A simple strategy to increase inhibitory activity of chitosan towards iron corrosion in acidic media

Abstract

The chitosan as a natural and inexpensive polymer is considered as an appropriate choice towards the corrosion inhibitory. Here, the corrosion and inhibition efficacy of iron sheets is examined in the H₂SO₄ solution and the presence of chitosan and potassium iodide as an inhibitor through gravimetry, potentiodynamic polarization, and impedance analyses. The inhibition performance is found to be enhanced by adding chitosan concentration. The experimental data demonstrate that the doping iodide ion to chitosan is efficient on the surface coverage and the inhibition performance. The introduced inhibitors are of the interface inhibitors → liquid phase → mixed type with the physical adsorption. The adsorption of iodized chitosan on the iron surface is followed Langmuir isotherm. These inhibitors, by changing the electrical double layer, increase the resistance of charge transfer. The existence of iodide in the chitosan structure improves the electron density of polymer and strengthens the interaction between inhibitor and metal.