhibited the corrosion of iron in the acid medium. Inhibition efficiency increases with increase in PAA concentration and synergistically enhanced on addition of iodide ions. Potentiodynamic polarization results suggest that PAA functions as a modest cathodic inhibitor. The adsorption of PAA onto the iron surface followed Temkin adsorption isotherm. FTIR analysis revealed that the synergistic effect due to co-adsorption of iodide ions and PAA is co-operative in nature.