Adsorption Behaviour of 1-phenyl-3-methylpyrazol-5-one on Mild Steel from HCI Solution

The adsorption of 1 – phenyl–3- methylpyrazol – 5-one (HPMP) on mild steel surface from 0.5 M HCl solution was studied by using gravimetric technique. The values for free energy of adsorption, , were calculated at each surface coverage, θ, of the studied compound by applying the mathematical model of Bockris – Swinkels adsorption isotherm. The variation of free energy of adsorption with surface coverage, θ, was interpreted in terms of heterogeneous nature of the electrode. A possible adsorption model of HPMP molecules on to the metal surface was suggested and discussed. The adsorption of HPMP molecules on the surface occurs without influencing the kinetic of corrosion process.