An assessment of expired drugs’ potential as effective inhibitors to combat carbon steel and mild steel corrosion

Abstract Metal corrosion is a destructive process that must be managed carefully to prevent unintentional material losses. Most organic and inorganic compounds reported as corrosion inhibitors are highly toxic, causing severe environmental pollution. Recently, expired drugs have been tried as green inhibitors for many metals. The effectiveness of expired drugs as corrosion inhibitors was investigated by techniques such as weight loss, linear polarization, potentiodynamic polarization, and electrochemical impedance spectroscopy methods. The surface morphology of specimen metals was tested before and after the addition of drug inhibitors using scanning electron microscopy, atomic force microscopy, X-ray diffraction, etc., to confirm the inhibition behavior of the drugs. Additional parameters by quantum chemical calculations and molecular dynamics study were computed, and the outcomes agreed with the experimental results. These investigations demonstrated the effectiveness of drugs as corrosion inhibitors and opened up possibilities for managing the disposal of expired drugs. The present paper gives an overview of the usage of expired drugs as efficient inhibitors to control the corrosion of carbon steel and mild steel. The comparison of inhibition performances of different expired drugs and the mechanism of corrosion inhibition have been discussed. The existing challenges faced in using expired drugs as inhibitors were highlighted.