Performance Evaluation of Bryophyllum Pinnatum Leaves Extract as Corrosion Inhibitor for Mild Steel in 1 M Phosphoric Acid

The severe consequences of corrosion process cause global issues most especially in petroleum refineries. This research investigates performance evaluation and optimization of bryophyllum pinnatum leaves extract for mild steel corrosion inhibition. The extract was subjected to phytochemical analysis to determine the inclusion of any bioactive component. Box-Behnken design was used to optimize process variables which include Temperature (30–60 °C), Immersion time (3–12 days), and amount of extract (0.2–0.8 g/l). Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) were used for characterization. Phytochemical analysis revealed the presence of flavonoids, tannins, saponins, alkaloids, terpenoids, and steroids. It was established from experimental results that temperature of 30 °C, immersion time of 3 days, inhibition concentration of 0.8 g/L gave the best process due to low weight loss and corrosion rate. Furthermore, the lower the corrosion rate the higher the inhibition efficiency. The results of SEM, EDS and FTIR revealed that mild steel via validated optimal process level had more protective film and was formed through adsorption. Hence, Bryophyllum pinnatum extract has been established as an effective corrosion inhibitor.