Experimental and theoretical investigation of mild steel corrosion control in acidic solution by Ranunculus arvensis and Glycine max extracts as novel green inhibitors

In the present research, the ability of Ranunculus arvensis (RA) and Glycine max (GM) extracts as green corrosion inhibitors of mild steel (MS) in 1 M HCl was investigated. The inhibiting potential of RA and GM was analysed employing electrochemical impedance spectroscopy (EIS), polarization curves, potentiometry, and theoretical investigations. An enhancement in the inhibition efficiency (I.E) with increasing inhibitors concentrations indicated by EIS data and polarization curves. According to obtained results both extracts indicated inhibitory effect, with their effectiveness following the order of RA > GM. In addition, the interactions between the inhibitors on the MS surface were assessed using B3LYP/6-311g(d,p) theory level in liquid water phase. The interaction energies for three orientations of RA and GM depicted that inhibitors have located parallel to the alloy surface. The preferred complex orientation is one in which the maximum number of inhibitor donor atoms interacted with the alloy surface. Finally, experimental and theoretical results were in accordance which confirmed the inhibition effect of RA and GM extracts.