An Expired Non-Toxic Drug acts as Corrosion inhibitor for Mild Steel in Hydrochloric Acid Medium

P.Geethamani^1* and P.K. Kasthuri², S.Aejitha^3
1Department of Chemistry, Sri Guru Institute of Technology, Coimbatore- 641110, India
²Department of Chemistry, L.R.G. Government Arts College for Women, Tirupur-638604, India
³Department of Chemistry, Asian college of engineering and technology, Coimbatore- 641110, India

A B S T R A C T
The inhibitive properties of expired non toxic drug of Asthaline Expectorant (AE) on the corrosion of mild steel strip in 1M hydrochloric acid medium was investigated using weight loss and electrochemical methods. The study revealed that the corrosion rate increases with increases in concentration of the inhibitor, immersion period (time) and temperature. Effect of temperature was investigated at temperature range (303-343 K). Polarization curves shows that this expired non toxic drug is a mixed – type inhibitor in acidic medium. This inhibitor obeys Langmuir, Freundlich and Temkin adsorption isotherm. Surface analysis was performed to emphasis the inhibition efficiency of the studied drug inhibitor. The inhibition activity is due to the adsorption of pharmaceutically active components which are found in the inhibitor AE.
Keywords: Mild steel, Corrosion inhibitor, Acidic medium, expired drug, non-toxic, weight loss.