Corrosion inhibition behaviour of synthetic 2-(phenylsulphonamido)-3-methylbutanoic acid on mild steel in alkaline solution

The corrosion inhibiting behaviour of synthetic 2-(phenylsulphonamido)-3-methylbutanoic acid (PSMBA) on mild steel in the presence of 0.1 M KOH was investigated using combined gravimetric, electrochemical and theoretical simulation corrosion monitoring methods. The gravimetric data showed that the inhibitor effectively protected the metal from alkaline corrosion and that the inhibition ability depended on concentration increase and reduced gradually with prolonged immersion time. The electrochemical impedance spectroscopy results show that the charge transfer resistance increased with the addition of the inhibitor while potentiodynamic polarization results showed that the corrosion current density decreased upon the addition of the inhibitor, theoretical simulation results revealed a low and comparable energy gap between the LUMO and HOMO energies. All these showed that 2-(phenylsulphonamido)-3-methylbutanoic acid functioned as a good corrosion inhibitor for mild steel in alkaline medium.