Deciphering properties of Dryopteris marginalis as green corrosion inhibitor for mild steel in HCl: Electrochemical, gas chromatography and DFT studies

This paper discusses the inhibitory influence of Dryopteris marginalis (DM) leaf extract on the deterioration of mild steel (M.S) in hydrochloric acid using electrochemical methods and computational studies. Analysis through Gas Chromatography Mass Spectrometry identified various compounds in DM. The corrosion current density significantly decreased from 1241 μAcm⁻² without DM to 474 μAcm⁻² upon the addition of 1000 ppm of DM. The change in corrosion potential following the introduction of DM was < 85 mV, signifying that DM demonstrates mixed-type inhibition characteristics. Furthermore, the presence of DM markedly enhanced the resistance to charge transfer, increasing from 3623 Ω cm² without DM to 8752 Ω cm² with the incorporation of 1000 ppm of DM. The extent of resistance to charge transfer was influenced by the dosage of DM. As the dose of DM improved, the efficiency of inhibition correspondingly enhanced. Results from DFT calculations indicated that the molecules present in the extract exhibit favorable electronic and adsorption characteristics typical of effective corrosion inhibitors, which aligns with findings from electrochemical investigations.