Adsorption of 3-(4-amino-2-methyl-5-pyrimidyl methyl)-4-methyl thiazolium chloride on mild steel

The adsorption of 3-(4-amino-2-methyl-5-pyrimidyl methyl)-4-methyl thiazolium chloride (AMMPTC) or vitamin B1 at the mild steel surface from hydrochloric acid (HCl) solution is studied using chemical techniques. The surface coverage with the adsorbed AMMPTC is used to calculate the free energy of adsorption, ΔGads0, of AMMPTC using Bockris–Swinkels isotherm. The dependence of free energy of adsorption, ΔGads0, with surface coverage, θ, is ascribed to surface heterogeneity of the adsorbent. The effect of AMMPTC is discussed from the viewpoint of adsorption model. The adsorption of AMMPTC molecules on the surface occurs without modifying the kinetic of corrosion process which is of first order with respect to mild steel.