In the present study, the corrosion inhibition characteristic of Sodium
Dodecyl Sulfonate (SDSO), a surfactant on corrosion of carbon steel in
hydrochloric acid was studied using weight loss method. The obtained
results reveal that SDSO is good inhibitor and shows very good corrosion
inhibition efficiency (IE) at relatively high SDSO concentration. The IE was
found to vary with concentration of inhibitor and acidity.
The effect of Brij 58 nonionic co-surfactant addition on IE of SDSO was
investigated. It was found that Brij 58 has synergistic influence on the
corrosion inhibition efficiency of SDSO. This would be attributed to
molecular association of SDSO-Brij 58 that would cause the enhancement
of co-adsorption of the two surfactants on carbon steel surface and
consequently increase the coverage of hydrophobic layer on Carbon Steel
(CS) surface.
Special importance is attached to the effect of inorganic additives on the IE
of SDSO. KCl and CaCl2 were found to be good promoters to IE of the
SDSO. This finding was explained on the basis of that K+ or Ca 2+ ions
would create active sites on the SC surface that would attract the
negatively charged of SDSO ions and consequently hydrophobic layer
(protective film) would be established on SC surface improving IE.
However, the addition FeCl3 deteriorates the Inhibitory action
(anticorrosion performance) of SDSO. This can be inferred to the formation
of ferric dodecyl sulfonate that have very low soluibility product that would
precipitate. This cause the deficiency of surfactant ions in the solution and
consequently decreasing the adsorption of SDSO on SC surface.