Corrosion inhibition efficiency of expired antimalarial drugs on stainless steels in acidic and basic media

The corrosion inhibition behaviour of 304L and 316L stainless steels (SS) in acidic (1 M Hydrochloric Acid, HCl) and basic (1 M Sodium Hydroxide, NaOH) media was investigated using expired antimalarial drugs, Lufart Double Strength (DS) and Lonart DS as potential green inhibitors. Potentiodynamic polarization measurements were used to evaluate the Inhibition Efficiencies (IE) of the inhibitors on each SS in each medium. X-ray fluorescence (XRF) was used to characterize the steel samples and Fourier Transfer Infrared (FTIR) Spectroscopy was used to predict the major constituents of the drug samples. The findings suggest that the expired antimalarial drugs contribute significantly to corrosion inhibition, offering an eco-friendly alternative to conventional inhibitors while providing a novel approach to pharmaceutical waste management. This study highlights the potential of these expired drugs as effective corrosion inhibitors for stainless steels, proposing their use as a sustainable solution in corrosion control applications. • Examined corrosion inhibition efficiency of expired antimalarials on stainless steel. • Inhibition efficiencies reach 98% in acidic media and 94% in basic media. • FTIR analysis reveals functional groups key to effective metal surface adsorption. • Concentration-dependent behaviour and Tafel shifts highlight inhibition mechanism. • Findings suggest potential industrial applications for repurposing expired drugs.