Corrosion inhibition of mild steel by methyl violet and bromide ion in sulfuric acid solution

Abstract

The corrosion inhibition behavior of methyl violet in the absence and presence of bromide ion on mild steel in sulfuric acid solution has been studied by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy. The results indicate that the corrosion of mild steel is obviously reduced by methyl violet in combination with bromide ion. Electrochemical studies show that methyl violet and bromide ion act as mixed type inhibitors retarding the cathodic and anodic corrosion reactions with emphasis on the former and do not change the mechanism of either hydrogen evolution reaction or mild steel dissolution. The corrosion reaction is controlled by charge-transfer process. The adsorption of the inhibitors on the mild steel surface obeys the Langmuir adsorption isotherm model. The calculated thermodynamic and kinetic parameters (DG o ads , DH o ads , DS o ads , K ads , and E a ) reveal a strong interaction between inhibitors and mild steel surface. The values of DG o ads show that the inhibitors are adsorbed on the mild steel surface in sulfuric acid by chemical adsorption mechanism.

Synergistic inhibition effect of N‐(furan‐2‐ylmethyl)‐7H‐purin‐6‐amine and iodide ion for mild steel corrosion in 1 mol/L HCl

“…This remarkable improvement could be due to the synergistic adsorption of FYPA and iodine ions. As expected, the C dl value tended to decrease in the presence of FYPA and combination with KI, resulting from a decrease of the local dielectric constant or the increase of the thickness of the electrical double‐layer capacitor . The results revealed that the inhibitor molecules were adsorbed on the steel surface acting at the interface electrode and solution.…”

Adsorption and corrosion inhibition properties of pyridine‐2‐aldehyde‐2‐quinolylhydrazone for Q235 steel in acid medium: Electrochemical, thermodynamic, and surface studies

“…As shown in Table , the values of R ct and η z increased significantly with increasing the concentration of inhibitor, and the maximum η z was as high as 95.93% when the concentration of PAQ reaches up to 3.24 mM, which shows that the inhibitor molecules can effectively inhibit the corrosion of Q235 steel in hydrochloric acid solution. Comparatively, the C dl value trends to decrease as expected with the increase of inhibitor concentration, which results from the decrease in local dielectric constant or an increase in the thickness of electrical double layer capacitor . It is revealed that the inhibitor molecules instead of water molecules on the steel surface and take effect by adsorption at the electrode/solution interface.…”