Original Article CORROSION INHIBITION PROPERTY OF EXPIRED FLUOXYMESTERONE DRUG ON THE ALUMINUM (AL) SURFACE IN 3 % NaCl SOLUTION NARASIMHA RAGHAVENDRA * , LEENA V. HUBLIKAR, ANJALI S. BHINGE, POOJA J. GANIGER Department of Chemistry, K. L. E. Society's P. C. Jabin Science College (Autonomous) Vidyanagar, Hubballi-580031, India Email: rcbhat3@gmail.com Received: 15 Feb 2019, Revised and Accepted: 11 Apr 2019 ABSTRACT Objective: Aluminum (Al) corrosion in the NaCl solution is an example of dissolution in the neutral medium. The ongoing corrosion research efforts to produce the eco-friendly corrosion inhibitors to protect the aluminum metal from the corrosive solution. Methods: Herein, mass loss and atomic absorption spectroscopy (AAS) techniques were conducted to explain the adsorption property of expired Fluoxymesterone drug on the Al surface in the 3 % NaCl solution. Results: All results show that the expired Fluoxymesterone drug molecules generate a stable invisible layer through adsorption mechanism on the electrode surface. The corrosion inhibition behavior mainly depends on the concentration of the expired Fluoxymesterone drug and contact time at 313 K. Conclusion: The corrosion inhibition property is due to adsorption of electron-rich molecules on the Al surface in 3 % NaCl solution. Keywords: Aluminum, Mass loss, Expired Fluoxymesterone drug, Contact time, Atomic absorption spectroscopy © 2019 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open-access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/) DOI: http://dx.doi.org/10.22159/ijcpr.2019v11i3.34100 INTRODUCTION Petroleum and other industries produce fuels and other products. Most of the oil and gas pipelines are made from the aluminum. Neutral solutions are widely employed in the industry for pickling, oil well acidizing and cleaning. The corrosion phenomenon for aluminum metal is prominent in these operations [1-3]. Hence, the search for the chemical species which can slow down the metal dissolution process is a never-ending task [4-7]. Therefore, much attention devoted to the synthesis, design and examination of a large number of species possessing P, S, N and O atoms. However, use of organic compounds as corrosion inhibitors has been restricted because of cost and toxic nature [8-10]. Hence, nowadays research focus shifted towards use of expired drug species as corrosion inhibitors. Medicinal compounds are important organic species possessing a wide range of pharmacological and biological properties. Expired drug products are not useful to the consumers, but, retains its potential property. Hence, in current research, selected expired Fluoxymesterone drug. The corrosion inhibition property of expired Fluoxymesterone drug was thoroughly examined by weight loss (mass loss) and atomic absorption spectroscopy (AAS) techniques at 313 K. MATERIALS AND METHODS Experimental section The 99 % aluminum was used in the present research. The Al electrode was mechanically abraded with different grades of emery papers and cleaned thoroughly. Expired Fluoxymesterone drug of four different amounts, namely 0.1 mg/l, 0.2 mg/l, 0.3 mg/l and 0.4 mg/l were prepared. The 3 % NaCl solution prepared as per the standard procedure. Weight loss (mass loss) experiment was carried out with 100 ml of 3 % NaCl solution on the Al surface as per the ASTM standard at 313 K with an immersion time of 5, 10, 15 and 20 h. After each test, the Al specimens were taken out from the corrosive solution, rinsed with double distilled water, dried and weighed accurately with the help of analytical digital balance. The experiment was carried out with three times and average values are recorded. Atomic absorption spectroscopy (AAS) experiment was carried out in order to support the weight loss results. The atomic absorption spectroscopy (AAS) experiment was performed at 313 K with an immersion period of five hours. RESULTS AND DISCUSSION Weight loss (mass loss) technique The results derived from the mass loss (weight loss) technique were summed up in the table 1 and fig. 1. The introduction of small amounts of inhibitor did not significantly reduce the corrosion rate of the Al. In contrast, the corrosion inhibitive behavior was more pronounced at higher amounts of inhibitor. As the concentration of expired Fluoxymesterone drug enhanced, more corrosion inhibition behavior could be gained in the concentration-dependent mode. At higher concentration, expired Fluoxymesterone drug molecules strongly interact with the Al metal, at higher amounts of expired Fluoxymesterone drug molecules, more and more expired drug species enter the double layer by replacing the water species. Hence, maximum protection behavior observed at 0.4 mg/l of expired Fluoxymesterone drug. The increase in the time of Al metal in the 3 % NaCl solution enhances the attack of corrosive ions on the surface of Al in the 3 % NaCl solution. At higher immersion period, the desorption process overtakes the adsorption process. The corrosive ions degrade the protective layer on the Al surface in the studied system. These phenomena more pronounced at higher immersion period suggesting that many Al active sites are blocked by corrosive ions due to an attack of aggressive chemical. As a result of this, Al weight loss increases with immersion time. Hence, protection efficiency decreases with a rise in the contact time. Atomic absorption spectroscopy (AAS) technique The results of atomic absorption spectroscopy (AAS) are shown in the table 2 and fig. 2. With a rise in the concentration of expired Fluoxymesterone drug species, Al surface area available for the corrosive reaction is greatly reduced and attack of corrosive ions to the surface of Al became more difficult. At low amounts of expired Fluoxymesterone drug species, a gradual decrease in the Al dissolution rate was observed. While at high amounts of expired Fluoxymesterone drug species, a significant reduction in the Al International Journal of Current Pharmaceutical Research ISSN- 0975-7066 Vol 11, Issue 3, 2019