Electrochemical Investigations of Pyridine-2-Carbaldehyde Derivatives as Potential Inhibitors against Copper Corrosion in 0.1M HNO3

Abstract

The corrosion inhibition efficiency of Pyridine-2-carbaldehyde-2-aminobenzoic acid (2PC2ABA) and Pyridine-2-carbaldehyde-3-aminobenzoic acid (2PC3ABA) on copper in 0.1M HNO₃ solution has been investigated and compared using electrochemical impedance spectroscopy, adsorption studies and potentiodynamic polarization analysis. The pyridine-2- carbaldehyde derivatives exhibited very good corrosion inhibition on copper in HNO₃ medium and the inhibition efficiency increased with the increase in concentration of the inhibitor. The adsorption of the inhibitor on the surface of the corroding metal obeys Langmuir and El-Awady adsorption isotherm for 2PC2ABA and 2PC3ABA respectively. Thermodynamic parameters (K_ads, ΔG⁰_ads) were calculated using adsorption isotherm. Polarization studies revealed that both compound act as a mixed type inhibitor.