TABLE OF CONTENTS
Table of contents
- Background of the Study
- Aim and Objectives of the study
- Scope and Limitation of the study
- Definition of Terms
- Literature Review
- Corrosion Inhibitors for metals.
- Characteristic of Green Inhibitors
- Expired drugs as green Inhibitors.
- Materials and Method
- Materials and Reagents used
- Sample Collection
- Result and Discussion
- Conclusion and Recommendation
The application of expired drugs as corrosion inhibitors provides a cost effective and environmentally benign alternative to otherwise tedious and costly disposal/degradation process. In this context, we herein investigate the use of expired atorvastatin (EA) for corrosion inhibition of mild steel in 1 M HCl solution using weight loss,electrochemical impedance spectroscopy (EIS), and potentio dynamic polarization (Tafel) methods. Fresh atorvastatin(FA) drug was also used for above studies for Comparison purpose to understand whether there is any significant difference between the inhibition efficiency of the two after the expiration date of the drug. EIS analysis shows an increase in polarization resistance due to the adsorbed inhibitor molecules on metal surface. Potentio dynamic polarization indicates that both the EA and FA act as mixed-type inhibitors but predominantly behave as cathodic inhibitors. The adsorption of EA and FA on mild steel surface follows the Langmuir adsorption isotherm.SEM shows a smoother surface of mild steel in the presence of FA and EA drug in acidic solution. Both the fresh drug and its expired counterpart showed almost similar results in all the studies, thereby verifying the validity of the expired atorvastatin drug as a novel and efficient corrosion inhibitor for mild steel.
- BACKGROUND OF THE STUDY
Since the onset of industrial revolution, mild steel has been used as an alloy for a number of structural and industrial applications (Golestani et al., 2014). Acid solutions are used in various industries during acid pickling, acid descaling, industrial cleaning and oil-well acidization, etc. (Dasami, et al., 2015). Acidic media results in a uniform corrosion of mild steel with pitting athigh concentrations of acid (Faustin et al., 2015; Esmaeili et al., 2015; AbdEl-Lateef (2015); Noor et al., (2008). The use of inhibitors is one of the most proficient methods for protection of metals from corrosion in acid medium. Organic compounds containing N, O, Sheteroatoms and p electrons in their molecules are considered as effective corrosion inhibitors (Dasami, et al., 2015; Faustin, et al., 2015, Esmaeili et al., 2015, Abd El-Lateef M. H. 2015). The inhibitor molecules form a protective film onmetal surface that prevents corrosion (Daoud, et al., 2015).