SOME NONIONIC SURFACTANTS AS INHIBITORS OF THE CORROSION OF IRON IN ACID CHLORIDE SOLUTIONS

The inhibition effect of the surfactants 1,2-hexanediol (HD), 1,2,3-oc tanetriol (OT); 1,2,3-nonanetriol (NT); and 3,7-dimethyl-1,2,3,6,7-oct anepentol (DOP) on the corrosion of iron in 1 M hydrochloric acid (HCl ) was studied, Results obtained from gravimetric methods showed inhibi tion efficiencies increased with increasing surfactant concentrations and attained a maximum around their critical micellar concentration (c mc). A comparative study of corrosion inhibition of surfactants indica ted DOP was the best inhibitor, Polarization measurements showed DOP w as a cathodic type-inhibitor and acted on the cathodic reaction withou t modifying the mechanism of the hydrogen evolution reaction. DOP appe ared to function through a general adsorption mode following the Langm uir adsorption isotherm The effect of temperature on the corrosion beh avior of iron in both 1 M HCl and 1 M HCl with addition of various con centrations of DOP was studied in the temperature range from 18 degree s C to 48 degrees C, The associated activation corrosion and free adso rption energies were determined.