Adsorption behavior and corrosion inhibition mechanism of a polyacrylamide on C-steel in 0.5 M H2SO4: Electrochemical assessments and molecular dynamic simulation

Anticorrosion activity and adsorption behavior of a polyacrylamide (PA) for C-steel corrosion in 0.5 M H2SO4 solution were analyzed by potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS), scanning Electron Microscopy (SEM) and molecular dynamics (MD) simulations. PP curves indicated that PA behaved as a mixed-type inhibitor and its Inhibition efficiency increased with increasing PA concentration to attain 93% at 4 x 10(-6) M and at 298 K. EIS data are analyzed and modeled by equivalent circuit adapted to a single time constant. Kinetic-thermodynamic parameters, were calculated and discussed, based on six linearized forms adsorption isotherms. Mixed and spontaneous mode of adsorption is proposed for the inhibition with repulsive lateral interactions in adsorbed inhibitory layer. MD simulations confirmed the better adsorption capacity of PA compared to corresponding monomer and dimer with a flat orientation on C-steel surface. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study analyzed the anticorrosion activity and adsorption behavior of polyacrylamide (PA) on C-steel corrosion in sulfuric acid solution using various techniques. The results showed that PA acted as a mixed-type inhibitor with increasing inhibition efficiency at higher concentrations, reaching up to 93%. The adsorption characteristics of PA were investigated through electrochemical impedance spectroscopy (EIS) and molecular dynamics (MD) simulations, confirming its superior adsorption capacity compared to the corresponding monomer and dimer.