Combined atomic-scale/DFT-theoretical simulations & electrochemical assessments of the chamomile flower extract as a green corrosion inhibitor for mild steel in HCl solution

Abstract

This investigation parallels the others hoping to address the environmental predicaments. Dealing with the corrosion progression of steel, being in battle with a harsh condition (HCl), using the novel Chamomile flower extract (CFe) could embody the advantageous lies in the green molecules of plants. The morphological influences of this plant extract were studied by exploiting the power of FE-SEM, EDAX, AFM, and contact angle examinations. Results were demonstrative of the surface smoothness increment after CFe inclusion into the medium; smoothing the surface as well as lowering the iron dissolution. Besides, the surface was characterized via GIXRD as well as Raman spectroscopy. In addition, the adsorption of the inhibitor was examined through UV–Vis analysis. The existence of functional groups like C = O and C = C, the reduction of iron dissolution, and the graphene-like compounds' existence confirmation on the metal surface, all subsequent to CFe loading, were the outcome of these assessments. The EIS and potentiodynamic polarization (PP) tests were performed. The outcome showed that the CFe could inhibit the corrosion proliferation substantially especially when the steel was exposed to 600 ppm solution for 8 h; a 98% inhibition efficiency was obtained. The calculations exhibited the CFe mixed inhibitive characteristic and Langmuir was the adsorption isotherm strategy of the studied inhibitor. Finally, the study was further expanded into the theoretical point of view in which the adsorption of inhibitor molecules on the surface was confirmed; in agreement with the experimental outcome.