Adsorption Kinetics of 4-Amino-5-Phenyl-4H-1, 2, 4-Triazole-3-Thiol on Mild Steel Surface

The adsorption of 4-amino-5-phenyl-4H-1, 2, 4-triazole-3-thiol (APTT) as a corrosion inhibitor on mild steel surface in hydrochloric acid (HCl) solution was studied using the weight loss technique. The surface coverage with the adsorbed APTT was used to calculate the free energy of adsorption, Delta G(ads)(o), of APTT using Bockris-Swinkels isotherm. The dependence of free energy of adsorption, Delta G(ads)(o), on the surface coverage, theta, is ascribed to the surface heterogeneity of the adsorbent. The effect of APTT was discussed from the adsorption model viewpoint. The adsorption of APTT molecules on the surface occurs without modifying the kinetic of corrosion process.