A new insight into corrosion inhibition mechanism of copper in aerated 3.5 wt.% NaCl solution by eco-friendly Imidazopyrimidine Dye: experimental and theoretical approach

A large number of mechanism were anticipated for copper since 1988 in NaCl medium. The detail electrochemical behavior leading to the anodic dissolution of copper, however, still remains uncertain. Herein, an Imidazopyrimidine Dye, named, 4-amino-3-(phenyldiazenyl)benzo [4,5] imidazo [1,2-a] pyrimidin-2(1H)-one, (APIP) has been used as a copper corrosion inhibitor in 3.5 wt.% (by weight) NaCl solution. The present investigation provides a brief mechanistic overview of the electrochemical mechanism of copper in aerated NaCl solution, simulating a static marine environment, with and without addition of APIP inhibitor. Potentiodynamic polarization (PDP) results confirmed that the APIP can suppress copper corrosion effectively at low concentration in 3.5 wt.% NaCl solution with an inhibition efficiency of 92.79% due to adsorption, along with the prediction of electrochemical mechanism. Electrochemical impedance spectroscopy (EIS) measurements showed that the corrosion inhibition of Cu proceeds via both diffusion and kinetic controlled processes. Adsorption of APIP on copper surface is well fit with the Langmuir isotherm model and mode of adsorption is proposed. Antimicrobial activity was also studied and the result obtained showed "eco-friendly" nature of APIP. Field Emission Scanning Electron Microscope (FE-SEM), Energy dispersion X-ray (EDX) and Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) observations of the copper surfaces confirmed the existence of adsorption of APIP thus can be potentially used in industries in which seawater is implied are numerous such as cooling water systems, desalination plants, power plants, and oil production units. Results obtained from theoretical calculations including quantum chemical density functional theory (DFT) method and molecular dynamics (MD) simulations confirms the experimental findings and provide further insight into the mode of adsorption on the copper surface.