Gatifloxacin as corrosion inhibitor for carbon steel in hydrochloric acid solutions

The inhibiting effect of Gatifloxacin drug (1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-7-(3-methyl-1-piperazinyl)-4-oxo-3-quinolinecarboxylic acid sesquihydrate) on carbon steel corrosion in 1.0M HCl solution was studied using weight loss, galvanostatic polarization and electrochemical impedance spectroscopy (EIS) methods. The inhibition efficiency was found to increase with increasing the concentration of the inhibitor and deceased with increasing the temperature. The polarization studies showed that drug compound acted as a mixed-type inhibitor. The inhibiting effect of this compound was interpreted in view of its adsorption on the metal surface. The adsorption of this compound was found to obey Langmuir adsorption isotherm. The possibility of chemisorption through a complex formation between metal ions and the inhibitor chelating centers was also discussed depending on the results derived from UV-visible spectrophotometric measurements as well as conductometric titration.