Biomolecule for Corrosion Mitigation: Electrochemical and Surface Studies

The work highlights the results of application of green inhibitor biopolymer glycogen for the corrosion mitigation of 6061 aluminum alloy in 0.01 N sulfuric acid medium. The corrosion rate measurements were done by electrochemical methods like electrochemical impedance spectroscopy and potentio-dynamic polarization techniques. Conditions were optimized to get maximum inhibition efficiency by varying the concentration of the inhibitor in the temperature range of 308–318 K. Kinetic and thermodynamic parameters were evaluated and discussed in detail. Results were fitted into an appropriate adsorption isotherm. Suitable mechanism was proposed for corrosion and inhibition studies. Surface characterization was performed before and after the addition of inhibitor using SEM–EDX and AFM techniques. Inhibitor underwent physical adsorption onto the metal surface and obeyed Langmuir adsorption isotherm. Surface studies confirmed the adsorption of inhibitor onto the metal surface, and according to AFM studies, surface had become remarkably smooth after the addition of inhibitor. Results obtained by potentio-dynamic polarization and impedance studies were in very good agreement with each other. Glycogen emerged as potential green inhibitor for the corrosion control of 6061 aluminum alloy in 0.01 N sulfuric acid medium with a maximum efficiency of 54.73% at 308 K for the addition of 0.8 g L⁻¹ Work is a contribution to corrosion chemistry using eco-friendly biopolymer as green inhibitor.