The inhibition effect of the surfactants 1,2-hexanediol (HD), 1,2,3-octanetriol (OT); 1,2,3-nonanetriol (NT); and 3,7-dimethyl-1,2,3,6,7-octanepentol (DOP) on the corrosion of iron in 1 M hydrochloric acid (HCl) was studied. Results obtained from gravimetric methods showed inhibition efficiencies increased with increasing surfactant concentrations and attained a maximum around their critical micellar concentration (cmc). A comparative study of corrosion inhibition of surfactants indicated DOP was the best inhibitor. Polarization measurements showed DOP was a cathodic type-inhibitor and acted on the cathodic reaction without modifying the mechanism of the hydrogen evolution reaction. DOP appeared to function through a general adsorption mode following the Langmuir adsorption isotherm. The effect of temperature on the corrosion behavior of iron in both 1 M HCl and 1 M HCl with addition of various concentrations of DOP was studied in the temperature range from 18°C to 48°C. The associated activation corrosion and free adsorption energies were determined.

Subject
Acids, Hydrogen concentration, Corrosion rate, Metal surfaces, Adsorption, Iron, Surfactants, Corrosion inhibitors, Polarization, Cathodic inhibitors, Chemical reactions, Electrodes, Electrode potential
Keywords:
acids, adsorption, hydrochloric acid, inhibitors, iron, mass loss, polarization, surfactants, temperature
NACE International
1996
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