A study on Jordanian green natural agro wastes as potential inhibitors of mild steel corrosion in hydrochloric acid solution

Mild steel is one of the most widely used materials in different engineering applications due to its mechanical properties, high availability, and low cost. However, the exposure of the steel to acids such as hydrochloric acid (HCl) accelerates its corrosion rate. Green organic corrosion inhibitors are among the most effective materials to reduce the mild steel corrosion rate in an acidic medium. These inhibitors are environmentally accepted, easy to extract, and non-toxic. This study investigates the feasibility of using different green Jordanian natural agro-wastes as green organic corrosion inhibitors and determines the efficiency of these inhibitors at different concentrations at room temperature. The potentiodynamic polarization test was used in two sets of runs; the first set of runs was used to screen ten extracted green inhibitors and choose three based on their highest efficiency. In the second set of runs, the test was performed only for the highest efficiency inhibitors selected from the first run. A weight-loss and Fourier-transform infrared spectroscopy test was also performed for the selected inhibitors. The results of the tests indicate that the green Zucchini (Cucurbita pepo) leaf extract (CPLE), Oak (Quercus) leaf extracts (QLE), and Okra (Abelmoschus esculentus) leaf extracts (AELE) were the selected inhibitors.