Corrosion inhibition of stainless steel 304 in hydrochloric acid solution using clindamycin antibiotic as eco-friendly inhibitor

Abstract

The corrosion protection of stainless steel 304 (SS 304) in 2M HCl solutions using Clindamycin antibiotic was investigated by weight loss (WL), electrochemical frequency modulation (EFM), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) tests. Electrochemical results showed that this compound is an efficient inhibitor for SS304 and the efficiency reached 93 % at 300 ppm. The inhibition efficiency (IE) increases with the drug concentration and decreases with rising temperature. Data from electrochemical measurements suggested that the drug functioned by adsorption of the molecule on the metal/corroding interface, inhibiting both the cathodic and anodic half-reactions of the corrosion process. The adsorption of this drug on SS304 surface follows Langmuir adsorption isotherm. The thermodynamic functions of activation and adsorption processes were calculated and discussed. The surface morphology of the SS304 specimens was evaluated using atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR).