Impact of an expired hemorheologic drug on the mitigation of zinc corrosion in acidic environment: Insights from chemical, electrochemical, and surface evaluation

Abstract

The deterioration of zinc metal surfaces is one of the most difficult problems to solve, as zinc is susceptible to many industrial processes such as pickling and descaling. The present work focuses on the potential activity of an expired hemorheologic drug Pentoxifylline (PTX) as a corrosion inhibitor for zinc metal in 0.1 molar Hydrochloric acidic medium in the temperature range of 303–333 K by employing electrochemical and chemical techniques. Potentiodynamic polarization and electrochemical impedance spectroscopy were employed in the experimental measurement and PTX exhibited 84 % inhibition for 300 ppm inhibitor addition at 303 K. PTX demonstrated electrostatic interactions with zinc metal surface and behaved as a mixed type of inhibitor by obeying Langmuir’s isotherm model. Surface characterization of uninhibited and inhibited zinc specimens, combined with elemental analysis data, spectral study via FT-IR, and surface roughness by AFM, all provided clear evidence for the formation of a protective adsorption layer of PTX on zinc surface, as well as measurement of water contact angle, which showed an increase in hydrophobicity of zinc metal surface with rise in inhibitor concentration. Furthermore, all the experimental protocols were augmented so as to acquire the best potential efficacy of PTX in suppressing the zinc metal corrosion.