Comparative analysis of guava and paw-paw leaves extract to investigate the corrosion process of mild steel in HCl environment

A great deal of research has shown that plant leaf extracts, like those from pawpaw and guava, are environmentally safe and capable of mitigating corrosion attacks on metal surfaces, and can be used to stop mild steel metal from corroding in acidic environments (like the Niger Delta creek region that was used as the case study). This research investigated the surface morphology after the corrosion inhibition process and characterized prepared extracts of pawpaw and guava leaves. The corrosion attack on mild steel in an acidic medium was investigated both with and without extracts present at different times, temperatures, and concentrations of the extract. A physiochemical analysis and performance evaluation of the extracts were conducted. The analysis showed that the extracts' peroxide values (PV) and acid values (AV) were 29.63 Meq/g and 38.25 Meq/g, respectively, and 7.86 mg and 4.63 mg of KOH. These values suggest the presence of compounds containing oxygen and alkaloids, which function as a protective layer to shield the metal from corrosive environments; pawpaw leaf extract performed better than guava leaf extract because it had more PV and less AV; the results also showed that the extracts' capacity to reduce corrosion attacks on the metal surface improved with increasing inhibition concentration; finally, temperature and time are significant variables that affect corrosion on the metal surface.