Eco-friendly methanolic Ajuga orientalis extract as corrosion inhibitor for aluminium in 1.0 M NaOH

Abstract

The inhibitory impact of the methanolic Ajuga orientalis (MAO) extract on Al corrosion in 1.0 M NaOH solution was examined using weight loss with electrochemical polarisation and scanning electron microscopy (SEM) techniques. According to the findings, the extract was an effective inhibitor in basic condition, as well as inhibition effectiveness increased with concentration. Furthermore, temperature studies revealed a loss in efficiency followed by a rise when temperature rose, followed by an increase and a fall in the fundamental media when the temperature increased from 30 °C to 50 °C. Frumkin, Freundlich and El Awady isotherms were used to mimic the inhibitor's adsorption properties. For the inhibitory behaviour, physical and chemical adsorption mechanisms are proposed. The adsorption process's thermodynamic parameters (ΔH*, ΔS* and Ea) were determined and explained. The inhibitor was examined as a mixed-type (anodic and cathodic) inhibitor based on polarisation studies. The inhibitor, according to the SEM data, is partially coating the metal surface, providing it with a reasonable amount of protection. The findings from weight loss, electrochemical polarisation, SEM and quantum chemical calculations collectively demonstrate a strong consensus, indicating that the MAO extract exhibits high effectiveness as an inhibitor for aluminium in a basic solution.