LAUSR

Abstract The inhibitory behavior of Mustard seed extract for mild steel (MS) in HCl solution was explored. The extract structures were studied by FT-IR analysis connected with UV–Vis spectroscopy. The surface studies were accomplished using contact angle and SEM/AFM tests. The corrosion studies were scrutinized utilizing electrochemical techniques of weight loss, impedance spectroscopy (EIS), and potentiodynamic polarization at different temperatures (25, 35, 45 and 55 °C) and extract concentrations. To corroborate experiments, detailed theoretical studies were conducted. The EIS examination proved the maximum inhibition efficiency of 94% for 200 mg·L−1 of the extract. By enhancing the solution temperature, the steel resistance against corrosion decreased, and the efficiencies of 93, 90, 91, and 93% were obtained at 25, 35, 45, and 55 °C, respectively. Potentiodynamic polarization results demonstrated that the steel corrosion happened under control of anodic and cathodic reactions even at higher temperatures. The weight loss analysis proved 97% inhibition efficiency for the acid solution containing 200 mg·L−1 extract. The study of the adsorption isotherms showed that the adsorption of Mustard seed extract molecules was in the line of Langmuir isotherm. Electronic/atomic simulations proved the adsorption of Mustard seed extract molecules onto the steel substrate.