Copper corrosion inhibition in acetic acid by some heteroatom organic compounds: case of glutamic acid.

Abstract

The heteroatoms organic compounds (HOP) namely Glutamic acid (GA), L-methionine (Meth), Cysteine (Cys) and phenyl mercapto tetrazol (PMT) have been regarded as copper corrosion inhibitor in Acetic acid (1M). In order to conduct this comparative study, potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS) are carried out. The first comparative study classifies the GA as the best inhibitor from the tested series. In second part of this work, the GA is detailed studied in terms of the inhibitor concentration influence on its inhibitive efficiency. As results, the increase of GA concentration increases its inhibition corrosion to attain 91% at 5.10^-4 M. the copper performance against corrosion in Acetic acid (AcA) is proved even at low concentrations. The inhibitive efficiencies obtained from electrochemical impedance spectroscopy and potentiodynamic polarization techniques are in good harmony. In fact, the adsorption of GA ‘on copper surface obeys the Langmuir adsorption isotherm with values of the free adsorption energy (ΔG°_ads) equal to – 41.5 kJ mol⁻¹.