The effect of two oleo-gum resin exudate from Ferula assa-foetida and Dorema ammoniacum on mild steel corrosion in acidic media

A comparative study of two oleo-gum resins exudate from Ferula assa-foetida (F. assa-foetida) and Dorema ammoniacum (D. ammoniacum), as inhibitors for mild steel corrosion in 2 M HCl solution was investigated by weight loss measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. Potentiodynamic polarization curves indicated that both oleo-gums behave as mixed type inhibitors. The effect of temperature on the inhibition efficiency was studied. At all temperatures, the experimental data fit Langmuir isotherm for both oleo-gum resin exudates. Quantum chemical calculations were performed to illustrate the adsorption process of some specific components of two oleo-gum resin exudates.

► In this study, a comparative study of two oleo-gum resins was performed.
► The adsorption of both oleo-gum resins is well described by Langmuir isotherm model.
► Oleo-gum resins behave as mixed type inhibitors.
► Inhibition efficiency of both oleo-gum resins in 2 M HCl decreased with rise in temperature.
► Quantum chemical calculations used to explain the difference in behavior of two resins.