The synergistic effect of poly(acrylamide-co-4-vinylpyridine) copolymer "AM-4VP-24" and iodide ion on corrosion inhibition

Abstract

The effect of iodide ions on the corrosion inhibition of mild steel in 1 M sulfuric acid in the presence of poly(acrylamide-co-4-vinylpyridine) copolymer abbreviated by (AM-4VP-24) newly synthesized has been investigated by weight loss measurements and electrochemical techniques (polarization curves and impedance spectroscopy) at 18°C. The obtained results showed that the inhibition efficiency increased with increasing copolymer concentration. It was also found that inhibition efficiency increased with addition of potassium iodide (KI) to the copolymer. A synergistic effect was observed between the copolymer and KI. On the other hand, it was found that the inhibiting effect of the system (copolymer + KI) increased with increasing immersion time. The inhibitor was adsorbed on the steel surface according to the Langmuir adsorption isotherm model.