The Activation Energy Parameters of Pumpkin Pod Extract as Corrosion Inhibitor for Stainless Steel in HCl Medium

Abstract

The inhibition effect of pumpkin pod extract (PPE) on the corrosion of stainless
steel in 2M HCl has been studied by weight loss technique. The process of
inhibition and temperature effects on inhibition efficiency, rate of corrosion, and
weight loss were determined with a temperature range of 313K – 353K at 7 hours
of dipping. An increase in temperature led to a decrease in both the inhibition
efficiency of PPE extract and the rate of corrosion of stainless-steel metal surfaces.
Parameters of thermodynamics activation such as; activation energy, enthalpy,
and entropy values range from 73.739 - 110.056kJ/mol, 70.936 – 107.252kJ/mol,
and 2.7610 – 100.373J/molK respectively. The higher value of activation energy
obtained in comparison to the enthalpy of adsorption suggests a physical
adsorption mechanism on stainless steel.