Abstract
The inhibition effect of two selected polyethylene glycols (PEGs) with different molecular weight and the synergistic effect with rare earth Ce4+ ions on corrosion of carbon steel in 0.1 M H2SO4 solution has been investigated by using electrochemical measurements, scanning electron microscopy, and quantum chemical calculations. The inhibition efficiency (Z%) increased with increasing PEG concentration and molecular weight and decreased with increasing temperature. The adsorption of the PEGs obeyed the Langmuir adsorption isotherm. Potentiodynamic polarization studies showed that the PEGs were mixed-type inhibitors of corrosion by H2SO4. The results reveal that incorporation of PEGs with Ce4+ ions improved the inhibition performance. The Z% value for the PEGs in combination with Ce4+ was higher than the sum of the Z% values for the individual PEGs and Ce4+ ions, confirming a synergistic effect. Some quantum chemical parameters were calculated to corroborate the experimental results.