Corrosion inhibitors are generally used in reducing metallic corrosive effects. Nevertheless, most inhibitory compounds have harmful effects on the environment, as well as being expensive and toxic. Therefore, there is growing awareness of the need to replace petroleum inhibitors with eco-friendly inhibitors. Eggshell agro-industrial waste (ESAW) is a compound with high inhibitive activity and its utilization is desirable to minimize the quantity of agricultural waste generated. Hence, this study aims to demonstrate the inhibition efficiency of eggshell extract, a waste compound, on mild steel (material frequently utilized in the oil and gas sector) in one molar hydrochloric acid solution accessed via weight loss and electrochemical methods. Potentiodynamic polarization results shows that the current densities of mild steel corrosion significantly decreased using eggshell agro-industrial waste. Similarly, electrochemical impedance spectroscopy results suggest that eggshell agro-industrial waste enhances the mild steel polarization resistance significantly. The inhibitor performance increases with increasing eggshell agro-industrial waste concentration, with optimum efficiency of 97.17%. The inhibition was due to the adsorption and adhesion of the eggshell agro-industrial waste constituents on the surface of the mild steel; the adsorption obeys the Langmuir adsorption isotherm model. Compared with various reported corrosion inhibitors in the literature, eggshell agro-industrial waste is very effective. Therefore, eggshell agro-industrial waste can be recommended as a potential inhibitor in the oil and gas sector.

There is a high demand for eco-friendly, effective, and high-performance corrosion inhibitors for industrial applications. Thus, the corrosion property of aluminum alloys was studied in essential oil-containing sodium chloride solution at various concentrations. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), surface tests, and weight loss analysis were used to study the corrosion inhibition mechanism of the essential oil. The essential oil showed the highest inhibition efficiency of 97.01% at 1000 ppm. A high efficiency of 96.03% was achieved even after 168 h of exposure. The potentiodynamic polarization test showed that the essential oil is a mixed-type inhibitor. EIS results show better adsorption of the oil on the surface of the aluminum at increased inhibitor concentrations. The Langmuir’s adsorption isotherm model was found to describe the adsorption behavior. The surface morphology of the uninhibited and inhibited specimens examined by a scanning electron microscope equipped with an energy-dispersive X-ray spectroscope confirmed the protective film of the inhibitor molecules on the aluminum surface.