Corrosion Inhibition Potential of Prosopis Juliflora Leaves Extract on Mild Steel in H2SO4 Solutions

The Alchornea laxiflora leaves were introduced as a sustainable corrosion inhibitor with excellent inhibition action on mild steel in 1.0M acidic medium solution. Alchornea laxiflora leaves are found throughout Africa, including three active compounds: quercetin, Quercetin-3-rhamnoside, and Quercetin-7-rhamnoside. The LC-MS and NMR are utilized using the gravimetric method to track the active components in the Alchornea laxiflora leaves extract. Potentiodynamic polarization, electrochemical current noise measurements, and scanning electron microscope (SEM) were conducted to investigate the corrosion inhibition role of various concentrations of Alchornea laxiflora extract toward mild steel corrosion in 1.0M acidic medium solution. Surface analysis, molecular dynamics, and quantum mechanics simulation methods were combined to get insights into inhibitor molecules’ adsorption on the mild steel surface. The results showed that the inhibitory capacity of the leaf extract increased with an increase in the concentration of the extract, whereas the corrosion rate of the steel material after immersion in the acidic solution decreased with increasing extract concentration. The structures were determined using nuclear magnetic resonance in 1D and 2D, and the molecular weight was determined using mass spectrometry. The electrochemical investigations revealed that the maximum inhibition efficiency of 98.8% was obtained in the present extract. The formation of protecting layer on the mild steel surface was proved by scanning electron microscope and atomic force microscope results. The results derived from Monte Carlo simulation MC and QM calculations revealed the adsorption of Alchornea laxiflora components on the steel substrate via donor-acceptor interactions.